Source: Ontario Ministry of Agriculture, Food and Rural Affairs
Selecting which breed of bull to buy when there are over 70 different beef breeds to choose from has always been a difficult decision. However the last few years has seen an increase in the availability of composite, crossbred and hybrid bulls. The common question each year is: “What is a composite and what effect, positive or negative, may they have on a breeding program?”.
Definition:
“Composites are a population made up of two or more component breeds, designed to retain heterosis (hybrid vigor) in future generations without crossbreeding, and maintained like a purebreed”.
Development:
Developing a composite requires a large population of females, approximately 500 to 750 cows and 25 or more sires per generation. It takes a considerable amount of time to make the initial crosses, get through three generations of within herd matings of the crosses and liquidate the parent stock. Obviously this requires a sizable investment of money, time and patience. After all of that, there is no guarantee that the composite will be acceptable to the breeder or to the industry. Selection of breeds going into the composite is critical. Breed differences should be fully exploited so as to match the composite with the environment in which it will be used and to match it with market specifications.
Use:
A composite herd has the advantage of being easier to manage while still maintaining a relatively high percentage of heterosis. Swings in biological type that often occur from one generation to the next in rotational crossbreeding systems can be avoided with a composite herd. Genetic antagonisms between traits, (i.e. lean yield and marbling) can be overcome, if traits were balanced rather precisely when parent breeds were selected.
Producers considering a composite program should investigate how the composite was formed and the selection criteria applied to the population. Genetics of each breed contributing to the composite must be widely sampled (15 to 20 sires per breed) or inbreeding and loss of heterosis can be a serious problem. Selection of inferior seedstock in the formation of the composite or breeds which do not match long term industry goals will lead to unsatisfactory results. Producers should also be aware that composite cattle may exhibit more variation in qualitative traits (i.e. colour, horns, etc.).
Summary:
Development and formation of the composite will be the determining factor on its applicability and value to Ontario producers. Composites have been developed to be managed as a purebreed and for the best results a breeding program utilizing composites should consist of cows and bull from the same composite population. Composite breeds that have been around for a period of time include Shaver Beefblend, Hays Converter and Beef Master. Many large breeders in the U.S. have started to develop composites but a consistent supply of reasonably priced replacement females and herd sires to avoid inbreeding will be a major concern for producers considering a composite breeding program in Ontario.
Author: Joanne Handley – Beef Cattle Geneticist/OMAFRA
