The Agriland Spring Calf Series is in association with Teagasc DairyBeef 500.
By Alan Dillon, DairyBeef 500 programme coordinator
The quality of calf housing is something that is found to be lacking on many Irish dairy and beef farms.
Often the calf house is a shed that initially had a different purpose, i.e, hay shed, roofed silage pit, cubicle sheds etc.
These buildings are often completely unsuitable for calves in terms of having too high a roof, no slope in the floor for draining, no ventilation from the sides or in the top of the roof, and often the environment is too cold or draughty for calves to thrive and remain free of sickness.
In this article we will look at some of the main areas that farmers need to address in terms of assessing if the environment they are rearing calves in is correct, and if any changes need to be made to existing housing to avoid health issues with calves down the line.
Ventilation
A significant factor associated with respiratory disease is the total airborne bacteria counts in pen air, with increased counts indicating poor ventilation.
The eight primary functions of ventilation are to:
- Eliminate noxious gases;
- Eliminate draughts;
- Eliminate areas of stagnant air;
- Maintain optimum ambient temperature;
- Maintain optimum environmental humidity levels;
- Decrease airborne dust contamination;
- Decrease airborne endotoxin levels;
- Decrease airborne pathogen concentration.
Dust and gas can have adverse effects on the health of the calf. Not only does dust irritate the respiratory tract and mucous membranes, it leads to permanent damage to the lungs and encourages micro-organisms.
Ammonia at levels of 25ppm irritates the mucous membranes and makes the animal more vulnerable to respiratory diseases. If air speed within the shed is greater than 0.5m/s, changes will need to be made to the ventilation in the calf shed.
Natural ventilation is the most efficient and least expensive system for providing an optimum environment within a building.
The objective is to provide a continuous stream of fresh air to every housed animal at all times of the day and night.
In Ireland, there is a predominance of natural ventilation in calf housing, which means that ventilation is provided by a combination of wind and stack effect. Natural ventilation works best when the building is positioned at right angles to the prevailing wind.
The image below shows the ideal shed design for calves – well ventilated with Yorkshire boarding and an escape outlet at the top of the apex with insulated board used to create a micro environment within the shed.
Space allowance
The majority of calves are housed in group pens once they reach two-weeks-old. This works well in terms of labour.
Ideally, group sizes should not exceed 20 calves where they are fed with multiple teat feeders. It is important to ensure all calves are drinking adequate volumes of milk at each feed.
With larger groups there is a risk that slow drinkers or weaker calves may not be able to ingest adequate levels of milk. Calves should be grouped by age and size.
The space required for calves in group pens varies according to their weight. Calves housed in small groups or larger groups require 1.8m² of pen area and a total floor space of 2.3-2.5m²/calf floor area (including the feed passage).
The minimum permissible pen floor area per calf is 1.5m² but this area must increase as calves grow bigger.
The correct feeder and drinking space must be provided to encourage feed and water intake and to discourage bullying. For bucket feeding, calves require 350mm of feed face each.
For automatic feeders there should always be more than one teat per pen. This reduces the risk of calves being without milk and then over-feeding when a teat is fixed.
The number of calves per feeder varies. Meal troughs should be 450mm above the floor, 100mm deep and 250mm wide.
Straw bedding
The cost of straw has increased in the past few years with lower acreages being planted along with higher transport costs leaving round bales of straw costing €30 or more per bale delivered in western, non-tillage counties.
While this is a big cost for what essentially will end up as farm yard manure, it is important to not skimp on bedding material in young calves.
These young dairy-bred calves have low levels of adipose tissue and will need a relatively warm environment. Deep straw bedding will be required that is refreshed daily to ensure calved stay warm and comfortable.
Dry looking beds may be wet. To check if beds are adequately bedded and dry, kneel with all your weight on the bedded floor. If the knees of your trousers are wet, the house is not bedded sufficiently.
Also pay attention to where calves lie in the shed. If they are all lying around the edges of the pen near the walls, there is a good chance the bedding may be damp also.
Other materials such as coarse hay are used on some farms to bed calves. This is a cheaper alternative if the farmer has made the bales himself, but care should be given to ensure the bales are not too dusty as this could affect the calves respiratory system and lead to issues with pneumonia.
Bark mulch or wood chip have been used on farms previously but these products lead to a cold environment for young calves as they are unable to nestle into the bed to stay warm.
Sheds should be cleaned out periodically during the rearing season and rebedded with fresh material.
Drainage
In sheds that are not designed specifically for calf rearing, it is unlikely that drainage in the shed floor will be adequate to keep beds dry.
Calves spend about 80% of their time lying down so they need a dry bed. A dry environment will also reduce the spread and growth of bugs.
All calf houses should be built with a damp-proof course to prevent rising dampness. A slope of 1:20 in the calf pen area is recommended (specification S124 DAFM).
A split drain has the advantage that it will get urine and associated smells out of reach of calves quickly.
Repurposing an existing shed for calves
For some farmers, there may be existing sheds on the farm that can be redesigned to suit rearing calves.
The important thing to remember is that all the steps taken on designing a new calf house must be followed to ensure that the calf remains warm, dry, has enough lying and eating space and adequate access to clean water.
These steps, when taken correctly, should ensure that calves can thrive at the required 0.7kg/day on milk, while remaining free of set backs such as pneumonia.
For any farmers considering retrofitting sheds, they should first consult an experienced advisor to ensure that the proposed works are carried on a shed that is worth investing in.
In some cases, due to a shed being built in the wrong location or facing the wrong way, it may be cheaper in the long-term to start again and build a new shed from scratch.