Dairy farming nutrition

Nutrition management systems

The range of topics covered within the nutrition section reflect the variety of management systems across Northern Ireland dairy farms. Within some systems grassland management will be a critical component. In high yielding herds issues such as dry cow management and concentrate feeding will be of greater importance.

Dry cow management

The period of time from drying-off through the dry period, pre-calving period, and calving is a time of transition. The management, nutrition, and health practices implemented during the transition period the cow’s lactation cycle will have profound effects on her productivity and profitability in the next lactation.

Transition cow management

The transition period is from when the cow is dried off to the calving period. Poor transition cow management can result in significant economic losses to the dairy farm business. Problems that can arise from poor management include udder oedema, milk fever, retained placenta (cleansings), displaced abomasum (stomach), laminitis (lameness), metritis (uterus infections), ketosis and fatty liver syndrome which all result in losses in profitability. Poor management may also result in increased calf mortality through difficult calvings and weak calves.

Successful dry cow management requires the farmer being able to recognise which disorders the dry cows are prone to, how to prevent them, and when necessary, how the farmer and veterinarian may treat them.

The dry period

Restoring body energy and nutrient reserves (body condition score), is more efficient if accomplished during late lactation rather than during the dry period. The dry period is necessary to allow the mammary gland to go through a normal period of repair and development and to ensure that the mammary cell numbers continue to multiply normally during early lactation. A short or absent dry period greatly reduces the number of secretory cells in the mammary gland and reduces milk lactation yields. Research has shown that cows dry for 60 days give approximately 125 KGs more milk the following lactation, compared to cows dry fewer than 40 days, which produce around 250 KGs less milk the following lactation.

Two considerations must be taken into account when deciding to dry off a cow:

• the gains that can be achieved in production and profits from extending the current lactation
• losses in production and profit in the following lactation resulting from fewer days dry.

When should the cow be dried off?

This will usually depend on the cow’s production and condition score, which may result in a dry period longer or shorter than 60 days. The production at which to dry off a cow generally is defined as

• the daily milk yield at which the return from milk sales is equal to the labour cost for milking plus the cost of additional feed above maintenance and pregnancy levels.

Several projects undertaken at ARINI/Hillsborough advise cows in their second or later lactations to be dried off for a minimum of six weeks. With regard to first lactation heifers, which continue to grow during the first lactation, an eight week dry period is advisable. This policy is being adopted with the cows and heifers in the herds at Greenmount Campus however, animals which are in particularly poor condition at drying off, (condition score <2.5, thin) are allowed an additional two weeks of a dry period, to allow them to gain body condition.

Drying-Off

If milk yield is above 10 litres approaching the drying off stage (seven weeks before calving), removal or reduction of the amount of feed offered is a useful tool to reduce the quantity of milk produced. Ideally, concentrate should be eliminated about one week before the dry-off day, which should reduce the cow’s milk production. Cows should not be milked partially (once a day) for several days as a means to dry off, because partial milking increases the incidence of mastitis flare-ups.

Immediately after the last milking disinfect all four teat ends with alcohol, then treat each teat individually with a dry-treatment antibiotic of suitable treatment length for the expected calving date and finally treat with a post-milking teat dip. In addition, animals should be observed daily for a week or until the mammary gland has begun to recess and is not secreting milk.

The mammary gland is very susceptible to new infection at this point in time. If animals are dried off during the indoor housing period, a clean and well-bedded environment is essential to help reduce the chance of udder infection. Indeed research has indicated that dairy cows are vulnerable to environmental mastitis in early lactation. This is the result of bacteria, which are inhabitants of the environment which multiply away from the cow’s udder for example, in dung and bedding. The dairy cow’s udder comes into contact with bacteria in the house and out doors during the dry period and consequently the udder becomes susceptible to infection, which may result in the dairy cow taking environmental mastitis shortly after calving.

Medication

Some vaccinations, parasite controls, vitamin-mineral boluses, and hoof trimming procedures should be performed during this main portion of the dry period. One advantage of using parasite controls during the dry period, is milk containing antibiotics cannot be milk into the milk tank since the cow is not milking. Cows at the drying off period at Greenmount Campus are treated with a mineral/vitamin bolus, a Rotavirus vaccine and they are dosed with a fluke drench. In addition, a routine examination of the cow’s feet is undertaken and any paring necessary and or treatments necessary applied.

Vaccination

Vaccines given at drying off offer several advantages:

• vaccination is done at a period of low stress and when milk production will not be affected
• vaccination at drying off should produce protective antibodies for calving time and early lactation
• vaccination during the dry period results in protective antibodies in colostrum for passive protection of the calf. Vaccine boosters for calf protection should be given three weeks prior to calving for maximum colostral antibodies

Vaccines for dry period

Respiratory viruses

• infectious Bovine Rhinotracheitis vaccine (IBR) used for prevention of respiratory diseases and abortion in cows
• bovine Viral Diarrhoea and Mucosal Disease vaccine (BVD and MD) – Prevention of diarrhoea and abortion in cows

Scour virus

• rotavirus - provides colostral protection for calf, use in calf with scour problems

Body condition score

In the dairy cow, body condition score is an indication of the amount of stored energy reserves held by the cow. Body condition score changes with stage of lactation. Fresh cows in peak lactation tend to be in a negative energy balance and therefore lose body condition. The ideal body condition score depends on stage of lactation.

One of the most critical points at the drying off period is the condition score of the dairy cow. Body condition is a method of evaluating fatness or thinness in cows according to a five-point scale, a scale of 0 denotes a very thin cow while 5 denotes an excessively fat cow. Condition score 3, is the most desirable for the cow at drying off and calving (Refer to Table 1).

Overconditioning, or fatness, (greater than condition score 3.5), may cause the dry cow to have difficulty at calving, be more susceptible to metabolic disorders and infections. Overconditioning usually begins during the last three to four months of lactation, when milk production has decreased, but concentrate and total nutrient intake have not been reduced accordingly. Another cause of overconditioning is prolonged dry periods or overfeeding during the dry period.

In contrast, undercondition, or thinness (less than condition 2.5), in the dry cow can frequently lower milk production, reduce the persistancy of the cow’s lactation and reduce protein content because of insufficient energy and protein reserves especially if the lactation diet is poor. Thin cows often do not show heat or concieve until they start to regain – or at least maintain bodyweight.

Altering body condition score of the dry cow

Ideally cows should be dried off in condition score 3 and maintained at this condition score until calving. Grouping and separate diets for dry cows is critical, but facilities are often lacking for separate feeding groups. In an ideal farm situation, cows at drying off should be grouped as fat, average or thin. Cows which are fat, should be offered a restricted food intake, this can be achieved by offering the animals straw or restricting their silage intake or grass intake. In contrast, cows which are thin should be offered high quality silage/grass plus a small amount of concentrate to gain body condition score. Remember, condition score of the dairy cow can be controlled by food and energy intake.

Dry Period Nutrition

Did you know that:

• 60 to 65 percent of the calf growth is in the last 60 days of gestation (before calf is born)
• the protein requirements of the developing calf increases in the last 60 days of gestation. Consequently, this is reason why dry cows are offered a protein concentrate containing a high DUP content.
• even though body condition doesn’t change, the cow should gain weight (as the calf grows inside of the cow)
• dry matter intake (DMI) tends to decrease during the latter part of the dry period due to increase in the calf size on reduction in rumen size
• due to this change in DMI, the diet nutrient density must be adjusted in the last 2 weeks to maintain nutrient intake. If this is not done, then actual quantities of nutrient intake will be decreased.
• expected daily dry matter intakes –
• early dry period = 1.9 to 2.1 percent of body weight

Close up dry period (last two to three weeks) = 1.6 to 1.8 percent of bodyweight.

There is a relationship between precalving and postcalving dry matter intake. Cows with poor intake precalving tend to have lower intakes postcalving.

Management during the dry period

Dry period up to four weeks before calving

This is a time when the body condition of the cows should dictate the amount/quantity of feed or energy being fed. Ideally cows should have a condition score of 3. It is important to feed bulky forage to keep the rumen expanded and working. As already mentioned, if cows are to fat or thin their energy or food intake in the diet should be altered to allow them to gain or maintain body condition score.

Transition diet during the last four weeks of the dry period

During the last four weeks of the dry period, many changes are needed in the nutrition and management of the dry cow. It is important that the rumen bugs and rumen papillae in these cows are adapted to the feedstuffs being fed to milking cows.

Much of the early dry cow’s diet has consisted of forage. However as the cow approaches calving the cow’s dry matter intake declines. Therefore, diet nutrient density needs to be increased due to the lower DMI. Supplementation during this stage is required to meet the dry cow’s energy needs due to the rapidly growing calf. Usually dairy cows in the Greenmount Campus herd are offered 1 – 2kg of a precalver feed containing 250 to 300 g digestible undegradable protein (DUP) freshweight/day. Sources of DUP include protected soya,or prairie meal.

At this stage of the gestation cycle, the developing calf has a large nutrient demand for protein,for this reason cows are offered a high protein concentrate daily."

Transition feeding – one week before calving

At Greenmount Campus, cows calving during the housing period are moved to a straw bedded court 5 – 7 days before calving. During this stage, dairy cows are fed the same concentrates and forages as the milking cows. This offers the opportunity to adapt the cow’s rumen to the higher levels of concentrate feeding after calving by introducing up to 2 KGs of concentrate before calving. Feeding the same diet before calving that is fed after calving aids the rumen adaptation and transition after calving and helps to reduce the stress of calving.

Summary

In a good dairy management programme, dry cows must receive the same level of care as the milk producing cows. At drying off, good hygienic husbandry to required to prevent the incidence of mastitis. Ideally cows should have a condition score of 3 at drying off. However, condition score gain or loss can be controlled by food or energy intake. Forages containing a high fibre content should be fed in the diet to keep the rumen expanded and working. In the last two weeks before calving, the cow’s dry matter intake declines, therefore it is important to supplement the cow’s diet with a concentrate to ensure the cow’s nutrient intake is maintained. Cows should be offered the same diet (silage and concentrate) as the cows in the milking herd, to allow the rumen bugs and papillae to adapt to the change of diet whenever the dairy cow calves down and commences lactation.

The main objective of the dairy farmer is to produce milk from the cow as profitability as possible. Management of the dairy cow is an important aspect of the cow’s lactation, which has a major impact on the health, efficiency and profitability of the dairy cow.

More useful links

• Planning winter feeding programmes
• Assessing the dairy cows winter diet
• Winter feeding of ruminant livestock