Key requirements for calf sheds on dairy farms

Although the start of the spring-calving season is months away, farmers have an opportunity now to make adaptions to their calf sheds that will benefit calf health and performance next spring.

Tom Fallon, Farm Buildings and Infrastructure Specialist, tells us the five key requirements for a calf shed are:

• Good ventilation to ensure air is fresh with no draughts.
• Adequate space: It is recommended to provide 2.0-2.3m² pen area per calf.
• Dry/good drainage: Young calves spend up to 70% of their time lying down so they need a dry bed.
• Warmth: Extra bedding is recommended especially for young calves when temperatures are low (<10°C).
• Clean and cleanable: Floors and walls should be easily cleaned.

Fresh air

Good ventilation removes stale, damp air, which helps ensure that viruses and bacteria cannot survive for long outside the animal. Fresh air is also required to limit dust and ammonia, which can irritate the respiratory tract and make the animal more vulnerable to respiratory disease. The recommended air inlet should be two to four times the required outlet. The outlet area should be a minimum of 0.04m²/calf. A capped ridge outlet is recommended with flashing, as required, to prevent wind-driven rain getting in.

Air inlets can be provided by ‘Yorkshire boarding’ (Figure 1) or vented sheeting. Yorkshire boarding has two staggered lines of vertical timber so it reduces air speed, water entry and the likelihood of draughts. Specification S101 from the Department of Agriculture, Food and the Marine (DAFM) stipulates that the minimum length of the boarding is 1.5 metres, that the laths are 25mm thick, a maximum width of 75mm with gaps of at least 25 mm. The two lines of laths are 25-50mm apart.

Space boarding can be satisfactory on the sheltered side of a calf house in a suitable site. If in doubt, use Yorkshire boarding because wind direction can change and calves are sensitive to draughts. A draught is essentially excessive air movement (air speed >0.5m/s) at calf level.

Figure 1: Space boarding on left and Yorkshire boarding on the right

Space

It is recommended to provide 2-2.3m² pen area per calf. Each large pen in Figure 2 is 4.8m x 4.6m =22m² divided by 2.3m2 = 9 calves/pen, the centre passageway is not included in this calculation.

Figure 2: Calf housing with penning boarding on the right

Dry with good drainage

Calves spend a lot of their time lying down (up to about 70% for young calves), so they need a dry bed. 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 as shown in Figure 3 has the advantage that it will get urine and associated smells out of reach of calves quickly.

This drain should be positioned approximately 0.8m inside the feed barrier. In large pens, typically where automatic calf feeders are used, there is merit in having this drain approximately three metres within the pen. This area will however have to be cleaned at least daily, preferably with a ‘hand yard scraper’ or a scraper mounted on a skid steer or quad since any use of water within the building should be kept to a minimum to keep down humidity.

Figure 3. A ‘split drain’, this can be constructed without the use of angle iron, contact your adviser for details. Cast iron ‘Acco’ drains are an alternative option.

Warmth

A young calf is comfortable between 10 and 26°C (‘thermoneutral zone’), whereas the equivalent for a month old calf is 0 to 23°C.

Deep beds of straw are effective in protecting calves from the cold so extra bedding is recommended for young calves in cold weather. Calves require 15-20kg straw as bedding per week or one 150kg round bale of barley straw to rear each calf. An extra feed of warm milk will also help calves cope with low temperatures.

Clean and cleanable

Floors and walls should be easily cleaned. Floors can be laid in bays of not more than 4.5m by 6m to avoid the need to make contraction joints. Ensure concrete is well compacted and properly cured to avoid plastic shrinkage cracks etc.

Natural light

Natural light is conducive to good animal health and provides for a good working environment. 15% of the roof area as translucent sheets is recommended (as listed on DAFM S.102).

Mistakes and challenges in calf housing

• Inadequate space: aim to provide at least 150m² of calf pen area for a 100-cow herd.
• Eave heights over 4m, calves do not generate enough heat to shift a big volume of air above them. Excessive ventilation.
• Yorkshire boarding with excessive space between the two lines of timber leading to draughts and rain entry.

This article first appeared in the Moorepark 2023 open day booklet. Access the full publication here.