Right Breeding Strategy A Must:

[mikey]

Right Breeding Strategy A Must
The right strategy in breeding livestock and poultry is more important than you think. That is why Dr. Syrian Baguio, assistant director of the Livestock Research Division of Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD), is worried. There are so many breeds of goats being imported and if everybody is going to breed and crossbreed without the right strategy (bara-bara in Tagalog), he is afraid the goat industry could be “mongrelized.” Mongrels, he explained, don’t have predictable performance.

He is afraid that growers would be crossing different kinds of animals without really having specific targets in mind. That could result in mongrel animals. When that happens, the offspring could be very variable. There’s no uniformity and that is bad for a commercial operation. Using the best-looking animals (the products of crossing) is not the best way to breed. That is often a mistake, according to Dr. Baguio. What is more important is to produce a pure or purified line with the right genes for breeding purposes. A purified line could be achieved through sustained selection until the animals produced are uniform in size, appearance, productivity, adaptability and other attributes.
Dr. Baguio laments the fact that we have not even produced an animal breed of our own. There is no purified native chicken, for instance. One that is uniform in size and appearance. He is somehow elated to know that one fellow in Negros Occidental, Johnny Tagamolila, through the help of the West Visayas State University is now producing native chickens that are more or less uniform in plumage. Dr. Baguio stresses that one should have a clear idea of what type of animal he is going to produce before embarking on his breeding program. He cites, for instance, what they plan to do to improve the milk yield of the native cattle in a project in Lanao. First, they will cross the native cattle with a purebred Jersey bull. Jersey is a dairy breed that is much smaller than the Holstein. The resulting cross will be smaller in size but with high milk yield. One advantage is that smaller animals require less feed.

The first generation offspring or F1 will be backcrossed to a purebred Jersey bull. That will produce the second generation or F2. The next step is to mate F2 with another F2 of the same breed but with different parents to avoid inbreeding. With constant selection of the best performing animals, the breeder would be able to produce the animal he is looking for. Constant selection will do the trick.

What are the traits they are aiming at in the case of the milk cow? One with high milk yield with the desired butterfat content, one that is adapted to the local environment, one with disease resistance, etc.

In the case of the native chicken, PCARRD’s program is not to increase the size or the egg-laying capacity of the bird. After a survey they made, they concluded that the market needs a chicken that is less than one kilo, with rounded body that resembles the shape of the banana blossom (preferred by traders). The PCARRD experts are after chickens that will have predictable performance. That is important in commercial production.
 

[mikey]

With regular purchase of flock sires from the same stud, the commercial flock makes genetic gains at the same rate as the stud, although it lags behind in terms of absolute genetic merit. Furthermore, the genetic progression (direction and speed) of the commercial flock/herd is the same as that of the stud, regardless of the individual sires used from the stud (see Figure 1).
GENETIC MERIT

In commercial flocks or herds, new sires that are genetically superior to those purchased previously are introduced each year. This means that the next offspring obtained are genetically halfway between the new sires purchased and the females on the property and so are a little better than the previous year's offspring.




Figure 2. Genetic merit of progeny
(by using a new group of herd sires)

Imagine that commercial-flock females are all mated to one group of new flock sires. The genetic merit of the offspring will be halfway between that of the sires and the females, as shown in Figure 2. Unless the offspring are backcrossed to the same sires repeatedly, the commercial flock will never get to a situation where it gets all the genes of those sires, and it will always "lag behind" in genetic merit.
SIRE SELECTION

Selection of sires is paramount, especially the sires that are to be used as replacement sires in the herd or flock. This is the engine room where genetic gains are made. Determining from which stud to buy sires is the sire buyer's most important decision. Evidence from many trials and experiments has shown that genetic differences between studs can be quite large. Only relatively minor differences can be made by buying different grades of sires from a particular stud.

[mikey]

 If a breeder uses sires from a different genetic source each year, the likely outcome is that little or no genetic gain will be made over time, and, in fact, there is a chance that genetic merit could be lost. The reason, as described above, is nonvalid comparison of animals between environments.
GUIDELINES FOR CHOOSING STUDS

1. Before attempting to identify a source of replacement sires or dams for improvement of a herd, first determine your own breeding objectives--in other words, the goals of the breeding program, the type of animal considered ideal, and how the current stock compares with the ideal.

Breeding objectives may relate to color, body weight, fleece weight, fiber diameter, degree of kemp within the fleece, and cria birth weight. Any number of characteristics can be bred for, but remember that some are not highly heritable. Furthermore, as the number of characteristics used as a basis for selecting individual animals increases, the slower will be the rate of change for each.

My recommendation is to look at and select animals on the basis of traits of commercial economic importance that can be objectively measured.

2. Visit potential sources of new genetic material and discuss breeding objectives of the property with owners or managers. Ask how, at what age, and how frequently they objectively measure and record data used for animal selection.

3. When you have identified genetic source properties with breeding objectives similar to your own, ask to see data of available animals before making your selection.

For example, if I were interested in male tuis, I would ask for data like fiber diameter, fleece weight, body weight, and fleece yield on all the male tuis and their averages. Remember that comparing data for animals of different ages is difficult.

Animals can then be culled from selection on the basis of physical faults first and then on the basis of your breeding objectives. To derive the best estimate of relative genetic merit, compare animals with one another and, more importantly, with the group average for a particular trait.

Remember: The smaller the population you are selecting from, the less confidence you will have in estimating genetic merit.

If a source of genetic material cannot or will not supply the data required to aid in your selection, it may be worthwhile to look at an alternate genetic source.

4. As explained above, once a source of genetic material has been identified, stay with that source for a reasonable period (five years) before considering a change based on rates of genetic improvement.

For most production traits, 20 to 40 percent of the observed superiority of an individual with respect to the mean of its contemporaries is of genetic origin; the remainder is of environmental origin.

Boy this gets really complicated??