Dairying Management Notes – November

November 1, 2020

Calf housing and management

Good calf and housing management is essential to achieve performance targets. The main areas to address are:

• Hygiene – thoroughly clean the shed and disinfect with a broad spectrum disinfectant before calves are born. While in use, pens should be frequently disinfected to prevent the buildup of disease organisms. The flooring/bedding also needs to be able to facilitate easy cleaning and removal of waste. Ideally bed calves every day and clean out pens weekly.
• Drainage – waste should not drain from one pen through another as this can spread disease.
• Improve drainage on concrete floors by having at least a 1:60 slope towards a channel.
• Ventilation – fresh air delivery should come from natural ventilation with additional fan ventilation provided if necessary. If natural ventilation is not sufficient to provide adequate air movement during the critical periods of damp calm weather, a fan and duct system should be fitted. Only use an extractor fan system in buildings with a low volume and a small number of inlets in the walls. Fan and duct ventilation systems are inexpensive to buy and run and can provide fresh air to all corners of a building. A calf house should have at least six air changes per hour. Micro-organisms die off more quickly when relative humidity is below 80%. However, relative humidity levels above 85% could occur during damp, dark days. Air space is also critical in calf housing. A minimum of six cubic metres total air capacity should be provided per calf at birth, increasing to ten cubic metres by twelve weeks of age. The greater the number of calves in a single air space, the greater the risk to health.
• Moisture level – this can be controlled through the use of sloped floors that ensure good drainage, fixing any leaks and good ventilation. Providing calves with a dry lying area by using a deep bed of straw will also help. Straw is superior to other bedding material in terms of insulation value. It has a high ‘nesting score’ which provides a preventative effect against calf respiratory disease in naturally ventilated sheds. Straw bedding should be at least 15cm deep and should be kept dry at all times. To reduce the amount of heat lost from calves their legs should not be visible when lying in the straw, especially during cold weather.
• Air speed – fresh air is an essential requirement for good health but draughts must be avoided at calf level. Fresh air delivery not only picks up aerial contaminants such as dust, fungal spores, gases and airborne pathogens, it is also an excellent biocide. Fresh air kills airborne bacteria and viruses ten to 20 times quicker than stale air.

November jobs checklist

• Identify cows to dry off in the next two months and assess body condition. Feed cows with a body condition score less than three additional concentrates to improve condition.
• Assess body condition of young stock, especially maiden heifers. Will they be in the right condition for service? Do you need to increase the feed rate?
• Carry out any vaccinations due, for example BVD, well in advance of the breeding season.
• Select suitable bulls to achieve long term breeding goals.
• Calibrate parlour and out of parlour feeders to ensure accurate feeding.