Farm Ireland

Wednesday 21 March 2018

Semi-starvation is not acceptable

Dr Dan Ryan

Spring-calving programmes are now resulting in very busy schedules on farms throughout Ireland. The weather has been extremely mild and grass growth rates have left an excellent carpet of grass on farms. However, the inordinately high rainfall has left ground saturated.

Some farmers have put freshly calved cows out on grass day and night, with a concentrate allowance of 2kg/day.

This system mainly lends itself short-term to low-cost milk production, but what are the long-term implications?

There are very few farms visited at present that will tolerate the soil damage created by strip-grazing cows on early spring grass. Grass dry matters are currently low. It is impossible to meet the demands for maintenance and production from grazed grass without shedding excessive weight post-calving.

The overall target for bodyweight loss should not exceed 0.5kg/day for the first six weeks post-calving. This is equivalent to 0.5 body condition score (BCS). Cows that loose greater than 0.5 BCS have poorer rates of uterine involution and a slower return to normal heat cycles.

In the New Zealand grass-based milk production systems, cows may lose more weight post-calving. With a flush of grass supply, there is compensatory gain and cows return to normal heat cycles. Cows failing to start to cycle are induced using PRIDs or CIDRs.

This system of semi-starvation is not acceptable on animal welfare grounds. It is essential that the cows' feed requirements for energy and trace elements are met to allow 0.5 BCS loss in the period of negative energy balance.

The genetic potential of your cows for milk production will dictate the concentrate supplementation required in the period of negative energy balance. Trace-element supplementation has to be based on the differential between that supplied in the diet and that required for maintenance and production.

Also Read

Remember that trace-element supply will have to be double in a ration when reduced from 8kg to 4kg and doubled again when reduced to 2kg. Trace elements are essential to metabolic function. The health implications caused by deficiency far outweigh the cost of trace elements.

As the number of freshly calved cows increases, you should also ensure that you have sufficient feed space for all cows to feed at one time and sufficient cubicle spaces for cows to lie down. First calvers will be the first to suffer where housing space is tight.

Bullying will result in the younger cows losing excessive BCS and a delayed return to normal heat cycles.

An adequate supply of clean water in multiple locations in the housing environment is essential. This should not be overlooked as inadequate water supply and quality are major stress factors on the cow.

A fresh supply of maize or silage has to be kept at the feed face at all times. Moist forages will heat rapidly in the current mild weather. This will create adverse cow health resulting in poor reproductive performance in two months' time.

Ensure adequate airflow by increasing ventilation, as the risk of pneumonia and IBR outbreaks increase in tightly stocked houses, especially during this type of mild weather.

The dry cows require attention at this time, too. Ensure that adequate, fresh silage with trace elements are fed on a daily basis. In-calf heifers also require mineral supplementation for eight weeks prior to calving. The primary objective with dry cow management is a fit cow post-calving that completes uterine involution within three weeks.

So to reiterate: feed freshly calved cows on the basis that body condition score loss in the first six weeks post-calving does not exceed 0.5.

The genetic potential of your cows for milk production has to be borne in mind when supplementing grazed grass or forages with concentrate.

Dr Dan Ryan is a breeding management consultant at

Indo Farming