22 December 1995

Good finishing is key to achieving profit margin

Market factors apart, its a tricky business to get quality beef at a profit. As

Jonathan Riley reports, finishing is about balancing fat deposition against growth rate

THE art of finishing cattle is to market at a high enough weight so that output exceeds costs, while ensuring growth rates are fast enough to minimise the amount of energy fed for maintenance.

So says Basil Lowman of the Scottish Agricultural College, Edinburgh, in the December issue of the Signet Beef and Sheep notes.

"Faster weight gain is more efficient because there are less days to slaughter, so less feed is used for daily maintenance requirements," says Dr Lowman.

"But faster growth means there is a higher proportion of fat laid down and cattle reach a certain fat class at a lighter overall weight.

Striking the balance

"For example a Holstein steer growing at about 1.3kg a day will reach fat class 3 at about 450kg liveweight. Growing at 0.8kg a day the same animal would reach the same fat class beyond 600kg."

Dr Lowman says that striking the balance between growth and fat deposition would be harder this winter as more concentrate would be fed to offset silage shortages.

"This will supply more energy, shorten finishing times by, on average, two weeks, and reduce slaughter weights by about 10kg to 15kg.

"To avoid financial penalties aim for carcass weights of about 280kg to 320kg – 510kg to 580kg liveweight – graded at fat class 3 to 4L," says Dr Lowman.

"Producers should decide on a finishing date and desired finishing weight and subtract the weight of the animal at housing," he says.

This will give desired number of days to slaughter and the difference in liveweight that must be made up over the finishing period.

"From this you can calculate the daily liveweight gain needed to achieve the final weight at the target slaughter date. For example, finishing at 600kg, less the weight at housing of 400kg, leaves 200kg to make up. If the desired finishing date is 200 days ahead then a growth rate of 1kg a day is needed," says Dr Lowman.

Concentrate supplements

"A good quality silage at 10.5MJ/ME/kg DM fed ad lib will provide growth rates of up to 0.9kg/day. If supplemented with 2kg to 4kg concentrate maximum gains will be about 1.1kg/day.

"Hay would need to be supplemented with about 3kg to 5.5kg for the same growth rate. But there is a risk of acidosis caused by the rapid breakdown of starchy concentrates in the rumen when daily concentrate levels reach this point unless feeds are split. No more than 2kg of concentrates should be fed in a single feed," he says.

Faster growth can be achieved by supplementing hay with 6kg to 7kg of concentrate. But labour costs for feeding increase. Straw needs supplementation levels of 7kg to 8kg. This will increase labour costs and the risk of acidosis still further.

At these rates Dr Lowman says it would be simpler to switch to an intensive or barley beef system where, despite intakes of up to 12kg a day, the animal regulates itself to several feeds a day of about 1.5kg each.

Dr Lowman advises that when purchasing by-products, quoted energy and protein was a useful guide for buying decisions when concentrates constituted less than a third of the diet DM. But, in systems where cereals account for more than 50% of the ration, expert advice on nutritional characteristics must be sought because by-products have differing sources of energy.

"Energy in a by-product may be derived from oil, starch, sugar or fibrous sources and certain products may have too much protein and oil leading to inefficient digestion and lower DM intakes." &#42

Striking the balance between growth and fat deposition could be harder this winter as more concentrates will be fed to offset silage shortages.

Dr Basil Lowman of the SAC says: "Aim for carcass weights of about 280kg to 320kg, graded at fat class 3 to 4L."