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The calf is born without an immune defence system. In time, this defence develops, but until then the antibodies from a special milk, colostrum, function as the defence system. The antibodies from colostrum protect the calf against disease until it has developed antibodies of its own.
The colostrum period is 5.7 days. During this time calves should be kept in dry, bright, and draft-free single boxes. The first drink of colostrum, 1.2 litres, must be given during the first three hours of the calf.s life. From then on it should be fed twice a day, and the daily quantity should be increased by about 1 litre per day. This means that the calf.s ration is 6.8 litres at the end of the colostrum period.
At birth, the calf.s digestion system is not yet developed. Of the four compartments, only the abomasum functions The calf is therefore dependent on milk as a nutrient source. From its third week, the calf should be fed solid feed, i.e. concentrates, hay and silage. The calf should also have access to clean water 24 hours a day.
As soon as the calf is eating regularly, the milk ration can gradually be reduced. If the milk ration is reduced slowly, and solid feeds are fed together with clean water, the calf will steadily develop into a ruminant.
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Calf diarrhoea is an ever-present threat to baby calves. A good programme of adequate nutrition and sanitation, and a comprehensive herd health programme, can minimize the incidence of diarrhoea and losses. |
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Calf diarrhoea causes more financial
damage to cow calf producers than any other disease-related problem they encounter.
In the USA, approximately 10% of all new born calves get diarrhoea, usually in the first 7.10 days of life. Up to 30% of those that survive never reach their potential. Many diarrhoea cases can be directly related to poor colostrum intake by the newborn calf.
The quality of colostrum intake has a major impact not only on diarrhoea, but also many other calf diseases. If a calf gets diarrhoea it should be immediately treated to stop dehydration, acidosis and electrolyte loss.
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A calf.s daily ration should consist of 2 up to 6.8 litres of colostrum;
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Several small meals are preferable. This is due to the small volume of the calf’s stomach (about 2 litres) and it will help the coagulation of milk in the abomasum;
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The temperature of sweet milk should be 38 °C. Sour milk can be fed at 15.20 °C; and
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The milk must be free of lumps and always freshly prepared.
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The calf should drink, in a natural angle, from a teat.
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The calf should drink minor rations, suited to the small abomasum volume.
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The milk should be served correctly tempered. Otherwise, there are major risks for diarrhoea.
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The milk ration should be reduced slowly over time. The calf should be eating at least 1 kg concentrates before the milk ration is reduced.
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The heifer can be the most neglected animal in the herd. Feeding heifers highquality feedstuffs is important since they are tomorrow.s dairy cows. The goal is for the heifer to be a milk producing cow within 24 months. To achieve this she should gain, on average, about 700 g in body weight per day. During puberty (between the age of 6.10 months), the heifer should be carefully fed. At this stage there is a risk that the heifer will develop too much fat tissue in her udder if she is reared too rapidly. To prevent this, the energy ratio should be restricted (see picture below).
Heifers do well on highly-digestible pasture if minerals are added. However, they do not grow well only on straw, late cut hay or late cut silage.
General rules:
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Feed plenty of fibre => medium growth, and a good dairy cow can develop;
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Suitable feedstuffs - hay, legume and grass silage; and
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Unsuitable feedstuffs - corn silage, wet corn and wheat (too much starch).
The energy ratio should be decreased a little during puberty.
The dry period takes place about 8 weeks before calving. Although milk is not produced, it is a very important period. Just like the marathon runner, the cow needs to be in perfect shape for lactation. Despite this, dry cows are often badly fed; in some cases overfed, and in other cases barely fed enough to keep them alive. For a high yielding cow, the dry period is a rest and repair period. Damages in the rumen can be repaired and the cow can prepare for the new lactation period. It is important that the cow is not too fat before calving.
The dry period can be divided into two sub-periods according to the task:
1. Resting period (3.5 weeks); and
2. Transition period (2.3 weeks).
1. Resting period
The energy demand during this period is low. Feed intake should only cover maintenance and pregnancy. Body condition should be watched closely. Thin cows should be allowed to fatten, while fat cows should be fed a restricted ration. Suitable feedstuffs are large amounts of long roughages (hay and ad-lib straw).
2. Transition period
The transition period starts about 2.3 weeks before calving. Feed should gradually contain more nutrients. This can be achieved by increasing the concentrates ration. The purpose of transition is to make a smooth change from low nutrition feed to lactation feed with a high nutritional content, thereby improving
health and production. Research shows that a proper transition period can result in an improvement of 1 000 kg milk per lactation. The transition period involves:
A. The rumen micro-organisms adapting from a low nutritional level to a new, rich diet;
B. The papilles that absorb nutrients in the rumen shrinking during the resting period because of the low-nutrition feedstuff. The rumen needs time to adapt to the more intensive feeding during lactation. Increased nutrition enlarges the papilles and makes them more effective in absorbing nutrients;
C. The level of feeding should not be too high during the transition period, since this can lead to health problems; and
D. In order to avoid disease there should be free access to good quality forage so that the rumen is well filled. The animals should also be kept where they are going to be milked after parturition.
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Feeding around calving
Feeding around calving is difficult. The cow is in a negative energy balance and must mobilise body fat to produce milk. It is therefore necessary to increase dry matter intake as fast as possible after calving without upsetting the rumen system.
This increase is necessary to minimise the loss of body fat and restore the energy balance. If a cow looses too much body condition it may result in reproduction problems. It is also vital in order to balance the vitamin and mineral intakes and to avoid deficiencies and disruptions in production.
Disturbances around calving
Paresis
Paresis is a paralysis which can occur one week before, to one week after, calving. The cow simply becomes paralysed due to blood calcium levels below the required level.
Paresis can be prevented by feeding the cow so that she does not get too fat around calving.
Laminitis
Laminitis is a hoof inflammation that particularly strikes first-lactating cows. The hoof pain caused by this disease decreases milk production. Rapid changes in feedstuffs and acidotic rations (with a high level of starch) all contribute to increased laminitis. Spreading the concentrate ration over the day will help keep the pH level in the cow.s rumen stable.
Feeding during the first period after calving
Characteristics of the weeks after calving:
- Insufficient feed consumption;
- Greatly increased milk production; and
- Great risk for nutritional shortage, for instance of protein and energy.
During this period it is difficult to supply the cow with enough nutrients. Instead of increasing feed consumption, which is difficult during the period after calving, the concentration of nutrients can be increased. The low feed intake also results in low production of the microbial protein produced in the rumen. To meet the protein requirement, the amount of undegradable protein should be increased.
The first lactation months
Feeding during the first 2.3 lactation months has the aim of supplying the cow with enough energy. This is achieved by a high feed intake. To help the cow reach this high energy intake, some general conditions have to be established:
- Healthy cow climate, high levels of comfort;
- Feedstuffs of a high hygienic quality; and
- Free access to clean water.
There are also some general needs regarding feedstuffs. The most basic ones are:
- High energy roughage -- This not only provides a higher concentration, but also the possibility of higher feed intake. Wilted silage is recommended due to its higher consumptionability.
- High-energy concentrates -- Concentrates should contain a lot of energy and should be chosen with care, based on structure and primary product. Fat is a good energy feedstuff in this phase of the lactation. The fat content should not exceed 5.7% of the total dry matter content.
Disturbances in early lactation
Rumen acidosis
Rumen acidosis occurs when the cow is fed excessive amounts of grain. Too much acid accumulates in the rumen, causing indigestion and off-feed (the cow does not eat). A cow that is affected by moderate rumen acidosis milks poorly and looses weight.
This disturbance may be prevented by:
1. Feeding concentrates during a steam-up period before calving;
2. Increasing grain slowly in early lactation; and
3. Correct the feeding of grain, i.e. providing many minor rations and feeding roughage before grain.
Ketosis
Ketosis is a metabolic disturbance that strikes high yielding cows between 10 days to 6 weeks after calving. The disease occurs when the energy output for producing milk is greater than the energy input from feed. The cow starts to utilise body fat to compensate for the loss and fulfil the demand. Toxic byproducts are the result of large-scale fat decomposition is t.
This disturbance may be prevented by:
1. Keeping the cows in proper body condition;
2. A careful transition period;
3. Encouraging maximum energy intake after calving: and
4. Feeding concentrates with high fiber content.
Displaced abomasums
Cows that are incorrectly fed in the first two lactation months may suffer displaced abomasums. The abomasum is filled with gases and expands like a balloon at the side of the rumen. A cow affected by the disease behaves like a ketosis cow. This means that she has a low feed consumption and her behaviour is dull.
This disturbance may be prevented by:
1. Providing the cow with free access to high quality and long fibre forage in the transition period; and
2. Avoiding fine chopped silage, i.e. less than 1/2 cm.
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Mid lactation takes place 4.7 months after calving. Characteristic for this period is the risk of overfeeding cows. The energy demand for milk production decreases and the cow becomes more likely to increase body fat. The risk for fat cows is therefore immediate.
Goals when feeding in mid lactation
- Maintaining high production with low feed costs.
- Watch for cows putting on fat.
Means
- Feed according to production.
- Decrease concentrates gradually.
- TMR with lower energy concentration.
Late lactation takes place during the last months before the dry period. The main concern during late lactation is to achieve the body condition of the cow that she will have at calving. Therefore, overfeeding or underfeeding in relation to milk production is sometimes necessary.
How to handle cows that are too fat:
- Decrease concentrate and forage quantity;
- Change to low energy roughage; and
- If milk yield low, an earlier dry-off than planned.
How to handle cows that are too thin:
- Increase the quantity of concentrated forage;
- Look for parasites or other health problems; and
- Dry off the cow 2 months before calving.
To dry off cows:
- Decrease feed suddenly, e.g. only provide straw and water.
- Stop milking.
- If possible, remove from milking cows.
- Check udder during first week.
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