Many factors impact colostrum yield from cows

ITHACA, N.Y. — High-quality colostrum intake by dairy calves is an essential component for healthy animals.

“Nationwide in the U.S., we’re seeing approximately one-third of dairy calves experiencing preweaning morbidity and 5% of those calves die,” said Trent Westhoff, dairy technical consultant for Elanco Animal Health.

Similar to milk, about 75% of colostrum is water.

“There are elevated concentrations of fat at 7% and protein at approximately 14%,” said Westhoff during a webinar hosted by the Dairy Calf and Heifer Association.

“There is also a very small portion of the colostrum that includes things like minerals, vitamins, hormones, immune cells, antimicrobial peptides, etc.,” he said.

“Eventually we hope to start to quantify how those molecules affect the calf, and maybe sometime in the future we’ll be able to extend our definition of high-quality colostrum to include some of these other factors.”

Dairy cows produce transition milk two to five milkings after calving.

“During this period of time we see a reduction in many of these including protein and fat, as well as hormones, immune cells, etc., and an increase in lactose, as well as water,” Westhoff said.

The amount of colostrum produced by dairy cows can vary throughout the year.

“We see reductions in yield during the fall and winter months and then it starts to rebound in the spring,” Westhoff said.

Most dairymen feed about one gallon of colostrum to calves at first feeding.

“During the summer months, we typically have enough colostrum. However, as we go into the fall and winter months, we start to experience times where some of our production is going to be hovering around the four liter mark,” Westhoff said. “That will stress our colostrum management program until we start to see it rebound.”

There is also a lot of individual variability between cows and some of that is associated with parity.

Westhoff collected records from about 18,000 cows in New York.

“There was a trend for increased colostrum yield for older cows,” he said. “The colostrum yield for a cow entering her first lactation was about four liters and that increased to 4.6 liters going from the second to fifth lactation.”

This study showed a similar trend for Brix percentage.

“For cows entering their first lactation, the median is 24.6 and it increases slightly to 25.7 for older cows,” the dairy technical consultant said.

To look at the association between dry period length and colostrum yield, Westhoff divided cows into three groups — a dry period of less than 47 days, a dry period of 47 to 67 days or greater than 67 days.

“A dry period of less than 47 days was associated with the lower colostrum yield, and as the dry period increased we saw increases in colostrum yield,” he said. “When we compare cows that are managed for a 60-day dry period, compared to 40 days, that resulted in a greater colostrum yield of 5 pounds.”

When harvesting colostrum, Westhoff said, generally there won’t be reductions in concentrations of immunoglobulin G, or IgG, until about nine to 12 hours after calving.

“If we are harvesting colostrum within nine hours of calving, there should be no change to the IgG concentration,” he noted.

“Sometimes bacterial contamination is an area we like to overlook,” he said. “Thoroughly cleaning and sanitizing the udder and milking equipment is a must and rapidly cooling the colostrum after harvest, because the faster we cool it, the more we can inhibit growth.”

Colostrum can be stored in a refrigerator for a maximum of two to three days from the time it was harvested to the time it is fed, Westhoff said.

“Rotate the supply and discard expired colostrum,” he said.

Colostrum stored in a freezer should be fed within eight months, Westhoff said.

“We want to avoid self-defrosting freezers because they go through phases when they warm the temperature to avoid frost accumulation,” he said. “But that can also warm up the colostrum, and when there is a freezing and thawing cycle, there’s a potential we could denature some of the important proteins in the colostrum.”

Freeze the colostrum in individual meal portions, Westhoff said, unless the farm is large enough where it is possible to use multiple meal portions in a timely manner.

“Avoid stacking thawed or warmed colostrum on top of frozen colostrum,” he said. “Because they will transfer heat until they reach equilibrium.”

Colostrum should be thawed between 113 to 140 degrees.

“Past 140 degrees, we’re going to get some denaturing of those important IgG molecules,” Westhoff said. “Be conscious of how you are thawing — don’t just drop the colostrum into a really hot water bath that is above 140 degrees.”

“For the volume of colostrum at first feeding, my recommendation is to feed between 8% to 10% of birth bodyweight,” he said. “If you want to feed more colostrum, my recommendation is to do that at a second meal.”

For most dairies, Westhoff said, the only constant on feeding protocol for colostrum is the volume that is fed. Everything else changes — the calf birth weight, the time from calving to feeding, the quality of the colostrum and the efficiency of IgG absorption.

“The result is changing concentrations of IgG,” Westhoff said.

“It is a very complex system that is very important to our calves,” he said. “But we have things like nutrition, environment management, genetics and health that influence the cow factor in its contribution to colostrum yield.”