19 November 1999

Heifers smooth entry into herd vital to profits

By Emma Penny

ENSURING heifers enter the herd on time – and in good health – is crucial for good profitability and better longevity.

For some producers, this requires a change in their approach to heifer rearing, believes ADAS dairy and food director Bridget Drew.

"We have to re-think the old philosophy that heifers dont produce anything, and so therefore receive the worst silage and feed. They are the herds future cows, and need to be managed with respect to ensure they have a long life," she told producers attending a Milk Development Council Focus Centre meeting at Harper Adams College, Newport, Shrops.

According to Dr Drew, the main objectives for heifer rearing should be to rear calves and heifers to a management plan, ensuring they achieve target and pregnancy rates, and minimising calving difficulties for a smooth entry into the herd.

Achieving good growth rates is essential to ensure heifers calve at two years old – the age advocated by Dr Drew – and that means setting and achieving targets (see table)

Ensuring good growth from birth to four months relies on ensuring calves receive adequate colostrum to start with. "Calves at ADAS Bridgets receive colostrum until 12-days-old. They then go on to either whole milk or milk substitute, depending on which is cheapest, so were currently using whole milk."

Up to three litres of whole milk is fed twice a day for 50 days, and calves receive concentrates ad-lib from seven-days-old to a maximum of 2kg/day.

From 50-56 days, calves are fed once a day. They are then weaned at 56 days providing they weigh at least 65kg, otherwise weaning is delayed.

However, weight gain from five to 10 months – the pre-puberty phase – is restricted as research shows that this results in better milk yields, said Dr Drew.

"I suggest growing them at not more than their mature weight expressed in grams rather than kg. For instance, a heifer which will weigh 650kg when mature shouldnt be grown at more than 650g/day."

This should help produce a well grown, but lean heifer which can be put onto a higher plan of nutrition before service to help boost conception rates, believes Dr Drew.

"On average, herds get about 50% of heifers pregnant to first service, but on some farms its as few as 30%. At Bridgets, wed be disappointed if we got only 70-75% pregnant to first service.

"Research shows that providing heifers with extra energy before service can boost conception rates. Ensure your heifers energy requirements are being met, and dont change their diet over the service period."

Avoid stressful situations

She also warned against changing the heifers environment and groups they are in, as well as avoiding transporting them and fluctuating temperatures. "Any stress can have a major effect on heifers – even including management during service."

When selecting bulls for use on heifers, she said that using an easy calving sire wasnt absolutely crucial. "Studies show that management has the greatest effect on calving difficulties, so my advice is to avoid choosing bulls which have very difficult calvings."

But managing heifers to avoid difficult calvings is crucial, she added. "Heifers want to be condition score 3-3.5 at calving. It is vital that they have adequate magnesium intake before calving as this has an effect on smooth muscle and if theres a shortage then the cervix wont dilate properly, and the uterus wont push properly."

At calving, there must be adequate supervision – but not too much. Environmental changes must also be avoided. "Dont bring a heifer in from the field to a calving box because you think she might have a bad calving as a change in environment can be detrimental.

"Be aware of when and how to assist, but know when to call in professional help, and ensure heifers calve in clean surroundings."

After calving, she advised waiting for five days before introducing heifers to the main herd. "By then she will have recovered from the trauma of calving, and forgotten about her calf so will be socially oriented again. Cows tend to be more socially active in the morning, so put heifers into the herd after evening milking to minimise bullying. Also ensure there are enough cubicles for the herd, and that heifers are trained to go into them."

&#8226 Milk producers attending MDC Focus Centre meetings at Harper Adams can choose the topic of their meeting on March 30. Focus Centre co-ordinator Brian Lindsay is keen to hear what producers are interested in, and can be contacted on (01952-820280). &#42

INTEGRATING HEIFERS

&#8226 Ensure heifers can compete.

&#8226 Wait five days post-calving.

&#8226 Add to herd in evening.

Growth targets for Holstein Friesian heifers

Age Liveweight gain/day (kg) Liveweight (kg)

Birth-4 months 0.90 150

5-10 months 0.65 280

11-13 months 0.80 350

14-17 months 0.90 460

18-22 months 0.90 595

23 months to calving 0.60 630