29 Jan 2018
Making sure all calves have consumed sufficient colostrum as soon as possible after birth is vital, as it provides both protective antibodies and high-quality nutrition. These help the calf fight disease and deliver high levels of performance.
Suckled calves should have drunk three litres of colostrum within two hours of birth. If not, they
should be given some via a nipple bottle or stomach tube.
The calf’s ability to absorb the immunoglobulins in colostrum reduces significantly from about six
hours after birth and has gone completely by 24 hours.
Colostrum quality depends on the cow’s body condition at calving and her pre-calving diet. First
calvers tend to have poorer quality colostrum than older cows. Particular attention should be
paid to trace elements and vitamins in the dry cow ration.
The focus of feeding dry cows should be to enable them to be at the correct body condition score at calving. Ideally, that means knowing calving date and being able to group cows by body condition score and feed them accordingly.
During the dry period, rations should:
• Satisfy the cow’s appetite – 1.5-2% of liveweight
• Provide sufficient trace elements and minerals
• Manage cows to reach target BCS for calving
Over-fat and too thin cows risk having problems at calving.
Cows that are too fat in late pregnancy will have difficulties due to deposition of fat narrowing the
birth canal. Thin cows can lack the strength for calving and produce weak calves and poor quality
Body condition tends to vary throughout the year with feed supply, but it is best to avoid extreme and rapid changes. Cows should be dry for at least five weeks before calving to ensure there is enough colostrum for the new calf.
A cow weaned at BCS 3 and on target to achieve a calving BCS of 2.5, will need to lose about 0.5 BCS. This, over five to six months of winter feeding, is a liveweight loss of 0.25kg/day. Although nutrient requirements increase through pregnancy, gradually at first and then at an ever-increasing rate, research has shown that feeding can be simplified by adopting a flat-rate regime. The cow is rationed according to her liveweight and the required liveweight change at a point eight weeks before calving. So the cow will be slightly over-fed at the beginning of the winter and under-fed at the very end of pregnancy.
However, in systems where accurate calving dates are known, there can be merit in increasing the feeding rate slightly, or including proportionally more silage in a grass silage/straw mix, in the four to six weeks pre-calving, to minimise body condition loss and promote colostrum production. Limiting feed to reduce calf weight during the last month of pregnancy can do more harm than good. It can reduce cow fertility and colostrum quality, cause problems for the calf and reduce cow stamina at calving.
If cows are too thin at weaning, eg less than BCS 2, they need to be fed to increase condition. For example, a thin cow needing to gain 0.5kg/day over three months would need access to either good quality (10.5MJ ME/kg DM) grass silage ad-lib, or poor silage supplemented with 1-2kg of high energy concentrates.