Alternative trace mineral supplementation strategies for improved cow performance

本研究将有助于制定最佳动物管理措施，以提高奶牛部门的盈利能力和微量矿物质（TM）补充方案，以提高肉牛的生产性能。这项工作将为养殖者在繁殖季节提供基于证据的矿物质补充策略建议，并减轻高硫酸盐水对繁殖的一些潜在影响。可注射TM溶液目前未在加拿大获得用于牛的许可；然而，使用有效的注射剂可以确保所有奶牛在进入繁殖季节时都有足够的TM状态。减少未怀孕奶牛的数量将导致更高的产犊率，增加断奶小牛的体重和奶牛企业的经济回报。一项为期3年的重复研究将在三个繁殖季节进行，涉及约240头成年肉牛。该研究将调查注射TM对生殖结果的益处（与单独补充TM自由选择相比）。产犊前4周测量奶牛矿物质状态基线值，按年龄随机分配阻断后进行处理。在产犊前4周、孕前4周和怀孕期间，每组抽取40头奶牛的血液样本以测定血清矿物质浓度。在产犊前4周、孕前4周、孕期和妊娠期，对所有奶牛进行身体状况评分。在繁殖季节，将管理63天的自然繁殖计划。在整个研究期间，将收集产犊前后的牧草剪枝和水样，并监测矿物浓度。将对血样进行TM浓度分析。在育种后35天，将使用超声波来确定是否怀孕。繁殖性能将通过测量总妊娠率和产犊率来评估。犊牛断奶体重也将每年记录下来，以确定每次处理的犊牛断奶公斤数。小牛的出生日期将被记录下来，以确定不同处理之间产犊分布的差异。将采用部分预算分析来比较提供多聚磷90和不提供可注射矿物的情况。

This study will help to develop best animal management practices to improve cow-calf sector profitability and trace mineral (TM) supplementation programs for improved beef cow performance. This work will provide producers with evidence-based recommendations for mineral supplementation strategies during the breeding season and mitigate some potential reproductive impacts of high sulfate water. Injectable TM solutions are not currently licensed in Canada for cattle; however, use of effective injections may ensure that all cows have adequate TM status entering the breeding season. A reduction on non-pregnant cows would then lead to greater calving rates, increasing the pounds of calf weaned and economic returns to the cow-calf enterprise. A 3 year replicated study will be managed over three breeding seasons and will involve approximately 240 mature beef cows. The study will investigate the benefits of administering a TM injectable (compared to supplement TM free choice alone) on reproductive outcomes. Baseline values of mineral status will be measured 4 wk pre-calving, and cows will be randomly allocated to treatment after blocking by age. At 4 wk pre-calving, 4 wk pre-breeding, and at pregnancy 40 cows per treatment will have a blood sample drawn to determine mineral serum concentration. At 4 wk pre-calving, 4 wk pre-breeding, at breeding, and at pregnancy, a body condition score will be determined for all cows. A 63-d natural breeding program will be managed during the breeding season. Pasture clippings and water samples will be collected pre- and post-calving and monitored for mineral concentration throughout the study period. Blood samples will be analyzed for TM concentration. Ultrasound will be used to determine pregnancy 35 d after breeding. Reproductive performance will be evaluated by measuring overall pregnancy rate and calving rate. Calf weaning weights will also be recorded each yr to determine kg of calf weaned per treatment. Calf birth dates will be recorded to determine differences in calving distribution between treatments.A partial-budget analysis will be used to compare provision of MultiMin 90 with no provision of injectable mineral.