By Karen Trebilcock
Farmers thinking of cutting costs by cutting grain fed to calves should think again, Complete Feed Solutions nutritionist Natalie Chrystal says.
Although traditionally reared beef calves are never fed grain, they also get large volumes of milk from their mothers well into summer giving them plenty of time for their rumen to develop before weaning in autumn.
However, dairy calves are given usually between eight to 10 weeks of milk feeds before weaning meaning their rumen development must be faster.
And the only way to do it is by feeding grain-based (wheat, barley, maize) feeds high in starch.
“This is because starch fermentation in the rumen results in the production of butyrate and propionate which are two volatile fatty acids which develop the finger-like papillae that line the inside of the rumen,” Natalie said.
“These papillae provide an extensive surface area for the absorption of volatile fatty acids produced in the rumen, ensuring they can provide the energy required by the growing calf.
“They also play an important role in helping to maintain a healthy rumen pH as they move the acidic volatile fatty acids out of the rumen, helping to keep the rumen pH within an ideal range.”
Feeding high quality hay, such as lucerne hay, and fresh grass encouraged some papillae development but not enough for an early weaning, she said.
“Hay tends to be high in fibre but low in starch compared with grain. Fresh grass, especially spring grass, while high in protein, is also very low in starch, and is also low in drymatter making it difficult for calves with a relatively small rumen to eat enough.
“Providing high quality protein is essential for lean tissue growth, especially in calves which have not yet been weaned. Good sources of protein for young calves are soya, canola and peas.”
Some other feeds which are suitable for older cattle, such as palm kernel, soya hulls, DDG (Distiller’s Dried Grains) and cottonseed meal should be avoided in the calf pens, as they are either low in starch or provide poor quality protein which can’t be digested by calves.
“For young calves eating only very small amounts of feed, it’s important to provide a 20% crude protein feed.
“This helps to ensure they can consume enough of the feed to provide all the essential amino acids they require. A 16% calf meal is ideal for older calves eating larger quantities of hard feed and grass.”
Starch levels should be around 40% and this should come from grains such as wheat, barley and maize in the calf grain.
Some calf feeds don’t show starch levels on the packaging so she recommended asking the feed manufacturer if in doubt.
Feeding calves a grain-based mix also had other benefits as many calf feeds also contained added vitamins, minerals and a coccidiostat.
“Coccidiosis is caused by a parasite that infects the cells that line the calf’s intestine.
“The parasite is naturally present in the farm environment. It’s hard to kill, and numbers can build rapidly in calf sheds and paddocks, especially if calves are weaned in the same paddocks year after year.”
Calves are infected by swallowing the parasites when they eat infected pasture and feed, drink contaminated water or even when they groom themselves and each other.
“Symptoms are diarrhoea, dehydration, reduced weight gain and obvious discomfort and although most animals do recover, the damage to their intestinal lining means they take a long time to regain condition and start growing again.
“Many animals may be infected without showing symptoms other than less than optimal growth.”
Farmers should make sure the calf feed they used, especially after weaning, contained a coccidiostat as this helped control the growth of coccidia during a period when calf immunity is challenged.
“It’s when calves are out on pasture they are most at risk so changing to a cheaper feed after weaning that doesn’t contain a coccidiostat is risky.”
