BETTER Farm: Cow condition impacts on calving and fertility

Cows that have been housed should be grouped and fed, according to body condition score (BCS). This involves getting into the pen and handling the animal, or running them through the crush. Whether you decide to stick to the five point scale, (BCS 1 = thin and BCS 5 = fattest), there is a major benefit in taking action now to have cows in the ideal body condition at calving. Looking at an animal and assessing fat covers is fine on a finishing steer, but cows are different.

The body condition in the final six weeks of the dry period will have an effect on the fertility of the cow after calving.

Thin cows (BCS 2 or lower) and first-calved heifers will take longer to start cycling again. Ideally, cows should come into heat around 40 days post calving. With thin cows, this is more likely to be around 60 days.

Remember, every missed cycle will add 21 days to the calving interval of the cow.

Furthermore, there is the cost of feeding that empty cow for 21 days.

A cow eating 45kg silage (€30/tonne), plus 2kg concentrates (€260/tonne), will be costing €1.87/day to feed. This amounts to €39 for every cycle that the cow missed. In addition, the calf will be lighter when weaning next autumn.

Changing a cow by one BCS is the equivalent of gaining or losing 70kg to 80kg of liveweight. When gaining condition, a typical daily liveweight gain for a cow is 0.5kg/day. Therefore, bringing a January calving cow from BCS 2.5 to BCS 3 will take approximately six weeks. This is why action should be taken now. Trying to rapidly gain condition in the final month before calving will lead to the cow depositing fat internally, including the birth canal, which causes calving problems.

Feeding to gain condition

With dry cows, this is straightforward. Isolate thin cows (below BCS 2.5) and feed high quality silage (70+DMD) on an ad-lib basis. With autumn-calving cows, remember that they will need extra energy for milk production so thin cows below BCS 2.5 should be fed ad lib 70+ DMD silage and 3kg of concentrates.

With average quality silage (68 DMD), increase concentrates to 3kg for calved cows. Dry cows eating 66 to 68DMD should be eating ad-lib silage plus 1kg of concentrates.

Feeding to lose condition

Fat cows can also have a negative effect on fertility. Reducing BCS should also be carried out over the same period as gaining BCS to avoid metabolic problems. Restrict silage intakes by 5kg to 10kg, depending on silage quality. Silage should only be restricted to cows if there is sufficient feed space available for all cows to feed at the same time.