All right, so what’s next with our weather? Ample rains earlier this year made harvesting high-quality forages a struggle in many parts of Illinois.
This fall, we have seen temperatures that were above average, so much so that hay was being baled during the first part of November. However, we all know that winter is just around the corner, and everyone with livestock must be prepared.
Low temperatures or rains and muddy conditions can significantly increase the energy required by livestock metabolism to provide enough heat for animals to maintain body temperature. But animals that have less body condition and fat might need to be supplemented sooner to be able to produce the energy needed to cope with the cold weather.
Animals have a thermoneutral zone — a temperature range in which the animal is most comfortable, not under any temperature stress and that is considered optimum for body maintenance, health and animal performance.
It also is the temperature range where the fewest nutrients are needed to maintain bodily functions. For example, cattle perform optimally when the temperature is between about 59 to 77 degrees, when they are neither too hot nor too cold.
However, livestock experience cold stress below the lower boundary of the thermoneutral zone. That is they have reach their lower critical temperature, and the animal’s metabolism, generally by shivering, must increase in order to maintain body temperature. Shivering requires more energy, either from fat stores or more energy intake in the diet.
The lower critical temperature is influenced by an animal’s size, age, breed, nutrition, housing conditions and hair coat or wool thickness. The thicker the hair coat or wool, the more the LCT decreases.
The LCT temperature of cattle for a summer hair coat or a wet hair coat is 59 degrees. The LCT temperature for a winter hair coat is 32 degrees, and for a heavy winter coat, it is 18 degrees.
The LCT for goats generally is considered as 32 degrees, and for sheep, the LCT is 50 degrees if freshly shorn or 28 degrees with 2.5 inches of fleece.
Livestock producers need to keep in mind that once an animal’s coat is wet, regardless of how heavy it is, the LCT actually increases because hair coats lose their insulating ability when wet.
This is particularly true for cattle, horses and goats. Sheep are the exception because wool is able to shed water therefore maintaining its insulating capabilities.
We feel the bite of wind during winter, and so do livestock. Wind speed produces wind chill and can further increase energy requirements for livestock when those values are below the LCT. Consider the combination of wind chill and wet hair coats — a potentially deadly combination.
Livestock require more energy, not protein, to make it through the winter months. More energy means additional high-quality forages and grains.
It is a myth that grain rations are hotter rations. High-quality forage rations actually provide more heat for livestock.
For cattle, the general rule of thumb is that energy intake must increase by 1 percent for each degree of cold below the LCT. It is estimated that for every one degree below the critical temperature, a cow’s energy requirement increases 1 percent.
It also is estimated that for every 10 degrees below the critical temperature, the digestibility of the ration decreases by 1 percent. This means that when the temperature drops below the critical temperature, livestock need to be better fed.
This also is where the nutritional level of the animal’s diet becomes a factor. If average to good quality hay is being fed, the animal might be able to increase intake enough to meet the additional need for energy.
If forage quality is low, it is unlikely that the animal can increase intake enough to meet increased energy demands. In the short run, if animals are in good body condition, they can burn fat reserves to compensate.
If poor quality forage is the only forage option or if there is an extended period of very cold weather, then some additional energy supplementation will need to be provided to the animals.
It is important to provide livestock access to barns or provide windbreak protection to reduce the effects of wind chill on energy requirements.
Livestock should have access to high quality forages or supplement poorer quality forages to increase energy intake by providing a high-energy, non-starch feedstuff. Ensure access to ample fresh clean water.
Remember the snow and cold blowing wind can be dangerous not only for you, but your livestock.