According to Gustavo Schuenemann, DVM, Ph.D., there are approximately 9.3 million dairy cows in the U.S., and there is a 33.8% pre-weaned (birth to 60 days) calf morbidity rate. Another 5% of calves are stillborn (either born dead or die within 24 hours). Through careful genetic selection, adequate housing, dry cow management, hygiene practices, colostrum management and vaccination timing, Schuenemann believes dairy farms can significantly lower these calving-related numbers.

“What I want to do is share with you what the best farms are doing in terms of maternity management and calf survival,” Schuenemann, Extension veterinarian – dairy, said in an Ohio State webinar. “We have a number of leading dairy farms achieving a 1% calf mortality rate at calving.”

Accounting for Genetics

Today, more than half of dairy cattle in the U.S. are bred with beef bulls – beef-on-dairy. Most beeves have a longer gestation length compared to Holstein cattle. The bull has a substantial effect on the gestation length of the dam and on calf birth weight.

Both traits could increase dystocia and calf mortality due to increased birth weight at calving. One way to prevent excessive calf mortality, in Schuenemann’s opinion, is to choose a beef sire that matches the gestation length of the dairy cow being bred.

Managing Mycotoxins

Mycotoxins in dairy feed is a worldwide problem, said Schuenemann. His research shows that approximately 25% of a cow’s feed could be contaminated with mycotoxins. Colostrum volume decreases when a cow consumes mycotoxins. Another negative effect is shorter gestations.

“Mycotoxins are pro-inflammatory. That means they can increase blood cortisol, and that triggers labor. When labor is triggered this leads to short gestations, which in turn increases calf mortality issues and most of the early lactation health problems,” Schuenemann said.

Broad spectrum binders (also known as adsorbents), fed as feed additives, are the most common tool to help livestock cope with mycotoxin-related health issues. These substances bind to and/or deactivate mycotoxins and prevent them from being absorbed in the digestive tract and into the blood circulation.

Timing of Vaccinations

Many farms Schuenemann works with use at least two vaccines on a dairy cow during the dry period – one for controlling mastitis and the other for preventing scours in their calves. Both vaccines require boosters about four weeks before calving.

During the dry period, many cows are also fed an anionic diet to help prevent milk fever. These two treatments – the vaccine boosters and the anionic diet – are asking the cow’s parathyroid gland to do two opposite things. The vaccine triggers inflammation for at least seven days, which inhibits the parathyroid gland; the anionic diet is trying to stimulate the gland to upregulate the calcium homeostasis in the cow.

Because of this conflicting demand on the parathyroid gland, Schuenemann recommends using the boosters on day 28 prior to calving rather than day 21. “What we found when we vaccinated on day 28 is a 46% reduction of subclinical hypocalcemia,” he reported.

Studies also show that vaccinating earlier increases blood glucose. The transfer of blood IgG (the main component of cattle colostrum) into the mammary gland is an active process, and it requires large quantities of blood calcium and energy (glucose). In response to the increased blood glucose, IgG concentrations went up by 20%. Increased concentration of IgG in colostrum is required to prevent scours in the first week of a calf’s life.

Avoiding calf mortality

Some basic practices used by farmers around birthing time can help lower the incidence of calf mortality. Photo courtesy of Gustavo Schuenemann

Monitoring the Feed Bunk with Technology

Pregnant dairy cattle, especially heifers, must have access to feed at all times. “Heifers are very sensitive to losing body weight prior to calving, which can trigger calf mortality at calving,” Schuenemann said.

He advocated for the use of simple technologies to monitor access to feed. One way to monitor is to set up a camera by the feed bunk and have it take a photo every 10 minutes for an entire week. This collection of images can then be grouped and watched by the people responsible for feeding the cattle.

Feeding Colostrum for Health & Survival

Schuenemann said that most farms that have a 1% mortality rate are feeding colostrum at a rate of 12% of the calf’s birth weight. Monitoring calf birth weight is very helpful to deliver the correct volume of colostrum.

Ideally, the first feeding will be 8% of the calf’s weight, fed within one hour of the calf’s birth. At the second feeding, about six hours later, the calf will drink the remaining 4% of its body weight.

This timing is critical because the calf depends on colostrum for its immunity and its intestine, which absorbs the IgG, starts closing at about 4% an hour. In 12 hours, the calf has lost 50% of its capacity to absorb IgG. New studies show that calves should receive 70 g/L of IgG rather than 50 g/L.

Schuenemann has worked with a number of farms that have moved away from a traditional colostrum feeding program to one that mimics mammals in nature. For example, feed 100% colostrum on day one; feed a 50/50 milk/colostrum blend on days two and three; and then from days four through 15 feed a blend of 90% milk and 10% colostrum. This management approach promotes health and growth, critical for calf survival and performance.

If pasteurizing colostrum, it should be done at 140º for 60 minutes. The proper refrigeration temp is 40º; frozen, it should be at -4º. Schuenemann recommends freezing colostrum in thin bag containers, otherwise people will be tempted to expedite the defrosting process by overheating the water and decreasing colostrum quality. Colostrum should be thawed at 104º.

Keeping an Eye on Cleanliness

Tools, like a SystemSURE Plus, can be used on the farm to test cleanliness of surfaces and objects like hoses, valves, calf bottles and nipples. Surfaces are swabbed and the sample is placed in a small handheld device. The device measures the amount of adenosine triphosphate (ATP) present.

The process of ATP testing is based on the principle of bioluminescence, which involves the production of light by living organisms such as E. coli. A high ATP reading indicates that the surface needs cleaning.

Hygiene is important because feeding calves with contaminated colostrum is associated with calf mortality.

by Sonja Heyck-Merlin