As there are many factors that influence milk production we need a large data set to estimate the effects of all factors and estimate breeding values with reasonable level of reliability. Thus, larger the dataset higher will be the reliability of BV estimates. One can, of course, estimate BVs with smaller data set but then reliability of breeding values will be smaller. There are theories giving method to estimate breeding values on smaller farm data, or data with no pedigree information or dataset with a few environmental factors.
Different projects have different follow-up levels, different rearing practices, different geography, etc. Hence, different projects have different daughter numbers or animal recorded numbers.
Is the accuracy of factors and breeding values is different for different projects? The first is the accuracy of data recording both production records and pedigree records- parentage , and the second is the volume of data. It is true that as a project grows older, the parentage errors decreases and the volume of data increases, and we get better reliabilities. As discussed above, projects differ in their reliability. Along with BV, we should always consider its reliability.
With less reliability, one is not confident whether this is really or with more information it will come down or go up. With higher reliability, we have more confidence on the estimates of breeding values and less risk. For AI bulls, risk should be as minimum as possible. With increasing information, reliabilities increase as shown in Figure 2. Figure 2. Reliability and load of information used in breeding value estimation. This is even more desirable if we wish to compare bulls from different sources like from a few organized farms, from farm and field together, etc.
Breeding values are expressed in terms of superiority over their population mean. If an animal is having BV for a trait, it means that this animal has superior genetic potential of producing kg. PTA is half of BV. PTA estimates what is passed on to the progeny from its sire or dam which is half of what the sire or dam transmits to their progenies. If breeding values are expressed as deviations from a population mean in which the testing has happened and the bulls are to be used in a different population with a different population mean, will we get the same level of genetic improvement in the other population?
If we have a population with an average of kg. When there are no genetic differences between the two populations, the phenotypic differences in production levels are attributed to environmental differences. In such conditions, the differences in BV may amplify meaning if difference between two bulls breeding value is in low producing population, the difference will be around in high producing population.
In our country, we can use BVs that have been estimated in one area to another area with reasonable confidence. However, if the genetic base of the two populations is different, the ranking will change considerably. Also if environment is drastically different, the ranking will change considerably. Here also bulls with very high BV will not have negative or very low BV in other population but ranking among bull will change considerably due to different genes may get activated differently in different environments.
Should we distribute bulls ranked 1 to 20 or say 1 to 50 based on breeding values irrespective of their breeding values?
Can we also define MSP for breeding value? Ideally, we should produce twice or thrice the numbers of bulls required through nominated mating and then select the best one third or one-half of bulls for semen production. The nominated mating also should be based on BV and not on raw-production records.
The bull calves with very small but positive BV will be average bulls. They will give small genetic gain. But consider the bulls selected from their raw-dam yields which may have negative BV.
Such bulls may lead to negative genetic progress. Initially, we may say bulls with positive breeding values should be used. Later as we progress we may set certain percentage of top bulls that may be used for semen production, but it should be dynamic.
It may not be advisable to fix a percentage limit, as what you select depends on the actual demand of bulls for semen production. In fact, we must think about a differential price system based on breeding values and demand as our systems of bull evaluation and production matures. Do we have any data or have we done any experiment wherein bulls with high breeding value are actually performing better under field conditions?
Table 1 shows that the bulls with higher BVs perform better than the bulls with negative breeding values. Table 2 shows that there is no difference among daughters of bulls with high dam yield and bulls with low dam yield. This clearly indicates that under field conditions, bulls with high BV are expected to produce better progenies not bulls with high raw-dam yields.
One can see that the difference of daughter yields between bulls with high dam yield and low dam yield bulls is not much. However, there is a big difference between bulls with high BV and low BV. You are looking at their conformation and the physical appearances of health. For raising meat kids, you don't need show-quality does. You should select does that are sound and ready to be productive. Good conformation soundness means:.
Goats that are sound in these areas should be able to range widely for forages, to bite and chew and digest those forages well, and to carry and feed kids. In addition to passing these tests, though, the goats you select must be healthy. Some visual indicators of good health are:. But if the seller's herd matches the above description, your odds of purchasing a healthy animal from it are very good.
The reverse is also true; if the seller's herd includes animals that are limping, emaciated, "dull", have abscesses, or appear "poor," chances are that the animal you buy will be carrying a disease, even if that disease is not obvious in that particular animal.
Because transmissible diseases including internal parasites may not be apparent in an individual, observing the condition of the herd of origin is important.
This is one reason why it is better to purchase animals on the farm, rather than at an auction. Also, sale barns receive a lot of unhealthy and otherwise unsuitable animals. They are the dumping grounds for goats that do not thrive, have contagious diseases, are terrible mothers or incorrigible jumpers, non-breeders or poor milkers.
If you shop for breeding stock at the sale barn, you may very well be bringing home diseases to infect the rest of your herd, or be bringing home animals that are unproductive and therefore unprofitable. If you are lucky enough to find some good stock at the sale barn, by the time those good animals have mingled with the unhealthy ones in the barn, suffered the stress of shipping and sale, and tracked through an environment where many unhealthy animals have been, their immune systems may be overwhelmed.
There really are no bargains at sale barns, even if they are cheap. Take someone who knows about goats with you when you go shopping. View details Got it. Download the app educalingo. Meaning of "breeding stock" in the English dictionary. Selective breeding. Synonyms and antonyms of breeding stock in the English dictionary of synonyms.
Examples of use in the English literature, quotes and news about breeding stock. This book deals specifically with the production of goats for meat and addresses all aspects of the industry that the producer is likely to encounter.
Barbara Vincent, Covers all aspects of cat breeding for both novice and experienced breeders, discussing breeding stock, the breeding process, potential problems, normal and assisted births, and neonatal kitten care. Dan Rice, Breeding Stud Sheep shows how to establish and manage a successful sheep stud. Murray Long, Cheap breeding stock is very expensive. Mothering Ability Animals selected should have a good mothering ability, That is animals with good natural instinct towards their young ones.
This will enable them to rear the young ones up to weaning. Prolificacy Animals selected should be highly prolific. That is, animals with the ability to give birth to many offsprings at a time larger litter. This is a quality that should be considered when selecting pigs and rabbits. Length Of Lactation Period. Calving Intervals. Age of the Animal, Fertility, physical Fitness, Health Of The Animal, Body Conformation and suitability of the enterprise-milk or beef Selection in sheep Consider the following; Level of performance which includes; Mothering ability Growth rate Wool quality Carcass quality Twining rate Age Suitability to the enterprise-wool or mutton Flocking instinct Health of the animal Physical fitness Inheritable defects Fertility Inheritable defects.
Heredity defects Selection in Camels Health of the animal. Progeny testing - is a offspring resulting from selected parents Family selection. In this method a group of progenies offrprings are used as an aid to increase accuracy in the selection ofa breeding stock.
This is method is used when the character to be selected is of low heritability and expressedby one sex only. This methodtakes upto nine years for the results to be seen Contemporary comparison Contemporaries refers to other heifers in the herd sired by the same bull. This is a progey tasting method which involves comparison of average production of daughters Heifers of each bull with that of the other heifer refered to as contemporaries.
In this methods it is assumed that thedifference between the herds of the same breed are non-genetic in origin. It eliminates difference brought about by the environment. It is accurate since we are using a large herd of animals. Climate change.
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