The end of summer means more than cooler nights, changing leaves, and football Fridays. It also brings with it a downward shift in colostrum production on dairy farms.
This seasonal shift is more than just a casual, on-farm observation. Washington State University researchers recently conducted a study examining the colostrum output patterns of nearly 3,000 cows on a Texas dairy. They found that:
- Cows produced an average of 9.4 pounds per head when averaged throughout the year. But that production ranged from a high of 58.4 pounds per head, to a low of no colostrum at all.
- The months of highest colostrum production were May and June, at an average of 10.6 and 14.5 pounds per day, respectively. December was the lowest month, with an average of just 5.5 pounds per head produced.
- Second-calf and older cows took the biggest seasonal hit. A stunning 35% of them produced no colostrum in December, compared to just 1% of first-calf heifers. Mature cows that calved in June produced 3 times more colostrum than their mature herd mates that calved in December.
Similarly, Cornell University researchers studied colostrum yield in 19 New York Holstein herds. Their results showed that the risk of a cow not producing any colostrum in December was nearly 10%, compared to just 3% in June. They observed the lowest colostrum yield in October for first-calf heifers and February for older cows.
And a Michigan State University study that stratified colostrum production from 3 commercial Michigan herds by season showed that average first-milking, per-head output was lowest in Winter (4.5 quarts), compared to Spring (5.7 quarts), Summer (6.2 quarts), and Fall (5.7 quarts).
Why the shift? While hard answers are in short supply, researchers point to photoperiod as one of the causes. Michigan State University Extension Dairy Specialist Martin Mangual explained that fewer daylight hours increases the concentration of melatonin secreted by the cow’s pineal gland.
“On days with a short photoperiod, melatonin concentrations are high and could inhibit the release of the hormones prolactin and IGF-1,” he noted. “These hormones are essential for the induction and maintenance of lactation.” Mangual also noted that changes in ambient temperature have not been correlated through research with changes in colostrum output.
While you can’t change the number of minutes Mother Nature is awake, some nutritional and management measures can support higher colostrum production. Rod Martin, Dairy Nutritionist and Business Development Consultant with Protekta, suggested dialing into pre-fresh nutrition by examining the factors that affect dry-matter intake like bunk management, particle size, moisture, and forage fermentation consistency.
Martin said the popularity of adding bulk to pre-fresh rations via straw and grass hay may lead to a higher incidence of ration sorting and introduce antagonists that interfere with the hormonal changes required for colostrum synthesis. He also advised working with a nutritionist to examine water access and intake for dry cows; metabolizable protein levels; energy intake; and vitamin and mineral supplementation.
Two other factors that could help are leaving the newborn calf with the dam longer (possibly facilitated with use of a “Cuddle Box”) and optimizing dry-period length. “Dry periods of less than 50 days are associated with lower colostrum yield,” stated Martin.
In the short term Mangual recommended advance preparation of on-farm colostrum stores, and/or stocking high-quality colostrum replacer, to address colostrum needs in anticipation of upcoming months of shortage.
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