Disease early in life has big effect on weaning weights

The income that cow-calf producers work so hard to earn is ultimately based on the weaning weights of their calves.

Dr. Liesel Schneider and Dr. David Smith of Mississippi State University’s College of Veterinary Medicine recently presented interesting information about weaning weights at the International Society of Veterinary Epidemiology and Economics conference.

The effect of illness in the calf has been known to have detrimental effects on eventual weaning weights.

An older study published in 1994 by Dr. T. Wittum demonstrated that calves that were sick at some time between birth and weaning tended to have a lower weaning weight by almost 16 kilograms.

Wittum’s research showed that calves that suffered from problems around birth such as mothering difficulties weighed 24.4 kg less at weaning, calves that suffered from respiratory disease weighed 16.5 kg less and calves that had experienced a case of diarrhea weighed 10.7 kg less than healthy calves.

Other research has also shown that cases of diarrhea and other diseases can reduce weaning weights.

Schneider and Smith set out to examine this question once more but also to evaluate in more detail how the timing of disease in calves can affect weaning weights.

They evaluated records from the U.S. Department of Agriculture’s Meat Animal Research Center (MARC) in Clay Center, Nebraska, over a 14 year period. The database comprised almost 15,000 individual beef calf records.

They found that seven percent of the calves had an episode of respiratory disease, four percent had an eye infection, two percent were diagnosed with lameness and another two percent with diarrhea.

The researchers examined three time periods for disease to occur:

  • Early period — zero-60 days.
  • Middle period — 61-120 days.
  • Late period — 121 days until weaning.

The calves were weaned at an average of 185 days of age.

As in previous studies, this research also demonstrated that calves that suffer from a disease tend to be lighter at weaning than calves that don’t get sick.

However, the MARC data also showed a surprising trend: calves that got sick early in life weighed dramatically less at weaning than calves that got sick later in life.

For example, calves that had respiratory disease in the early period were 25 kg lighter than healthy calves at weaning. Calves that experienced respiratory disease in the middle or later period were only eight kg lighter than healthy calves at weaning.

Similar results were found for calves in the early period with eye lesions (28 kg loss) and diarrhea (23 kg loss). Lameness was the only disease that did not follow this trend.

The researchers from Mississippi State were able to demonstrate that the timing of an illness has as much impact on weaning weights as the illness itself.

For example, infections that occur within the first 60 days of life had a far greater reduction in weaning weight. Even though these calves all recovered, there was a long-lasting impact on their growth potential and ultimately their weaning weight.

These findings emphasize the importance of a calf’s first few days and weeks of life.

The current high prices for weaned calves mean producers can afford to spend some money to avoid these drops in weaning weight.

Here’s a good place to start:

  • Take steps to avoid calving problems.
  • Ensure calves suckle early and receive adequate levels of colostrums.
  • Use an appropriate vaccination program that will help prevent early calf diseases.

We probably cannot completely eliminate all diseases in young calves, but this research would demonstrate that preventing early diseases in calves can ultimately result in more money in our pockets when weaning time comes around.

John Campbell is head of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.

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