In most areas of Oklahoma, calving season is just around the corner. In the craziness of this time, do not forget the importance of colostrum for the future performance of calves. This is a busy time as producers continue to feed, fix fence, manage the crazy winter weather and grind away at their winter commotion lists. In the midst of all this, sometimes simply getting a calf born alive is a huge success! Adequate colostrum intake within the first 24 hours of life can play a huge role in future health and performance of calves.
The definition of colostrum is the first milk extracted from the mammary gland within 24 hours of birth. During the first day of life, the gut of the baby calf can absorb a unique set of immunoglobulins or large proteins that provide passive transfer of immunity from the cow. The clock starts ticking at birth as the absorptive capacity of these proteins is reduced over time. The gut of a baby calf will have 66 percent absorptive capacity to these proteins 6 hours after birth, 50 percent at 12 hours and intestinal closure is finalized 24 hours post birth. In reality, most absorption occurs within 12 hours of birth solidifying the importance of a strong lively calf that is motivated to nurse.
The passive transfer of maternal antibodies through the colostrum will provide a calf with exclusive immunity to diseases that may be encountered later in life. In fact, research from the USDA Experiment Station in Clay Center, Nebraska demonstrated that colostrum might be the key to lifelong health in calves. In this particular study, blood samples were obtained from 263 calves 24 hours after birth to determine colostrum intake reflected by passive transfer of maternal antibodies. Growth performance and health were monitored on these calves through weaning and into the feeding period.
Data from this study established that calves with inadequate maternal antibodies were 6.4 times more likely to be sick in the first 28 days of life as compared to calves that received adequate colostrum. In fact, the risk of death before weaning was 5.4 times greater in calves with poor transfer of immunity. In addition, inadequate colostrum reduced expected weaning weights by 35 pounds and the risk of being sick at the feedlot tripled. This study is a great illustration that passive transfer of immunity is a very important factor of calf health and performance before weaning and into the feeding period.
So what can be done to improve colostrum intake and chances of a healthy calf crop? Many factors of immune transfer are impacted by the cow. Genetics of the cow may influence the quality and quantity of colostrum that is produced. However, tangible factors of cow age, body condition, and udder structure can be more easily addressed by the producer. Mature cows will produce more colostrum compared to a first calf heifer and additional protection may be provided in these older cows due to their exposure to disease and vaccinations. As one would expect, cows in lower body condition and poor health will produced lower quality colostrum for their calves. Udder shape and size can also prevent sufficient colostrum intake. Large teats or a pendulous bag can prevent a new calf from locating the teat and nursing in a timely manner.
Stress is also a crucial player in the timing of colostrum consumption and many factors of stress can cause calves to be sluggish at birth. Long and difficult deliveries, inclement weather, and separation from the cow can hinder intake. In these situations, stress can reduce the absorptive capacity of the intestinal wall even if high quality colostrum is available.
In the event that a calf may not have received adequate colostrum, consider having frozen or replacement colostrum on hand. Keep a tube and bottle in your calving kit for the situation when calling a vet or making a trip to town is not possible. Always thaw frozen colostrum slowly and read label directions on colostrum supplements. Sources recommend providing 5-6 percent of the calf’s body weight in colostrum within the first 6 hours and follow with another feeding at 12 hours. Consult your veterinarian for colostrum guidance and assistance choosing the best supplemental colostrum product.
Is colostrum in your thought process this calving season? Expensive vaccines and attentive management may not be as valuable to an operation as the simple aspect of colostrum intake in the first 24 hours of a calf’s life. If you have any questions dealing with colostrum or would like to learn more, contact your local county Oklahoma Cooperative Extension office.
Time to Evaluate Beef Cow Herd Breeding Potential
With spring calving approaching, now would be good time to evaluate the breeding potential of your cows. Research has shown that the body condition score (BCS) of beef cows at the time of calving has a huge impact on subsequent rebreeding performance. Body condition scoring is a practical management tool to allow beef producers to distinguish differences in nutritional needs of beef cows in the herd. Simply put, BCS estimates the energy status (fat cover) of cows. The scoring system used is a 1 to 9 point scale where a BCS 1 cow is extremely thin while a BCS 9 cow is extremely fat and obese. A BCS 5 cow is in average flesh or body condition. A change of 1 BCS is equivalent to about 90 pounds of body weight. To optimize pregnancy rates, mature cows should have BCS of 5 or greater at calving and 1st calf heifers should have a BCS of at least 6 at calving.
Research has shown that the BCS of beef cows at the time of calving has a huge impact on subsequent rebreeding performance. This occurs because the BCS of a cow influences days to first estrus after calving and calving interval. For a cow to maintain a 365 day calving interval, she must conceive within about 82 days after calving (283 day gestation + 82 day postpartum interval = 365 days). 90 percent of the beef cows with BCS >5 at calving showed signs of estrus by 60 days post-calving, whereas only 59 percent of beef cows with BCS 4, and only 41 percent of beef cows with BCS
Research suggest that increasing calving BCS from 3 to 4 would increase pregnancy rate by about 35 percentage points (from 32 to 68 percent). Increasing calving BCS from a 4 to a 5 would increase pregnancy rates by about 20 percentage points (from 68 to 88%). Note this same effect of BCS at calving on pregnancy rates has been observed in different regions of the country (Florida, Oklahoma, and Texas).
In addition, thin cows at calving (BCS 4 or thinner) produce less colostrum, give birth to less vigorous calves that are slower to stand and these calves have lower immunoglobulin levels, thus reducing their ability to overcome early calf-hood disease challenges. All of these data illustrate the importance of targeting mature cows to calve in a BCS of at least 5. Since 1st-calf-heifers have only reached about 85 percent of their mature weight after calving and require additional nutrients to support growth, it is recommended that they be fed so they are a BCS of 6 at calving.
If your cows currently have inadequate condition, there is still some time to change the BCS prior to calving. Manage your mature cows for a BCS of 5+ at calving. If the cows are in BCS of 5 at calving, a slow gradual weight loss after calving is acceptable. Whereas, if the cows are less than BCS 5 at calving then one needs to hold or increase BCS (weight gain) after calving. However, increasing BCS from calving until breeding will be difficult and costly since cows are lactating.