Near the end of most winters, diagnosticians at the veterinary labs, veterinarians, and producers see a few aged beef cows in poor body condition and a rumen full of forage material (hay) just ‘run out of gas’ with a belly full of hay and green grass just around the corner. However, this winter, they have seen these ‘malnutrition’ cases on a much more frequent basis, at a much earlier date, and have seen younger cows affected.
The winter of 2013-14 has presented long periods of colder temperatures and greater snow/ice cover than most Kentucky beef producers have encountered in the past 20 years or so.
University studies have demonstrated that the lower critical temperature for cows with dry, heavy winter coat is 18F. If cows are wet, the lower critical temperature is surprisingly high, at 59F. For every degree drop below the low critical temperature, a cow must expend 2 percent more calories in order to maintain body heat and condition, and wind-chill. With the extended periods of low temperature this winter, if producers were not supplementing cattle with adequate energy and protein sources, hay alone was likely not providing sufficient nutrition to meet the animals’ needs. This sometimes resulted in depletion of body fat stores, breakdown of muscle protein, and death due to insufficient nutrition.
While the Spring/Summer of 2013 presented good growing conditions with greater hay production than in recent years, rainy conditions sometimes hampered efforts to take hay until it got ‘over-mature’. Even though hay may be put up dry, after waiting out rainy spells, it loses nutritional content. So, even though hay may look good, unless it is tested for nutritional content, it is difficult to know what the true feed value is. Cattle can actually ‘starve to death’ while consuming all the hay they can eat, especially if crude protein levels are 3-4 percent and TDN is less than 30 percent.
It is important to understand that the winter of 2013-2014 has been exceptionally difficult for cattle in Kentucky and cows are “pulled down” much more than we typically see in late winter. Consider supplemental feed to help your cattle through the next month or so until grass is growing and is past the “watery” stage. Adequate nutrition is not just important today but also down the road.
Continued milk production, the return to estrus and rebreeding, and overall herd immunity are also impacted over the long term. Continue to offer a trace mineral mix high in magnesium in order to prevent “grass tetany” at least through the first of May.