Update on Research Activities at the Rayner Dairy Research and Teaching Facility, University of Saskatchewan

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Source: SaskMilk

Dr. T. Mutsvangwa, Professor of Ruminant Nutrition

This is the final portion of the three-part series about research activities at the Rayner Centre. more detailed information, please contact the principal investigators (P.I.) for the individual projects using the contact details provided. Planned Research Projects

▪ Evaluation of quinoa seeds as a feed ingredient in dairy cow diets. Quinoa (Chenopodium quinoa Wild) is a high value, pseudocereal crop that is grown for its edible seeds. It has become one of the most popular health foods across the world because, inter alia, it is gluten-free, is high in protein and anti-oxidants, and has an excellent balance of all the nine essential amino acids. Because of a growing demand for quinoa seed for human consumption, available data indicates that the total acreage of quinoa grown has increased from 5,000 acres in 2015 to more than 35,000 acres in 2017, representing a 600% expansion in quinoa acres. The total harvest in 2017 was 12,250 MT. Of this amount, 3,675 MT were off-grade, and could not be used for human consumption. Quinoa seed contain relatively high levels of starch (38.5-46.9%), protein (12-13.4%), and fat (4.04-5.08%), so it has potential to be used as a feed ingredient in dairy cow diets. This study will evaluate the impact of feeding graded levels of quinoa seeds (as an alternative feed ingredient) on production in dairy cows. Partial funding support is available from an industry partner, and there are efforts to secure additional funding from ADF. The P.I. on this project is Dr. Tim Mutsvangwa (306-966-1695; tim.mutsvan@usask.ca).

▪ Evaluating the optimum calcium content in low-energy, pre-partum diets with or without anionic salts for dairy cows. In early lactation, dairy cows often fail to consume adequate amounts of feed to meet their nutrient requirements for milk production, thus they “milk off their backs” to support nutrient requirements for production. This can put cows at risk of metabolic diseases, which can result in unhealthy cows that produce less milk, often require veterinarian care, are less fertile and thereby cause economic losses for dairy farmers. In the last few years, research studies and on-farm observations have provided evidence that feeding low energy pre-partum diets might improve feed intake in fresh cows, thereby decreasing the incidence of metabolic diseases in fresh cows. With this approach, pre-partum diets are fed to far-off and close-up dry cows that contain less energy (~1.30 Mcal NEL/kg) than previously recommended (~1.60 Mcal NEL/kg), thus avoiding the undesirable overconsumption of energy prior to freshening. This approach has gained popularity on dairy farms in western Canada; however, it has not been established if the inclusion of anionic salts in close-up, low energy diets is necessary. Traditionally, anionic salts have been included in close-up dry cow diets to manipulate the dietary cation-anion balance (DCAB) as a strategy to minimize the risk of milk fever. Also, it has not been established what the optimum dietary content of calcium is in low energy close-up diets. Traditionally, a dietary calcium content of 0.60% has been recommended but there is anecdotal evidence that a calcium content of 1.2% might be beneficial in terms of minimizing the risk of milk fever. A study will be conducted to determine the interactions of DCAB and dietary calcium content on the risk of milk fever in dairy cows. Efforts are underway to secure funding from ADF. The P.I. on this project is Dr. Tim Mutsvangwa (306-966-1695; tim.mutsvan@usask.ca).

▪ The evaluation of flaxseed products as energy and protein sources for high-producing dairy cows. Canada produces about 40% of world flaxseed (also called linseed) production. Of the Canadian flaxseed production, Saskatchewan accounts for 60% of Canadian production. The recent 5-year average yearly Saskatchewan production was 736,000 MT. A high proportion (~80%) of flaxseed that is produced in Canada is exported; however, there is some recent activity by new processors, especially for oil (for the Chinese market) and whole flax products, and this could potentially result in increased local use of flaxseed. The primary market for disposal of the flaxseed meal will be dairy herds in western Canada. Typically, whole flaxseed contains 42-46% oil and 21% protein, making it a good supplement for dairy cows because of its high contents of energy (fat) and protein. Recent research on feeding whole flaxseed or flaxseed meal to dairy cows is lacking, with limited previous studies using dairy cows that were producing 14 kg of milk/d in a diet containing 10% expeller- or solvent-extracted flaxseed meal. Today’s dairy cows can produce well over 50 kg/d, so their energy and protein requirements are much greater than those of cows that were used in previous studies. This study will evaluate the effects of feeding whole flaxseed, solvent-extracted flaxseed meal and cold-pressed flaxseed meal to dairy cows on production in dairy cows. The P.I. on this project is Dr. Tim Mutsvangwa (306-966-1695; tim.mutsvan@usask.ca).

▪ Characterization of temporal changes in the peripheral neutrophil function of dairy cows during the pre- and post-calving period. Dairy cows have an increased susceptibility to illness and infection around the calving time that has been related to temporary immunosuppression during this period. Currently, it is unknown when neutrophil function is altered (pre- or post-calving period), how long it persists or how it differs in cows with different metabolic/production statuses. This study will allow the identification of risk factors for the development of endometritis and may allow the development of management strategies to improve individual animal health during this period. The overarching aim of the study is to understand the temporal changes in peripheral neutrophil function. The P.I. on this project is Dr. Dinesh Dadarwal (306- 966-7095; dinesh.dadarwal@usask.ca).