The right bull finish
Published 31/08/2010 | 05:00
AS REFERRED to in my previous article, I return to the subject of finishing bulls. Judging by the volume of calls I have received in the past few weeks, it is evident that great interest exists in this area. Young bulls currently account for almost 20pc of the prime male slaughterings in Ireland. Most of these animals are entering the prime beef markets and they are finding good acceptance there.
There are conflicting suggestions on suitable production systems for bulls, particularly for Holstein-type bulls. Bulls are not reaching their full potential under production systems currently advocated. There is a huge danger associated with grazing bulls late into the autumn. Shortened days combined with the animals reaching sexual maturity increases the aggression of these animals. This problem is particularly prevalent among Holsteins and Holstein crosses. Furthermore, the quality of carcasses from bulls slaughtered off grass is totally unsatisfactory for most meat plants. These carcasses tend to have a very poor cover of fat and are also prone to a dark colour of meat, ie, dark cutters. The percentage kill out is also at a reduced rate, thus reducing the total value of the carcass. It is therefore essential, I feel, to house bulls of all breeds in order to finish them correctly.
Generally, bulls that are grazing in the autumn are either one of two categories: spring-born bulls of 16/18 months or autumn-born bulls from the previous year that are set for housing for finish on the farm or for imminent sale. In both situations, these animals are at a stage where they should be meeting their maximum weight gain, optimum feed conversion efficiency and 'covering' with fat that ensures they meet market specification. Feeding grass only or supplementing with concentrates meets none of these requirements. The grazing and exercising leaves an energy deficit and anybody who has ever grazed bulls will know what one 'bad night' will do to the thrive of these animals. Maximising the energy intake of these animals is the primary objective during the final stage of finish, so grazing is totally unsuitable to this end.
Housing these animals and choosing the correct feeding strategy is essential to attain the performance targets and ensure correct finishing. House the animals in small groups and retain them in these groups right up until slaughter.
Continental cross bulls that exceed 500kg live weight should be brought to slaughter in a maximum of 120 days (gaining 1.7kg per day). Most Friesian/ Holstein-cross bulls will probably be between 420-480kg live weight and will require a minimum of 140 days (gaining 1.3-1.4kg per day) to be brought to have the correct degree of finish.
Slow introduction on to feed is advisable to avoid digestive upsets. Total mixed ration (TMR) feeding allows for much faster introduction onto the full ration. The choice of energy and protein sources will depend on the forage base used in the ration, ie, rapeseed meal as a protein source can be used when feeding maize silage or root crops but is not advisable to use as the sole protein source when grass silage is used in the diet. There is no room in the finisher ration for low-energy feeds. Priority has to be given to high-starch feeds such as wheat, barley and maize grain. There is the obvious risk of acidosis when using cereals, but this can be countered by selecting a suitable digestible fibre and using long fibre (straw) to improve rumen function that naturally buffers the rumen. Using quality co-products from licensed sources may have an important role. However, the cost, availability and likely storage losses need to be considered.
Feeding a good-quality mineral supplement will ensure that the animals receive an immunity boost when housed and will be well set up for the remainder of the feeding season. The current fad promoted by some of feeding limestone is, in my opinion, ill-advised and wasteful. There is limited buffering effect from feeding limestone at low levels and there is a serious feed displacement effect from its usage at high levels. There is likely only to be a placebo effect on the farmer and no positive effect on the animal.