Rumen-protected Fat Research Articles

Insulin-dependent whole-body glucose utilization and insulin-responses to glucose in week 9 and week 19 of lactation in dairy cows fed rumen-protected crystalline fat or free fatty acids

Whole-body insulin-dependent glucose utilization and insulin responses to glucose in euglycemic-hyperinsulinemic clamps (EHGC) and in hyperglycemic clamps (HGC) were evaluated in high yielding dairy cows fed rumen-protected fat (triglycerides), free fatty acids, or a starch-rich ration ( n = 5 per group) in Week 9 and Week 19 of lactation. The experiment was performed under conditions of nonsignificant differences in energy and protein balances in Week 9 and Week 19 and in the three groups. Basal (pre-infusion) concentrations of glucose were lower (P < 0.05) in Week 9 than in Week 19 of lactation and were higher (P < 0.05) in Week 9 in cows fed free fatty acids than in cows fed the starch-rich ration. In EHGC, glucose infusion rates were similar in Week 9 and Week 19 and in the different groups, indicating similar insulin-dependent glucose utilization. Furthermore, because insulin concentrations in EHGC in Week 9 and Week 19 and in the three groups were very similar, metabolic clearance rates of insulin were not affected by stage of lactation and feeding. In addition, insulin responses to the same glucose increments in HGC were not different in Week 9 and Week 19 and in the three groups, indicating that insulin secretion was not affected by stage of lactation and feeding. In conclusion, insulin secretion, insulin metabolic clearance rate, and insulin-dependent glucose utilization between Week 9 and Week 19 of lactation were stable. Furthermore, feeding rumen-protected triglycerides or free fatty acids did not significantly modify insulin secretion, insulin metablic clearance rate and glucose-dependent glucose utilization compared with starch-rich feeding.

Effects of graded levels of dietary rumen-protected fat on milk characteristics of Comisana ewes

Comisana ewes (27) were divided into three groups of nine. Control group was fed a vetch and oat hay and a pelleted concentrate. The other two groups were given the control ration supplemented with 4 and 8% rumen-protected fat. The feeding treatment caused significant variations in the characteristics of milk, and these variations showed a good correlation with the level of protected lipids in diets. Caproic acid (C 6:0), caprylic acid (C 8:0), capric acid (C 10:0), lauric acid (C 12:0) and myristic acid (C 14:0) contributed mostly in the control group, while palmitic acid (C 16:0), oleic acid (C 18:1) and linoleic acid (C 18:2) were predominant in the groups fed with the supplemental rumen-protected fat. Also, a significant increase in the ratio between medium- and long-chain fatty acids (C 16:0+C 18:1+C 18:2) and short-chain fatty acids (C 6:0+C 8:0) was found to be a major source of variation related to the rumen-protected fat supplementation. Dietary lipid supplementation was effective in improving the unsaturated-to-saturated fatty acid ratio in milk ( P<0.01), but had a detrimental effect on milk protein content ( P<0.01). Therefore, these results suggest that the addition of rumen-protected fat in diets for lactating ewes may improve the composition of milk fat, but it should be associated with supplemental dietary protein or, better still, rumen-protected amino acids to alleviate the decrease in milk protein due to fat supplementation.

Potential of various fatty feeds to reduce methane release from rumen fermentation in vitro (Rusitec)

The effects of coconut oil and whole crushed oilseeds (rapeseed, sunflower seed and linseed) on rumen fermentation, as well as on methane and hydrogen release, were evaluated in vitro employing the rumen simulation technique (Rusitec). A low-fat diet served as the negative control and a diet with rumen protected fat as the positive control. By using two different proportions of concentrate in the diet, 6% and 9% of total lipids were supplied with each of the five fat supplemented diets, whereas the control diets contained about 3% total lipids. The 12 diets were provided at daily amounts of 11 g and 22 g dry matter. Rumen-protected fat as well as rapeseed had small effects on fermentation pattern and methane formation, which presumably resulted from the exchange of carbohydrates by fat. In contrast, coconut oil, sunflower seed and linseed significantly reduced protozoa count and methane release. An increased fat supply by the higher concentrate proportion further supported the suppressing effects of these types of fat on protozoa and methane. Coconut oil completely eliminated protozoa from rumen fluid after four to nine days of application, and this period was shorter by more than 30% on average at the higher level of supply. As compared with the low-fat treatment, coconut oil suppressed methane by 43% with medium and 57% with high concentrate level. The maximum methane reduction with sunflower seed and linseed accounted for about 40%. An increase in hydrogen release was found with coconut oil and oilseeds which, however, was considerably lower than the hydrogen quantities that were less incorporated into methane. In these situations, hydrogen recovery, as calculated from hydrogen balance, was reduced.

Longissimus dorsi muscle diameter, backfat thickness, body condition scores and skinfold values related to metabolic and endocrine traits in lactating dairy cows fed crystalline fat or free fatty acids.

An experiment was performed using 18 dairy cows with > or = 2 lactations from parturition until week 20 of lactation to investigate the effects of feeding rumen-protected crystalline fat (group A) or free fatty acids (group B) compared with a control group not fed supplemental fat or fatty acids (group C). The feeding effects studied were those on milk yield and composition, body weight (BW), body conditions scores (BCS), skinfold values (a measure of subcutaneous fat tissue thickness), backfat thickness and longissimus dorsi muscle diameter (measured by ultrasound), as well as on blood plasma metabolic and endocrine traits. Fat and fatty-acid feeding reduced roughage intake. Net energy and protein balances during the first week of lactation were negative. Milk yield was similar in all groups, but concentrations of milk fat were reduced in group B and of milk protein in groups A and B. BW, BCS, skinfold value, backfat thickness and longissimus dorsi muscle diameter similarly decreased in all groups until weeks 8-12. Concentrations of glucose and fructosamine decreased transiently during early lactation, whereas levels of beta-hydroxybutyrate, urea, total protein and albumin increased reversibly and similarly in all groups. Concentrations of creatinine decreased similarly in all groups until week 4 and those of nonesterified fatty acids until week 12. Triglyceride concentrations increased continuously until week 18, whereas concentrations of phospholipid and cholesterol increased until week 10 and then remained elevated. Triglyceride, phospholipid and cholesterol concentrations were higher in group B than in groups A and C throughout the experiment. Concentrations of insulin, insulin-like growth factor-1, thyroxine and 3,5,3'-triiodothyronine started to increase after the first 6-8 weeks of lactation, while those of growth hormone were transiently low in week 16. None of the hormones exhibited group differences. In this study rumen-protected fat or fatty-acid supplementation failed to improve the energy and protein balances during early lactation and did not affect milk yield, likely due to decreased roughage intake. BCS, skinfold values and backfat ultrasound measurements of subcutaneous adipose tissue mass and of longissimus dorsi muscle diameter indicated mobilization of fat tissue and protein mobilization in early lactation and were mirrored by typical changes of metabolic and endocrine traits.

Milk production response of lactating dairy cows to dietary fat from three sources

Feeding fat to increase metabolisable energy content of lactation rations for dairy cows is now a common practice. It generally increases milk yield but decreases milk protein concentration. In North America whole oil seeds (cotton seeds, soya beans, sunflower seeds, etc.) containing high levels of linoleic acid are often fed as a fat source in a total mixed ration (TMR). Rape seed has also been fed and provides higher levels of oleic acid, but rape seed must be processed to be digested. Historically dietary fats for dairy cows have been rendered inert in the rumen to minimise negative effects on fibre digestion. In North America it is now recognised that unsaturated fats fed as whole oil seeds in a TMR do not have deleterious effects on digestion or intake, but these rations typically do not contain grass. Therefore our objective was to determine the intake and lactation response to feeding whole oil seeds (cotton seed and rape seed) in a grass silage-based ration and compare the response to that obtained using a rumen protected fat source as a positive control.

Milk production response of lactating dairy cows to dietary fat from three sources

Feeding fat to increase metabolisable energy content of lactation rations for dairy cows is now a common practice. It generally increases milk yield but decreases milk protein concentration. In North America whole oil seeds (cotton seeds, soya beans, sunflower seeds, etc.) containing high levels of linoleic acid are often fed as a fat source in a total mixed ration (TMR). Rape seed has also been fed and provides higher levels of oleic acid, but rape seed must be processed to be digested. Historically dietary fats for dairy cows have been rendered inert in the rumen to minimise negative effects on fibre digestion. In North America it is now recognised that unsaturated fats fed as whole oil seeds in a TMR do not have deleterious effects on digestion or intake, but these rations typically do not contain grass. Therefore our objective was to determine the intake and lactation response to feeding whole oil seeds (cotton seed and rape seed) in a grass silage-based ration and compare the response to that obtained using a rumen protected fat source as a positive control.

Evaluation of the ruminal effects of supplemental fat in lucerne hay and maize silage rations using rumen evacuation and ruminal metabolite concentrations

Four mature, rumen-cannulated Hereford × Brahman yearling steers (455 kg) were used in two 4 × 4 Latin square design experiments. Dietary treatments consisted of 3.5 kg per animal day −1 (dry matter basis) of maize silage (Experiment 1) or medium quality lucerne hay (Experiment 2) supplemented with either a maize-soyabean meal control (CON), 5% added fat as rolled whole soyabeans (WSB), 10% added fat as rumen-protected fat (RPF), or 5% added fat as WSB + 5% added fat as RPF (WSB-RPF). After 9-day dietary adjustment periods, the rumen of the steers were completely evacuated 24 h after feeding and samples of rumen liquor collected 3 and 24 h after feeding. In both experiments, steers fed CON generally had less total dry matter (DM) and fiber components remaining in the rumen 24 h after feeding than steers fed supplemental fat. However, the degree of apparent inhibition of ruminal fermentation seemed to depend upon forage type. Steers fed maize silage supplemented with fat (Experiment 1) had 43% more DM remaining in the rumen compared with those supplemented with CON. In contrast, steers fed lucerne hay supplemented with fat (Experiment 2) had only about 5% more DM remaining than those supplemented with CON. Furthermore, although the acetate:propionate ratio was reduced when fat was added to maize silage rations, supplemental fat seemed to have little effect on the acetate:propionate ratio when steers were fed lucerne hay. The RPF source used in these experiments seemed to be only partially inert and negatively affected ruminal fermentation. Based on rumen evacuation and ruminal acetate:propionate ratios, when WSB and RPF were fed together (WSB-RPF) the deleterious effects of RPF on rumen fermentation seemed to decline. Overall, the data are interpreted to suggest that single-time-point complete rumen evacuation represents a viable means for assessing the effects of source and level of supplemental fat on ruminal fermentation.

Protein-Fat Bypass Supplement for Lactating Dairy Cows

Holstein cows (n = 46) were fed free choice a silage mixture balanced weekly throughout lactation using 13 and 36% CP grains to individualize CP for each cow; grains contained 15 and 20% of distillers grains with solubles, respectively. Cows were blocked by parity (1 vs. >1) and assigned at calving to receive a commercial bypass protein-fat supplement at 0 (control) or 6% of weekly projected 4% FCM yield throughout lactation. In peak lactation, supplementation raised dietary fat from 4.3 to 6.0% of DM, NEL from 1.64 to 1.70 Mcal/kg of DM, and undegradable protein from 42 to 47% of CP and contributed about 25 and 20% of total CP in early and late lactation. Supplement reduced forage and total DMI significantly, which negated the potential nutritional value of the supplement. Reduction in protein content of milk from supplemented cows was small but significant; BW and yields of milk, SCM, and 4% FCM were not significantly affected by treatment. Supplementation increased fat test in parity 1 cows and lowered it in older cows. In wk 5 to 8, 21 to 24, and 37 to 40 postpartum, cows consumed 100 to 116% of the NRC recommendations of undegradable protein but only 65 to 94% of degradable CP needs; NEL intake generally was adequate except for primiparous cows in early lactation. Supplementation lowered Lys intake in early lactation. Addition of rumen-protected fat and undegradable, high quality protein mixture to the diet of lactating cows cannot be effective if its use reduces DMI or if degradable protein intake is inadequate.