Nutrition During Gilt Development and Genetic Line Affect Reproduction

[mikey]

Nutrition During Gilt Development and Genetic Line Affect Reproduction
Twenty-five per cent energy restriction during development delays sexual maturity of gilts but has no effect on reproductive rate to parity 1 of those reaching sexual maturity, according to Rodger K. Johnson and co-authors in a paper published in the 2009 Nebraska Swine Report.

 

Summary
Effects of allowing gilts ad libitum access to feed until breeding age or developing them with 25 per cent energy restriction from 123 days of age to breeding on reproductive success through parity 1 were studied with a total of 639 gilts of two lines that differ in lean growth and reproduction.

Gilts of the two lines had common sires, an industry maternal line, but dams were from different populations. One line of gilts, LW × LR, represented standard industry Large White × Landrace cross females. The other gilts, L45X, were daughters of Nebraska selection Line 45 that has been selected 27 generations for increased litter size with additional selection for increased growth and decreased fat in the last seven generations.

More L45X than LW x LR gilts (95 versus 88 per cent; P<0.01) and more gilts developed with ad libitum intake than with restricted intake (96 versus 86 per cent; P<0.01) expressed puberty by 226 days of age. For gilts that expressed puberty, mean age at puberty was six days less (P<0.01) for L45X than LW × LR gilts but did not differ between gilts on the two developmental regimens.

For all gilts, the likelihood of expressing puberty increased with increasing weight at 123 days of age. It was also greater for gilts that attained heavier weights with greater backfat at 226 days of age, but the effect varied among lines and gilt developmental regimens. Increasing weight and backfat at 226 days of age increased the likelihood of producing a parity 1 litter for L45X gilts developed with restricted feeding but not for other groups.

Number of live born pigs per litter was affected by line, being greater for L45X gilts (P<0.05) but not by gilt developmental regimen. Neither line nor gilt developmental regimen affected maternal ability as measured by number and weight of pigs weaned.

A 25 per cent energy restriction during gilt development decreases the likelihood that gilts express oestrus by 226 days of age but has little effect on subsequent reproductive performance.


Introduction
It has been shown in several species that prolonged periods of energy restriction initiated post-weaning, without limiting other nutrients often results in increased longevity that is approximately proportional to the level of restriction. However, reallocation of nutrients often occurs such that animals cannot combine high rates of fecundity with extended life-spans. Research with mice has shown that this outcome is not always true. A recent publication of one experiment contains data showing that female mice restricted in energy intake post-weaning lived longer without a reduction in reproductive rate.

Today's commercial gilts are often managed to achieve weights of at least 136 kg (300 lb) with adequate backfat at breeding, although the amount of backfat that is adequate is not well defined. These targets are often achieved with management practices that include ad libitum access to feed. However, consistent with the findings in mice, a series of reports containing data from experiments at the USDA Meat Animal Research Center demonstrated that moderate feed restriction during pre-pubertal development of gilts may increase reproductive efficiency through first parity.

Optimum gilt development regimens may depend on the prolificacy and lean growth rate of the genetic line.

The authors initiated an experiment with the overall objective of estimating the effects of 25 per cent restriction of energy vs. ad libitum access to feed from 123 days of age to breeding on reproduction and longevity through parity 4 of females of two lines that differ in rate of lean growth and litter size. The experiment was done in four replications with a total of 661 gilts. The 2008 Nebraska Swine Report contained articles summarising effects of line and gilt developmental regimen on growth of gilts to 226 days of age and subsequent reproductive performance of females through parity 4 for gilts of replications 1 to 3.

Since that report, replication 4 gilts produced parity 1 litters, providing a complete dataset through parity 1.

The objective of this experiment is to summarise effects of line and energy restriction on reproductive performance through parity 1. Effects of variation in measures of growth (weight, backfat, and longissimus muscle area at different ages) on the likelihood of expressing puberty and producing a parity 1 litter are also presented.

Materials and Methods
Gilt populations
Two populations of gilts were used. One was the Large White × Landrace crossbred female used regularly in the University of Nebraska–Lincoln swine nutrition programme. The project gilts were the progeny of Large White- Landrace cross sows that had been inseminated with semen of industry maternal line (LM) boars and are designated as LW × LR cross. Gilts that were progeny of UNL selection Line 45 sows that had been inseminated with semen of the same LM boars used to produce LW × LR gilts comprised the other population. These gilts are designated as L45X. Line 45 has been selected 27 generations for increased litter size with additional selection for increased growth and decreased backfat in the last seven generations. Based on previous data, L45X gilts were expected to be more prolific than LW × LR gilts but to also have somewhat slower growth and greater backfat thickness.

Gilt management and dietary regimens
The experiment was done in four replications in which project gilts were born in batches during December 2004 and January 2005 (Rep 1), May 2005 (Rep 2) and November 2005 (Rep 3), and May and June 2007 (Rep 4). A total of 661 gilts began the experiment (157 to 185 gilts per replication) at 60 days of age; 639 of them completed the growth phase of the experiment that ended at 226 days of age.

Dams of project gilts were managed alike during the farrowing/lactation period. After weaning, all gilts were managed alike in the nursery until approximately 60 days of age (21 kg (46 lb)). They were then moved to the grow-finish facility where they were penned (10/pen) by line-treatment designation.

All gilts were allowed ad libitum access to a corn-soybean meal-based diet and were managed alike until 123 days of age. A three-phase growing- finishing diet was used: phase 1, 1.15 per cent lysine (60 days to 80 lb); phase 2, 1.0 per cent lysine (80 to 130 lb); and phase 3, 0.90per cent lysine (130 lb to 123 days).

At 123 days of age, pens of gilts on the ad libitum regimen (A) were allowed ad libitum access to a corn-soybean meal-based diet (0.70 per cent lysine, 0.70 per cent Ca, 0.60 per cent P) until they were moved into the breeding barn. Gilts treated with the restricted intake regimen (R) received a corn-soybean meal based diet at approximately 75 per cent of the energy intake as A-fed gilts until moved into the breeding barn. Energy restriction was achieved by predicting intake with a quadratic equation of average daily feed intake on body weight of A-fed gilts. The predicted ad libitum intake (based on the projected body weight for the upcoming two-week period) was multiplied by 0.75 to determine the daily feed intake for R gilts. The diet contained 0.93 per cent lysine, 1.0 per cent Ca, and 0.80 per cent P. All vitamins and minerals, except selenium, were increased so that daily intake of these nutrients per unit of body weight was expected to be equal for gilts on both diets. Additional details of the diets and management are in two articles in the 2007 Nebraska Swine Report.

During the growing period, gilts were weighed and backfat and longissimus muscle area were recorded every 14 days until final measurements were recorded at an average age of 226 days. Beginning at approximately 140 days of age, gilts were moved by pen to an adjacent building where boar exposure and oestrus detection occurred. Date of first observed oestrus and each additional oestrus were recorded.

Breeding and lactation management
Gilts in good health and that could be mated at third or later oestrus during a predetermined breeding period were identified as breeders and moved to the breeding barn at approximately 230 days of age.

Breeding commenced approximately 10 days later. A breeding period of 25 days (Rep 1), 24 days (Rep 2), 26 days (Rep 3), and 28 days (Rep 4) was used to match the unit's production schedule.

Gilts were checked twice daily for oestrus and were inseminated each day that they were observed in oestrus. Insemination was with semen of boars from a commercial terminal sire line. Gilts were in pens of approximately eight per pen until inseminated and then were moved to gestation stalls. Gilts that did not express oestrus, those that were mated but diagnosed open with an ultrasound pregnancy test 50 days post-breeding, and those that were diagnosed pregnant but did not farrow a litter were culled. Lame gilts and those in poor health also were culled.

While in the breeding barn and during gestation, all gilts were fed a standard corn-soybean meal based diet (13.8 per cent protein, 0.66 per cent lysine) at the rate of 4.0 lb daily until 90 days of gestation when feed intake was increased to 5.0 lb daily. At approximately 110 days of gestation, females were placed in farrowing crates in rooms of 12 crates per room and fed 6 lb daily of a corn-soybean meal based lactation diet (18.5 per cent protein, 1.0 per cent lysine). Sows were provided only a small amount of feed on the day they farrowed, 6 lb during the second day and 10 lb during the third day of lactation, and then were given ad libitum access to feed.

Total number and number of live pigs were recorded for each sow. Pigs were fostered among litters without regard to line or gilt developmental regimen to reduce variation in number nursed per sow. Litters were weaned at an average age of approximately 17 days and number weaned and total litter weight were recorded.

Traits and data analysis
Gilts completing the growth test were coded as 0 if they had not expressed a pubertal oestrus and 1 if they had. Then, based on females designated for breeding, they were coded as 1 if they farrowed a litter at parity 1 and 0 if not. These scores, which are measures of success/failure to reproduce, were fitted with general linear models designed for binomial data to determine the importance of line, gilt treatment, and interaction of line with treatment. Then, weight, backfat, and longissimus muscle area at 123 and at 226 days of age were fitted as co-variables to determine how they affected the likelihood of expressing puberty or farrowing a litter. Effects of age at puberty on likelihood of farrowing a litter also were estimated. Covariate effects were estimated by predicting mean probabilities at various levels of the covariates and predicted means were graphed to illustrate relationships.

Results
A total of 639 gilts completed the growth phase of the experiment. Of these gilts, 567 expressed an oestrus by 226 days of age and 510 were designated as breeders. Of the 57 gilts that expressed oestrus but were not designated as breeders, 20 were randomly culled, five within each line × treatment combination, to reduce breeding numbers to fit the production capacity. The remaining 37 gilts were culled for health or because they expressed oestrus so late that they could not be mated at third or later oestrus. This culling was not related to line or treatment. Distributions of gilts with a pubertal oestrus and that farrowed a litter across lines and treatments are in Table 1.



Table 1. Number of gilts that did and did not express pubertal oestrus, number designated as breeders and number of breeders that did and did not produce a parity 1 litter





Table 2. Mean reproductive rates for Large White × Landrace (LW×LR) and Line 45 cross (L45X) gilts developed with ad libitum feeding (A) or 25 per cent energy restriction (R)
Table 2 contains the probability that gilts expressed oestrus, mean age at puberty for those that did express oestrus, the probability that gilts designated for breeding produced a parity 1 litter, and mean litter size for those that farrowed. Both line and gilt developmental regimen significantly affected the proportion of gilts that expressed a pubertal oestrus. The probability that gilts expressed a pubertal oestrus was 0.95 for Line 45X gilts and 0.88 for LW × LR gilts (P=0.006). The probability of expressing pubertal oestrus also was greater for gilts developed with ad libitum access to feed than those developed with restricted energy intake (0.96 versus 0.86; P=0.0001). The interaction was not significant as effects of gilt developmental regimen were similar for both lines.

For those gilts designated as breeders, the probability of producing a litter was greater for L45X than for LW × LR gilts, although the difference was not significant (P=0.33). For gilts designated as breeders, the developmental regimen they had been on did not affect the likelihood they farrowed a parity 1 litter.

Interaction of line and gilt developmental regime existed for total number of pigs farrowed per litter, but not for live pigs per litter. Total born per litter was greater for LW x LR gilts developed with ad libitum access to feed than when developed with restricted intake, but the reverse occurred for L45X gilts as those developed with restricted intake farrowed more total pigs. This interaction did not exist for live pigs per litter, but L45X gilts produced more live pigs than LW × LR gilts (11.79 versus 11.02; P=0.03). Gilt developmental regimen did not affect live pigs per litter.

Number of pigs weaned per litter and litter 17-day weaning weight were standardized for the number of pigs after pigs were fostered among litters, and thus do not reflect line and treatment differences in live pigs per litter (Table 3).



Table 3. Mean number weaned and litter weaning weight for Large White × Landrace (LW×LR) and Line 45 cross (L45X) gilts developed with ad libitum feeding (A) or 25 per cent energy restriction (R)
After this standardisation, neither line nor gilt development regimen significantly affected number or weight of pigs at weaning, even though litter weaning weight was 14 per cent greater (P=0.12) for gilts developed with restricted energy intake than for those developed with ad libitum intake. Thus, given an opportunity to raise the same number of pigs, gilts of the two lines developed with either regimen did not differ greatly in maternal ability.

Relationships between weight at 123 days of age and the probability of expressing a pubertal oestrus are illustrated in Figure 1. Response was curvilinear, but in general, the probability of expressing pubertal oestrus increased with increasing 123-day weight. The effect was greatest (P=0.04) for L45X gilts developed with restricted energy intake. The effect was not significant in other groups (0.10



Figure 1. Effect of 123-day weight on probability of pubertal oestrus
Final weights and scan backfat and longissimus muscle areas were recorded after oestrus checking was terminated. However, weight and backfat at 226 days of age were related with the probability a gilt expressed oestrus. A strong relationship with weight existed in each line by treatment class (0.002



Figure 2. Effect of 226-day weight on probability of pubertal oestrus


Figure 3. Effect of 226-day backfat on probability of pubertal oestrus
The relationship of backfat at 226 days with the probability of having expressed pubertal oestrus was similar to that of 226-day weight (Figure 3) but was not significant for any class (0.11
Relationships of 226-day weight and backfat with the probability a gilt farrowed a parity 1 litter are in Figures 4 and 5, respectively.



Figure 4. Effect of 226-day weight on the probability gilts produced a parity 1 litter





Figure 5. Effect of backfat at 226 days on probability of farrowing a litter
The effect of weight was somewhat odd. For three groups, all except L45X gilts developed with restricted energy intake, the probability of farrowing a litter decreased with increasing weight. However, none of those relationships were significant (0.090.15).

The implications of this research are that if gilts are targeted for breeding at second or later post-pubertal oestrus and to farrow by 365 days of age, then the replacement gilt pool must be approximately 10 per cent larger to produce a specified number of litters than if gilts are developed with ad libitum feed intake. Management of gilts early in life is also important. Increased 123-day weight but not backfat or longissimus muscle area, was associated with increased likelihood of attaining puberty, regardless of which gilt development management regimen was used. For gilts that could be bred at second or later post-pubertal oestrus, the likelihood they farrowed a litter and their litter size were not affected by the developmental regimen. It is commonly thought that the likelihood of reproductive success increases for gilts with greater weights and backfat when they enter the breeding herd. However, this result occurred only for L45X gilts developed with restricted energy intake. Therefore, weight and backfat of breeding age gilts are not good predictors of subsequent reproductive performance.

Rodger K. Johnson and Phillip S. Miller are professors; Roman Moreno is a graduate student and research technician in the Animal Science Department; Matthew W. Anderson is manager; and Jeffrey M. Perkins, Kelsey Rhynalds, Trevor J. Glidden, Donald R. McClure and Thomas E. McGargill are technicians at the University of Nebraska-Lincoln Swine Research Farm.


September 2009

[gunder_3910]

Hello Mikey,

This is an interesting research. Wished I could catch up as a newbie, really. I was tracking the ad libitum and the ones that were restricted (R), to quote:
     "ad libitum regimen (A) were allowed ad libitum access to a corn-soybean meal-based diet (0.70 per cent lysine, 0.70 per cent Ca, 0.60 per cent P) until they were moved into the breeding barn. Gilts treated with the restricted intake regimen (R) received a corn-soybean meal"

Rodger K. Johnson and co-authors in a paper published in the 2009 Nebraska Swine Report seem to have been silent as to the outcome of these 2 groups. Is it assumed that both had the same characteristics because they are silent regarding the results of the gilts?

[gunder_3910]

In this topic to quote: "Twenty-five per cent energy restriction during development delays sexual maturity of gilts but has no effect on reproductive rate to parity 1 of those reaching sexual maturity..." This leads me to 2 basic questions: First, when they say 25% restriction, does this means that 25% as to volume or weight of food intake? When Mr. RK Johnson et. al. says “reproductive rate to parity 1 of those reaching sexual maturity” what does he mean? What does reproductive rate to parity 1 mean?

[mikey]

I am not sure if he is talking about volume or weight. weight makes more sense

this analysis is that hogs having average and above weaning weights performed better than hogs having below average weaning weights.


parity-number of piglets borne by 1 sow.    consistency,likness,unformity,sameness,similarity,equality
the way it was explained to me is this.1st parity,first time a sow farrowed,2nd parity,2nd time she farrowed and so on,there is a comparsion made between each litter of piglets.We are getting into some real science here.One compares each litter to the last litter.I hope it makes some sense to you,its complicated.Basically-the better you care for your sow(s) and your gilt(s) the greater your chances for susccess.Breed also has an effect on the outcome.

you might find this interesting to read:

Feeding the Lactating Sow
F. Aherne, Swine Nutrition and Management Consultant, Edmonton, Alberta

Introduction

Years of selection for rapid growth rate and increased lean has resulted in modern pig genotypes that have larger mature body weight and reduced voluntary feed intake at any given weight. If modern genotypes are mated at the same weight or age as they were some years ago they will begin their reproductive life at a lower proportion of their mature body size and they will be physiologically younger. These animals will be still actively growing during pregnancy so there will be competition for nutrients between lean growth and the developing fetus. A further consequence of leaner, heavier sows is an increase in energy requirements for maintenance. Although modern genotypes have reduced appetites, maximum milk yield has increased by up to 30% and the energy content of sows milk has increased by 14%. The length of lactation has been reduced to 21 to 26 days or less which means that there is very little opportunity for the gilt or sow to achieve a positive energy balance before weaning. So, modern sows are larger, more productive and have smaller appetites than sows of 10 to 15 years ago and they are being bred at a younger age. The consequence of all this is that many sows do not consume sufficient energy or nutrients to meet their nutrient demands and therefore they break down their own body tissues to meet their requirements.

Many studies have shown that sows, especially primiparous sows, losing excessive amounts of live weight or body condition (both protein and fat) will have extended remating intervals, a lower percentage in estrus within 10 days of weaning, reduced pregnancy rate and reduced embryo survival. Feed intake in lactation does not appear to reduce ovulation rate. It is obvious that sow feed intake during lactation can very significantly affect subsequent reproductive efficiency. For a thorough review of this subject see the reviews by Aherne, 1997; Aherne and Williams, 1992; Close and Mullan, 1996; Einarsson and Rojkittikhun, 1993, Whittemore, 1996.

Energy, protein and lysine requirements of lactating sows.

Energy requirements

The energy and lysine requirements of a lactating sow depend on the weight of the sow, her milk yield and its composition, and the change in body weight and body composition. Estimates of the energy cost of milk production are 2 Mcal DE/kg milk. Over 80% of the energy requirement of a lactating sow is for milk production. It requires 4 kg milk to produce 1 kg litter gain. Therefore, we can estimate milk production and the energy required by the sow from an estimate of litter weight gain. NRC (1988) suggested that sows of 145 to 185 kg live weight at farrowing, housed at 18 to 20 C and with daily feed intakes of 4.4 to 6.1 kg of a corn-soybean diet containing 3.34 Mcal DE per kg, 13% protein and 0.6% lysine would produce 5 to 7 kg milk per day and lose approximately 6.5 kg live weight in a 28 day lactation. However, recent estimates of milk production have shown that modern sows produce 10 to 12 kg milk/day and therefore, would require much higher lysine and energy intakes than those suggested by NRC (1988). An energy balance for a 150 kg sow producing 9.4 kg milk per day is shown in Table 1. As can be seen, this sow would require an average of 7 kg feed per day of a diet containing 3.34 Mcal DE/kg.

Table 1. Predicted feed and energy requirements for a 150 kg lactating sow with 10 piglets.
   Week
1
 Week
2
 Week
3
 Week
4
 Mean
 
Piglet wt, kg 2.5
 4.0
 6.0
 8.0
   
Growth, g/day 160
 220
 280
 280
 235
 
Milk yield, kg/day 6.4
 8.8
 11.2
 11.2
 9.4
 
Energy required Mcal DE/d 17.5
 22.3
 27.1
 27.1
 23.5
 
Feed/day, required, kg* 5.2
 6.7
 8.1
 8.1
 7.0
 
Actual feed/day, kg 4.4
 5.5
 6.0
 5.9
 5.5
 
Sow wt loss, kg/wk 2.6
 4.1
 7.5
 7.8
 Total 22 kg
 

* Diet containing 3.34 Mcal DE/kg
 

The sow used in this example is suckling 10 piglets and the average piglet weight at 7, 14, 21, 28 days of age is 2.5, 4.0, 6.0, and 8.0 kg. To produce this weight gain will require 6.4, 8.8, 11.2, and 11.2 kg milk per day in weeks 1,2,3 and 4 of lactation, respectively. The feed intake required for sow maintenance and milk production and the expected daily feed intake are also presented in Table 1. The feed intake shown for this sow throughout a four week lactation is typical of that reported in many surveys. As can be seen in Table 1, approximately 75% of the energy required goes to milk production and 25% for maintenance. This sow does not consume enough food to meet her needs. Therefore some of the energy and nutrients required by the sow must be derived from mobilization of body tissues during lactation. In this example the sow would lose nearly 22 kg body weight during a four week lactation.

In a recent experiment, it was shown that increasing the energy density of the diet from 2.98 to 3.80 Mcal DE per kg diet did not increase piglet growth. However, average daily feed intake of the sows was not influenced by energy content of the diet. Therefore DE intake increased with an increase in energy density of the diets up to 3.34 Mcal DE/kg. This energy level would be typical of a corn-soybean diet without added fat. Weaning-to-service interval and number of pigs born alive in a subsequent litter were not affected by energy density of the diet.

Protein and lysine requirements

A protein and lysine balance for the 150 kg sow used in the energy balance is shown in Table 2. For a 150 kg sow weaning 10 pigs of 8.0 kg, average daily protein and lysine intakes of 1080 and 63 grams / day are required. At the expected feed intakes shown the diet should contain 19.67% protein and 1.05% lysine. These protein and lysine levels are considerably higher than the values recommended by NRC (1988).

Table 2. Predicted protein and lysine requirements of a 150 kg lactating sow with 10 piglets.

  Week
1
 Week
2
 Week
3
 Week
4
 Mean
 
Milk prod, kg/d 6.4
 8.8
 11.2
 11.2
 9.4
 
Feed intake, kg/d 4.4
 5.5
 6.0
 5.9
 5.5
 
Protein required, g/d 780
 1020
 1260
 1260
 1080
 
Lysine required, g/d 45
 59
 74
 74
 63
 
Dietary lysine required, g/d* 43
 55
 67
 67
 58
 
Dietary composition           
% Protein 17.7
 18.6
 21.0
 21.4
 19.7
 
% Lysine .97
 1.00
 1.12
 1.13
 1.05
 

* Some of the sows lysine requirement is met by weight loss.

For a 150 kg sow lysine requirement for maintenance would be about 2 g/d and would be more than adequately met by the lysine supplied by lean tissue loss. By far the largest requirement for amino acids is for milk production. A requirement of 26 g/d of lysine per kg of litter gain has been suggested, which is in close agreement with our estimate of lysine requirement. There is a strong interaction between the energy and lysine level in the diet. As energy intake increases the response to increased levels of lysine also increases. Thus, milk yield is dependent on both lysine and energy intake.

The concept of an ideal protein or ideal amino acid balance is widely used. It is assumed that the dietary amino acids should be supplied in the diet in the same proportions as they are in sows milk. For example, methionine + cystine would be supplied at 60% of the lysine level, threonine at 72% and tryptophan at 18%. However, in one experiment feeding an ideal protein based diet versus a more conventional diet to lactating sows did not influence sow performance and increased sow weight loss.

In a recent experiment gilts fed 1.3% dietary lysine weaned heavier pigs and had 1.2 more pigs in their subsequent litter than gilts fed lower levels of lysine. Piglet growth rate was also highest for sows fed 1.31% lysine. However, this data clearly demonstrates the danger of using percentages without relating them to total feed intake. Using the recommendation of 26 g lysine per kilogram litter gain suggested previously the lysine requirement of the sows fed 1.06% lysine could be calculated to be 50 g per day (9.4 pigs, 206 g piglet growth per day at 26 g lysine per kg piglet gain). But they were fed only 44 g lysine per day. Clearly lysine requirements are animal specific and should be determined on the basis of expected litter gain. Because the appetite of first litter sows is usually low it has been suggested that it may be advisable to formulate two lactation diets, one containing 1.2% lysine for parity one sows and one with lower (0.90% lysine) for later parity sows.

Pattern of feed intake in lactation

The feed intake levels shown in Table 1 are for sows fed ad libitum on the day after farrowing. Adoption of a commonly practised feeding program that gradually increases feed intake over at least the first 3 to 5 days of lactation could significantly increase the nutrient deficit in week one of lactation.

There is evidence that pattern of feed intake during lactation can significantly affect post-weaning reproductive function. In a recent experiment restricting gilts to 40% of the energy intake of ad libitum fed gilts (L) for any week of a 3 week lactation delayed post-weaning return to estrus compared to ad libitum fed sows (H) (Table 3).

Table 3. The effects of energy intake during a 21 day lactation on weaning-to-estrus interval
 

Energy HHH
 LLL
 LHH
 HLH
 HHH
 
Wean to estrus, days 9
 23
 15
 20
 18
 

University of Minnesota, 1994.
 

We have also shown that a 50% restriction of feed intake in the first two weeks of lactation completely prevented the development of follicles. But ad libitum fed gilts had substantial follicle development two weeks after farrowing. We have also confirmed that restricting feed intake at any stage of lactation will increase a weaning-to-service interval and decrease ovulation rate compared to ad libitum fed sows (Table 4).

Table 4. Effects of pattern of feed intake in lactation on post-weaning fertility of sows.

Feed/day, kg       
D 1-21 4.1
 4.1
 2.1
 
D 22-28 5.3
 2.0
 5.2
 
Sow wt loss, kg 11.0
 21.0
 25.0
 
Ovulation rate 19.9
 15.4
 15.4
 
Embryo survival % 87.5
 64.4
 86.5
 
Wean-to-estrus, days 3.7
 5.1
 5.6
 

University of Alberta, 1995.
 

Embryo survival was reduced in sows restrict-fed during the last week of lactation. Note how increasing feed intake of the restricted sows during the last week of lactation increased embryo survival.

Feed intake of lactating sows

As mentioned previously there is considerable evidence that the voluntary feed intake of modern day lactating sows is low, especially for the first and second parity sows, and often does not provide sufficient energy or other nutrients to meet the sows requirements. Recent survey data suggests that nearly 60% of sows show a dip of 1 to 2 kg in feed intake for two or more days at the end of the second week of lactation. However, we have not observed such dips in feed intake. The authors of the survey suggest that to avoid a dip in feed intake in lactation, feed intake in early lactation should be restricted and increased gradually over the first week of lactation. However, many herds can feed sows ad libitum immediately after farrowing with no detrimental effects on the sow or litter. For such herds feed intake during lactation is likely to be 10 to 15% larger than that of herds using a restricted - feeding system. Some of the factors that influence the voluntary feed intake of sows during lactation are:

! Genotype, parity, litter size, length and stage of lactation, body composition (prior nutrition)

! Barn temperature, humidity, floor type, water flow rate, access to drinker, feeder design

! Digestibility, palatability of diet, level of feeding, frequency of feeding, nutrient balance in the diet, physical form of diet (particle size, mash, pellet).

Of these factors, genotype, body composition at farrowing and farrowing barn temperature are probably the most important factors influencing feed intake. To maximize daily feed intake in lactation target 20 mm backfat at farrowing with a barn temperature of 18 degrees C. Addition of fat (5 to 10%) to the diet will increase energy intake only slightly. The main effect of fat supplementation of lactation diets is to increase the fat content and gross energy of the sow's milk. Therefore, the effect of fat supplementation on sow weight loss will be small. Fat supplementation of the sow's diet will be most effective during hot weather and can maintain energy intake under high temperature conditions.

References

Aherne, F.X., 1997. Nutrition of the early weaned sow. Proc. 18th Western Nutr. Conf., pp43-61. Winnipeg Man

Aherne, F.X. and I.H. Williams, 1992. Nutrition of optimising breeding herd performance.
Vet. Clinics of N. America: Food-Anim. Proc. 8(3): 589-608.

Close, W.H. and B.P. Mullan, 1996. Nutrition and feeding of breeding stock. In: Pig Production. Ed. M.R. Taverner and A.C. Dunkin. Elsevier, NY. pp 169-202.

Einarsson, S. and T. Rojkittikhun, 1993. Effects of nutrition on pregnant and lactating sows.
J. Reprod. Fert. Suppl. 48:229-239.

NRC (1988). Nutrient requirements of swine. Washington, D.C. National Academy Press.

Whittemore, C.T., 1996. Nutrition-reproduction interactions in pumparious sows. A review. Livest. Prod. Sci. 46:65-83.

[nemo]

Most researches tell that a bigger animal at weaning would result a heavier carcas/ heavier animal for slaughter.

At the same time the more problem you encounter in the first 30 days would result in runt animals.

[gunder_3910]

Hi Nemo & Mikey,

I find the articles you post interesting. Although I have to admit that I do not have any educational background about it (...that's probably why I find it fascinating... ). Another is because your topics deal primarily with nutritional formulation and breeds of hogs (which I have no idea at all) And to be honest, I have to catch up with everything written there. One thing I find positive is that the inputs written in your article is somewhat similar to my recent experiments/observation. I had been looking for cheaper sources of Lysine and other amino acids to cope with my basic feeds. Your posts give a detailed recored however. It challenges me to apply their studies in order to attain high efficiency at minimal costs. But the main reason why I try to find time absorbing these two papers you posted is because I am in pursuit of ways to look for agriculturally viable feed materials for the hogs with minimum cost without compromising their growth pattern. I am positive that there are a lot of secrets just waiting to be discovered.

Last year I experimented by raising 10 piglets and have come about 6 "breedable" sows in my family's farm lot. I was not successful with the 4 & I had to cull them last Christmas & my daughter's birthday. But I am impressed with my 2 sows out of 6 remaining. Mind you, these are expensive projects. However, these 2 remaining sows have encouraged me to pursue further my hog raising project because I could be able to cut 50% cost and hopefully to a staggering 70 % compared to the commercial feeds with rice bran, finely ground corn, food scraps & an ingredient I applied to these sows. With Nemo's advice of selling/culling non performing pigs/piglets, I am in pursuit of raising 6 piglets to become sow breeders from of those 2 original breeding sows.

I have bumped into several websites recently that eventually led me to discover how I could be able to attain a financially viable hog raising project. Your posts (& those that are apparently available for reading) I find important because curious surfers can interact in a Filipino setting about our projects. Thanks for taking time posting these articles & to those who have in a way contributed in asking & answering questions. I'm looking forward interacting in this topic.

[mikey]

Gunder
Good for you.Research can/does help us producers to have a better understanding of what is involved in this business.So true commercial feeds are expensive and the main reason why I only keep 11 sows myself now.Nutrition is the key here along with breed selection.When one can find the right combination one has a better chance for success in the long run.
The only 2 countries I am aware of today making money from hogs is Thailand and Russia,all of the rest are struggling just to survive.
I have talked with another foreigner in the Philippines and he claims to have fed a hog only on dried and fresh malunggay,it grew but was too lean but interesting that it could live on malunggay leaves only.Malunggay has protein but no carbs.I was thinking to myself what if he had added corn for carbs what would have been the outcome.Research and experimenting holds the key for reduced feed costs and more money in ones pocket.

I have no scientific background myself other than basic but do find reading these reports interesting and somewhere in all this material one might find the key to solve our main expense,feed.

Best of luck to you.The answers are out there somewhere,we just have to keep looking and reading.

mikey

[mikey]

Swine Dysentery – a Question of Nutrition?
Veterinary treatment, disinfection and fly and rodent control, feed formulation and feed additives all play a significant role in the control of swine dysnetery, according to Franz Waxenecker, Director Product Development for Biomin GmbH.


 

Efficient pig production requires animals with good intestinal health. Indigestion, caused by malnutrition or infections, has an immediate effect on the pigs' health and well-being – and subsequently on the profitability of the business.

Antibiotic performance enhancers have proven to be supportive in maintaining intestinal health. Ileitis, or PIA, was not an issue until tylosin phosphate was prohibited in the EU in 2000 because the pathogen, Lawsonia intracellularis, was kept in check by this antibiotic growth promoter. The ban of the remaining antibiotic performance enhancers in 2006 led to the exclusion of many substances, including salinomycin sodium (although it could remain in use as a coccidiostat). This ionophore was able to, and still could, keep the bacterium which causes swine dysentery, Brachyspira hyodysenteriae, under control.

Swine dysentery (SD) is a disease which affects mainly the large intestine (Figure 1). It occurs primarily in pigs of about 30kg to 80kg. The symptoms include grey or brown diarrhoea (Figure 2). Infected animals also show inclination of the flanks, anaemic colour and poor growth. The disease can be identified in laboratory tests using faeces smears. Out of numerous strains of Brachyspira, only B. hyodysenteriae and B. piloscoli are recognized as pathogens. The percentage of farms that have been affected by B. hyodysenteriae in the US, Sweden and Denmark is estimated at 10 to 26 per cent (Mapother, 1993; Fellström, 1998; Möller, 1998), although this data dates back to the time before salinomycin sodium was banned in the EU.



above: Figure 1. Brachyspira colonize and cause damage to the intestinal mucous membrane
below: Figure 2. Brachyspira cause grey and brown diarrhoea
SD is spread by oral contact with the pathogens in the environment, or with the faeces of infected animals. B. hyodysenteriae are capable of surviving within manure for up to two months, especially at low temperatures (winter). The pathogens are shielded from the stomach acids and also from feed additives such as organic acids by an outer protective layer, enabling them to pass through to the intestines unharmed. They colonise the mucous membrane of the large intestine, multiply and then infiltrate and destroy the intestinal cells. This is what causes blood loss in the large intestine and, consequently, bloody diarrhoea.

From the animal nutrition point of view, these bacteria are complicated to deal with, making it difficult to effectively prevent the disease merely on the basis of diet. First of all, the outer mucous layer protects Brachyspira, and secondly, it is more difficult to exert nutritional influence in the hind gut, where Brachyspira accumulates.

In order to prevent swine dysentery, and in case swine dysentery occurs on a farm, the following steps should be taken:

Diagnosis by a veterinarian (identification of the pathogen)
Room and slurry disinfection
Reduction of transmission vectors, such as rodents and flies, and
Dietary measures and feed composition
Veterinary Diagnosis
In order to ensure that the symptoms are in fact due to swine dysentery, contact a veterinarian.

Reduction of pathogens
Due to the fact that most Brachyspira infections are spread by contaminated manure, an AIAO management programme, as well as room and slurry disinfection is an appropriate way to reduce pathogenic pressure.

Rodent and fly control
Continuous extermination of mice, rats, and flies is essential in preventing dysentery. Mice and rats are known carriers of B. hyodysenteriae, spreading the disease through their faeces, making it possible for them to set off the disease again after the pens have been cleansed. Flies primarily carry the pathogens from the excretion area to the livestock area of the pens.

Dietary measures and feed composition
The ability to control B. hyodysenteriae with nutritional measures is limited, although it is possible to positively influence the course and severity of the illness with dietary means:

The higher the digestibility of the ration and the lower the amount of non-degradable starch, the lower the risk of developing dysentery. Supplying the livestock with highly digestible rations based on rice and animal protein led to a lower incident of dysentery, compared to feeding rations based on barley, which caused the infection to break out in all animals. Diets based on heat-treated corn led to a lower incidence of SD compared to barley (Pluske et al., 1996). This was also confirmed by Prohaska and Lukacs, 1984 and Siba, 1996, who noticed that fewer pigs developed the disease when supplied with rice and animal protein ¡V which is certainly of no practical relevance. The most cases of dysentery were observed when feed consisted of a mixture of wheat, barley and lupins.

Corn silage has a positive effect due to the natural composition of corn, as well as its low buffer capacity, and the partial 'predigestion' during ensilage. Protein sources, such as canola meal, canola cake and sunflower cake show a lower protein digestibility compared to soy products. At the same time they contain higher levels of fermentable substances. Therefore a maximum amount of five per cent of these components should be included in the feed rations of pigs once dysentery has occurred within the population. In healthy livestock, of course, these raw materials can be used in higher percentage. Furthermore, low-protein diets can minimise the level of protein that is available for fermentation in the hindgut.


Unlike other gastrointestinal infections, dysentery occurs primarily in poor eating animals. This emphasises the importance of good quality raw materials. It has been observed that the number of pigs, which developed SD following artificial oral infection, rose from 60 per cent to 100 per cent when pigs starved two days prior until two days after the infection. Several stress factors, which lead to a reduction in feed intake, seem to support the outbreak of the disease (Heinrizi, 2001).

The higher the number of fermentable substances in feed, the better the conditions for Brachyspira bacteria to multiply, causing greater risk of developing dysentery. Feed containing high levels of fibre, as well as fermentable substances, do promote Brachyspira reproduction (Hampson et al., 1997; Siba et al., 1994).
Amount of bacterial fermentable substances (BFS) in various feedstuffs
Feedstuff BFS
(g/kg dry matter)
Lignocellulose ±0
Triticale 25
Wheat 43
Corn 52
Rye 66
Barley 71
Oats 75
Soybean meal 48% 157
Sunflower seed meal 163
Soybean meal 44% 189
Wheat bran 191
Canola meal 215
Canola cake 261
Sugar beet pulp 664

A low pH-value within the large intestine (colon pH 6) inhibits the growth of Brachyspira, whilst a higher pH in the colon promotes Brachyspira development and subsequently the outbreak of dysentery (Prohaska and Lukacs, 1984). The pH-value within the stomach has no effect upon Brachyspira bacteria or on the development of dysentery (Jacobson, 2003).

It is essential to bear in mind that it is difficult to influence the pH-value of the large intestine by organic or inorganic acids. Most of the organic acids, especially those that are added directly to the feed, are active only in the first segments of the digestive system. This is where Brachyspira are able to survive due to their protective mucous layer. One method of successfully transporting an acidifier to the large intestine, and subsequently influencing the pH, is to use an organic acid that has been combined on a sequential-release-medium (SRM), which releases the acid throughout the gastrointestinal tract, including the large intestine.


Feed additives which are able to improve digestibility of the diet can reduce the nutrient flow into the hind gut and help to prevent aggregation of Brachyspira. Phytogenics are well known to increase digestibility of the diet and to reduce ammonia in the hindgut. Furthermore, feed additives are known to support regeneration of the intestinal mucosa, which can be heavily destroyed during SD.
Swine dysentery, as well as other gastrointestinal diseases, requires multifactorial solutions. Veterinary treatment, disinfection and fly and rodent control do play a significant role, as well as feed formulation and feed additives. This becomes more important when antibiotics and growth promoters are restricted in use or even banned.

 
October 2009

[mikey]

Heavy Pigs at Weaning Improve Growth, Efficiency and Carcass Value
Weaning weight affects subsequent performance and carcass quality, according to Hypor, which is why their breeding programme fouses on the sow's 'weaning capacity'.


Growth, Efficiency and Carcass Value
One of the key principles of the Weaning Capacity approach to genetic selection is that the focus on quality and consistency of the weaned pig provides the potential for fast, lean efficient growth after weaning. Both research and commercial experience demonstrate a clear relationship between weaning weight and growth rate to market. Also, faster growing pigs are more efficient converters of feed and deposit lean tissue faster, resulting in better carcass quality and a higher value per pig sold.

Clearly, weaning weight is a function of weaning age and growth rate during the suckling period. Generally, weaning age has been increasing in many European countries such that it is around 24 to 25 days on average. Even in North America, where a large part of the industry changed to weaning at 16-18 days during the 80s and 90s, there is now a realisation that later weaning has major benefits in terms of growth and production costs. In addition to optimising weaning age, implementing management measures to increase weaning weight as outlined in the article Maximising weaning weight will help to ensure rapid post weaning growth.

The Nursery Phase
The period immediately after weaning is one of the most critical because it determines growth rate right up to market weight. Weaning weight is a major determinant of growth because bigger pigs eat more feed, have fewer health problems and therefore grow faster (Table 1).


In this large-scale trial, pigs were weaned at ages from 12 to 21 days. As weaning age and weight increased, feed intake and feed efficiency improved, resulting in a higher weight at 42 days post weaning. Mortality also fell sharply as weaning age increased.

Heavier pigs at weaning have a better developed digestive system and are able to digest solid feed more efficiently, which not only leads to faster growth but also results in a lower incidence of health problems such as scouring.

The Finishing Stage
Weaning age continues to have a large influence on the performance of pigs at the finisher stage, because they enter the finishing barn at a higher weight and consequently continue to grow faster and more efficiently.

Because the majority of feed used is consumed at this stage, differences in efficiency have a large effect on production costs and margins (Table 2). In a system with fixed availability of finishing space, more rapid growth results in a higher carcass weight and more revenue, as shown in the table. Although production cost per pig increases due to the heavier slaughter weight and consequently more feed consumed, the income over variable costs continues to increase with weaning age.


Growth Effects on Carcass Quality
There has recently been considerable interest in the effects on growth and carcass quality of reduced birth weight resulting from the rapid increase in numbers born achieved in some countries. While this is a complicated topic, it seem quite clear that pigs with a lower birth weight (and by extension a lower weaning weight) not only grow more slowly and have more health problems, but have poorer carcass quality at the same carcass weight (Table 3).


In this study, the percentage of body fat was higher and the size of the cells in the fat tissue was larger in the low birth weight pigs. Additionally, the lean meat content of the carcass was considerably lower, while tenderness of the meat was significantly reduced.

Growth rate during the nursery phase has been shown to influence carcass quality, especially loin eye depth, but also backfat depth. Weaning weight is the biggest influence on nursery growth rate but any factor that results in a reduction in growth rate – such as disease, poor environment or inadequate diets – will also adversely affect carcass quality.

This is because in the early stages of growth pigs are depositing lean and very little fat and the more rapidly they lay it down the higher the lean content in the carcass. Conversely, slow early growth means that more fat is deposited at the later stages of growth and the loin is less well developed at market weight.

November 2009

[mikey]

Environmental Impact of Improvements in Genetics and Nutrition over 25 Years
The environmental impact of improvements in genetics and feeding programmes for pigs over 25 years has been studied at North Carolina State University (NCSU), reported by Eric van Heugten and published in the University's Swine News.



Introduction
Both genetics and dietary improvements have contributed significantly to increased growth performance of pigs over the last 25 years. Genetic selection has increased the amount and efficiency of lean growth, which allows more nutrients to be deposited in tissue and fewer nutrients excreted in manure. Many changes have taken place in the design of diets for pigs compared to 25 years ago. These include the use of enzymes, crystalline amino acids, improved nutrient balance, improved feed processing, e.g. pelleting, and more sophisticated phase feeding programmes.

The objectives of the study study were to compare the effects of genotype and diet on nutrient digestion and retention, ammonia emission and odour in manure of growing-finishing pigs.

Materials and Methods
First parity white line females were obtained from an unselected commercial population formed in 1980 that has been maintained at NCSU since 1989. These sows were mated using frozen semen of Hampshire or Duroc boars that were typical of those used in 1980. Pigs representative of 2005 genotype of similar age were obtained from a North Carolina swine production company.

All pigs were reared at the North Carolina Swine Evaluation Station in Clayton. After farrowing, 28 piglets (14 pigs of the 1980 genotype and 14 pigs of the 2005 genotype) were selected and allotted to a 2 × 2 factorial randomised complete block design. Factors included: 1) genotype representative of 1980 and 2005, and 2) feeding programme representative of 1980 and 2005. The characteristics of the feeding programmes are shown in Table 1.

Comparison of characteristics of 1980 versus 2005 feeding programmes
1980 feeding programme 2005 feeding programme
Diet formulation common to 1980

No antibiotics

No synthetic amino acids

Simple nursery diets

Simple feeding programme

No enzymes

Meal feed
 Diet formulation common to 2005

Antibiotics

Synthetic amino acids

Complex nursery diets

Phased feeding programme

Phytase

Pelleted feed
 

The nutrient levels for the four-phase 1980 feeding programme (e.g. lysine from 1.05 to 0.62 per cent and ME from 3,262 to 3,317 kcal/kg) were based on formulations from the 1978 Pork Industry Handbook (PIH). The 2005 feeding programme consisted of a seven-phase programme using pelleted diets similar to diets used by North Carolina pork producers, e.g. lysine from 1.51 to 0.73 per cent and ME from 3,428 to 3,651 kcal/kg.

Pigs (n=28) were transferred to metabolism crates once they reached a body weight of approximately 65 kg. The 1980 diet (corn-soybean meal, meal form) and the 2005 diet (pelleted, supplemented with amino acids and phytase) fed during the metabolism period contained, respectively 13.3 versus 14.7 per cent crude protein, 3,317 versus 3,655 kcal/kg ME, 0.67 versus 0.43 per cent calcium, 0.56 versus 0.41 per cent phosphorus, and 0.62 versus 0.94 per cent total lysine. After an adaptation period of seven days, faeces and urine were collected quantitatively for three days. A portion of the faeces and urine was then mixed together and homogenised within respective animal at the rates they were produced to form fresh manure. Half of this fresh manure was aged anaerobically for 21 days to create aged manure.

Both fresh and aged manure were sampled for odour evaluation by a professional odour panel. The panelists were asked to smell each sample individually and assign a designation of degree of pleasantness or unpleasantness according to a -10 to +10 hedonic tone scale, with 0 being neutral. They also were asked to assign a score for strength of odour by smelling the sample and comparing it to standards of n-butanol at increasing concentrations to generate a 1 to 5 scale (very faint, faint, moderate, strong and very strong).

Ammonia emission of the manure samples was determined by placing 400ml of the manure mixture in a rectangular container. Air was drawn through the container with manure, and then through a gas dispersion tube placed in a 500ml Erlenmeyer flask containing dilute sulphuric acid in order to trap the ammonia released from the manure. This sulphuric acid solution was sampled at 12, 24, 36, 48, 72 and 96 hours and analysed for ammonia.

Results
Pig average daily gain was greater for the modern genetics and feeding programme, resulting in heavier body weight when the metabolism study was initiated (69.9 versus 63.5 kg, P=0.04; and 73.1 versus 60.3 kg, P<0.001, respectively).

To account for the differences in body weight, all other data were expressed per unit of metabolic body weight, which eliminates bias due to weight difference of pigs.

Intake of nitrogen tended (P=0.07) to be greater (1.15 versus 1.02 g/BW-0.75/day) and intake of phosphorus was lower (P<0.001; 0.20 versus 0.26 g/BW-0.75/day) for the 2005 diet compared to the 1980 diet (Table 2).

Table 2. Effect of genotype (1980 versus 2005) and nutrition programme (1980 versus 2005) on nutrient digestibility and nutrient balance
  Genotype Nutrition P value1
  1980 2005 1980 2005 Genotype Nutrition Genotype
×
nutrition
INTAKE
g/BW-0.75/day               
- Nitrogen 1.04 1.12 1.02 1.15 0.27 0.07 0.91
- Phosphorus 0.22 0.24 0.26 0.20 0.25 <0.001 0.74
EXCRETION
g/BW-0.75/day               
- Total faeces 16.7 18.4 20.0 15.1 0.29 0.003 0.46
- Total urine 46.5 39.7 48.3 37.9 0.08 0.01 0.70
- Faecal N 0.17 0.19 0.20 0.17 0.30 0.08 0.44
- Faecal P 0.14 0.14 0.16 0.12 0.91 <0.001 0.70
- Urinary N 0.26 0.25 0.20 0.30 0.82 0.02 0.03
DIGESTIBILITY
%               
- Gross energy 87.3 87.2 85.5 89.0 0.98 <0.001 0.12
- Nitrogen 83.2 82.7 80.5 85.4 0.66 <0.001 0.14
- Phosphorus 37.9 41.3 37.4 41.9 0.36 0.22 0.33
1 Probability value for genotype, nutrition programme and the interaction between genotype and nutrition programme.
A probability value of <0.05 indicates that the values are significantly different.
Faeces (15.1 versus 20.0 g/BW-0.75/day) and urine (37.7 versus 48.3 g/BW-0.75/day) production were lower (P<0.01), faecal nitrogen excretion (0.168 versus 0.196 g/BW-0.75/day) tended to be lower (P=0.08) and faecal phosphorus excretion was lower (P<0.001; 0.117 versus 0.162 g/BW-0.75/day) for the 2005 diet when compared to the 1980 diet.

Digestibility of nitrogen (85.3 versus 80.3 per cent) and gross energy (88.9 versus 85.3 per cent) was greater (P<0.05) for the 2005 diet compared to the 1980 diet (Table 2).

Urinary N excretion was greater in 1980 pigs when fed 2005 diets compared to 1980 diets (0.35 versus 0.16 g/BW-0.75/day) but no differences between diets were observed in 2005 genetic pigs.

Cumulative ammonia emission in fresh manure was greater (P=0.05) for 2005 pigs at 24 hours but not at any of the other time points.

In aged manure (Figure 1), ammonia emission was 86, 52, 29, 18 and 12 per cent greater (P<0.05) for the 2005 diet at 12, 24, 36, 48 and 96 hours, respectively. No differences in manure odour were observed.



Figure 1. Effect of genotype (1980 versus 2005) and nutrition programme (1980 versus 2005) on in vitro cumulative ammonia emission manure aged for 21 days
Conclusion
Consistent with improvements in growth rate in the present study, the researchers have previously demonstrated a 15 per cent reduction in days to slaughter and a 30 per cent improvement in feed efficiency due to improvements in genetics and nutrition programmes.

These positive impacts on pork production can be calculated to result in a reduction in nutrient excretion of approximately 23 per cent.

In addition, the researchers observed improved nutrient utilisation for the 2005 diet, which will further reduce manure output and nutrient excretion. However, they also demonstrated that modern feeding programmes may increase ammonia emission when measured in vitro at one point in time.

November 2009


Reproduced Courtesy

[mikey]

Improving Key Performance Indicators: Pre-Weaning
Increasing the number of pigs born alive and piglet survival rate through to weaning have a significant impact on profitability. BPEX offers advice on improving those key performance indicators in number 24 in its series Action for Productivity.



Piglets that are successfully reared through to weaning are the essential building blocks for the sale of finished pigs and income to the business. Improving the number of pigs born alive and piglet survival rate through to weaning has a significant impact on profitability – an increase of 1.3 pigs weaned per litter – the difference between average and top 10 per cent performance – improves net margin by £60 per sow per annum (based on costs and prices reported in the BPEX Yearbook 2009).

Targets
Total born: aim for 13+
Born alive: aim for 12+
Pre-weaning mortality: aim for 10 per cent or less
Based on top 10 per cent national figures 2009

As well as having a significant impact on herd profitability, piglets born and mortality are two of the most straightforward areas of the pig herd to record and monitor. All the activity you need to record happens over a short period (farrowing to weaning) and, on indoor units, within a relatively compact and dry space.

An individual sow card can be used to record numbers born and the age, piglet condition and causes of pre-weaning mortality. Keep the recording as simple as possible and capture useful information, for example to track piglet fosterings.

Sow number & parity   Starvation   
Farrowing date   Weak/poor viability   
Number born alive   Chilled   
Number born dead   Agalactia/mastitis   
Number born mummified   Overlaid   
Piglets fostered on   Savaged   
Piglets fostered off   Splayed legs   
Pre-weaning deaths –
Record number and age of piglets deaths   Infection/diarrhoea   
  Other: note detail e.g. deformity, meningitis etc   
Small non-viable   Total weaned   

It is important to decide with your staff the definitions you will use to ensure you are consistent in the way you record deaths. For example, agree how you will differentiate between small non-viable piglets and those that are weak and of poor viability.

Analysing Data from Records


Are piglets too hot or too cold?


Are piglets getting enough milk?Totalling up each month or per farrowing batch will illustrate your successes and highlight areas where you can improve.

Total born tells you about the overall lifetime management of the sow, from gilt introduction to point of first service, sow condition, nutrition, service, environment and management of the parity profile.

Mummified pigs may indicate a herd health problem and possibly the need for improved hygiene and a vaccination programme.

Pigs (healthy) born dead tells you whether your management at and around farrowing is adequate. It is important to record these piglets as usually they were capable of life but a slow farrowing resulted in death. Monitoring and assisting farrowings where appropriate, especially for older sows, can reduce stillbirths and improve the survival of pigs born alive.

Small, non-viable pigs may be linked to an aged herd profile, with older sows having more variable piglet weights, inducing sows to farrow too early, herd genetics and PRRS (Blue Ear). It can also indicate that you need to look at how you feed the sow during gestation.

Pre-weaning mortality and causes provides valuable pointers to how survival rates can be improved. It is important not to rely on recorded data alone, but to combine this with quality stock observations. For example your records might highlight that a major cause of death is overlying. Stock observation will help you determine whether this is primarily due to:

over fat clumsy sows
creeps that are too hot or cold
drafts leading to restless sows and chilled pigs
poor crate design
lack of milk so piglets are continually close to the sow and in the danger area.

It is also important to look at the data in a joined-up way. For example high stillbirths can be associated with increased post-weaning mortality as piglets born alive may have been weakened as a result of a protracted farrowing and be more susceptible to overlying.

Farrowing Performance
The farrowing performance of similar herds can be used to provide a standard to assess your herd’s performance against and the scope for improvement. Setting your own targets will enable you to track progress as you put new management practises into effect. Use the table below to set targets for your unit.

Industry averages Average Top Third Top 10 Per Cent Your herd Your targets
Born alive per litter – average all herds
Outdoor herds
Indoor herds 11.1

10.9
11.4 11.7

11.3
12.0 12.2

12.0
12.3     
Born dead per litter – average all herds
Outdoor herds
Indoor herds 0.6

0.5
0.6 0.7

0.5
0.7 0.7

0.6
0.8     
Mummified – average all herds
Outdoor herds
Indoor herds

Total born per litter – average all herds
Outdoor herds
Indoor herds 0.2
0.0
0.3

11.9

11.4
12.4 0.3
0.0
0.4

12.63

11.8
13.1 0.2
0.0
0.1

13.1

12.6
13.2     
Pre-weaning mortality (%) – average all herds
Outdoor herds
Indoor herds 12.6

12.3
13.0 11.1

11.2
10.5 10.3

11.8
9.6     
Reared per litter – average all herds
Outdoor herds
Indoor herds 9.7
9.5
10.0 10.4
10.1
10.7 10.9
10.5
11.1     
Source: BPEX PigYearbook 2008



Financial Benefits of Increasing Survival Rates


It is important to allocate time to establish newborn piglets.There has been a gradual reduction of time available for the farrowing department and individual litter management with batch farrowing enterprises.

With the data collected providing important signposts for improving performance, it is important to reassess the cost benefit of strategic labour deployment to allow time for the adoption of colostrum management techniques and the effective establishment of new born piglets. Further information is given in other publications in the Action for Productivity series: 14. Newborn management (indoors)and 17. Colostrum: Food for life.

The following table provides a means of evaluating the potential financial benefits of increasing survival rates and how you can assess the benefit of this against anticipated extra labour costs.

  Example Your herd
(A) Number productive sows and gilts 350   
(B) Farrowing index 2.33   
(C) Current number piglets born dead & number of pre-weaning deaths 0.8 plus 1.4   
(D) Target number piglets born dead & number of pre-weaning deaths 0.6 plus 1.2   
(E) Number extra pigs weaned per litter (C – D) 0.4   
(F) Number of additional pigs weaned/annum (A x B x E) 326   
(G) Increase in net margin/year assuming no additional labour costs required (based on BPEX Yearbook 2009 costs and prices for breeder finisher herds) £20/pig weaned   
(H) Increase in net margin/year for the unit assuming no additional labour costs required (F x G) £6,560   
(I) Additional cost of extra labour/year (Estimate the amount of additional cost
to achieve targeted performance improvements, for example 10 hours/week
at £8/hour for 52 weeks) £4,160   
(J) Increase in net margin/year after deduction of additional labour costs (H – I) £2,400   

Further Reading
 - You can find other Action for Productivity publications from BPEX by clicking here. 

November 2009