Volume 12: Livestock Farming
5. Breeding programmes and techniques
The UK cattle herd's composition
Factors influencing breeding decisions
Breed trends

Factors influencing breeding decisions

5.2 The genetic makeup of the national herd reflects decisions made by farmers and those in the breeding services industry. Farmers are responsible for day-to-day decisions on which cows and heifers to breed from, and which bulls to use. The main options available are:

• home-bred or bought-in cows and heifers mated with home-bred, bought-in, borrowed or imported bulls;
• artificial insemination of home-bred or bought-in cows and heifers using either semen from the UK, or imported semen from countries such as Canada and New Zealand (see paragraphs 5.13-5.14 and 5.20-5.33); and
• embryo transfer from home-bred or bought-in cows with proven milk production ability (see paragraphs 5.15-5.19)
  
  
  1. mated with home-bred or bought-in or borrowed bulls; or
  2. mated by artificial insemination using semen from tested bulls or imported semen.

5.3 When deciding on breeding programmes, beef farmers aim to improve the weight and quality of beef produced at slaughter, and dairy breeding farmers mainly seek to increase or maintain the milk yield produced by the herd and its milk quality (assessed with reference to butterfat and protein content, for example).

5.4 Dairy farmers also try to obtain maximum value from surplus calves that are not needed as herd replacements, and use them instead for beef production. If dairy cows and heifers are mated with beef breeds such as Hereford, Charolais and Limousin, the resulting calves command a higher price since they produce a better beef carcass compared with Friesian and Holstein dairy calves. Such practices have produced a high incidence of crossbred beef cows in the national herd. These cows are mated with beef breeds (domestic and continental) to produce beef cattlefor fattening.

5.5 AI allows cows to be inseminated by a bull with superior genes. Many different bulls are available on the market. Each has been progeny-tested for particular production traits such as milk yield, proportion of butterfat in milk, and ease of calving. The farmer decides which traits are most desirable for his or her farming purposes and buys in the appropriate bull's semen. ¹

5.6 Until its demise in 1995, the Milk Marketing Board monitored genetic improvements in production traits of dairy cows, such as milk yield and butterfat. Since then the Milk Development Council has funded the Animal Data Centre (ADC) to undertake this task. Farmers can use this monitoring service to compare production in their herds with the national herd.

5.7 Despite the options available, when choosing a bull to sire calves, most farmers seek the same genetic characteristics. Extensive use of relatively few bulls has narrowed the gene pool in the national herd. ² For example, at a meeting of representatives of the cattle AI industry in 1987, it was noted that 19 sires had at least 80,000 daughters in 2,500 herds. ³

Breed trends

5.8 By 1986 the British Friesian breed accounted for 86 per cent of the dairy herd in England and Wales, as a result of its dual characteristics of high milk yield and the suitability of its calves for beef production. Between 1986 and 1989 Friesian/Holstein crosses gained in popularity for milk production - see Table 5.1. ⁴

Table 5.1: Dairy cow breeds in England and Wales

Breed of cow	1986	1989 a
	% of total dairy cows
Ayrshire	2.2	1.9
Friesian	85.8	74.5
Holstein	3.9	3.4
Guernsey	1.8	1.4
Jersey	1.6	1.7
Dairy Shorthorn	0.5	0.6
Friesian/Holstein cross	3.9	16.2
Friesian/Ayrshire cross	b	b
Other	0.3	0.3
TOTAL	100	100
Source: Dairy Facts and Figures

a 1989 is the most recent year that figures on breeds are available b Included in 'other'

5.9 Around 1986, the Hereford/Friesian crossbreed dominated beef suckler production. Furthermore, about a third of dairy cows and almost three-quarters of dairy heifers were inseminated with semen from beef breeds, such as Hereford and Aberdeen Angus. ⁵ By 1989, the continental breeds Simmental, Limousin and Charolais were becoming increasingly important as crossbred or purebred suckler cows or as crossbred or purebred cattle for finishing. The rapid growth rate and lean carcasses of the crosses, and particularly the purebreds, increased their utility and popularity. Accordingly, the trend towards increased use of continental breeds continued into the 1990s. ⁶

5.10 Most of the early cases in the BSE epidemic were Friesian dairy cows, leading to initial suggestions that this breed might be more susceptible than other breeds to the BSE agent. However, an analysis in 1990 of confirmed cases from 1986 to December 1989 failed to demonstrate any increased susceptibility to BSE associated with breed type. ⁷ It is now understood that the high incidence of BSE in Friesians was simply a reflection of their preponderance in the national herd.