High time to examine issues around purchasing of calves

THIS is the time of year that calves are becoming available for purchase from dairy farms and it is timely to look at some of the considerations around the calf rearing enterprise.

It is preferable to source calves from farms which have control programmes in place against economically important diseases such as calf scours, calf pneumonia and bovine viral diarrhoea.

Calves should be at least 14 to 21 days old at the time of movement and have good weight for age. It is recommended that calves are 45 to 50 kg weight at 2 weeks of age. Ideally select calves from as few sources as possible and preferably from known farms.

The first visual check of calves should be that they have healthy coats – this is always a good indicator of vigour. Calves should be inspected thoroughly prior to purchase.

Any calves showing clinical signs of disease (being dull or listless, signs of diarrhoea; eye, or mouth or nasal discharges) should be rejected.

A range of measures are critical to disease prevention in calves including colostrum management and subsequent nutrition. Purchased calves should be isolated from resident calves for one week to allow them to be monitored for any disease problems.

This also ensures that they do not carry or spread infection to the remainder of the herd.

On arrival on your farm the first feed for each calf should be electrolytes and the second feed should be 100% calf milk replacer.

Keep a constant check on calves for signs of illness. Where signs of illness or lack of vigour are noticed the first action should be to take rectal body temperatures. Temperatures over 39.5oC (103.1oF) are an indicator of infections of some type. Calves showing high temperatures should be taken to a sick pen for diagnosis and possible treatment by or upon advice of a veterinarian. Diarrhoea is generally the most common cause of morbidity and mortality in pre-weaned calves especially calves in the first month of age. Following this period, though diarrhoea continues as significant health threat, pneumonia becomes a more significant issue.

Give each calf a multivitamin injection and vaccinate against pneumonia. Place calves in a dry well-bedded pen that is draught free and yet adequately ventilated. Keep clean fresh water available at all times placed at the calf’s head height. Place fresh palatable concentrate with the calves and replace as necessary. Keep a good “stockperson’s” eye on purchased calves for at least the first ten days. It is important to deal with any signs of sickness promptly whether this involves treating yourself or requiring veterinary assistance. Biosecurity is important so maintain quarantine periods to avoid cross contamination from purchased calves. Over-stocking in pens should be avoided. Calves may be kept in single pens, in groups, or in a combination of both.

When group penned, the minimum permissible pen floor space per calf weight and age is from 1.7 to 1.8 square metres. Dry and draught free housing will reduce the environmental stresses on calves and will reduce the infection load on the calves especially from pneumonia.

Where pneumonia does occur in well ventilated buildings the severity of the disease will be less and the mortality associated with it will be reduced.