Profit - replacements from the beef herd

Both suckled calf producers and beef finishers have found the influence of the Holstein in the dairy sector has led to:

Fortunately, modern technology and breeding tools are available and if used correctly, can help in selecting the correct bull. It is important, however, to base a purchasing decision on both visual assessment and genetic information.

The EBV important in relation to breeding heifer replacements is the 200 day milk trait, as shown in Table 1. This value is based on cattle weights collected by AI Services from pedigree breeders in Northern Ireland, which are then processed by Signet, through the Beefbreeder service. This is possible due to a powerful computer program, Best Linear Unbiased Prediction (BLUP). It is able to separate out the genetic factors influencing an animal’s performance from the environmental factors, ie. feeding level and feed type. EBV’s are determined by the animal’s own performance and also the performance of it’s relatives. They are an indication of the bull’s genetic ability, which should be considered in conjunction with the bull’s appearance during the selection process.

	unit of measurement	A positive figure indicates	A negative figure indicates
200 Day Milk	kg	Daughters with above average milk	Daughters with below average milk

A bull’s EBV for milk is calculated from the performance of his grandchildren. A bull produces 2 types of grandchildren, one group being sired by the bull’s sons and the other group being born to the bull’s daughters. Assuming the bull and his sons are mated to average cows and his daughters to average bulls, we would expect similar growth rates to 200 days of age in all his grandchildren. However, if those calves born to his daughters always grow faster, it suggests that his daughters are above average in terms of their milk production and this is reflected in the bull’s 200 day milk EBV.

The 200 day milk EBV has an accuracy value, which is expressed as a percentage, ranging from 0 to 100. Generally, the accuracy of this trait is low, as it is a maternal trait only expressed by the females. But similar to other traits the greater the value the more accurate the EBV.

Compare the use of two bulls. Each is identical for all traits except the 200 day milk trait. See Table 2.

	Bull A	Bull B
200 day milk EBV - of the bull - of the bull's daughters	-5kg -2.5kg	+5kg +2.5kg
Daughters retained (10 daughters/year for 5 years)	50	50
Grandchildren produced (each daughter reas 7 calves during lifetime)	350	350
Difference in weight of calf reared from bree average (350 calves * daughters 200 day milk EBV)	-875kg	+875kg
Difference in returns (each kg is valued at £1.00)	-£875	+£875

It is also important to note that bulls selected to produce heifers should not have high positive figures for calving ease or the multi-trait calving value index. If they have, their daughters, though easily calved as calves themselves, may have difficulty in calving their own calves, as a result of slightly reduced pelvic width.

In 1997, a self-contained suckler herd was set up at Greenmount College. The stock bull in the herd is Cuil Madrid. He was bought on the basis of both a good visual appearance and EBV for 200 day milk. He is in the top 10 per cent of recorded Saler bulls for the 200 day milk trait.