Livestock producers should be taking calves off cows within six hours of birth to prevent calf illnesses, according to Willunga, SA, veterinarian Simon Edwards.
"You should remove the calves from the cow as soon as you can," he said.
"Ideally, I would say less than six hours.
"But if you get them off within six hours and they get colostrum, they are moved into the calving pens, the risk of disease is significantly reduced."
Dr Edwards, who presented at a Dairy SA calf workshop on Wednesday last week, said bovine Johne's disease was not a huge risk in SA, but from a Johne's point of view, the sooner they were separated, the better.
"If you are working in a system where you are only going around twice a day, I would get them off when the calf is still wet," he said.
"In a perfect world I would probably give that calf an hour or so to get its legs, but the reality is, we are not working in a perfect world.
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"I'd rather you pick the calf up there and then, than pick it up in 12 or 24 hours.
"If you could pick them up at any point then I'd at least let them get their legs and stop shivering."
Dr Edwards said producers could not guarantee the calf would drink enough colostrum from the cow at the level required to get sufficient passive transfer of antibodies.
"Dairy cows within 12 hours have gone from having an udder that is full of colostrum to diluting it down to build up a full udder of what we know as vat milk," he said.
"If you waited 24 hours to get the cow in to milk, the colostrum is diluted almost to 100 per cent milk.
"In dairy cows there has been an enormous amount of research that tells you get better passive transfer and, in general, less disease if the calves can get the colostrum within 12 hours."
Dr Edwards said not to rely on the cow to feed an adequate amount of colostrum.
"I'd be giving those calves colostrum as soon as they are born," he said.
"The original recommendation was two litres straight after calving and another 2L, 12 hours later, but what they found was the second 2L had no benefit.
"Now the recommendation through Dairy Australia and internationally as well is if you give a 40-50 kilogram Friesian calf 4L of colostrum straight up, whether it be tubed or bottle fed, then you are more likely to get enough antibodies into the calf."
Dr Edwards said the four Qs of colostrum were quality, quantity, quickly and squeaky clean.
"The percentage of colostrum that is absorbed through the gut at one hour is about 40 per cent, so for every 1L you give, 400 millilitres gets absorbed across," he said. "Once we are down to six hours, it's down to 15pc and once we are down to 12 hours, it drops to 5pc, so you can see it drops off rather quickly.
"You get far more absorption across the gut wall when you give 2L of colostrum in the first couple of hours and that's equivalent to 6L at 12 hours - same colostrum, same concentration.
"You would need to have the calves in within six hours to administer enough colostrum for the best passive transfer result."
SHED DESIGN VITAL TO STRONG START
Dr Edwards said shed design was also critical.
If there is not decent air movement or good drainage or a combination of both, then high levels of ammonia can build up in calf sheds.
"That can have a very significant impact on a calf's immune system and their respiratory system," he said.
"They are far more likely to get pneumonia in an environment where there is an ammonia build up."
READ MORE: Attention to detail key for calf rearer
Dr Edwards said airflow and bedding was a crucial consideration when designing a calf shed.
"Airflow is really important, as the ammonia can build up in bedding quite quickly," he said.
"It's heavier than air, so we would not notice it - the calves are on the ground where the ammonia sits.
"If you have got movement, it will push the ammonia around and out of the shed. You won't really notice it unless you are on your hands and knees - down at calf level - which most of us are not."
Dr Edwards said new sheds needed a lot of thought when it came to design, construction and placement - both on the farm and of the external structure of doors and openings.
"The calving shed should be fit for purpose and provide protection from heat, wind and rain," he said.
"The challenge with ventilation is producing an environment that is draught-free at the level of the calf, but with enough air movement above the calf to remove pollutants."
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