Cattle Farm Management Notes: 15/12/2009
Feeding Autumn Calving Cows
By Liam Fitzgerald, Cattle Specialist, Athenry
Guidelines for feeding suckler cows is based on a fairly simple principle namely, feed to body condition score in relation to the stage of the production cycle. There are ideal body condition scores to aim at during the various stages throughout the year depending on whether the cows are spring calving or autumn calving. Body condition scoring involves regular assessment of body condition of individual cows and calculation of the herd average. The appropriate body condition score varies with the stage of the production cycle. Table 1 gives a guide to recommended condition scores for autumn and spring calving cows.
| Production Stage | Autumn Calving | Spring Calving |
|---|---|---|
|
Calving Mating Weaning |
>3.0 2.5M 2.5 |
2.5 2.5 >3.0 |
The figures in table 1 refer to herd averages and indicate that the herd body condition scores for both autumn and spring calvers should move in the range of 2.0 to 3.0 or slightly higher. Obviously, individual cows will be 0.5 to 1.0 scores outside this range. Having cows much above condition score 3.0 is wasteful and increases calving difficulty if they are over-fat at calving. However, the bigger loss occurs with cows that are under 2.0 at calving or mating. Research by Prof. Michael Diskin shows that cows that are under 2.0 at calving will be up to 3 weeks slower going back in calf and where there are a significant number of cows in a herd under 2.0 at calving, the calving interval (period between calvings) will not be maintained at close to the 365 day target. There are always the one or two exceptional cows in a herd that are at or close to condition score 2 around calving and still maintain high reproductive performance.
Feeding Levels
Ideally, the autumn calvers should be at, or somewhat above condition score 3.0 at calving and should not lose more than 0.5 of a condition score up to mating. Once the cow is settled in calf a further 0.5 condition score can be lost with no adverse effect on production or fertility. The feed requirement of autumn calvers depends on condition score at calving and the level of milk production. If the cow is at condition score 2.5 at calving she cannot afford to lose any condition up to mating. In energy terms, a 600 kg cow requires 5.5 UFL (units of energy) for maintenance (equivalent to 5.5 kg of standard barley or 36 kg silage @ 20% DM and 68% DMD). Each litre (1 kg) of milk requires about 0.45 UFL. The feed requirement of a suckler cow giving 5 litres of milk is approximately 45 kg of silage at 68% DMD plus 1.0 kg of concentrates per day. A cow giving 10 litres of milk per day would need 3.0 kg meal with the 45 kg of silage to stay at the same body condition. The milk yield of beef cows is usually 5 to 8 litres per day in the first 3 months of lactation. First cross Friesian suckler cows are likely to give 8 – 10 litres of milk per day and will lose more condition in early lactation than their more beef type comrades if fed the same diets. In practical terms, relatively good silage ad lib and 1 – 2kg meal per day up to mating should keep adequate condition on autumn calvers. Cows that calve at condition score 3.0 or better can lose 0.5 of a score up to mating which is equivalent to saving about 1.0 kg meal per day. Therefore if your cows are at condition score 3.0 at caving rather than 2.5 you will save 1 kg meal per day. High quality silage is much more important for autumn calvers than the spring calvers, e.g. silage of 75% DMD fed ad lib to lactating suckler cows is capable or providing maintenance (no condition loss or gain) plus 8 litres of milk per day.
Once the cow is settled in calf, further condition loss - back to condition score 2.0 is acceptable, which could represent a reduction in the meal allowance of 1.0 kg per day in the 8 – 10 week period before turnout. It is more efficient to divert meal feeding towards the calves while indoors than feeding the cow. High quality silage has adequate protein for a suckler cow giving 6 – 8 litres of milk. As digestibility falls, both energy and protein intake also falls. On lower quality silage, feed a 16% crude protein ration. Each 5 units drop in DMD from 70 % requires an increase in the meal input of about 1.0 kg per day. A post-calving mineral of about 100 grams per cow per day should be fed on the silage or as part of the concentration ration.
