Ask the Vet

Dr. Ken McMillan, Contributing Columnist

READER: We had to pull a calf from a first-calf heifer, and she ended up paralyzed. We worked with her for several days, but it looked like she just gave up and quit eating and drinking, and we had to put her down. What can we do to avoid this from happening again?

DR. McMILLAN: Good heifer development is critical to avoid these issues and, more importantly, for profitability. Traditionally, it has been recommended that heifers should be at least 60 to 65% of their mature weight at breeding and 85 to 90% at calving. However, some recent studies have shown that numbers as low as 50% can lead to acceptable performance as long as they are developed to reach their target weight at calving.

In any case, I like them in body condition score 6 at calving. This is the "Goldilocks" zone; not too skinny but certainly not too fat. Both can be an issue. In fact, too heavy may be worse because of fat laid down in the birth canal and too many calories that can lead to larger calves. Meanwhile, skinny heifers may not have the reserve energy to deliver a healthy, vigorous calf, produce adequate high-quality colostrum, breed back and wean a calf.

Pelvic measurements can help assist in your culling decisions. About 30 days before breeding, your veterinarian can use a special tool to assess the size of the birth canal. An additional benefit is your veterinarian can perform a reproductive tract evaluation to make sure heifers are ready to breed at that time, too. Heifers with small pelvic measurements and immature reproductive tracts should not be retained for breeding.

Next, focus on bull selection. Don't just focus on bulls with low birthweights. A better tool is the calving ease direct (CED) expected progeny differences (EPD). This EPD incorporates birthweight and the calving ease scores that seed stock producers report. Phenotypic observation can also be a good tool in bull selection, so don't just focus on EPDs. Remember, the "E" in EPD is for expected. The leading cause of calving paralysis is fecal/maternal mismatch.

Another significant factor in calving paralysis is the time a calf is lodged in the birth canal. This is like sitting with your legs crossed for too long -- supersized.

Next is a controlled breeding season leading to a controlled calving season. It's a fundamental management tool, and so much builds on this. Human nature and our time have proven that producers can and will observe cattle more closely over the 45- to 90-day calving season rather than all year long. Cows, especially heifers, should be observed, in my opinion, at least twice a day and be in a location where they can easily be moved in a timely manner to a working facility if there are calving issues.

READER: My neighbor says that bulls can breed cows for several weeks after castration. I find that hard to believe. Is that possible?

DR. McMILLAN: In theory, it could happen. Semen can live in the upper reproductive tract for several weeks after castration. I have never seen it happen, but I guess it's possible. So, if you band or castrate bull calves that are close to or are sexually mature, it would be best to keep them away from breeding age heifers and cows for three weeks.

If any readers have ever had this happen, please let us know.

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-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

-- These are only my thoughts and general guidelines. Please get with your veterinarian and together develop the best program for your herd.

-- Email Dr. Ken McMillan at vet@dtn.com

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