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Effects of untreated and heat-treated canola presscake on milk yield and composition of dairy cows
Institution:1. Department of Animal and Poultry Science, University of Saskatchewan, 72 Campus Drive, S7N 5B5 Saskatoon, SK, Canada;2. Department of Animal Science, McGill University, Macdonald Campus, 21111 Lakeshore, Ste-Anne-de-Bellevue, QC, Canada H9X 3V9;1. MTT Agrifood Research Finland, Animal Production Research, Tutkimusasemantie 15, FI-92400 Ruukki, Finland;2. Department of Agriculture for Northern Sweden, Swedish University of Agricultural Sciences, S-90183 Umeå, Sweden;1. Department of Animal Science, University of Nebraska–Lincoln, Lincoln 68583-0908;2. USDA Agricultural Research Service, US Meat Animal Research Center, Clay Center, NE 68818;3. Poet Nutrition LLC, Sioux Falls, SD 57104;1. Sherbrooke Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada J1M 0C8;2. Département de Sciences Animales, Université Laval, Québec, QC, Canada G1V 0A6;2. Institut für Kulturpflanzenwissenschaften, Fachgebiet Biostatistik, Universität Hohenheim, 70599 Stuttgart, Germany;2. INRA, UMR1348 Pegase, F-35590 Saint-Gilles, France;3. Agrocampus Ouest, UMR1348 Pegase, F-35000 Rennes, France
Abstract:Five primiparous and five multiparous Holstein cows were used in two Latin square design experiments to determine effects of feeding unheated and heated canola presscake on milk yield and composition, and milk fatty acid concentrations of lactating dairy cows. Five diets that differed in level and source of dietary fat were formulated: a low fat control diet with 30 g kg?1 fat from tallow, an unheated canola presscake supplemented diet (50 g kg?1 fat), a heated canola presscake supplemented diet (50 g kg?1 fat), a high tallow plus unheated canola meal supplemented diet (50 g kg?1 fat), and a high tallow plus heated canola meal supplemented diet (50 g kg?1 fat). In sacco ruminal degradability of heated and unheated canola presscake was compared with that of heated and unheated canola meal in a randomized complete block design using two ruminally fistulated cows. Heat treatment reduced ruminal DM and CP degradability of canola presscake. Multiparous cows fed diets supplemented with heated or unheated canola presscake produced more milk than those fed diets containing similar levels of fat from tallow with heated or unheated canola meal, respectively. High levels of fat from any diet reduced milk fat percentage for cows of either parity. Feeding heated canola products increased milk and milk protein yields in primiparous cows only, but cows of both parities fed diets containing canola presscake produced milk with lower concentrations of C12:0, C14:0, and C16:0 fatty acids than cows fed the canola meal and tallow diets, although concentrations of C18:1 n-9 were unaffected by fat source or level. Feeding canola products to dairy cows can alter milk fatty acid profile, but only primiparous cows have increased productivity as a result of feeding heated, versus unheated, canola presscake.
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