Reproductive Health

Why would my cows be open?

Open cows are simply a fact of the cattle business. Managing to achieve a 100% pregnancy rate is simply not cost effective, nor should it be your goal. Having a few open cows every year implies some selection pressure is being put on fertility and animals best-fit for your environment. However, if the number of open cows is excessive (greater than 5%), evaluation of management, nutrition, and herd health needs to take place.

Body condition score matters for reproductive health.

Research illustrates a strong link between body condition score (BCS) of cows and their ability to breed back. Numerous studies (Selk et. Al., 1988; Pruit & Momont, 1990; Houghton et al., 1990) have shown that BCS plays a role in subsequent pregnancy rates. Cows in better condition (BCS >5) have a greater probability of breeding early and a greater chance at becoming pregnant and staying pregnant. Thin cows at calving generally do not breed up well. Remember back to calving -  were cows thin? This may be the cause of poorer preg-check results and signal to you to increase nutrition ensuring better cow BCS.

Nutritional plane or the weight gain pattern of females may also be the culprit. Cattle losing weight often do not get pregnant or stay pregnant. Dairy cattle have battled negative energy balance and the subsequent effects on conception rate for years. It makes sense: if your cattle cannot support weight gain or maintenance then why should they support pregnancy? Thus, if cattle were losing weight at time of breeding, then likely they would not conceive in high percentages.

Grazing comes with challenges.

Research conducted here at the Orr Research Center looked into the effect of supplementing lush, spring pastures. The wet, high protein grass may cause nutritional challenges to high producing beef cows. Our research showed a numerical benefit of a 4 lb./hd/d supplement on AI conception rates. In summary, preparing cattle to gain weight, or certainly not lose it, during breeding season could benefit your preg rates.

Many producers are forced to haul cows to different pastures. Transporting cows can result in stress that can effect conception.

The rule is do not to haul cows 4 to 45 days after breeding. This coincides with embryo implantation, a sensitive time when trying to get a cow pregnant.

That leaves a couple options. Many cattlemen have gone to timed AI and haul cows to pasture within 3-4 days of breeding. Others may breed and graze pastures for some time before hauling a group to another pasture. Be aware transportation stress may play a role in conception and pregnancy rates.

Feeds and water have additional challenges.

Drought and higher feed costs have enticed producers to feed some questionable feeds at times. Feeds containing mycotoxins such as aflatoxin, fusarium, zeralenone, etc. can be responsible for abortion of a cow if levels are too high. Testing high risk feeds is a must. Eliminating the feed from the ration or addition of a toxin binder may be necessary.

Water is another possible source of contamination to animal nutrition. Excess minerals may be causing mineral interactions. Also, elevated nitrate levels could be present and hurting the ability of cows to hold a pregnancy.

Compromised herd health is many times worthy of investigation.

Your veterinarian will have the best ability to diagnose herd health issues. Visual appraisal as well as blood work is usually needed to determine what disease may be causing failure of cattle to breed and hold a pregnancy. Some common diseases that can result in abortion or failed breeding are

  • Anaplasmosis
  • Bovine Respiratory Disease (BRD)
  • Leptospirosis
  • Leukosis
  • Neospora
  • Consult your veterinarian for more information on the possibility of these diseases being the culprit of a poor preg-check.

Bred cows are still valuable property. Opportunity remains to pull in a profit if costs are controlled and pregnancy rates are good. Maintaining proper health and nutrition that leads to desired pregnancy results is a must for cattlemen looking to stay competitive in this market.

About the author