Livestock producers have at least four months of winter ahead of them. Andrea Hanson, livestock extension specialist with Agriculture and Forestry, looks at the importance of developing a feed supply strategy at this time of year.
“By testing the various feeds and knowing the nutritional values of each, producers can avoid future issues and know that they are feeding the right feeds at the right time,” explains Hanson. “For every dollar winter feed costs are reduced, the net return or benefit to the operation is more than two dollars.”
Many of Alberta’s commercial cow herds are into their second trimester of pregnancy in November, and a cow’s needs are quite different in her first, second, and third trimester of gestation.
First trimester – “If cows came off pasture with a body condition score of less than 3 on a scale of 5, these thinner cows will require more feed to stay warm through the winter and grow a healthy calf,” she says. “Thinner cows would benefit from being sorted from the rest of the herd and fed separately, or perhaps with the first calf heifers.”
Second trimester – As long as the cows are in good condition, Hanson says that cows in this trimester just need to maintain maintaining body weight.
“Crop residue or swath grazing are two great feed sources that can reduce the overall cost of feeding the herd. To fully use feed while keeping nutrition at a consistent level, limit grazing is recommended. If the herd is provided the entire area at once, the cows eat all the heads and finer matter first, leaving the stems and course material for later. This is counter-productive at a time when their plain of nutrition needs to be increasing, not decreasing.”
Hanson says that throughout the time the cattle are on a cereal based diet - high in phosphorus - to monitor their calcium/phosphorus ratio to ensure this remains optimum. “Magnesium is typically deficient in cereal crops, increasing the risk of downer cows, or winter tetany. Feeding a 3:1 mineral during this time may be necessary. The addition of limestone to a 1:1 or 2:1 mineral is recommended.”
Third trimester - As a cow gets closer to calving, her dietary requirements for calcium and magnesium increase due to the growing calf and the cow’s production of colostrum. Four to eight weeks before calving, the cow’s body begins to mobilize calcium and magnesium from her bones to develop the colostrum. As a cow ages, her ability to mobilize those minerals decreases and along with high milking cows that just require more calcium and magnesium in general.
"During the third trimester, producers should start to supplement the cow’s diet with an alfalfa grass hay to bump the calcium content in the ration and provide more protein,” says Hanson. “Legumes are high in calcium so saving that alfalfa or alfalfa-grass hay for the last months of the third trimester and into lactation is a good idea.”
Monitoring the weather throughout the winter feeding season is also extremely important. “Cows can withstand cold temperatures as long as they have the body condition, or fat, to insulate them. Days of cold weather with no extra energy provided can decrease a cow’s body condition. A 1350 lb. cow at the end of her second trimester, with a BCS of 3.5 on swath grazing can eat free choice barley or oat greenfeed without any nutritional concerns in a daytime temperature of -10 C and a 10 km per hour wind. When the weather changes to -40 C for a daytime high and the same wind speed, in order for her to maintain her body weight, she needs to consume an additional five lb. of barley grain.”
“Feed is the biggest expense in a cattle operation,” she adds. “Producers need a strategy for their feed supply at the start of the year when they have more choices and can ensure that the right feeds are provided during the best time of the feeding season. If feed resources need to be purchased, finding the proper forage or grain can ensure that the cows’ nutrition is optimized.”
Source : Alberta agriculture and forestry