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1008 PD: Manage for nutrition and welfare of the dairy cow

Marina A.G. von Keyserlingk and Daniel M. Weary Published on 30 June 2008

One of the most important challenges that any animal faces is ensuring its daily food supply.

In intensive dairy cattle production, cows are completely reliant on our ability and knowledge to provide them with food that supports growth, productivity, health and welfare. Problems with access to appropriate food and water pose some of the most severe threats to the welfare of dairy cattle.

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Nutrition during the first weeks of life is particularly important. Feeding regimes used on most dairy farms’ calves require that calves be separated from their mothers within a few hours of birth and then fed milk by bucket or bottle until 4 to 10 weeks old. This phase of management creates many serious welfare issues, including inadequate colostrum intake and underfeeding of the milk-fed calves. The importance of adequate colostrum intake has been well recognized for decades, but still more than 40 percent of calves fail to receive enough colostrum to provide the immunological protection from disease. This failure to protect calves and resulting high rates of disease and mortality is likely the most serious welfare concern facing the dairy industry, and also one that is easiest to rectify. Every calf needs to receive at least 4 quarts of high- quality colostrum (50 milligrams per milliliter of immunoglobulin G) within 12 hours of birth, ideally within the first two hours. The job of the producer and professionals working in this industry is to ensure that this happens – every time!

For many outside of the dairy industry, the early separation of the cow and calf is also a concern, but this concern can also be quieted with improved nutrition. Calves bawl in the hours after separation, but only if fed the low quantities of colostrum that they typically receive (about 10 percent of bodyweight per day). If calves are allowed to consume more colostrum within this first 24 hours after birth, they rarely vocalize, showing that improved colostrum feeding keeps calves healthier and happier!

Underfeeding is a concern throughout the milk-feeding period. Recent research has shown that calves prefer much higher milk allowances than they are typically provided – calves consume about 10 quarts of milk a day when allowed free access. Providing extra milk provides for improved growth, health and more efficient weight gains. This milk can be provided by bucket, but there are advantages of using teat feeding systems that allow calves to express natural sucking behaviors; calves fed this way are much less likely to suck on each other, facilitating the use of more efficient group-housing systems.

Transitioning animals from one diet to another is an age-old nutrition and welfare problem, with one of the key examples being weaning of calves from milk to solid feed. In nature, cows slowly restrict milk availability and calves stop nursing at about 8 to 12 months old. On most dairy farms, this transition is abrupt and occurs at 1 to 2 months old, resulting in high rates of vocalizations, increased activity and a growth check. The effects of weaning can be reduced if the calf is eating sufficient solids before milk is withdrawn. Calves typically consume little solid food before 3 weeks old, likely due to their immature digestive system. Solid intakes are higher if calves are underfed milk, but this causes other problems described above. Gradually reducing the milk ration over a number of days results in a rapid increase in solid intakes, reducing the distress response and growth check at weaning.

Weaning from milk to calf starter is simply the first of many dietary transitions that cows experience in most production systems, but little research has addressed how best to wean cows from one diet to another. The “transition period” in the weeks around calving is when cows are most likely to become sick. Metabolic diseases such as ketosis and clinical hypocalcemia (milk fever) are common, and these arise directly from inadequate or inappropriate nutrition. Susceptibility to certain infectious diseases also peaks at this time. The high prevalence of infectious disease during transition may also be due to inadequate nutrition, as these diseases often occur as a secondary illness to metabolic disease. Inadequate nutrition may also contribute to the well-documented depression of the immune system that occurs around calving time. The health status of the transition cow is a major welfare issue for dairy production and continued research is needed.

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Cows face another dietary transition at dry-off. Unfortunately, some producers prevent or limit access to food or water as a means of drying off cows. We strongly discourage these methods as they severely affect cow welfare by causing prolonged hunger and thirst. A much better technique is to continue to provide ad libitum access to food, but provide a feed with reduced energy density and digestibility, such as eliminating the concentrate portion of a TMR or offering only low-quality forage. Even this will cause some distress, but this response can be reduced by gradually changing the diet, much as described earlier for milk weaning.

Indoor-housed lactating cows are generally fed a mix of concentrates and forage. These can be provided separately, which is predominant in Europe, or mixed together in a total mixed ration (TMR), which is the predominant method in North America. Feeding concentrates increases the risk of welfare problems associated with acidosis or sub-acute ruminal acidosis (SARA). SARA is considered by some to be one of the major threats to the welfare of lactating dairy cows and may affect 20 percent of lactating dairy cattle in early to mid-lactation. Unfortunately, accurate diagnosis is difficult, making the development of practical and effective assessment methods a priority for new research.

Access to pasture can provide welfare benefits for dairy cattle; for example, this allows cows freedom of movement and the ability to perform natural grazing behavior. However, risks to animal welfare arise when either the availability or quality of the grass is low. Even brief periods of feed deprivation likely cause hunger in cows. Longer-term effects of inadequate food intake include lost bodyweight and body condition, and poor body condition can increase the risk of disease such as milk fever. If sufficient feed is not available for cattle, there may be benefits associated with leaving cows on pasture, as grazing behavior provide a natural outlet for the cows and may help reduce sensations of hunger relative to limit-feeding indoors.

Having access to a sufficient quantity of good quality water is essential for the health and welfare of cattle. Water forms the largest component of an animal’s body and is an essential nutrient required for all biological functions including temperature regulation, digestion, fecal development and milk production. Almost every dairy farmer is aware of these needs, and lactating cows normally have good access to water. Unfortunately, many milk-fed calves are still not provided with free access to water, causing thirst, slowing the intake of solid feed and increasing the risk of mortality associated with calf scours.

There has been great progress in the field of dairy cattle nutrition over the years. We are now better able to estimate the dietary needs of dairy cattle and meet these needs through carefully formulated diets. In many cases, improvements to cattle welfare can be achieved by simply getting these good practices onto farms. For example, improving colostrum feeding practices and the availability of water for calves will save calf lives, improve farm profitability and much improve calf welfare. In other cases, new nutritional and welfare research is changing our views of previously accepted practices; it now seems clear that underfeeding of the milk-fed calf reduces the growth, heath and welfare of the young calf.

Research on behavior and welfare is now broadening our understanding of cattle nutrition; the question is no longer just what do they eat, but how do they eat it, and this improved understanding of behavior is helping to avoid practical problems like cross-sucking among group-housed calves and competition at the feedbunk among adult cows. PD

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Marina A.G. von Keyserlingk and Daniel M. Weary for Progressive Dairyman

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