26 May 1995

Care at calving can boost later milking

Dry cow management is crucial to subsequent lactations, as this special focus explains. Here Sue Rider details the dry cow management regime at ADASBridgets Research Centre

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Dry cow management has encouraged better stockmanship to such an extent on one Dorset dairy farm that 97% of stock calve unassisted, total calf mortality is under 3% and there has been no serious case of milk fever in over 1500 calvings.

Dry cow enthusiast and FW Farmer Focus contributor Mike Lemmey believes management during this eight-week "resting" stage is critical to the cows lactation cycle.

He runs a simple dry cow regime for his 100 cows at Liberty Farm, Halstock, Yeovil and cites numerous benefits (see Stock & Sales Update, p33).

He also offers some useful pointers on dry cow management.

&#8226 Milk Protein. Feeding small amounts of undegradable protein in the last 3-4 weeks of the dry period boosts milk protein and cow fertility in the next lactation. The source of the protein supplement is critical. It should be digestible undegradable protein (DUP).

&#8226 Fertility. Heifers offered extra DUP needed only half the services a pregnancy as those offered no DUP supplement. Condition the rumen to some of milkers ration in the last two weeks before calving and keep it full with palatable roughage (hay, straw, or silage). This will avoid rumen stress which effects eggs produced and hence fertility.

&#8226 Condition score. Dry cows off at condition score 2.5-3 and maintain this until calving. Fat cows are bad news (retained cleansings, "whites" which affect fertility, fatty livers, low dry matter intakes, metabolic disorders),.

&#8226 It is important to run two dry cow groups – an eight-to-four-week group and a close to calving group. Limit grass intake and get the rumen working with roughage and special dry cow feed.

&#8226 Minerals. Feed the correct minerals, vitamins, and trace elements in the last three weeks of the dry period. Magnesium is the key dry cow mineral. (It triggers calcium release at calving. Without it calcium release is delayed 48-hours and the cow gets milk fever.)

MANAGE dairy cows well in the three weeks either side of calving and the reward is improved performance in the next lactation, says ADAS Bridgets herd manager, Robert Bull.

Mr Bull, who has joined the team at Martyr Worthy, Winchester, Hants, from J G Quicke and Partners Saintcyres herd in Devon, is a stickler for good dry cow management.

It starts eight weeks before expected calving date when cows are dried off and tubed with a long-acting dry cow antibiotic.

Cows are dried off at condition score 3 to 3.5. Those 8-3 weeks from calving are kept in one group in which the aim is to maintain a stable body weight. That means stocking tightly at over 10/ha (4/acre).

Mr Bull maintains it is vital to restrict grass intake during the dry period, as calcium in the fresh herbage prevents the cow mobilising the mineral at calving, with milk fever the result.

The all-important dry cow management stage starts three weeks before calving. Cows are still stocked tightly but it is time to start acclimatising the rumen to the milking ration, says Mr Bull.

Cows are offered small quantities of the feeds that will be in the lactation ration. The aim is to improve the quality of the diet, putting the cow on a rising plane of nutrition to meet the increasing demands of her calf. It is also essential that the animal does not lose condition. Rather she should increase bodyweight by 0.5kg a head a day.

He advises increasing the dry matter and bulk of the diet by feeding lots of dry, bulky forages such as straw, hay and silages. "We are trying to maximise intake," says Mr Bull, who targets a daily intake of 12kg DM a cow.

High intakes help maintain rumen flow rates and stimulate rumen size. This is important, for the rumen is its smallest at calving. Keeping it as large as possible while she is dry gives her a head start in early lactation. "Try to help the cow maximise intakes as quickly as possible after calving so that she runs into negative energy balance for as short a time as possible."

Cows are offered (fresh weight) 6.5kg straw, 5kg grass silage, 6.5kg maize silage, 4.5kg brewers grains and 2kg of 48% Brazilian soya. This ration only need be fed for three weeks, stresses Mr Bull.

He says that by maintaining rumen flow rates with high intakes of bulky forage, less soya may be degraded in the rumen, so it can then contribute to the supply of by-pass protein (digestible undegradable protein (DUP)) for use by the cow. "The quantity of DUP appears to be more important than the source," he says.

During the three-week stage cows are also offered 100g a head a day of in-feed magnesium chloride (which can also be metered into the water supply) and a reverse ratio mineral with no calcium and which is low in phosphorus.

Mr Bull ensures that for the three weeks pre-calving and during early lactation 1g a day of vitamin E is offered, especially to high yielders and when the milking ration contains large quantities of maize silage or cereals.

"Vitamin E is essential to renew the uterine lining, and supplementation speeds its repair after calving, encouraging healthy breeding systems," he says. "The vitamin E also has an antioxidant effect in high forage diets."

For 4-5 days after calving cows are housed in a special group and offered a medium energy diet.

"At this stage production is out-running intake, so providing a medium energy dense diet helps to stimulate feed intake. It also assists rumen function minimising digestive upsets."

Ideally Mr Bull likes to calve cows at condition score 3.5. That provides an extra condition score (equivalent to 50-70kg of body weight) as a buffer to mobilise while intake struggles to meet production needs in early lactation.

All dry cows are checked twice a day and those in the close-to-calving group are observed every three hours.

&#8226 ADAS Elite herd sponsors, including FARMERS WEEKLY, will be the first to hear the results of a dry cow study at their July open day. It has compared two sources of DUP fed at two levels.

A further study with the Elite cows takes the research one step further by asking whether it is energy or protein that is responsible for the protein response. Both diets supply identical energy. Control cows are being offered the DUP which produced the best results in the first trial, treatment cows a higher level of DUP from the same source.

Cows will be grouped according to their protein reserves.


Management three weeks to

calving

&#8226 Dry, bulky forages to increase intake and condition rumen.

&#8226 Quantity of DUP, not source, important.

&#8226 100g a head a day of magnesium chloride.

&#8226 Offer low phosphorus, nil calcium mineral and 1g a head a day of Vitamin E.

ADAS Bridgets herd manager Robert Bull believes the quantity of DUP (digestible undegradable protein) to be more important than the source.