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Rearing heifer calves as herd replacements is the second-largest cost on dairy farms, accounting for approximately 20% of total production expenses.
Speaking during an Alltech webinar on calf health, Lauren Henry from the company outlined advice to get calves off to the best possible start.
“Calves that develop scour in early life never fully recover and lifetime milk production will be negatively impacted.
“When feeding colostrum, there is only one opportunity to get it right.
“Research shows 44% of colostrum samples collected on NI farms do not have adequate levels of immunoglobulins,” Henry stated.
She recommended following the 3-2-1 rule, with three litres of colostrum fed within two hours of being born as the first feed, adding the first five milkings should be fed to calves.
Weight gain
With heifer calves, the aim is to double birthweight by weaning age. For a 40kg calf, this means a liveweight gain of 0.6kg/day if weaning at 10 weeks old.
“Around 25% of calves will not meet this target and have lower subsequent yields as a result. In contrast, for every 0.1kg/day increase above target weight gain prior to weaning, first lactation yield increases by 150kg to 155kg of milk,” she said.
Diet and environment
To hit target weight gain, calves should be offered high-quality milk replacer with 26% crude protein content.
Straw, concentrate and fresh drinking water should also be introduced immediately to stimulate rumen development.
In calf houses, animals up to three weeks of age need air temperatures at 15°C or above.
“Below this, they are burning more energy to stay warm, rather than gain weight. This means feed intakes need to increase,” advised Henry.
Scour
Also speaking during the webinar, veterinary consultant, Dr Catharina Berge said that when calves develop scour and do recover, on average, their first lactation yield is down 300 litres.
Regardless of whether calf scour can be caused by a bacteria, virus or protozoa, Berge said the first step in treating animals is rehydrating with electrolytes.
“Dehydration is the primary cause of death linked to scour, so keep replenishing fluids. There are commercial electrolytes available, but a home mix with salt, sugar and bicarb of soda will also work,” she said.
To identify if a calf is dehydrated, Berge advised farmers to pinch the skin of a calf. If the skin bounces back into place immediately, the calf is properly hydrated. If it takes one to three seconds for the skin to return to normal, the calf is between 6% and 8% dehydrated.
“If it takes five seconds, the calf is 10% dehydrated. For a 50kg calf, this means getting five litres of fluid into the animal,” Berge outlined.
Treatment
Feeding via a bottle is preferable to tubing, which in turn is better than intravenous methods. The advice was to give affected calves a non-steroidal anti-inflammatory, but not antibiotics.
“Dutch research shows using antibiotics to treat scour increases the rate of crypto. Calves routinely treated with antibiotics had twice as much scour as those sporadically treated for other sickness.
Concentrate intakes were also lower, as was weight gain. An antibiotic should only be used if the calf has a fever,” she said.
Berge also advised farmers to keep feeding milk replacer as well as electrolytes during a scour outbreak, as the calf needs energy to aid recovery, and to make sure this milk is at body temperature when fed.
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