Weather and birth weight
Does winter weather influence calf birth weights? Based on some new research from the University of Nebraska’s 1996 Beef Cattle Report, the answer appears to be yes.
Groups of heifers were fed and managed the same for each year of the study (1992-95). They were kept on native range until January and then fed bromegrass hay freely with alfalfa hay as a supplement. Heifers had similar precalving condition scores and pelvic sizes in each of the years. Heifers were artificially inseminated as yearlings to the same four Angus sires.
Read Also
VIDEO: Green Lightning and Nytro Ag win sustainability innovation award
Nytro Ag Corp and Green Lightning recieved an innovation award at Ag in Motion 2025 for the Green Lightning Nitrogen Machine, which converts atmospheric nitrogen into a plant-usable form.
Data collected
Among the calving data collected was birth weight and calving difficulty. Calf birth weights were analyzed by week, month and year with the effects of calf sire and sex removed.
High and low air temperatures and wind chill data was collected from October through March in each year.
After the data was analyzed, the winter of 1992-93 was considered severely cold, while that of 1994-95 was quite mild.
Calf birth weights were found to be an average of 11 pounds lighter in 1995 compared to 1993, along with a 22 percent decrease in calving difficulty. Average air temperatures and wind chills were 6 C warmer in 1995. The increased blood flow to the uterus due to cold temperatures was believed to be the major factor increasing fetal growth.
Although Nebraska researchers indicated more work is needed to confirm these findings, they concluded that in a cold winter producers could probably expect heavier calves at birth and more calving difficulty.
The use of shelter or wind protection during these winters would reduce the wind chill effects and be beneficial at calving.
– Animal Industry Nutrition Update
