13 June 2011

4 minute read

Animal productivity

To ensure high levels of profitability from suckler beef production systems, animal productivity, or output per livestock unit, must be high. High output per LU is determined by weight for age and carcass quality of the progeny and reproductive performance of the suckler cow herd.

Weight for age and carcass quality

Drennan and McGee (2009) identified three important factors influencing growth rate and carcass quality of suckler progeny: 1) use of late-maturing continental breeds, 2) availing of hybrid vigour and, 3) milk production of the dam. Drennan and McGee (2009) concluded that suckler dams should have at least 50 per cent and preferably 75 per cent of a late-maturing continental breed to produce progeny suitable for higher-priced markets as a result of improved conformation and leaner carcasses. Murphy et al. (2008a,b) found that progeny from crossbred cows with Friesian or Simmental ancestry had higher carcass weight for age than ¾ or purebred beef breed suckler cows (Table 4). These differences in carcass growth reflected differences in calf pre-weaning gain due to milk yield of the dam. However, progeny from cows with Friesian ancestry had poorer conformation and were fatter than those from purebred beef breed cows.

Table 4. Impact of suckler cow breeding on weight for age and carcass conformation and fat score of progeny

The implications of weight for age were investigated in a whole farm systems context to elucidate the impact of this single variable on beef output for suckler beef system (Table 5). This analysis suggests that weight for age is a key determinant of carcass output and hence profitability. The implications of this for whole farm profitability were that, for each 25 g/d increase in live weight, net farm margin was increased by €30/ha. Thus, it is apparent that weight for age (and also taking into account carcass traits, as the final product must be commercially saleable and of high value), is an important factor determining profitability for suckler beef production systems.

Table 5. Impact of live weight for age on the carcass weight and beef output of suckler beef production systems

Reproductive performance

Data from the Irish Cattle Breeding Federation (ICBF) suggests that average calving rate (i.e. number of live calves produced per cow on the farm) for Irish suckler beef farms is 0.81. In other words, for every 100 cows, only 81 weanlings are produced. This low level of reproductive performance is an obvious contributor to low levels of profitability on Irish suckler beef farms as the cost of carrying each suckler cow is only offset by 0.81 weanlings.

The calving rate is largely a function of two variables; calving interval and pregnancy rate. Analysis of data from spring-calving suckler cows at Grange between 1987 and 1999 showed that a calving interval of 367 days and a pregnancy rate of 94 per cent were achieved (Drennan and Berry, 2006). This analysis also showed that earlier calving cows had longer calving intervals than those calving later in the spring, however, there was no difference in calving rate. The results show that under appropriate levels of management, good reproductive performance can be attained in a spring- calving suckler herd.

Table 6 shows that sectoral averages and Grange target levels of animal productivity. As a result of higher calving rates and higher weight for age, output per LU is greater for the Grange systems. Target output per LU is 50 per cent greater for the Derrypatrick Herd when compared to the current sectoral average. It is anticipated that improvements in reproductive performance and animal liveweight gain could increase output per LU by 11 kg by 2018. When these levels of individual animal performance are allied to much higher stocking rates, it is evident that live weight and carcass weight output is also much greater.

Table 6. Sectoral average and Grange target levels of animal productivity