Nutrition and environmental differences between spring and fall calving herds are important to understand and manage. Depending on location, heat and cold stress can both be factors in the fall breeding season. If farther south, heat stress at the beginning of the season can still be a concern. So, ensuring shade, good water availability, and good ventilation is important.
In contrast, winter weather can be a challenge late in the fall breeding season. Cold stress can be mitigated with windbreak, bedding, and shelter. Cold weather, freezing conditions, and icy terrain can make breeding more difficult and dangerous for both the cow and the bull. Keeping cattle on solid ground and away from rough terrain can reduce injury risk. If housing cows in lots, pen conditions and stocking rate can greatly impact expression of estrus and safety of a natural breeding scenario.
As winter sets in, grazing opportunities decrease, and rations shift to harvested feeds. Thus, stored forages and feedstuffs need to be evaluated. Test forages for nutrient analysis. This will aid in least-cost ration balancing and ensure adequate nutrients are being delivered in the ration. If growing conditions were adverse, testing for nitrates, mycotoxins, and bacteria could be necessary. Feed contaminants could interfere with hormones and cause health challenges leading to breeding failure.
Source : illinois.edu