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The evaluation of heat and lignosulfonate treated canola meal as sources of rumen undegradable protein for lactating cows

University of British Columbia

Two studies were conducted to evaluate the effectiveness of moist heat and lignosulfonate (LS0₃) in increasing the rumen undegradable fraction of canola meal for use as a protein supplement for dairy cattle. In the first study, the in situ nylon bag and mobile nylon bag techniques were utilized to determine the dry matter (DM) and crude protein (CP) degradability of canola meal treatments in the rumen, intestines and total tract. Treatments consisted of untreated canola meal and canola meal heated at 100°C, with or without 5% LS0₃ (wt wt*1), for 0, 30, 60, 90 or 120 min. Results indicated that treatment of canola meal with or without 5% LS0₃ and heated at 100°C for 120 min was effective in reducing (P<0.05) the rumen degradation of DM and CP compared to untreated canola meal. The corresponding intestinal CP disappearances for untreated, heat treated, and LS0₃ plus heat treated canola meal following 8 h rumen pre-incubation were 15.9, 23.5 and 34.2%, respectively. The shift in degradability from the rumen to the intestines was accomplished without reducing total tract disappearance. The second study was undertaken to evaluate the effects of feeding diets containing three canola meal protein supplements, varying in rumen degradability, on nutrient digestibility and animal performance. Eighteen lactating multiparous Holstein cows were randomly assigned to treatment sequences in a 3 x 3 Latin Square design, replicated six times. Total mixed rations were formulated to be isonitrogenous and to contain approximately 30% corn silage, 20% grass silage, 24% barley, 4% soybean meal, 1% mineral and vitamin mix and 21% of one of the following canola meal sources: 1) untreated (U-CM); 2) heat treated (HT-CM); or 3) LS0₃ plus heat treated (LS0₃-CM) on a DM basis. Milk production and dry matter intake (DMI) were measured daily during each 42 d experimental period. Milk, blood and rumen fluid samples were taken during the third and fifth weeks. Total collections of urine and feces from nine cows occurred during the last 5 d of each experimental period. Milk production was greater (P<0.05) for cows fed LS0₃-CM diet (36.6 kg d"1) than U-CM diet (34.8 kg d'1), but did not differ from HT-CM diet (35.4 kg d"1). Cows supplemented with LS0₃-CM showed reduced (P<0.05) apparent CP digestibility and concentrations of rumen ammonium N, blood urea nitrogen and milk urea nitrogen compared to cows supplemented with U-CM and HT-CM. DMI and apparent digestibilities of neutral and acid detergent fibre were increased (P<0.05) in cows fed LS0₃-CM diet when compared to cows fed U-CM and HT-CM diets. The urinary excretion of N, as a percentage of N intake, was reduced (P<0.05) in cows fed LS0₃-CM diet relative to cows fed U-CM and HT-CM diets. The results of these studies showed that treatment of canola meal with 5% LS0₃ followed by heating at 100°C for 120 min was an effective means of increasing the proportion of protein digested in the intestines. When supplemented in the diets of lactating cows, the protein in LS0₃-CM was used more efficiently and was more effective as a rumen undegraded protein source than was the protein in HT-CM or UCM.

Thesis/Dissertation

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2009-06-29

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http://hdl.handle.net/2429/9822

Animal Science

University of British Columbia

UBCV

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