The cold, muddy conditions resulting from the ice and snow this year mean that cattle require more energy in their feed to maintain body weight and produce milk until grass is growing again.
If hay quality is poor, supplemental feed will be required to meet basic nutritional needs.
Dr. Michele Arnold, the University of Kentucky Ruminant Extension Veterinarian, shared the following thoughts on safeguarding the nutritional needs of a cow herd this winter.
An animal has several defenses against cold. The first is the hair coat which grows longer in winter and, when fluffed up and dry, helps conserve heat and repel cold. In winter conditions, a wet and muddy hair coat and easily double energy requirements, particularly if the animal is not protected from the wind.
Cold conditions are not too difficult for cattle but when rain and wind are added, heat loss is substantial. Supplementing cattle with adequate energy and protein feed sources is absolutely required to meet the animal’s basic needs if hay is of poor nutritional quality.
Not providing supplement results in depletion of body fat, followed by breakdown of muscle protein, and eventual death due to insufficient nutrition. The first symptom is a cow getting weak in the rear end, which is often mistaken for lameness.
Later she is found down and is unable to stand. Death follows within a day or two after going down. Multiple animals may die within a short time. At necropsy, the pathologist finds a thin animal with no body fat stored but the rumen is full of bulky, dry forage material (poor quality hay).
Despite having had access to free-choice hay, cattle can die from starvation. Although hay may look and smell good, a laboratory test for nutritional content is the only way to discover the true feed value.
Crude protein in the hay below 7-8% is inadequate and requires a supplement. Protein below that level does not provide enough nitrogen for the rumen “bugs” to do their job of breaking down fiber and starch for energy. Digestion slows down and cattle eat less hay because there is no room for more in the rumen.
Cattle are expected to eat roughly 2-2.5% of their body weight in dry matter but this may fall to 1.5% on poor quality hay. Many producers purchase “protein tubs” varying from 16-30% protein to make up for any potential protein deficiencies but fail to address the severe lack of energy in the diet.
In the last 60 days of pregnancy, an adult cow requires feedstuffs testing at least 50-55% TDN (energy) and 8-9% available crude protein while an adult beef cow’s needs in the first 60 days of lactation increase to 60-65% TDN and 10-12% available crude protein. Cold weather and mud will increase these requirements.
In addition to malnutrition in adult cattle, inadequate nutrition and weight loss severely affect the developing fetus in a pregnant cow. Correct nutrients and minerals are required in pregnancy to properly develop the calf’s immune system.
A weak cow may experience difficulty calving resulting in lack of oxygen to the calf during delivery, leading to a dead or weak calf. Calves born to deficient dams have less “brown fat” so they are less able to generate body heat and are slower to stand and nurse compared to calves whose dams received adequate nutrition during the last 100 days of pregnancy.
Trace mineral supplementation is another area of concern, as copper and selenium levels are often far below acceptable levels. Grass tetany may occur in late winter and early spring if lactating beef cattle are not offered a free-choice, high magnesium trace mineral continuously until spring. The absence of these vital nutrients is a major factor in disease development.
The best cattle nutrition program is to test hay and supplement with enough feed to make up for the deficits. Energy and protein are both crucial; protein tubs will not be sufficient to fulfill energy requirements.
Milk production, the return to estrus and rebreeding, and overall herd immunity are all improved with adequate nutrition. Actual feed/forage intake and body condition should be monitored throughout the winter and early spring.
Cattle should also have access to a complete mineral supplement and clean drinking water at all times.
Clint Hardy is the agricultural extension agent for the Daviess County Extension Office. He can be reached at 270-685-8480.