Fall calving is fairly common in the southern U.S. but is becoming increasingly popular in more northern climates. Fall-calving herds reported reductions in calf losses immediately after birth as well as less stress on the calving crew. In long-term research from Tennessee, fall-calving cows produced 0.4 more calves during their lifetime but weaned lighter calves and were later in recycling. In addition, fewer fall-born calves were born early in the calving season. In contrast, other studies did not observe a negative effect of fall calving on weaning weight. Managing fall-calving cows for rebreeding success may require different strategies than spring-calving cows. Making these adjustments could improve rebreeding success and calf performance.
Nutrition
Cows need to calve in body condition score (BCS) 5 or 6 and maintain body condition to ensure early resumption of cycles and high rebreeding rates. Fall-calving cows usually calve in better body condition than spring-calving cows due to plentiful summer forage. Comparisons of BCS at calving between spring- and fall-calving cows from the same genetics show fall-calving cows being 1 to 2 BCS better than spring calvers. However, to achieve this improvement in BCS, ranchers need to be aware of late summer and early fall forage quality. Protein and, perhaps, energy supplementation may be needed.
After calving, fall-calving cows are at a disadvantage to spring-calving cows. Fall pasture, especially range, fails to meet the nutrient needs of lactating cows, so supplementation of protein and energy may be necessary. Byproducts such as distillers grains or corn gluten feed are good options for supplementation, as are commercial range cube products. Grazing alternatives that may meet lactating cow needs include ryegrass and stockpiled fescue in the South and hay aftermath in the North. Mineral supplementation, especially trace minerals, is needed for fall-calving cows. The concentrations of macrominerals such as calcium and phosphorus should be adjusted based on forage and supplement.
Delayed resumption of cycles: Nutrition or photoperiod?
Multiple studies report that fall-calving cows were delayed by 10 to 20 days in the return to estrus after calving. One cause could be the lower forage quality for lactating fall-calving cows if they are not properly supplemented. Increasing cow nutrient needs pre-breeding coincides with colder temperatures, so diets may need further adjustments to prevent weight loss and delayed estrous cycles.
Some well-designed studies in Wisconsin examined the impact of photoperiod on resumption of cycles in fall-calving cows. Cows that experienced normal winter photoperiods had a longer period of post-calving anestrus than fall-calving cows provided with artificial long days. The delay in resuming cycles was particularly dramatic in first-calf heifers. The short days of late fall and early winter may delay estrous cycles after calving.
Reproductive management strategies
Clearly, proper nutrition is the key to effective reproductive management. Certainly, turning lights on for fall-calving cows is not an option. However, ranchers can use sound management and technology to enhance pregnancy rates. The focus should be on enhancing the percentage of cows conceiving early in the breeding season.
Bull management
Natural-service sires used for breeding in late fall and early winter (fall calving) tend to get overconditioned during the non-breeding season unless they were used to breed cows earlier in the year. Canadian researchers determined that BCS 4-6 was optimum condition for breeding bulls. In fact, there was a huge reduction in semen quality and fertility in bulls that were BCS 7 and up. Reductions in semen quality due to overconditioning or late-summer heat stress can take up to 60 days to repair. So bulls need exercise starting in early fall. Putting mineral supplements and water at opposite ends of the pasture creates forced exercise.
Bull breeding soundness exams are a must for high fertility. Even bulls that passed a breeding soundness exam in the spring or bred cows in spring/summer need a new exam. Remember, passing a breeding soundness exam means a bull is not infertile; it does not guarantee him as an effective breeder. Bulls should be observed during the first few days of the breeding season for libido, ability to identify cows in heat and success in servicing cows.
Estrous synchronization for artificial insemination (A.I.) and natural service
Since fall-calving cows may be delayed in resuming cycles, using estrus synchronization involving a controlled internal drug release device (CIDR) will cause acyclic cows to come into heat earlier. The progesterone in the CIDR triggers a change in the cow’s brain post-calving to initiate estrous cycles. For more information on estrous synchronization systems for A.I. and natural service, consult the Beef Reproduction Task Force website.
Cold-weather breeding
In northern areas, extreme cold can be an issue for A.I. or natural service. However, cold rain and deep mud in the South are also stressful for cattle. Providing windbreaks and areas with good footing can improve natural-service pregnancy rates. Having proper facilities, preferably with heat, as well as electric gun warmers, is essential to minimize cold shock of semen during A.I. Cold, wind, rain, snow and mud all create additional nutritional needs for cattle. Research over the past several years clearly demonstrates that reducing energy intake (or increasing demands) can increase early embryonic mortality. So feed to cattle needs to be adjusted to compensate for weather conditions.
Fall calving has its advantages for calf survivability, marketing and reducing calving stress. However, the challenges of fall and winter breeding require some adjustments to management to ensure success.
