Farm Ireland

Saturday 16 December 2017

Keep cows 'happy' for increased fertility and immunity

Dr Dan Ryan

Spring breeding is now well under way on most farms, with just a small proportion of farmers who will wait until the second week of May to begin their breeding programmes. The weather has been ideal for grass growth and grazing cows throughout the last month.

Late calving cows are a major concern on many farms. There is little opportunity of getting these cows back in calf for spring 2012 if they calve in May and June. Many of the late calvers are kept indoors until they calve and are fed poor quality silage. This exacerbates the reproductive problems encountered in these late calvers.

Farmers need to give priority to the conservation of top- quality silage for the dry cows. Silage high in potassium can result in hypocalcaemia, uterine infections post-calving and an increased calving-to-pregnancy interval. Ensure slurry applications do not result in contaminated silage. Avoid cutting grass too tight which can result in soil being brought in and poor conservation of silage. Finally, avoid precision chop silage as long fibre is beneficial to rumen function.


Rumen acidosis is very stressful on cows. This frequently arises on farms where cows are grazing lush grass which is low in fibre. One of the first features of this condition is a drop in milk butterfat close to or below milk protein. This will impact negatively on reproductive performance. Cows which may have previously been cycling will stop cycling and pregnancy rate to services will drop dramatically.

This health problem needs to be avoided by ensuring sufficient fibre in the diet. Some farmers put out round bales of hay, while others buffer feed with silage, straw and low protein concentrate supplement.

Cost-efficient milk production may dictate a grass-only diet but beware that this may in fact be detrimental to longevity of the herd if acidosis is not prevented.

Avoid any form of stress on the cow during the breeding programme. Maximising reproductive performance during the critical 10-week period has to be your key priority. Golf ball grazing is a severe stressor. We have to get our priorities in order. Maintaining pasture quality by tight grazing may have a negative impact on the immune system of our cows.

Also Read

If your cows are stressed, immunity to disease is reduced. The efficiency of vaccination programmes for IBR, BVD, leptospirosis and salmonella is reduced when cows are stressed. Therefore, you can have outbreaks of these diseases in vaccinated herds where the protection given by the vaccination programme is reduced when cows are severely stressed.

The key here is to keep cows 'happy' while grazing grass as the primary input is the milk production system.

Compact calving with 90pc of the herd calving in a nine- to 10-week period (20pc replacement rate) can be achieved if you focus on avoiding all forms of stress during the critical breeding period.

If you haven't conducted a pre-breed scan, ensure you present cows not detected in heat and over two weeks calved when you reach the end of the fourth week of the breeding season.

Grass is an essential part of the diet, but it needs excellent management to ensure a 'happy cow'.

Dr Dan Ryan is a breeding management consultant and can be contacted at

Indo Farming