What you need in the ideal pen

RESEARCH over many years has shown the ideal pen is twice as long as it is wide, with solid barriers between each pen, with at least 1.5m² per calf. The goal is to keep calves warm, dry, and in good air which is why it’s best for a pen to be more rectangular than square if possible.

“It’s to do with air flow, and it’s to do with how calves behave,” says long-time farm vet Rosemary Milne. “If your pen is longer than it is wide, you can put your feed and water at one end. This means that the calves have a ‘wet’ area at the front, and a ‘dry’ sleeping area at the back which creates a healthy, comfortable environment. Calf pens tend to come in all shapes, but the general principles of separate wet and dry areas are important to remember."

Another key part of a pen is a solid barrier between each pen, essential to prevent the spread of disease. For many people that can be metal sheets, rubber or plastic. Corflute is a cheap, lightweight barrier that is easy to attach to existing gates or fences between pens.

Calf rearing facilities don’t need to be brand new – old sheds can be repurposed if you keep the basics in mind says Wendy.

“As long as those calves are out of the draught, they’ve got somewhere they can get away from prevailing wind and rain and you’ve got good air flow as well. You’ve got to find a balance of the calf not being in a draught but with good-enough air exchange to take away the gases.

“If a shed is not airy enough you get a build-up of ammonia. If you go into a shed and you can feel ammonia stinging your eyes and in the back of your throat, your calves are certainly being affected by it – you should get down to calf level to see what they’re experiencing.”

The other side of the ventilation equation is draughts.

“Calves are ok in the cold, but if they’re sitting in a draught or sitting in wet bedding, they’re going to get colder and they’re going to use their energy for keeping warm rather than growing. For young calves, once they get below about 15°C, they struggle to regulate their body temperature.”

The best bedding is one that is free-draining, dry, cheap and easily available. In the South Island that’s usually straw says Wendy, in the North Island it tends to be wood chips.

“But it doesn’t really matter what you use, as long as it’s free-draining and the calves have got a dry bed; again while you’re kneeling on the floor checking for draughts, feel if your knees are getting wet. It needs to be a thick-enough layer, at least 15cm deep in terms of thickness, then free draining, draining down and then away from the calf shed.”

Keep calves in groups according to age

Calves start life with no immunity other than what they get from ‘true’ colostrum (the very first milk their mother produces in the hours after their birth), and it takes several weeks for their bodies to start developing the antibodies that will protect them from disease. Even small differences in age matter: a week-old calf has a lower immunity than a two week old calf, so it’s important to keep calves in groups of the same age (and therefore similar immunity levels) and the group number no more than 20.

“If any calves have picked up any organism that causes scours, they’ll be excreting them out in their poo, and that will then build up in the environment,” says Rosemary. “We don’t want calves in the same group to be more than a week apart in age: their immune systems are at different levels and they have different susceptibilities to disease.”

what to do if your calves are scouring

There are not a lot of specific treatments for the common causes of scours. For example, antiobiotics are only effective against bacterial infections, whereas the most common causes of calf scours are viral says Rosemary. There are a few options if your calves get cryptosporidiosis (known as ‘crypto’,

pronounced ‘crip-toe’).

“When calves get diarrhoea in the first month of life there’s 4-5 common causes,” says Rosemary. “You can’t tell the difference – they all look the same externally – so you have to do tests to find which pathogen is involved. It’s important to know what it is you’re trying to deal with; in a lot of cases, there’s often more than one pathogen involved. If you know what is causing the disease in your calves, there may be a specific treatment.

"For example, for cryptosporidiosis, there is a specific treatment and preventative product available called Halocur . If you’ve got a viral problem,

® then you may need to look at other factors in terms of trying to prevent it.

"Knowing what's causing disease on your farm can influence what kind of disinfectants you want to look at, how you manage your animals, how you manage your calf pens from one year to the next, and if vaccination may be an option in preventing disease in subsequent years.” Research shows women make better calf rearers than men, possibly because they are more observant of small changes. That kind of observation is key says Rosemary.

“The sooner you can detect something is going wrong, the more quickly you can act, the more likely you are to get a positive result. Some diseases strike really quickly and a dead calf may be your first sign of any problems.

"However, some start more slowly and if you can spot a calf looking a bit sad, slightly droopy ears, a bit slow coming up to the feeder, doesn’t drink a full feed, all these are tell-tale signs there’s something going on. If you can address that calf then, you have a much better chance of it returned to full health than if you left the calf until the next morning when it’s lying at the back and not wanting to get up.” One of the biggest issues for vets is people not acting quickly enough. The more quickly you respond, the more options for treatment your vet will have, and you will prevent other animals getting sick, saving you money in terms of vet bills, your time and effort, and the loss of an animal.

“A lot of people are worried about money,” says Rosemary. “But even a phone call can be useful; have a chat to your vet about it, get some advice, that can stop a situation getting a lot, lot worse.

"Scours is a challenging disease and if a lot of calves get really, really sick, it is unlikely that you can save all of them, and that’s a really tough time emotionally and financially… it takes a big toll.”