Animal Health & Welfare

Advances in genetics and breeding have resulted in a rapid increase in milk yield equating to a 3.7% increase per year since the 1980s.

Sixty percent of this increase is directly attributed to advances in genetics, whilst the remaining 40% has been achieved through changing management practices. For more information on advances in dairy cattle breeding for productivity, see the MDC Evaluations link on the right.

The drive for productivity has generated a significant metabolic burden for high yielding dairy cattle. In recent years it has been acknowledged that breeding programmes that focus only on productivity traits and do not take account of welfare-relevant traits may be contributing to poor welfare in dairy cattle.

Selection for an increased yield has directly contributed to:

• A decrease in fertility within the national herd
• An increase in somatic cell count (SCC) which is positively correlated with mastitis risk
• A decrease in longevity
• An associated increase in the rate of involuntary culling

The full effect of these problems is currently being alleviated by advances is herd management. However if selection of dairy cattle continues unchanged it is likely that increases in health and fertility problems will outstrip management advances.

Developments at SAC

Research at SAC has found that it is possible to maintain the profitability of the national herd whilst working to halt the deterioration in health and fertility traits.

SAC, with other partners, have developed a new index to allow cattle to be bred for a combination of health, longevity, fertility and production traits. The most recent versions of this index have been known as the Profitable Lifetime Index (or £PLI). Application of this approach is expected to improve, or at least halt, the increasing incidence of lameness and mastitis. Further information on the £PLI index and other breeding initiatives at SAC can be found under the ‘Selection indices’ tab below and under ‘New tools for sheep and cattle breeders’ on the right.

The current movement towards organic production and the associated reduction in the use of antibiotic agents has increased the importance of using cattle capable of resisting microbial challenges. Recent work has looked closely at how heterosis (‘hybrid vigour’) can best be exploited in organic systems. For more information on crossbreeds in organic dairying, click on the 'Breeding for organic systems' tab below.