Originally published in the November 4, 2019 edition of Agri-News
A look at some of the issues facing cow-calf producers as temperatures drop.
“Feed quality and quantity in the province is all over the map this year,” says Barry Yaremcio, beef and forage specialist at the Alberta Ag-Info Centre. “That could create issues for cow-calf producers who are trying to wean a good size calf and maintain high levels of reproductive performance next spring.”
“If calves were not provided with creep feed over the summer, weaning weights will be lower than in most years – as much as 150 lb per animal,” he says. “A farm made mixture of one third peas and two thirds of barley or oats or a mix of the two cereals works well as a creep feed.”
He suggests weaning the calves 30 to 60 days early if the cows have lost condition and are thin.
“The calves can then be put on a good ration to maintain good rates of gain. Nutrient requirements for a dry cow are 25% lower than for a lactating cow. Having lower requirements may result in the cows gaining back the weight prior to the cold setting in. It is much easier for a cow to gain weight in the fall than in the cold winter months.”
Yaremcio adds that depending on the quality of the pasture, providing supplemental feed to the cows may be necessary. Putting cows into dry lot to prevent overgrazing the pasture is another option.
Cows entering winter in thinner than normal condition affects all aspects of production and reproduction.
“If a cow is 200 lb lighter than normal, a majority of the weight loss will be fat,” he explains. “The loss of fat reduces the amount of insulation the cow has to shield itself against the cold. Heat loss increases energy requirements, which in turn requires the animal to eat more feed.”
Yaremcio says that a thin cow will need an extra 1400 lb of hay just to stay warm over the winter – an additional cost of $84 per cow when hay is valued at $120 per ton.
“If temperatures drop below -20 C at noon, the animal will not be able to eat enough hay to keep warm. For every 10 C drop below -20 C at noon, an additional 2 lb of grain above the regular ration should be fed. Over a 3 week cold spell, it is possible for cow weight to drop 100 lb or more if additional grain is not fed.”
He adds that with the difficult conditions experienced when making hay this summer – frequent showers and rains, weather damage, turning of windrows – oxidation of the vitamin A and E precursors was much more rapid compared to years with good weather.
“Instead of waiting until the cows are in the last trimester, feeding of vitamins should start now to prevent deficiencies and nutrition related problems.”
A cow develops colostrum 6 to 8 weeks prior to calving, and he adds that it is critical that the ration has adequate nutrition especially sufficient amounts of vitamin E – 300 IU per day.
“Most of the vitamin E is passed through the colostrum to the calf and not through the milk. A thin cow cannot produce as much colostrum as an animal in good condition. The colostrum’s quality is compromised which can result in the calf not receiving an adequate amount of vitamin E or antibodies. Without these components, a calf will not have a strong enough immune system to combat illness at birth and for the first few months of its life.”
Milk production in a cow peaks around 8 weeks after calving, and maximum feed intake occurs 12 weeks after calving.
He notes that feed test results indicates that most of the forages are very low in protein and energy this year.
“A post-calving cow needs to eat forage, but also grain to supply energy and a source of supplemental protein such as canola meal, peas, lentils, faba beans or a commercial 32% supplement more than hay during early lactation.”
“The feeding of an ionophore such as Rumensin or Bovatec will improve digestive efficiency and allow the animals to get more out of the feeds they are eating. Otherwise, she will not receive adequate nutrition, and that can cause peak lactation to decline.”
“This loss of milk production continues throughout the entire lactation. If the energy supply is deficient, a cow can mobilize up to 1 lb of fat per day to offset the lack of energy to maximize milk production. It is almost impossible to have cows gain weight after calving.”
Cows that drop weight after calving can take 40 to 60 days longer to start cycling compared to those that maintains their weight.
He adds that first service conception rates are also 20 to 25% lower for thin cows compared to cows in good shape.
“Having cows deliver a calf one cycle late or 21 days after the start of the calving season can result in a calf weaning weight that could be 42 lb lighter. At current prices, that is roughly $80 per head loss in income. It is difficult to get cows to move up in the calving profile. If the cow is late one year, it is probable that the same problem will occur the next year.”
“First calf heifers typically have the highest open rate of any breeding group on the farm or ranch when they are trying to conceive their second calf,” he says. “These animals are only 85% of mature body weight when they calve out the first time.”
Yaremcio adds that they are expected to provide milk to their calf, increase their own body weight and become pregnant again.
“Feed the bred heifers separate from the main cow herd. Providing them with a higher quality ration prior to first calving improves their probability of becoming pregnant the second time. If possible, continue to feed the second calf heifers separate from the main cow herd as well.”
“Feed testing and balancing rations this year is very important especially with the use of non-traditional forages or when using straw based rations,” he says.
“If necessary, feed straw-based rations with grain prior to calving and save the good hay for after calving. There are big differences in what is required for mineral and vitamin supplementation when using straw, slough hay, or byproduct feeds such as wheat distillers’ grains with solubles.”
He adds that using an ionophore such as Rumensin or Bovatec improves digestive efficiency by 6 to 7% and is a good investment when feeding high fibre diets.