The genetic and financial consequences of selection amongst dairy bulls in artificial insemination

Abstract

SUMMARYA numerical model of male and female replacement processes in a dairy cattle population was constructed in order to describe the long-term genetic and financial consequences of selection amongst bulls in AI.Changes with time in the relative contribution of different generations of offspring to the total genetic improvement of the population were described. It was shown that the genetic change resulting from a single selection process amongst the males eventually approaches an equilibrium many years after selection is practised. Owing to the delays involved in the progeny test, individual males made no genetic contribution for a period of 10 years and a small but constant contribution thereafter.The costs of bull testing and selection, and the monetary benefits obtained from it, were estimated. Current selection procedures proved to be highly profitable at prevailing market prices. Capital invested in the testing programme was recovered within 2 to 5 years of the first offspring calving.The effect of changes in milk prices and feeding costs on monetary returns was examined. It was concluded that sire testing programmes are likely to prove unprofitable only under extremely adverse economic conditions.

The effects of continuous sire selection on the structure and age composition of dairy cattle populations

“…Hinks, 1971). For young bulls which complete test inseminations within their first year at AI, y = 2.…”

The effect of inflation and form of investment on the estimated value of genetic improvement in farm livestock

“…The simplest way to study the returns from a breeding programme is to consider a single unit of breeding input and to follow the resulting unit of improvement through the period over which its value is recouped (Hinks, 1971). The simple approach can then be extended to inputs in subsequent periods.…”

“…MANY authors have used discounted cash flow methods to assess the value of livestock improvement programmes, and to compare alternative breeding schemes (Soller, Bar-Anan and Pasternak, 1966;Hill, 1971;Hinks, 1971;James, 1972;Petersen, Christensen, Andersen and Ovesen, 1974;Brascamp, 1975;Cunningham and Ryan, 1975;Everett, 1975) but there has been little discussion of the appropriate discount rate to use. With the rates commonly used (8 to 15%) the value of genetic gains are substantially discounted, especially in the large farm animals with long generation intervals.…”

Cost-Effectiveness and Population Structure in Cattle Breeding Programmes

“…In fact it is probably fair to say that most of the dialogue between breeders in the traditional sense and scientists involved in breeding has never progressed beyond this initial question. (H INKS , 1971 ) he looked at the longer-term consequences of alternative dairy programmes, using as a measure of cost-effectiveness the discount rate at which a particular programme recovered its total costs a specified number of years the conclusion was that the main factors of importance were the bull selection intensity and the marginal profitability of milk production.…”