Influences of saturation ratio of supplemental dietary fat on digestion and milk yield in dairy cows

Dietary supplementation of phytoncide and soybean oil increases milk conjugated linoleic acid and depresses methane emissions in Holstein dairy cows

The objective of this study was to determine whether adding phytoncide oil (PO) and soybean oil (SBO) to the dairy cow diet could increase milk conjugated linoleic acid (CLA) and depress methane (CH4) emissions in Holstein dairy cows. Rumen fermentation was conducted at four levels of SBO (0, 1, 2, and 4%, on DM basis) and two levels of PO (0 and 0.1%, on DM basis) with in vitro experiment. To evaluate blood parameters, fecal microbe population, milk yield and fatty acid compositions, and CH4 production, in vivo experiment was conducted using 38 Holstein dairy cows divided into two groups of control (fed TMR) and treatment (fed TMR with 0.1% PO and 2% SBO as DM basis). In the in vitro study (Experiment 1), PO or SBO did not affect rumen pH. However, SBO tended to decrease ruminal ammonia-N (p = 0.099). Additionally, PO or SBO significantly decreased total gas production (p = 0.041 and p = 0.034, respectively). Both PO and SBO significantly decreased CH4 production (p < 0.05). In addition, PO significantly increased both CLA isomers (c9, t11 and t10, c12 CLA) (p < 0.001). Collectively, 0.1% PO and 2% SBO were selected resulting in most effectively improved CLA and decreased CH4 production. In the in vivo study (Experiment 2), 0.1% PO with 2% SBO (PSO) did not affect complete blood count. However, it decreased blood urea nitrogen and magnesium levels in blood (p = 0.021 and p = 0.01, respectively). PSO treatment decreased pathogenic microbes (p < 0.05). It increased milk yield (p = 0.017) but decreased percentage of milk fat (p = 0.013) and MUN level (p < 0.01). In addition, PSO treatment increased both the concentration of CLA and PUFA in milk fat (p < 0.01). Finally, it decreased CH4 emissions from dairy cows. These results provide compelling evidence that a diet supplemented with PSO can simultaneously increase CLA concentration and decrease CH4 production with no influence on the amount of milk fat (kg/day) in Holstein dairy cows.

Ruminal responses, digestibility, and blood parameters of beef cattle fed diets with different oilseeds

It aimed to evaluate the effects of different whole oilseeds in lipid-rich diets on nutrient intake, apparent digestibility, ingestive behavior, and ruminal and blood parameters of steers. A control diet (without oilseed) and four diets containing whole oilseeds (cotton, canola, sunflower, and soybean) were tested. All diets used the whole-plant corn silage at 400 g/kg as roughage. Five diets, being a control diet (without oilseed) and four diets containing whole oilseeds (cotton, canola, sunflower, and soybean), were tested. All diets used the whole-plant corn silage at 400 g/kg as roughage. Five rumen fistulated crossbreed steers, in a 5 × 5 Latin square design were distributed using five periods of 21 days. The steers fed cottonseed and canola diets had lower dry matter intakes (6.6 kg/day). Steers showed higher averages of time in rumination for treatments with sunflower, soybean, and cottonseed (406, 362, and 361 min/day, respectively). There was no treatment effect for the ruminal pH and ammonia (NH₃) variables. There was an effect of the treatment on the volatile fatty acid concentrations. The animals that received soybean showed a higher plasma urea concentration (50.7 mg/dL). Animals fed the control diet showed lower serum cholesterol levels (111.8 mg/dL) than those fed diets containing whole cottonseed, canola, sunflower, and soybean (152.7, 137.1, 146.9, and 138.2 mg/dL, respectively). We recommended using whole soybean or sunflower seeds to formulate lipid-rich diets with 70 g/kg of ether extract for crossbreed steers in the feedlot.

Novel Process Methods for the Whole Cottonseed: Effect on the Digestibility, Productivity, Fat Profile, and Milk Gossypol Levels in Lactating Dairy Cows

In this study, we aimed to determine the effect of mixed-process methods on the ruminal degradability of whole cottonseed (WCS) both in situ and in vitro, and the effect on the production performance of dairy cows. Eight WCS process methods were tested on the ruminal digestibility, including crush-alkali 1 (CA1), crush-alkali 2 (CA2), crush-alkali 3 (CA3), alkali 1-crush (A1C), alkali 2-crush (A2C), alkali 3-crush (A3C), crush-only (CO), and non-processed. Alkali 1, 2, and 3 indicate the supplementation of alkali to WCS at the dose of 4% on dry matter (DM) base as followed: 4% NaOH, 2% NaOH + 2% CaO, and 2% NaOH + 2% CaCl₂ alkaline, respectively. Among all treatments, CA2 showed the highest WCS ruminal degradation in situ and the highest intestinal digestibility of WCS in vitro. Furthermore, an animal experiment was conducted for 60 days on 30 Holstein dairy cows, using a diet without WCS (CON group), a diet containing 8% non-processed WCS (NP group), and a diet containing 8% CA2-treated WCS (CA2 group). The results indicated that the dry matter intake, 4% fat-corrected milk production, milk protein, milk fat, and content of short-chain saturated fatty acid of milk in the CA2 group were significantly higher (P < 0.05) than CON group. Furthermore, DMI, the CLA was significantly greater (P < 0.05) in the CA2 group than the other groups. Additionally, the free gossypol concentration in serum or milk was under safety level in the three groups. Overall, crush and alkalization (NaOH: CaO = 1:1) treatment could improve the utilization of WCS in dairy farms.

In Vitro and In Vivo Studies of Rumen-Protected Microencapsulated Supplement Comprising Linseed Oil, Vitamin E, Rosemary Extract, and Hydrogenated Palm Oil on Rumen Fermentation, Physiological Profile, Milk Yield, and Milk Composition in Dairy Cows

The aim of the present study was to evaluate the effects of adding dietary rumen-protected microencapsulated supplements into the ruminal fluid on the milk fat compositions of dairy cows. These supplements comprised linseed oil, vitamin E, rosemary extract, and hydrogenated palm oil (MO; Microtinic® Omega, Vetagro S.p.A, Reggio Emilia, Italy). For in vitro ruminal fermentation, Holstein-Friesian dairy cows each equipped with a rumen cannula were used to collect ruminal fluid. Different amounts (0%, 1%, 2%, 3%, 4%, and 5%) of MO were added to the diets to collect ruminal fluids. For the in vivo study, 36 Holstein-Friesian dairy cows grouped by milk yield (32.1 ± 6.05 kg/d/head), days in milk (124 ± 84 d), and parity (2 ± 1.35) were randomly and evenly assigned to 0.7% linseed oil (LO; as dry matter (DM) basis) and 2% MO (as DM basis) groups. These two groups were fed only a basal diet (total mixed ration (TMR), silage, and concentrate for 4 weeks) (period 1). They were then fed with the basal diet supplemented with oil (0.7 LO and 2% MO of DM) for 4 weeks (period 2). In the in vitro experiment, the total gas production was found to be numerically decreased in the group supplemented with 3% MO at 48 h post in vitro fermentation. A reduction of total gas production (at 48 h) and increase in ammonia concentration (24 h) were also observed in the group supplemented with 4% to 5% MO (p < 0.05). There were no differences in the in vitro fermentation results, including pH, volatile fatty acids, or CH4 among groups supplemented with 0%, 1%, and 2% MO. The results of the in vitro study suggest that 2% MO is an optimal dosage of MO supplementation in cows' diets. In the in vivo experiment, the MO supplement more significantly (p < 0.01) increased the yield of total w3 fatty acids than LO (9.24 vs. 17.77 mg/100 g milk). As a result, the ratio of total omega-6 to omega-3 fatty acids was decreased (p < 0.001) in the MO group compared to that in the LO group (6.99 vs. 3.48). However, the milk yield and other milk compositions, except for milk urea nitrogen, were similar between the two groups (p > 0.05). Collectively, these results suggest that the dietary supplementation of 2% MO is beneficial for increasing omega-3 fatty acids without any negative effects on the milk yield of dairy cows.

Effects of supplementing Holstein cows with soybean oil compared with palmitic acid-enriched triglycerides on milk production and nutrient partitioning

Both insulin and trans-10,cis-12 C18:2 (t10c12CLA) can be increased by high-starch diets; thus, it is difficult to determine whether insulin or t10c12CLA mediates nutrient partitioning toward body tissues during milk fat depression. To minimize insulin secretion while manipulating t10c12CLA levels, diets supplemented with palmitic acid-enriched triglycerides and soybean oil were fed to cows. Thirty-two Holstein cows (93 ± 35 d in milk) were included in the crossover experiment with each treatment period being 28 d. Treatment diets contained 25% neutral detergent fiber, 32% starch, 18% crude protein, and 4.6% fatty acids (dry matter basis). Treatment diets contained either palmitic acid-enriched triglycerides (2.5% dry matter, BergaFat T-300, Berg + Schmidt America LLC, Libertyville, IL; PAT) or soybean oil (2.5% dry matter; SBO). Cows were blocked by milk yield, body weight, and parity, and then randomly assigned to 1 of 2 treatment sequences (PAT-SBO or SBO-PAT). Cows fed PAT produced milk with only 3.1% fat, indicating milk fat depression; SBO decreased fat content further to only 2.4%. No effect of treatment was observed on dry matter intake, apparent net energy intake, milk yield, body condition score, or fat thickness over the rump and rib. However, compared with PAT, SBO decreased fat-corrected milk yield, energy-corrected milk yield, milk fat yield, de novo fatty acids, and 16-carbon fatty acid yield, whereas SBO increased body weight gain. Neutral detergent fiber digestibility tended to be lower in SBO, whereas fatty acid digestibility was higher. Additionally, the concentration of plasma insulin, nonesterified fatty acids, and triglycerides, and milk metabolites (trans-10 C18:1 and t10c12CLA) were all higher in SBO. In conclusion, with similar dietary starch content, the diet containing palmitic acid-enriched triglycerides partitioned more energy toward milk synthesis, whereas the diet containing soybean oil partitioned more energy toward body tissue gain.

Effect of toasting and decortication of oat on rumen biohydrogenation and intestinal digestibility of fatty acids in dairy cows

This experiment quantified the effect of decorticated and toasted oat (Avena sativa L.) on fatty acid (FA) supply, ruminal biohydrogenation (BH) of FA, and intestinal digestibility of FA in 4 ruminal and intestinal cannulated Danish Holstein cows. Experimental diets containing untreated oat, decorticated oat, toasted oat, and decorticated and toasted oat were fed ad libitum to the cows in a 2 × 2 factorial arrangement in a Latin square design throughout 4 periods. Unless otherwise mentioned, the results of this study indicate the main effect of decortication and toasting. Decortication increased the intake of FA by 40.3 g/d and increased feed-ileum digested FA, whereas toasting decreased the intake of FA by 69.3 g/d. Toasting increased both feed-ileum and total-tract digestibility of FA by 59.8 and 67.4 g/kg of FA intake, respectively. The proportion of C18:2n-6 in FA intake increased, and the C18:3n-3 proportion in FA intake decreased due to decortication. Toasting resulted in a dramatic reduction of the C18:2n-6 proportion in FA intake, and it increased the proportions of C18:0 and C18:3n-3 in FA intake. Toasting reduced ruminal BH of C18:1n-9 and C18:2n-6 by 134 and 11.7 g/kg of FA intake, respectively, and toasting increased the proportion of unsaturated FA to saturated FA in the duodenal FA flow. Decortication decreased the ruminal BH of C18:3n-3 by 38.0 g/kg of FA intake. Decortication increased small intestinal digestibility of C12:0, C15:0, C20:0, and C22:0. Toasting increased the small intestinal digestibility of C15:0, C18:0, trans-C18:1, C20:0, and C24:0. Toasting reduced the small intestinal digestibility of C18:1n-9, C18:2n-6, and C20:1n-9. This study showed that decortication successfully increased the intake of FA and flow of FA at the duodenum and feed-ileum digested FA. However, toasting oat at 121°C caused a remarkable decline in FA concentration in oat, and thereby FA intake; therefore, toasting cannot be recommended.

A 100-Year Review: Fat feeding of dairy cows

Over 100 years, the Journal of Dairy Science has recorded incredible changes in the utilization of fat for dairy cattle. Fat has progressed from nothing more than a contaminant in some protein supplements to a valuable high-energy substitute for cereal grains, a valuable energy source in its own right, and a modifier of cellular metabolism that is under active investigation in the 21st century. Milestones in the use of fats for dairy cattle from 1917 to 2017 result from the combined efforts of noted scientists and industry personnel worldwide, with much of the research published in Journal of Dairy Science. We are humbled to have been asked to contribute to this historical collection of significant developments in fat research over the past 100 years. Our goal is not to detail all the work published as each development moved forward; rather, it is to point out when publication marked a significant change in thinking regarding use of fat supplements. This approach forced omission of critically important names and publications in many journals as ideas moved forward. However, we hope that a description of the major changes in fat feeding during the past 100 years will stimulate reflection on progress in fat research and encourage further perusal of details of significant events.

Transcriptional regulation of milk lipid synthesis by exogenous C16:0 and C18 fatty acids in bovine mammary epithelial cells

The objective of this study was to examine the effects of removing one fatty acid from a combination of long-chain fatty acids (LCFA) on milk lipogenesis in bovine mammary epithelial cells. The incubation concentration of LCFA was determined, and 100 μmol L−1 of C16:0, 5 μmol L−1 of C18:0, 100 μmol L−1 of cis-9 C18:1, 25 μmol L−1 of n-6 C18:2, and 1.2 μmol L−1 of n-3 C18:3 were used in the study. Treatments were C16:0, C18:0, C18:1, C18:2, and C18:3 combinations as control; control absent of C16:0 as A-C16:0; control absent of C18:0 as A-C18:0; control absent of C18:1 as A-C18:1; control absent of C18:2 as A-C18:2; control absent of C18:3 as A-C18:3. Results showed that compared with control, fatty acid synthetase expression was reduced by A-C18:0 and A-C18:1. Palmitic acid decreased expression of lipoprotein lipase. Compared with control, the expression of stearoyl-coenzyme A desaturase-1 and cluster of differentiation 36 was reduced by all treatments. Peroxisome proliferator-activated receptor-α expression was down-regulated by A-C16:0, A-C18:0, A-C18:1, and A-C18:2. Sterol regulatory element binding factor-1 was decreased when treated with A-C18:0, A-C18:1, and A-C18:2. Cells lack of 18-carbon fatty acid synthesized lower amount of intracellular triglyceride compared with control.

The effects of adding fat to diets of lactating dairy cows on total-tract neutral detergent fiber digestibility: A meta-analysis

The objective of this meta-analysis was to determine the effects of supplemental fat on fiber digestibility in lactating dairy cattle. Published papers that evaluated the effects of adding fat to the diets of lactating dairy cattle on total-tract neutral detergent fiber digestibility (ttNDFd) and dry matter intake (DMI) were compiled. The final data set included 108 fat-supplemented treatment means, not including low-fat controls, from 38 publications. The fat-supplemented treatment means exhibited a wide range of ttNDFd (49.4% ± 9.3, mean ± standard deviation) and DMI (21.3 kg/d ± 3.5). Observations were summarized as the difference between the treatment means for fat-supplemented diets minus their respective low-fat control means. Additionally, those differences were divided by the difference in diet fatty acid (FA) concentration between the treatment and control diets. Treatment means were categorized by the type of fat supplement. Supplementing 3% FA in the diet as medium-chain fats (containing predominately 12- and 14-carbon saturated FA) or unsaturated vegetable oil decreased ttNDFd by 8.0 and 1.2 percentage units, respectively. Adding 3% calcium salts of long-chain FA or saturated fats increased ttNDFd by 3.2 and 1.3 percentage units, respectively. No other fat supplement type affected ttNDFd. Except for saturated fats and animal-vegetable fats, supplementing dietary fat decreased DMI. When the values for changes in ttNDFd are regressed on changes in DMI there was a positive relationship, though the coefficient of determination is only 0.20. When changes in ttNDFd were regressed on changes in DMI, within individual fat supplement types, there was no relationship within calcium salt supplements. There was a positive relationship between changes in ttNDFd and changes in DMI for saturated fats. Neither relationship suggested that the increased ttNDFd with calcium salts or saturated FA was due to decreased DMI for these fat sources. A subset of the means included measured ruminal neutral detergent fiber digestion. Analysis of this smaller data set did not suggest that ruminal neutral detergent fiber digestibility is depressed by fat supplementation more than ttNDFd. Adding fats, other than those with medium-chain FA, consistently increased digestible energy density of the diet. However, due to reduced DMI, this increased energy density may not result in increased digestible nutrient intake.

Soybean oil suppresses ruminal methane production and reduces content of coenzyme F420 in vitro fermentation

This experiment examined which type of oils was a superior suppressor to methane mitigation in ruminants. Four oils, peanut, rapeseed, corn and soybean oils, varying in the contents of unsaturated fatty acids as indicated by their iodine values, were used to investigate their effects on methane production and on the content of the F420 enzyme of ruminal methanogens in an in vitro fermentation. The control group was added with calcium palmitate (100% saturated 16C fatty acid). The results showed that the total gas production over a period of 36 h varied from 20.61 mL to 39.67 mL, and were lower in rapeseed, corn and soybean oil treatments than the control (P < 0.05), but not in the peanut oil treatment. The methane concentration in the total gas differed significantly among groups (P < 0.05), and decreased with the increases of unsaturation degree of the oils. The coenzyme F420 content, as indicated by F420 fluorescence intensity in supernatant of the medium, was significantly lower in the oil treatments than in the control (P < 0.05), and the intensity values decreased with the increases of unsaturation degree of the oils, except for the rapeseed oil treatment. Furthermore, there was a close correlation between F420 content and methane production (r = 0.916). By comparison, soybean oil treatment had higher dehydrogenase activity and bacteria density than the other groups (P < 0.05); but was lower in methanogens and genus entodinium (P < 0.05), except for the rapeseed oil treatment. Overall, soybean oil contained a high level of unsaturated fatty acids, and could be used as an ingredient of ruminant diets for methane suppression.

Intestinal digestibility of long-chain fatty acids in lactating dairy cows: A meta-analysis and meta-regression

The objective of this analysis was to examine the intestinal digestibility of individual long-chain fatty acids (FA) in lactating dairy cows. Available data were collated from 15 publications containing 61 treatments, which reported total and individual FA duodenal flows and calculations of intestinal digestibility. All studies involved lactating dairy cows, and estimates of digestibility were based on measurements either between the duodenum and ileum (18 treatments) or between the duodenum and feces (43 treatments). Fatty acid digestibility was calculated for C16:0, C18:0, C18:1 (cis and trans isomers), C18:2, and C18:3. Digestibility of C18:0 was lower than for C18:1 and C18:3, with no difference in digestibility between saturated FA (C16:0 and C18:0). We weighted the studies by the reciprocal of the variance to generate best-fit equations to predict individual FA digestibility based on duodenal flow of FA and dietary independent variables. The flow of C18:0 negatively affected the digestibility of C18:0 and was also included in the best-fit equations for all other 18-carbon FA using duodenal flow characteristics. The type of fat supplemented had an effect on digestibility of individual FA, with whole seeds having reduced digestibility. Our meta-analysis results showed minimal differences in the digestibility of individual FA. However, C18:0 flow through the duodenum had a negative effect on the digestibility of several individual FA, with the largest negative effect on C18:0 digestibility. The mechanisms that reduce C18:0 absorption at high concentrations are unknown and warrant further investigation.

Whey protein gel composites in the diet of goats increased the omega-3 and omega-6 content of milk fat

Previously, feeding whey protein gels containing polyunsaturated fatty acids (PUFA) reduced their rumen biohydrogenation and increased their concentration in milk fat of Holstein cows. Our objective was to test the efficacy of whey protein isolate (WPI) gels produced in a steam tunnel as a method to alter the fatty acid (FA) composition of the milk lipids. Four primiparous Lamancha goats in midlactation were fed three diets in a 3 × 4 Latin square design. The WPI gels were added to a basal concentrate mix that contained one of three lipid sources: (i) 100% soya bean oil (S) to create (WPI/S), (ii) a 1:1 (wt/wt) mixture of S and linseed (L) oil to create (WPI/SL), or (iii) 100% L to create (WPI/L). Periods were 22 days with the first 10 days used as an adjustment phase followed by a 12-day experimental phase. During the adjustment phase, all goats received a rumen available source of lipid, yellow grease, to provide a baseline for milk FA composition. During the experimental phase, each goat received its assigned WPI. Milk FA concentration of C18:2 n-6 and C18:3 n-3 reached 9.3 and 1.64 g/100 g FA, respectively, when goats were fed WPI/S. Feeding WPI/SL increased the C18:2 n-6 and C18:3 n-3 concentration to 6.22 and 4.36 g/100 g FA, and WPI/L increased C18:2 n-6 and C18:3 n-3 to 3.96 and 6.13 g/100 g FA respectively. The adjusted transfer efficiency (%) of C18:3 n-3 to milk FA decreased significantly as dietary C18:3 n-3 intake increased. Adjusted transfer efficiency for C18:2 n-6 did not change with increasing intake of C18:2 n-6. The WPI gels were effective at reducing rumen biohydrogenation of PUFA; however, we observed a change in the proportion increase of C18:3 n-3 in milk FA suggesting possible regulation of n-3 FA to the lactating caprine mammary gland.

Caroço de algodão na dieta de cabras saanen no semiárido paraibano

Objetivou-se com o presente trabalho avaliar o efeito da suplementação alimentar com diferentes teores de farelo de caroço de algodão sobre a produção leiteira e o efeito do ambiente sobre as respostas fisiológicas de cabras Saanen no semiárido paraibano. Utilizou-se 16 cabras com peso vivo médio de 55kg ± 1,41Kg . Para análise da produção leiteira utilizou-se um delineamento em quadrado latino 4x4 (quatro animais e quatro períodos de 15 dias) com quatro tratamentos, e para os parâmetros ambientais e fisiológicos foi utilizado um delineamento inteiramente casualizado com dois tratamentos (manhã e tarde) e 16 repetições. Na análise da produção leiteira os tratamentos consistiram na inclusão de quatro teores de caroço de algodão à dieta (0; 3; 6 e 9%), e na avaliação dos parâmetros ambientais e fisiológicos os tratamentos foram constituídos por dois turnos (manhã e tarde). Avaliaram-se os parâmetros ambientais temperatura do ar, umidade relativa, temperatura do globo negro e fisiológicos: frequência respiratória, temperatura retal e superficial. Nos parâmetros ambientais e também nos fisiológicos observou-se que houve efeito de turnos, com elevação da temperatura ambiente e da frequência respiratória, temperatura retal e superficial. Pela análise de regressão foi verificado que não houve efeito entre os teores de caroço de algodão e a produção média diária de leite, o que permitiu concluir que o caroço de algodão pode ser administrado como complemento na dieta de cabras em lactação e que cabras Saanen, apesar de terem mantido a homeotermia com o aumento da taxa respiratória, se mostraram susceptíveis ao clima semiárido.

Milk composition in free-ranging polar bears (Ursus maritimus) as a model for captive rearing milk formula

The goals of this study were to have an improved understanding of milk composition and to help create a suitable milk formula for cubs raised in captivity. Milk samples were evaluated for fat, fatty acids, carbohydrate, vitamin D(3), 25(OH)D(3), vitamin A (retinol), vitamin E (α-tocopherol), protein, and amino acids. Total lipids in milk did not differ for cubs (mean ± SEM = 26.60 ± 1.88 g/100 ml vs. yearlings 27.80 ± 2.20 g/100 ml). Milk lipids were of 23.6% saturated fatty acid for cubs and 22.4% for yearlings. Milk consumed by cubs and yearlings contained 43.8 and 42.0% mono-unsaturated fatty acids and 23.4 and 21.9% polyunsaturated fatty acids, respectively. Carbohydrate content was higher in milk for cubs (4.60 ± 0.64 g/100 ml) than for yearlings (2.60 ± 0.40 g/100 ml). Vitamin D(3) concentration of milk was 18.40 ± 5.00 ng/ml in early lactation compared with 7.60 ± 2.00 ng/ml for mid-lactation. 25(OH)D(3) was lower in milk consumed by cubs (162.00 ± 6.70 pg/ml) than in milk consumed by yearlings (205.00 ± 45.70 pg/ml). Vitamin A concentrations were 0.06 ± 0.01 and 0.03 ± 0.01 µg/ml for cubs and yearlings, respectively. Vitamin E was higher in milk consumed by cubs (20.16 ± 4.46 µg/ml) than by yearlings (7.30 ± 1.50 µg/ml). Protein content did not differ in milk available to cubs (11.40 ± 0.80 g/100 ml compared with milk for yearlings 11.80 ± 0.40 g/100 ml). Taurine was the most abundant free amino acid at 3,165.90 ± 192.90 nmol/ml (0.04% as fed basis).

Effects of supplemental dietary fatty acids on milk yield and fatty acid composition in high and medium yielding cows

The present study tested the hypothesis that supplemental dietary fatty acids (FA) affect the energy corrected milk yield in proportion to the milk production level of dairy cows, and increase both long chain FA proportion of milk FA and milk fat globule diameter. Sixteen Danish Holstein cows were divided into four 4x4 Latin squares with two squares of medium yielding cows (32.2 kg energy corrected milk (ECM)/d; 158 days in milk (DIM)) and two squares of high yielding cows (40.0 kg ECM/d; 74 DIM). Experimental length was 12 weeks, with three weeks for each of the four periods. The four treatments were no supplementation (17 g FA/kg dry matter (DM)) and three diets with supplemented FA (29, 40, and 52 g total FA/kg DM, respectively) obtained by substituting barley with Palm Fatty Acid Distillate (PFAD) fat. Diets were offered as total mixed rations with 63% grass/clover silage (DM basis). Dry matter intake decreased with increasing FA supplementation, but net energy intake was not affected. The general linear responses to 10 g/kg DM increase in FA level were 1.1 kg ECM (P<0.0001), 0.061 kg milk fat (P<0.0001), 0.012 kg milk protein (P=0.09) and 0.052 kg lactose (P=0.0002) per day, and linear responses in milk composition were 0.39 g fat (P=0.07), -0.71 g protein (P<0.0001) and 0.05 g lactose (P=0.3) per kg milk, and 0.092 microm (P<0.0001) in milk fat average globule diameter. Fatty acid supplementation decreased short- and medium-chain FA and C16:0 and increased C18:1 proportions of total FA in milk. Supplemental dietary FA increased ECM yield but not in proportion to production level as anticipated, and increased average FA chain length and milk fat globule diameter.

Effect of the rate of increase in concentrate allowance with concentrates high or low in starch on the performance of dairy cows in early lactation

The effect of the rate of increase in concentrate allowance after calving with two concentrate mixes (A and B) differing in composition was evaluated using 64 Finnish Ayrshire cows during the first 100 days of lactation. After calving, the concentrate allowance of multiparous cows was increased stepwise from 4 to 17 kg/day, and of primiparous cows from 3 to 13.5 kg/day over 12 days (F rate of increase; multiparous 1.08 kg/day, primiparous 0.88 kg/day) or 24 days (S rate of increase; mutiparous 0.54 kg/day, primiparous 0.44 kg/day). The concentrates were formulated to have similar crude protein and metabolizable energy concentrations but differing starch and NDF concentrations. For concentrate A the starch and NDF concentrations were 421 and 167 g/kg dry matter (DM) and for concentrate B 258 and 251 g/kg DM. All cows received grass silage ad libitum. The higher concentrate intake during weeks 1 to 4 of lactation with F compared with the S rate of increase caused higher DM, energy and protein intake. The higher concentrate intake for F than for S treatment in early lactation did not cause a large decrease in silage intake (8.8 v. 8.3 kg DM/day). The intake of concentrate A and B after calving did not differ for S treatment. However, for F treatment the intake of fibrous concentrate B increased faster than starch-rich concentrate A during weeks 1 to 4 of lactation. The concentrate composition had no effect on energy-corrected milk (ECM) yield during weeks 1 to 4 of lactation for S treatments, but with F treatments the cows fed B concentrate produced more milk. The F rate of increase in concentrate allowance compared with the S rate increased the calculated energy balance after calving. The rate of increase in concentrate feeding post partum or concentrate composition had no effect on DM, energy or protein intake during the whole 100-day experiment. The average ECM yield over days 1 to 100 of lactation was higher for S than for F treatments and tended to be higher with concentrate B than A. Results of this study showed that by the fast rate of increase in concentrate allowance after calving on a grass silage diet, it was possible to improve the energy status of the cows in early lactation. This had, however, no effect on production later in lactation.

Milk Fatty Acids. I. Variation in the Concentration of Individual Fatty Acids in Bovine Milk

Data from 29 published experiments on Holstein cows, providing 120 dietary treatments, were collated to obtain means, standard deviations, and ranges for the concentrations (mg/g) of 26 major individual fatty acids in bovine milk fat. The influence of diet type (total mixed ration- vs. pasture-based diet) on concentrations of individual fatty acids was examined. Pairwise correlations for concentrations (g/kg) of individual fatty acids in milk showed that almost all of the individual de novo fatty acids were significantly correlated with each other and with the total concentration of de novo fatty acids. Concentrations of individual unsaturated preformed fatty acids were generally positively correlated with each other but were negatively correlated with concentrations of total de novo fatty acids. Substantial variation was found in the concentrations of individual milk fatty acids and, apart from those synthesized de novo, concentrations of individual fatty acids did not vary in concert. The adequacy of literature data for the development of a model to predict the production of the major individual fatty acids in milk is discussed. The limitations associated with the currently available studies that may be used in a predictive model are 1) failure of many publications to adequately describe dietary details, 2) reporting poorly defined milk fatty acids, 3) aggregating a number of closely related fatty acids under a single category, and 4) the selective reporting of only those fatty acids that are present in milk fat in appreciable quantities. Despite these limitations, the data are sufficient to enable development of a model to predict the concentrations and production of major individual fatty acids in milk fat. The extreme variability in concentrations of individual milk fatty acids and the complex matrix of positive and negative correlations among the concentrations of many individual fatty acids suggest that separate equations will be needed to predict the production of each individual milk fatty acid.

Feed Value of Supplemental Fats Used in Feedlot Cattle Diets

The inclusion of supplemental fats in growing-finishing diets for feedlot cattle also improves diet "condition." Quality factors that may influence the feeding value of fat include the source of fat; moisture, impurities, and unsaponifiables; free fatty acid concentration; degree of saturation or titer; and rancidity (peroxide value). The net energy value of fat declines linearly with an increasing level of supplementation because of constraints on postruminal fatty acid digestion. The authors recommend that receiving diets not contain more than 2% supplemental fat. Little evidence suggests that the feeding value of fat is different for Holsteins than for conventional beef breeds. Fat supplementation is not consistent in its effect on intramuscular fat distribution (marbling), longissimus (rib eye) area, and fat thickness, but can be expected to increase dressing percentage and kidney, pelvic, and heart fat percentage.

Performance and ruminal fermentation of dairy cows fed whole cottonseed with elevated concentrations of free fatty acids in the oil

Twenty-four lactating Holstein cows were used in an 8-wk completely randomized design trial to examine the effects of feeding whole cottonseed (WCS) with elevated concentrations of free fatty acids (FFA) in the oil on intake and performance. Treatments included WCS with normal concentrations of FFA (6.8%, control) and 2 sources of WCS with elevated FFA [HFFA1 (24.1%) or HFFA2 (22.3%)]. The 2 sources of WCS with elevated FFA differed in that HFFA2 were discolored from being initially stored with excess moisture, which led to heating and deterioration during storage, whereas HFFA1 were normal in appearance and the increase in FFA occurred without heating and visible damage to the WCS. Nutrient concentrations were similar among WCS treatments, which provided 14% of the total dietary dry matter. Dry matter intake tended to be higher for cows fed HFFA2 compared with control and HFFA1. Yield of milk and components was similar among treatments, but milk fat percentage was lower for HFFA1 and HFFA2 compared with control. In a concurrent 3 x 3 Latin square trial with 6 ruminally cannulated Holstein cows, molar proportions of isobutyrate were higher for HFFA2 than control and HFFA1, but no differences were observed in acetate or propionate. Results of these trials indicate that feeding WCS with high concentrations of FFA decreases milk fat percentage but does not alter dry matter intake, milk yield, or concentrations of other components. The minor changes in ruminal fermentation that were observed do not account for the decrease in milk fat percentage.

Effect of Varying Levels of Fatty Acids from Palm Oil on Feed Intake and Milk Production in Holstein Cows

To determine the optimum feeding level of fatty acids of palm oil (PALM; Energizer RP10; 86.6% palmitic acid) on milk production, lactating cows (n = 18) were randomly assigned to a treatment sequence in replicated 4 x 4 Latin squares. Animals were assigned to squares by parity (3 multiparous and 1 primiparous squares with primiparous in the incomplete square). The 4 diets were designed to provide 0, 500, 1,000, and 1,500 g of PALM per day. Cows were fed individually with feed intake measured daily. Each period lasted 16 d with milk production and composition determined the final 2 d. Milk production, milk composition and feed intake data were analyzed using the MIXED procedure of SAS. Milk yields were 30.9, 34.0, 34.2, and 34.2 kg/ d (SEM = 1.9) for the 0, 500, 1,000, and 1,500 g levels, respectively. Milk yield was increased by the addition of PALM; however, there were no differences among the levels of PALM. Milk fat percentage was also increased from 3.44% for 0 g to 3.95% (SEM = 0.17) across all levels of PALM but there were no differences among the PALM treatments. Dry matter intakes were 23.3, 26.4, 24.7, and 23.8 kg/d (SEM = 1.4) for the 0, 500, 1,000 and 1,500 g levels, respectively. The addition of PALM increased milk yield and milk fat percentage, and no adverse effects on dry matter intake were observed.

Short communication: Further validation of the fat sub-model in the Cornell-Penn-Miner Dairy model

Recently, a fat sub-model was introduced into the Cornell-Penn-Miner Dairy model (CPM-Dairy; Moate et al., 2004). The principal aim of the work reported here was to validate this fat sub-model in terms of its accuracy in predicting the apparent absorption (intake - feces) of total long-chain fatty acids (LCFA) in lactating dairy cows. The fat sub-model in CPM-Dairy was used to predict the amounts (g/d) of total LCFA apparently absorbed from 63 diets described in 14 published experiments. These predicted amounts (PLCFA) were regressed against the amounts reported to be apparently absorbed (RLCFA). The regression equation was: PLCFA = - 24.8 +/- 25.2 + 1.011 x 0.029 x RLCFA; R2 = 0.95, RMSE = 55.2 g/d. The results show that for a diverse range of diets, the fat model in CPM-Dairy can accurately predict apparent absorption of dietary total LCFA.

Ruminal Fermentation and Amino Acid Flow in Holstein Steers Fed Whole Cottonseed with Elevated Concentrations of Free Fatty Acids in the Oil

The influence of feeding whole cottonseed (WCS) containing elevated concentrations of free fatty acids (FFA) in the oil on ruminal fermentation and amino acid (AA) flow to the abomasum was evaluated in a 4 x 4 Latin square trial. Four ruminally and abomasally cannulated Holstein steers were fed diets containing 12.5% of dry matter as WCS with concentrations of 8.0, 11.3, 14.7, or 18.0% FFA in the oil. Intake, ruminal digestibility, and flow to the abomasum of dry matter, organic matter, and acid detergent fiber were not affected by FFA level of WCS. Intake of neutral detergent fiber and total kilograms of neutral detergent fiber digested in the rumen were similar for all treatments. Ruminal neutral detergent fiber digestibility was lower for 8 and 14.7% FFA, resulting in a cubic effect on flow to the abomasum. Ruminal pH, molar proportions of isobutyrate, and total branched-chain volatile fatty acids (VFA) decreased linearly, whereas molar proportions of acetate and acetate:propionate ratio increased linearly as FFA in WCS increased. Total VFA were lower, and molar proportions of propionate were higher, for 8 and 14.7% FFA, resulting in a cubic effect. Intake of N, total N flow, and nonmicrobial N flow to the abomasum were similar among treatments. Flow of microbial N was lower for the 11.3% FFA treatment, resulting in a quadratic response. Only nonsignificant differences were observed in AA flow to the abomasum. Results of this trial indicate that WCS with FFA up to 18% may result in small changes in rumen fermentation.

Milk production and composition from cows fed high oil or conventional corn at two forage concentrations

Twelve multiparous Holstein cows (63 +/- 24 d in milk) were used in a replicated 4 x 4 Latin square with 28-d periods to evaluate conventional and high oil corn grains when fed at two different forage-to-concentrate ratios. Dietary treatments consisted of conventional or high oil corn supplementing a diet with a 25:25:50 mixture of corn silage: alfalfa: concentrate mix, or a high forage diet with a 30:30:40 mixture of corn silage: alfalfa: concentrate mix. Dry matter intake (28.1, 28.7, 26.9, and 26.2 kg/d for normal diets with conventional and high oil corn, and high forage diets with conventional and high oil corn, respectively) and milk yields (36.8, 37.2, 35.5, and 35.2 kg/d) were similar for conventional and high oil corn diets and were lower with the high forage diet, regardless of corn source. Milk fat concentrations were greater when cows were fed diets containing 60% forage (4.03 vs. 3.88%, for the 60 and 50% forages, respectively), but milk protein concentrations were not affected by forage content. Corn source did not affect milk fat or protein concentrations. Long-chain fatty acid concentrations, unsaturated fatty acid concentrations, and total 18:1 fatty acid concentrations were greater when cows were fed high oil corn but were unaffected by forage content of the diet. Concentrations of transvaccenic acid (0.58, 0.81, 0.62, and 0.69 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.28, 0.39, 0.32, and 0.33 g/100 g of fatty acids) were greater when cows were fed high oil compared with conventional corn when fed 50% forage but were similar for both corn sources at 60% forage. Total n-3 fatty acids were not affected by corn source or forage content. High forage diets decreased milk production and increased milk fat concentration. Feeding high oil corn increased concentrations of long-chain, unsaturated, transvaccenic, and conjugated linoleic fatty acids in milk; however, production of transvaccenic and conjugated linoleic acids were attenuated by high forage diet.

Increasing dietary levels of cracked pima cottonseed increase plasma gossypol but do not influence productive performance of lactating Holstein cows

Lactating Holstein cows were fed diets with increasing levels of cracked Pima cottonseed to determine its effects on plasma gossypol concentrations as well as milk yield and composition and dry matter (DM) intake in a short-term study. All diets contained 12.8% cottonseed, 43.5% concentrate, and 43.7% chopped alfalfa hay on a DM basis. The proportion of whole Upland cottonseed to cracked Pima cottonseed in the four dietswas 100:0, 67:33, 33:67, and 0:100. Four primiparous cows were fed the diets in a 4 x 4 Latin square design, and three multiparous cows were fed the diets in a Youden square design with five periods. All periods were 35 d. Upland and cracked Pima cottonseed contained 0.64 and 1.00% total gossypol (DM) with 41 and 52% of gossypol as the (-) isomer, respectively. Gossypol is a natural defense compound in the plant that protects it against pests and diseases, but can have antinutritional quality effects when consumed by dairy cattle. Total plasma gossypol concentrations increased linearly with increasing proportions (100:0, 67:33, 33:67, and 0:100) of cracked Pima cottonseed in the diet for primiparous (4.4, 6.0, 7.7, and 8.9 microg/ml) and multiparous (4.3, 7.3, 9.7, and 11.4 microg/ml) cows, respectively. While primiparous cows responded similarly to gossypol intake, the response of plasma gossypol intake in multiparous cows differed among cows. This indicates the importance of animal variation when relating plasma gossypol levels with gossypol intake. Milk yield, as well as its components and DM intake, were not affected by increasing dietary inclusion levels of cracked Pima cottonseedup to 8.6% of DM intake for either primiparous or multiparous cows, even though plasma gossypol concentrations increased sharply over this dietary inclusion range. Although the highest dietary inclusion level of Pima cottonseed (i.e., 12.8%) numerically depressed performance of cows of both parities, these differences failed to reach statistical significance in these short-term trials with few cows.

The composition of bovine milk lipids: January 1995 to December 2000

Data from recent publications on bovine milk lipids are presented and discussed. This includes extraction of lipids, triacylglycerols, phospholipids, other complex lipids, sterols, isoflavones, and fatty acids. Improved gas-liquid and high performance liquid chromatography were used. Data on the trans and cis isomers of fatty acid and of conjugated linoleic acids are given, and the analyses are described. Papers about the lipids in milks and dairy products from the United States are few; where with the exception of trans-fatty acid isomers and conjugated linoleic acids, almost no research has been reported.