Research Shows Long Term Benefits of Feeding Beef Calves Higher Planes of Nutrition

9 September 2019

Feeding beef calves on higher rates of milk replacer is known to improve weight gain in the pre-weaning period but new results show benefits right through to slaughter on an intensive system.

“There has been considerable interest in feeding elevated levels of milk replacer to dairy replacements,” Georgina Thomas, Ruminant Technical Manager with Trouw Nutrition GB comments.  “Our Lifestart programme has lead the way in researching the benefits of elevated feeding, showing better growth and organ development, which translates into superior performance when the heifers enter the milking herd.  The question then became would we see similar benefits in beef calves?”

In the studies at Harper Adams University funded by Trouw Nutrition GB and Wynnstay and overseen by Principal Lecturer and Beef Specialist Simon Marsh, calves fed on higher rates of milk replacer as pre-weaned calves performed better with higher daily weight gains through to slaughter than calves initially fed lower rates of milk replacer. The increased carcase value easily covered any increase in feed costs.

 “The objective of our studies was to examine if there were similar benefits in artificially fed beef calves,” Simon March explains. “While it is generally now recognised by livestock rearers that Continental bull calves should be fed 750g/day on milk replacer, can this be increased further?”

Simon Marsh explains that in the study 34 British Blue x Holstein calves had been reared on either 750g/day or 900g/day of Wynngold Bloom milk replacer. Both groups were fed ad lib Wynnstay Start ’n’ Wean 18%CP early weaning concentrates. Milk feed rates were gradually reduced through to weaning at 42 days.

At weaning the calves fed on the elevated rate of milk replacer had averaged 0.91kg/day DLWG compared to 0.73kg/day achieved by calves on the lower rate.  At 12 weeks they had gained 5.6kg more and scored higher on wither height, hip height and last rib girth showing they were bigger framed.

“Concentrate intakes were the same between the groups although we expected calves fed higher rates of replacer would eat less concentrates. This led to feed costs being 5p/kg gain higher on the elevated feed rates but the number of calves requiring medical treatments was significantly lower. When we added the costs of morbidity to the feed costs, the cost per kilo of liveweight gain was lower for calves fed higher rates of milk replacer.”

The question then remained about whether having larger, healthier, better framed calves at weaning would translate into higher valued animals at slaughter. The calves were then taken through to slaughter on an intensive cereal beef system and their performance monitored.

“From 12 weeks old the cattle were fed a barley-based 14% crude protein, 37% starch concentrate ad lib with straw available ad lib as well.  Cattle were selected for slaughter at a target fat class 3.

“The calves fed on 900g of milk replacer recorded significantly higher daily gains and were slaughtered 16 days sooner.  Carcase weights were also 7.7kg heavier.”

Mr Marsh says the bulls fed on the higher level of milk replacer recorded slightly lower fat classifications and could possibly have been slaughtered older at a similar age to the bulls fed on the lower rate of milk replacer. This would have meant they would have achieved significantly heavier carcase weights.

“When we look at the financial impact, the calves fed 900g milk replacer recorded an extra £33 carcase value, easily recovering the £13 extra pre-weaning feed costs.

“In addition, as they were slaughtered 16 days earlier they would have consumed around 150kg less concentrates, increasing margins by a further £30 per bull.

“Beef producers need to do all they can to achieve carcase specification as cost-effectively and as quickly as possible. Based on our trials, beef producers who artificially rear Continental cross calves should seriously consider feeding an elevated rate of milk replacer as the financial benefits through to slaughter on an intensive system are significant.”

CMR Feed rate (g/day)

750g

900g

Slaughter weight (kg)

575

582

Age at slaughter (days)

417

401

DLWG from birth (kg)

1.27

1.33

Carcase weight (kg)

321.1

328.8

Kill out (%_)

55.8

56.5

Conformation

R-

R-/R=

Fat class

2=/2+

2=

Carcase price (£/kg)

3.32

3.35

Carcase value (£)

1068

1101