Effects of Winter Grazing on Performance of Gestating Beef Cows in Northern Ontario
The project funded the feeding of 58 multiparous, pregnant cross-bred cows (approximately 675 kg liveweight) at the New Liskeard Agricultural Research Station over the fall and winter of 2014. These cows were in their last trimester. Twenty head were initially housed outdoors while the remaining 38 head were housed in the Calan gate barn where feed intakes for individual cattle were measured. Five management regimens were examined in the study. Cattle housed outdoors included 10 cows housed on paddocks for stockpile grazing and 10 cows housed in a corn field with access to standing whole corn plants and a round bale feeder filled with a legume/grass hay. Cattle in the barn were fed one of 3 diets which included ad lib feeding of: 1) alfalfa haylage, 2) 75% haylage/25% wheat straw diet, 3) 75% haylage/25% wood fines diet. Wheat straw and wood fines were incorporated into the diets to dilute the amount of high quality forage being fed to the cows to lower cost of feeding the cows and allow the high quality forage to be used for classes of cattle that have greater nutrient demands than gestating beef cows. The wood fines represent a low cost feedstuff which can be used as a filler to satiate the cow while lowering feed costs for the cow-calf producer. The cows were weighed every 14 days with body condition score determined. The cows were bled at the start and the end of the trial along with the cattle being ultrasounded at the start, mid-point, and end of the trial to determine body composition. Wet weather delayed the start of the trial for cattle grazing outdoors. Once the trial began, a major ice storm developed such that cattle were no longer able to access the stockpiled forage and the cows had to be moved to the Calan gate barn within 30 days of being placed on the stockpiled pasture. The summer of 2014 turned out to be a bad year for growing corn at New Liskeard such that grain deposition was limited in the cobs so that the cattle were consuming mostly forage. A harsh winter ensued such that by January 9th, the cows were no longer grazing the corn and were spending most of their time huddled by windbreaks. Based on ensuring animal welfare, the cows were removed from the corn field and placed in the Calan gate barn. Not surprising, the cows fed ad lib haylage gained the most weight over the winter feeding trial with no changes in body condition score. The cows fed haylage with straw or wood fines gained lower amounts of weight over the winter feeding trial but were able to maintain their body condition throughout the trial. The cattle that started outdoors on pasture or in the corn field were not able to maintain their body condition despite being placed on a haylage/straw diet once they arrived in the barn. While these cattle had the lowest overall weight gains of all the cows in the trial, there was no effect of management regimen on calf birth weights or weaning weights. As previously stated, weather impacted standing corn quality with limited grain deposition, the start of the trial for cattle housed outdoors, and the length of time that cattle were able to graze stockpiled forage or the standing corn. While we did provide hay to cows in the corn field, the harshness of the winter resulted in the cows remaining by the windbreaks and not actively consuming the standing corn or conserved forage. The cows were moved indoors and the grazing corn trial ended earlier than planned. The wood fines used in the barn trial are commonly used as bedding material for livestock producers. This study found that replacing haylage with wood fines at 25% of the diet produced comparable animal performance as cows fed a haylage diet where 25% wheat straw was fed in the diet. Often high quality forages are fed to cows which can result in the consumed nutrients well exceeding the cow’s requirements despite the cow being in the third trimester when the nutrient requirements are the greatest for gestation. The study found that low cost wood fines can replace high quality forage in a gestating cow diet without affecting cow condition, calf birth weights, and calf weaning weights. This provides the opportunity for beef cow-calf producers to better utilize high quality forage for cattle that have greater nutrient requirements than gestating cows or to possibly market the high quality conserved forage as an additional revenue stream.
The immediate outcome of this study is that the weather plays a major role in how cows perform when winter grazing in northern Ontario. Poor weather conditions compromised access to stockpiled forage such that cows had to be removed from extended grazing. Harsh winter conditions compromised the welfare and behavior of the cows on pasture such that they had to be removed when they stopped normal grazing and feeding behaviors. The study found that low cost wood fines can be used to replace high quality forage in a gestating cow diet without affecting cow condition, calf birth weights, and calf weaning weights. This widely available material is normally used for bedding. Based on this study, this material can be used to dilute the diet of the gestating beef cow so that she is satisfied with the quantity of feed she is getting per day as compared to a limit feeding strategy which the cows may be continuously looking for something to eat as they are still hungry when provided limited amounts of feed on a daily basis. Our findings with the wood fines provide the opportunity for beef cow-calf producers to better utilize high quality forage for cattle that have greater nutrient requirements than gestating cows or to possibly market the high quality conserved forage as an additional revenue stream. More work is needed to examine progeny performance from these cows and to examine if cow longevity is affected.
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