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Calf mortality: Can it be too low?

Trent L. Lartz for Progressive Dairy Published on 16 November 2020

The U.S. calf mortality rate is 6% to 8% (7.8%, USDA, 2007; 8.1%, USDA, 2010; 6%, USDA, 2017), inclusive of all housing types. According to Dairy Calf and Heifer Association Gold Standards, the target mortality rate from 24 hours old to 60 days old is 3% or less.

They also state goals of less than 10% of calves having a case of respiratory disease (pneumonia) and less than 15% of calves having a case of scours. Meeting these goals is more important than meeting the mortality rate. A mortality rate for a farm can be too low if it costs too much to keep the calf alive.

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When you look at the rising cost of replacement heifers, keeping calves healthy and productive before and after arrival is critical to a dairy’s bottom line. When treating calves for scours, you have treatment and labor costs of treating the calf. Once the calf improves, that scours episode decreases the heifer’s likelihood of surviving to calving. Research shows that calves with scours before 14 days old are 2.5 times more likely to be culled before calving. Heifers that had been treated for scours were 2.9 times more likely to calve after 900 days of age. Besides higher death losses, a heifer treated for scours can experience reduced productivity over her lifetime. The goal of any operation should be to reduce the prevalence of scours in their calves to reduce potential financial losses from reduced production.

Respiratory disease (pneumonia) in a pre-weaned calf can have a long-term impact on its overall lifetime performance. This disease can cause irreparable damage to lung tissue, which forces the animal to work harder to exchange carbon dioxide for oxygen, thereby using energy that could be used for milk production or growth. Evidence suggests that scours and respiratory disease during the first 4 months of life has a negative impact on subsequent milk, protein and fat production. Studies have shown that pneumonia in pre-weaned calves can reduce first lactation milk yield by 4% and second lactation milk yield by 8%. Heifers that had a relapse of pneumonia had further reductions in milk yield during their first and second lactations, by 5% and 10% respectively. The same correlation is there for dairy beef calves. The feed efficiency of calves that had respiratory disease is much lower than those that did not have respiratory disease as young calves.

Calf raisers should not look at mortality rates as more important than treatment or morbidity rates. The goal should be to lower treatment rates. This, in turn, should lower mortality rates. If there is too much weight put on a herd’s mortality rate, more calves may be treated too many times just to keep them alive. This may lead to calves that will not develop into productive members of the herd. This will negatively affect the bottom line of the farm. Serious thought needs to take place to determine if a calf is treated more than once for a disease process, especially respiratory disease. Someone may lean toward treating an animal more than once for respiratory disease if they are able to treat the disease early with a high success rate, which leads to minimal lung damage. One may look to cull an animal if it needs to be treated more than once and if there is a surplus of replacements. This may lessen potential stocking density issues later on in the operation.

Treatment records should be maintained and reviewed at least annually to determine if changes need to be made in vaccination protocols, treatment protocols, bedding protocols and/or ventilation, if calves are housed in a barn (Table 1).

110620 lartz tbl1

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In summary, calf operations should focus on keeping treatment rates as low as possible. The goal should be less than 15% for respiratory disease and less than 10% for scours. If these numbers are reached, then the mortality rate will be low for your herd. If these numbers cannot be reached, then every aspect of the calf operation needs to be scrutinized. This would mean looking at colostrum management, feeding programs, vaccination protocols, housing and treatment protocols. Consult with your herd veterinarian to assist in achieving these goals.  end mark

Trent L. Lartz works at Ridge View Animal Consulting. Email Trent Lartz.

References omitted but are available upon request. Click here to email an editor.

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