P. S. Mir

Effect of full-fat hemp seed on performance and tissue fatty acids of feedlot cattle

Gibb, D. J., Shah, M. A., Mir, P. S. and McAllister, T. A. 2005. Effect of full-fat hemp seed on performance and tissue fatty acids of feedlot cattle. Can. J. Anim. Sci. 85: 223‐230. Sixty individually penned steers (380 ± 39 kg) were fed barley-based finishing diets containing 0 (control), 9 or 14% full-fat hemp seed (HS) and effects on performance and tissue fatty acid profiles were assessed. At harvest, samples of pars costalis diaphragmatis (PCD) and brisket fat were collected from each carcass. Feeding HS did not affect (P > 0.25) dry matter intake (DMI), average daily gain (ADG), or gain feed ‐1 . Carcass traits were also unaffected (P > 0.35) by treatment. Feeding HS linearly increased (P < 0.001) proportions of C18:0, C18:3 and C18:1 trans-9 in PCD, and 18:2 trans, trans in both PCD and brisket fat. As well, HS linearly increased cis-9 trans-11 CLA (P < 0.001), total saturates (P = 0.002) and polyunsaturated fatty acids (PUFA) (P = 0.01) in PCD. The presence of C20:4, C20:5 and C22:5 was detected only in tissues of cattle supplemented with HS (P < 0.06). Linear reductions (P < 0.002) in C16:1 cis, C17:1, C18:1 cis-9, C20:1, and total unsaturates in PCD, as well as linear decreases in C17:0 (P = 0.04) and C17:1 (P < 0.001) in brisket fat were observed when HS was fed. Levels of HS up to 14% of dietary DM exerted no detrimental effect on the growth or feed efficiency of cattle as compared to cattle fed a standard barley-based finishing diet. Including HS in the diet had both positive (increased CLA content) and negative (increased trans and saturated fats) effects on fatty acid profiles of beef tissues.

Effects of synthetic conjugated linoleic acid (CLA) or bio-formed CLA as high CLA beef on rat growth and adipose tissue development

Two rat feeding experiments were conducted, concurrently, for 48 d, to determine the effects of feeding synthetic food-grade conjugated linoleic acid (CLA) containing 53% cis 9, trans 11 CLA and 44% trans 10, cis 12 CLA or bio-formed CLA as high CLA beef on adipose tissue development. In exp. 1, 30 (10/diet) weaned male Wistar rats (51 ± 0.65 g) were fed, ad libitum, a control diet, control with sufficient added synthetic CLA to achieve CLA concentrations of 1.1% of diet DM or the control, where the soybean oil in the diet was replaced with sunflower oil. In exp. 2, 20 (10/diet) weaned male Wistar rats (52.5 ± 2.5 g) were fed, ad libitum, diets in which freeze dried beef replaced the casein as the protein source. The meat in the two diets was derived either from steers raised without dietary oil or from beef from steers fed oil to increase CLA content by 144% from 3.36 to 8.20 mg g-1 lipid (high CLA beef). At the end of the experiment the rats were humanely sacrificed and the organs, muscles and the retro...

Effects of sunflower seed supplementation and different dietary protein concentrations on the ciliate protozoa population dynamics in the rumen of sheep

The effects of feeding a linoleic acid-rich sunflower seed supplement and different levels of dietary protein on protozoal numbers and fermentation parameters in rumen fluid were determined in an 84-d experiment with rumen-cannulated sheep. The experiment comprised four treatments, two with low crude protein diets [12% of dietary dry matter (DM)] and two with high protein diets (16% of DM). On both low and high protein diets, one treatment was without (Control) and one with the sunflower seed (high linoleic acid variety 6150) supplement (14% of dietary DM). The four diets used were based on corn silage and corn grain, and soybean meal was used to achieve the desired concentration of dietary protein. The sheep were fully fed each morning and rumen fluid samples were taken 2 h later on various days of the experiment (daily during the first 14 d for enumeration of protozoa). In addition, rumen fluid was sampled at different hours after feeding on day 43 of the experiment. Results showed a protozoa-decreasing...

Effect of feeding sunflower seeds on the performance, carcass characteristics, meat quality, retail stability and sensory characteristics of pasture-fed and feedlot finished beef

This study examined the effects of whole sunflower seed (WSS) supplementation on production parameters, carcass traits, and organoleptic characteristics of beef from steers slaughtered directly off pasture or after receiving a finishing diet. Ninety-six yearling steers (410 kg; SD = 44 kg) were randomly allocated to three pasture (P) dietary treatments: (1) supplemented with P-WSS (n = 48), (2) supplemented with cracked barley grain (P-BAR, n = 24), and (3) not supplemented (P-CON, n = 24). Steers rotationally grazed meadow bromegrass-alfalfa pasture for 66 d during the summer and consumed WSS and BAR at a rate of 0.75 and 1.79 kg head-1 d-1, respectively. At the end of summer grazing half the steers from each pasture dietary treatment group were moved to a feedlot (F) where they were fed high barley-based finishing diets. The remaining 48 steers continued with their dietary treatments on stockpiled pasture for an additional 47 d (SD = 11) until they were slaughtered directly off pasture. In the feedlot, ...

Effects of increasing dietary grain on viscosity of duodenal digesta and plasma hormone, glucose and amino acid concentrations in steers

Effects of increasing the proportions of dietary barley grain or corn on viscosity of duodenal digesta supernatant and concentrations of cholecystokinin (CCK), glucose and amino acids in portal plasma and concentrations of CCK, insulin and glucose in jugular plasma were determined. Four steers (374 ± 6.4 kg) were surgically fitted with ruminal and duodenal cannulae and indwelling portal vein catheters. The steers were fed diets containing 20, 40, 60, and 80% rolled barley or cracked corn (DM basis) replacing respective silages, in two experiments with 4 × 4 Latin square design. After adjusting the steers to the diets for 14 d, digesta samples from the duodenum and blood samples from the portal and jugular veins were collected twice daily for 5 d. Increasing the proportion of dietary barley or corn increased the viscosity [measured as centipoise (cP)] of duodenal supernatant (from 1.3 to 2.0 and from 1.5 to 2.8 cP, P < 0.05), respectively. Portal plasma CCK concentration increased linearly (2.4 to 4.9 pmol...

Effect of sunflower seed supplementation on the fatty acid composition of muscle and adipose tissue of pasture-fed and feedlot finished beef

This study examined the effects of whole sunflower seed (WSS) supplementation on pasture and in finishing diets on the fatty acid profile of muscle [gastrocnemius (GN), longissimus thoracis (LT), intercostals (IC)] and adipose tissue [subcutaneous (SQ), intermuscular (IM)]. Ninety-six yearling steers averaging 410 kg were randomly allocated to three pasture (P) dietary treatments: (1) supplemented with WSS (P-WSS, n = 48); (2) supplemented with cracked barley grain (P-BAR, n = 24), and (3) not supplemented (P-CON, n = 24). Steers rotationally grazed meadow bromegrass-alfalfa pasture for 66 d. After 66 d on pasture, half the steers from each dietary treatment were trucked to a feedlot where they were adjusted to finishing diets. The remaining 48 steers continued with their dietary treatment on stockpiled pasture for an additional 47 d (SD = 11) until they were slaughtered directly off pasture. In the feedlot, half the steers from each pasture dietary treatment were fed either a control (83% rolled barley, ...

Effects of dietary sunflower seeds on lactation performance and conjugated linoleic acid content of milk

The conjugated linoleic acid (CLA) concentration in milk and the lactation performance of cows fed either a control (CON) or a sunflower seed [SS; 7% of dietary dry matter (DM)] containing diet were compared in a 12-wk lactation trial, starting from week 3 after calving, with 17 multiparous and 8 primiparous cows. The CON and SS diets were isonitrogenous and provided 4 and 6% crude fat in the total mixed rations and were fed to 13 and 12 cows, respectively. Daily DM intake (DMI ), milk production and weekly body weights were recorded. Milk samples collected weekly at four consecutive milkings were individually analyzed for fat, protein and lactose content, and fatty acid composition. The DMI and milk production of the cows fed t he CON and SS diets were 20.5 ± 0.80 and 20.2 ± 0.80 kg d-1 (P > 0.05) and 38.2 ± 1.71 and 38.2 ± 1.71 kg d-1 (P > 0.05), respectively. No differences due to diet were observed for cow body weight, body condition score, or for content and yield of milk fat, protein and lactose. Th...

Effect of dietary soybean or sunflower seeds on milk production, milk fatty acid profile and yield of conjugated linoleic acid

Eight cows in mid-lactation were used to determine the effects of feeding diets containing soybeans (SBS) or sunflower seed (SFS) on conjugated linoleic acid (CLA) yield and concentration in milk during two 3-wk periods. All cows were fed a standard pre-trial diet for 2 wk, before assignment to treatment diets in both periods of the 2 × 2 cross-over design used in the study. The two treatment diets contained on a dry matter (DM) basis: (1) SBS: 20% barley silage, 34.7% barley grain, 30% alfalfa cube, 13% crushed soybean seed and 0.36% sunflower oil, and (2) SFS: 17% barley silage, 34.6% barley grain, 40% sunflower seed incorporated into alfalfa cubes (cubes comprised 18% whole sunflower seed and 82% alfalfa hay), and 6.5% heat-treated soybean meal. The ingredients in the two diets were adjusted so that they would provide similar levels of energy (1.5 MCal kg-1) and have similar nutrient composition with regard to protein (16.7%), ether extract (5.2%) and fibre components (41%). Milk samples were collected...

Residual metabolizable energy intake and its association with diet and test duration

The objective was to determine if end-of-test residual metabolizable energy intake (RMEI) is correlated with RMEI values calculated earlier in the test on steers fed two forage (silage) or four forage-grain diets. As the days on test increased the variation in RMEI decreased in all diets. In all but the 85% alfalfa + 15% barley grain diet, test duration for RMEI may be reduced from 105 to 84 d. In the 100% alfalfa silage diet, it may be further reduced from 105 to 63 d (Spearman r = 0.90; Pearson r = 0.94; P < 0.01). The duration of testing required to obtain reliable estimates of RMEI may therefore also depend on the type of diet being fed. Key words: Residual metabolizable energy intake, crossbred steers, correlations, forage-grain diets, test duration

Dietary oil rich in polyunsaturated fatty acids for ruminants: Post-ruminal digesta characteristics and their implications on production

Maximizing the production of ruminants requires high intakes of feeds that are energy dense, therefore feeds that are usually high in starch. Under these conditions there can be significant passage of partially digested feed starch and fibre to the small intestine. These digesta components interact in a manner that can diminish post-ruminal digestion and absorption. However, in ruminants, the effects of digesta composition on causing physical constraints to digestion and absorption, via increased digesta viscosity have not been given adequate consideration. While elevation of digesta viscosity as a means of reducing rate of nutrient absorption and re-absorption of compounds detrimental to health is a valid approach in humans, digesta viscosity may reduce the production potential of livestock. Thus, there is merit in reviewing the feeding strategies that lead to increased viscosity and how its mitigation can be managed through inclusion of oil in ruminant diets. The interactions between digesta composition...