|Endecott, Rachel - MONTANA STATE UNIV|
Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 2, 2008
Publication Date: June 23, 2008
Citation: Endecott, R.L., Waterman, R.C. 2008. Use Of A Self-Fed, Small-Package Protein Supplement For Beef Cows Post-Weaning. Proceedings, Western Section, American Society of Animal Science 59:322-325. Interpretive Summary: Low amounts of supplemental protein, particularly from sources high in ruminally undegradable protein (RUP), may enhance the efficiency of nitrogen utilization. Further, nutrient restriction also increases the efficiency of nitrogen utilization in cows. Supplement based on small quantities of high-RUP ingredients combined with salt and minerals has been demonstrated to maintain ruminal function with low quality forage diets and exhibited controlled and consistent consumption patterns by cows grazing desert range. In a 3-year field study in central New Mexico, gestating cows consuming a small-package, self-fed supplement (25% feather meal, 25% blood meal, and 50% mineral mix) maintained weight and body condition during late fall and early winter, and had similar performance to cows fed a traditional, hand-fed oilseed-based supplement. The objective of this study was to evaluate the effectiveness of a self-fed small-package supplement for maintaining body weight of post-weaning beef cows grazing native range in the Northern Great Plains. Strategic protein supplementation with a small-package, self-fed supplement did not impact cow performance. However, target intakes were not achieved, which may have contributed to the lack of response to supplementation with the mineral-protein mix.
Technical Abstract: A 60-d supplementation study conducted at Miles City, MT from mid-October to mid-December 2007 evaluated responses of beef cows (n = 141; avg BW = 535 kg) grazing dormant native range (8.8% CP (OM basis), 70.4% NDF (OM basis), 76.7% IVOMD) to two different supplementation strategies. Cows were stratified by age and weight at weaning and then assigned to one of two supplements: 1) self-fed loose mineral mix (MIN) or 2) self-fed mineral plus high-bypass protein sources (MIN+PRO; 50% mineral mix, 25% feather meal, 25% fish meal). Target intakes were 70 g/d for MIN and 140 g/d for MIN+PRO. Cows were weighed and hip height and girth measurements were taken at the beginning and end of the study. Weight-to-height and weight-to-girth ratio changes were calculated. Data were analyzed with cow age, supplement and their interaction in the model. Cows fed MIN consumed 28 g/d and MIN+PRO cows consumed 93 g/d, which was lower than the expected target amount for both supplements. Cow age × supplement interactions were not observed (P>=0.22). Weight change, weight-to-height ratio change, and weight-to-girth ratio change were similar regardless of cow age (P>=0.79). Cows lost similar (P = 0.62) amounts of weight during the study regardless of supplement treatment (-28 and -30 ± 4 kg for MIN and MIN+PRO, respectively). Likewise, weight-to-height ratio change (-0.31 and -0.32 ± 0.03) and weight-to-girth ratio change (-0.13 and -0.15 ± 0.02) were similar (P>=0.63) for MIN and MIN+PRO cows, respectively. Protein supplementation at this level did not impact cow performance. However, target intakes were not achieved, which may have contributed to the lack of response to supplementation with the mineral-protein mix.