62 NEBRASKA CATTLEMAN January 2025 The easiest and most practical management strategy to decrease nighttime calving is to feed cows at dusk. It is uncertain the physiological mechanism behind how time of feeding can program when a beef female will calve, but some hormonal effect is likely involved. Rumen motility studies indicate the frequency of rumen contractions falls a few hours before calving/parturition. Pressure in the rumen begins to fall in the last two weeks of gestation, with a more rapid decline during calving. It has been suggested that night feeding causes this intraruminal pressure to rise at night and decline in the daytime. Data Supports Nighttime Feeding: • A rancher in Manitoba first developed this feeding management strategy after he discovered that 80 percent of his cows calved between 7 a.m. and 7 p.m. when they were fed later in the day. This included twice-a-day feeding, with the first feeding between 11 a.m. and noon and the second feeding between 9:30 and 10 p.m. • In research conducted at Iowa State University, cows were fed once per day at 4 p.m., starting two weeks prior to the expected start of calving. This feeding strategy resulted in 82 percent of cows calving between 6 a.m. and 10 p.m. Calves born between 5 a.m. and 11 p.m. (75 percent of the 24-hour day) was 91 percent. Only 9 percent of calves were born outside this time frame. When heifers were separated from the data set, 90 percent of the heifers also calved in this same time frame. • A survey collected from 15 beef producers in Iowa and Missouri reported that feeding once daily between 5 p.m. and 10 p.m. resulted in 85 percent of cows calving between 5 a.m. and midnight. By comparison, cows in these herds fed in the morning (a more traditional feeding schedule) resulted in 50 percent calving during the day and 50 percent at night. This is the most convincing data because it included 1,331 cows with 15 farms contributing to the survey. • Researchers at U.S. Department of Agriculture’s Agricultural Research Service at Miles City, Mont., completed a threeyear study evaluating differences in feeding time on calving time, but the numbers were not as dramatic as the Canada and Iowa State data. However, there was a consistent 10 to 20 percent decrease in the number of cows calving between 10 p.m. and 6 a.m. in the late-fed cows compared to the early-fed cows. • For cows grazing pasture and supplemented to meet a nutrient deficiency, feeding the supplement at dusk will likely not result in more cows calving during the daytime. A supplement would be feeding a small amount of a feed to meet a nutrient gap, so it is not like feeding cows a full feed of hay. NIGHTTIME FEEDING, DAYTIME CALVING CONTINUED FROM PAGE 60 CONTINUED ON PAGE 64 © Doverspike www.wvmcattle.com wvm@wvmcattle.com (530) 347-3793 Market where you’re a Name, Not a Number Monday, January 6 - North Platte, NE Thursday, January 23 - Red Bluff, CA Friday, February 28 - Cottonwood, CA Upcoming Sales
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