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Green Acres Update - 4 January 2022

Key management tips Calf rearing | Vaccination | Calf housing

Key management tips

  • Ensure calf rearing facilities are in order before the arrival of calves.
  • Contact you calf supplier to assess the availability of calves and the expected arrival date.
  • Source calves from trusted and local sources to reduce the risk of any disease setbacks and to limit the amount of time calves spend in transit.
  • Have milk replacer, concentrates, electrolytes and feeding equipment to hand before the arrival of calves.
  • Ensure calf pens are clean and are adequately bedded with straw before the arrival of calves.
  • Avoid mixing calves from various source herds if possible to limit the potential spread of disease between calves from different herds.
  • Discuss a vaccination programme with your vet and Teagasc advisor to ensure that calf health is protected during the weaning period.

Calf rearing

One of the many key elements to the success of a calf-to-beef system is ensuring animals are adequately fed. It is critical that calves double their birth weight by eight weeks of age (e.g. – 40kg to 80kg in 56 days). To realise this, animals must gain 700-800g/day during the milk feeding stage. This can be achieved with inputs of ~25kg of milk replacer and 120kg of concentrates.

Milk replacers of various specifications are available on the market, but a number of nutritional value boxes must be ticked. For calves destined for dairy-beef production, a protein content of >20% is necessary, the oil component must be 18-20%, while ash and fibre levels of no greater than 8% and 0.15%, respectively, are desired. In addition, the replacer must be derived from milk proteins (skim milk powder or whey protein concentrate) and it must also be easily dissolved without leaving residuals on the feeding equipment.

Once a suitable milk replacer, meeting the above specifications has been sourced, the next step is ensuring that is mixed appropriately. It’s important to note that mixing rates may vary between products and the manufacturer’s guidelines should always be adhered to. However, for a calf arriving at two weeks of age, a recommendation is that calves should receive at least 13-15% of its birth weight in a good quality milk replacer. This typically equates to 6L/day for a Friesian calf until it is 35 days old. At this point, the quantity of milk replacer being offered can be reduced until weaning. Ideally, milk replacer needs to be reconstituted to a solids rate of 12.5%, as this closely matches the solids profile available in cow’s milk. To achieve this, 125g of milk powder should be reconstituted with 875L of water to make 1L of mixed milk.

When carrying out the mixing process, careful attention should be given to hygiene, accuracy and the temperature of the water used. Mixed milk replacer should be offered to calves at body temperature (37-39 degrees Celsius); avoid using boiling water when mixing milk replacer as this may damage the milk proteins available to the calf; a water temperature of 40 degrees Celsius is recommended for mixing.

Other considerations

  • Concentrate supplementation is critical for rumen development.
  • A highly-quality, palatable starter concentrate should be available to calves freely, shortly after arrival and be offered to calves fresh daily.
  • A crude protein content of 17-18% is desired, with an energy value of at least 12MJ/kg or 0.95UFL.
  • Straw is recommended as a forage source as it is an easier roughage for calves to digest.
  • Weaning decisions should be made on the basis of concentrate intake and weight, not age.
  • Calves should be consuming 1kg/head/day of calf starter for three consecutive days prior to ceasing liquid milk feeding.

Vaccination

Along with ensuring the calf is fed appropriately, the protection of health is also critical and this can be achieved through the implementation of an appropriate vaccination programme, providing cover for pneumonia, IBR and clostridial diseases.

Pneumonia is the most common disease associated with housed calves, with mortality rates of approximately 3% recorded in calves in the first three months of life. Not only does pneumonia have a monetary cost in terms of mortality, it also leads to reduced animal performance and additional labour. Animals affected by pneumonia take two months longer to finish; animals exposed to pneumonia pathogens – but not visibly affected – can take an additional month to finish.

A range of vaccines are available which cover the most common pneumonia causing viruses and bacteria. Vaccines are available in intranasal form to cover the two most common viral forms – RSV and Pi3 - and can be administered to calves from a young age depending on the vaccine brand used. Other vaccines are available in injectable form to cover these two viruses as well as a major bacterial pneumonia form – Mannheimia haemolytica – and can be given to calves from two weeks old.

Infectious Bovine Rhinotracheitis (IBR) is a viral disease causing acute inflammation of the upper respiratory tract. It can significantly reduce animal performance, resulting in economic losses. The virus can lie dormant in the animal’s system and flare up at times of increased stress. The animal will then begin to shed the virus, spreading the disease to herd mates.

Intranasal and injectable vaccines are available for IBR and can be administered at the same time as the pneumonia vaccines outlined above – depending on the product used. In herds where IBR is widespread, intranasal IBR vaccines can be used from two weeks of age. Injectable IBR vaccines can be given from three months of age.

Vaccination is not a fix all; factors such as nutrition, colostrum intake, housing hygiene and ventilation, overcrowding and stress must all be correct. When considering implementing a vaccination programme for your farm, have a detailed discussion with your vet and local Teagasc advisor to draw up a herd health programme.

Calf housing

Before calves begin to arrive this spring, an evaluation of the calf housing available must be completed to see if it is fit for purpose and to rectify and problems or issues that may have occurred last spring. Remember, it’s important to provide the correct housing environment for calves to not only promote performance but to also avoid stress and other health issues.

  • Is adequate space provided to each calf? Better performance and less disease is associated with a space allowance of 2-2.5m2/calf.
  • Is the shed adequately ventilated to eliminate noxious odours, draughts and stagnant air, while also providing fresh air?
  • Can temperatures of 15-20 degrees Celsius – the range in which calf performance is maximised – be maintained?
  • Is at least 7m3/calf of total air capacity available to young calves?
  • Can calves spend 80% of their time lying down?
  • Did beds become damp in previous springs and are calf pens adequately drained to remove any excess moisture?
  • Can the shed be easily cleaned and disinfected between batches of calves?
  • Does calves have access to clean water at all times?