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How to improve the performance of dairy calves

Johanna Marsden BVSc MRCVS, Molecare Farm Vets

Calves are an important investment for the future, giving them the best start in life will see better returns in milk production, health status and fertility. Improving their performance is a multifactorial approach from the dam’s condition and health status to the calf’s colostrum management, housing and nutrition. It is a huge topic and this article will highlight just some of the main areas of concern.

New-born calves are the most susceptible to disease on farm and therefore the environment they are born into is very important. Hygiene is key and the calving yard or pens needs to be kept clean and disinfected when possible. Johne’s positive cows should calve separately from the rest of herd and their calves treated according to your Johne’s control plan.

Colostrum is crucial in developing the calf’s immune system. It gives them the antibodies they need to help protect them from infections and diseases on farm. The protective antibodies in colostrum are produced from the cow having been exposed to viruses and bacteria on the farm. Knowing what diseases are present your farm, for example BVD, and ensuring the cattle are up to date with their vaccines will provide protection to calves during the pregnancy and an increased concentration of antibodies in the colostrum.

The cow’s condition will also affect the quantity and quality of the colostrum. Cows with a low body condition score (<2) will produce less colostrum and those with a high body condition (>4) will often have colostrum with lower antibody concentration. Therefore, keeping a consistent condition through the dry period, between 2.5 – 3, is optimal for colostrum production and the cow’s health.

Here are the 6 Q’s to follow for colostrum management:

  • Quality – the level of maternal antibodies (IgG) should be greater than 50g/L. This can be tested easily with a Brix Refractometer, with any colostrum registering as less than 22% deemed inadequate.
  • Quantity – they should receive 3L or 10% of their body weight in their first feed.
  • Quickly – the first feed should be fed within one to two hours of birth, with the second feed of the same volume before the calf is 12 hours old.
  • sQueaky clean – if the colostrum is heavily contaminated with bacteria it will compromise the calf’s immune system due to a reduction in antibody uptake.
  • Quantifying – total proteins (TP) can be monitored to ensure they have received an adequate amount of good quality colostrum. The blood tested for the TP should be over 55g/L.
  •  Quietly – they should be fed in a stress-free manor. Stressed calves will have a lower absorption of    antibodies.

It is also important that stocking densities are carefully monitored, as appropriate housing with low stocking densities, as well as good nutrition will ensure calves are healthy and strong, with the risk of conditions such as scour and pneumonia being reduced.

The problem with high stocking densities is that it can increase calf stress levels as there will be an increase in food and water competition as well as a reduction in lying and loafing space. Disease also spreads much more quickly through immune supressed animals and combined with close contact will affect the whole group. During the first week of life calves should be kept in small groups of no larger than 6, and in order to comply with welfare standards calves in individual hutches must have nose to nose contact with at least one other calf. Certain milk contracts will not allow the use of single hutches for rearing calves. Once over a week old, depending on the calves’ progress, they can be in groups of up to 12. Each calf needs a minimum of 1.5m² floor space, however, it is recommended for calves up to 3 months old should have 3m².

Calves spend up to 80% of their time lying down and loose most of their heat through the floor, ensuring they are well bedded (at least 15cm deep straw) and not lying on direct concrete will decrease energy loss. Bedding should be kept clean and dry through good drainage and regular bedding up. Solid walls between the pens will reduce contamination spread between groups and in-between calf batches pens should be thoroughly cleaned and disinfected using a disinfectant that targets both Coccidia and Cryptosporidium, which will decrease pathogen load on the next group of younger naive animals. If you have any questions or would like any advice on the appropriate products to use for cleaning, please speak to your local veterinary team.

Good ventilation is very important in calf housing as it will reduce the risk of pneumonia outbreaks and also increase calf comfort. A continuous flow of fresh air into the house, as well as an outlet for stale air is crucial, as without this dust, ammonia and other respiratory pathogens will circulate. High ammonia levels and dust circulating within a house can damage the cells that line the trachea and lungs, which can subsequently lead to an increased risk of respiratory disease and permanent lung damage. To assess ventilation, smoke bombs can be set off from ground level and you can watch the direction of flow within the building. If you are concerned about your ventilation system, or would like some additional advice on ways in which it can be improved, speak to your vet who will be able to advise on how to make the most out of your current buildings.

Any calves that are showing signs of disease scouring should be isolated from the rest of group and treated accordingly. In the case of scours they should be isolated for 1 week extra after recovery as animals will continue to shed the pathogens into the environment for several days. Your vet can investigate the potential cause of disease and advise on preventative measures that can be put in place, for example vaccinating calves for pneumonia or preventative cocci treatment.

Vaccination programmes that are aimed at preventing the introduction of respiratory diseases can also support the calf in early life, helping to reduce the risk of diseases such as pneumonia. Protecting youngstock from diseases such as pneumonia will also help to keep calves on track of their target growth rates by reducing lung damage and improve their overall health and welfare.

Nutrition and feeding also plays an important role in the overall health, wellbeing and performance of calves. Pre-weaning calves need to be fed a good quality milk replacer in the right quantities in order to achieve a daily live weight gain (DLWG) of at least 0.7kg. They can be fed a skim or whey-based milk replacer, but it should contain 20-26% crude protein and 18-20% fat. Each calf should receive at least 6L of milk at a concentration of 150g/L a day, split between a minimum of 2 feeds in a 24 hour period.  

Rumen development in calves is stimulated by forage, concentrates and water and starts functioning properly between 5-28 days of age. Forage maintains a healthy rumen lining and helps with rumen muscle development, whereas concentrates and water provide nutrients to the rumen microbes helping them to multiply. Fresh water and a starter concentrate should be available from day 1 and good quality forage can be given from day 3 of life.

Weighing calves monthly will help you to keep the calves on track. If they are growing less than 0.7 kg/day pre-weaning and 0.8kg/day post-weaning it will signal that there may be underlying issues that are not readily seen. Achieving target weights in calves will result in a higher milk yield during their 1st lactation compared to later maturing heifers.

If you would like to learn more about how you can improve the performance of your dairy calves, get in touch with us by calling 01392 872934 or email [email protected]

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