Increasing palmitic acid and reducing stearic acid content of supplemental fatty acid blends improves production performance of mid-lactation dairy cows.

We determined the effects of altering the ratio of palmitic (C16:0) and stearic (C18:0) acids in supplemental fatty acid (FA) blends on production responses of mid-lactation dairy cows. Twenty-four multiparous Holstein cows (mean ± standard deviation; 47.1 ± 5.8 kg of milk yield, 109 ± 23 DIM) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were a control diet not supplemented with FA (CON), and 3 diets incorporating 1.5% of dry matter (DM) FA supplement blends containing 30% C16:0 + 50% C18:0, 50% C16:0 + 30% C18:0, and 80% C16:0 + 10% C18:0. Additionally, the FA blends were balanced to contain 10% of oleic acid (cis-9 C18:1). The FA blends replaced soyhulls in the CON diet. Diets were formulated to contain (% of DM) 31.0% neutral detergent fiber, 27.0% starch, and 16.9% crude protein. The statistical model included the random effect of cow within square and the fixed effects of period, treatment, and their interaction. Preplanned contrasts included CON versus overall effect of FA supplementation and the linear and quadratic effects of increasing C16:0 in FA blends. Overall FA treatment had no effect on dry matter intake (DMI), but increasing C16:0 linearly increased DMI. Compared with CON, overall FA treatment increased yields of milk, 3.5% of fat-corrected milk, energy-corrected milk, and milk fat but did not affect milk protein yield. Increasing C16:0 linearly increased milk fat yield and tended to linearly increase the yields of 3.5% of fat-corrected milk and energy-corrected milk. Fatty acid supplementation decreased the yield of de novo milk FA but increased yields of mixed and preformed milk FA compared with CON. Increasing C16:0 in FA treatments did not affect the yield of de novo milk FA, linearly increased the yield of mixed, and decreased the yield of preformed milk FA. In summary, feeding FA supplements containing C16:0 and C18:0 increased milk production responses with no effect on DMI compared with a control diet. Mid-lactation cows producing ∼40 to 50 kg/d milk yield responded best to increasing supplemental C16:0 in FA supplements, demonstrating that FA supplements higher in C16:0 and limited in C18:0 improves production responses.

Effect of peri-conception high-fat diets on maternal ovarian function, foetal and placentome growth, and vascular umbilical development in goats.

The objective of this study was to determine whether a high-fat diet (HFD) fed to goats for a brief period during peri-conception would optimize reproductive and foetal responses. Thirty-four Anglo-Nubian crossbred adult goats were allocated into three groups: control (n = 11), fed with a total mixed ration (TMR) based on chopped elephant grass and concentrate; HFBM (n = 11), given TMR supplemented with soybean oil on a 0.5% dry matter basis for 11 days starting nine days before mating (BM); and HFAM (n = 12), fed with soybean oil included in the TMR for 15 days after mating (AM). The TMR diets differed in their fat content (7.5% vs. 2.9%). All goats had oestrus synchronized for 14 days BM by intravaginal administration of 60 mg MPA sponge for 12 days. Forty-eight hours BM, the sponge was removed and 0.075 mg PGF2α was applied intramuscularly. After 36 h, 1 ml GnRH was administered intramuscularly, and goats were mated after sponge removal. The fat groups showed lower feed intake (p < .001) and higher cholesterol levels (p < .001) when HFD was administered. Doppler and B-mode ultrasound evaluations revealed a greater (p < .05) number of small (<3 mm, 10 ± 0.6 vs. 8 ± 0.5) and large (≥3 mm, 6 ± 0.4 vs. 5.0 ± 0.2) follicles and intraovarian blood area (p < .05) in the HFBM group during sponge removal (57.6%) and mating (24.2%) than those of the no-fat group. During AM, the fat-fed groups exhibited higher glutathione peroxidase levels (p < .05) and a reduction (p < .001) in corpus luteum size (19%) and vascularized Doppler area (41%). No difference (p > .05) between groups was found in foetal traits, placentome and umbilical vascular development, except for the embryonic vesicle where HFAM twin pregnancy showed a smaller size than the control (26.1 ± 3.5 cm vs. 33.7 ± 2.7 cm; p < .01). Thus, HFD applied during peri-conception of goats has no impact on later foetal development but improved the follicular growth when given before the mating. Thus, the use of HFD in periconception has no impact on foetal development but increases follicular growth before breeding time.

Replacing stearic acid with oleic acid in supplemental fat blends improves fatty acid digestibility of lactating dairy cows.

The objective of our study was to determine the effects of altering the ratio of stearic (C18:0; SA) and oleic (cis-9 C18:1; OA) acids in supplemental fatty acid (FA) blends on FA digestibility and milk yield of dairy cows. Eight multiparous Holstein cows (mean ± SD; 157 ± 11.8 d in milk) were randomly assigned to treatment sequence in a replicated 4 × 4 Latin square design with 14-d periods. Digestibility and production data were collected during the last 4 d of each period. The treatments were an unsupplemented control diet (CON), and 3 diets incorporating FA supplement blends at 1.4% of diet dry matter (DM) containing (as a % of total FA) 50% SA and 10% OA, 40% SA and 20% OA, or 30% SA and 30% OA. The FA blends were balanced to contain 33% palmitic, 5% linoleic, and <0.5% linolenic acids. The FA supplements replaced soyhulls in the CON diet. Preplanned contrasts were as follows: (1) overall effect of FA treatments [CON vs. the average of the FA-supplemented diets; (50:10 + 40:20 + 30:30)/3], (2) the linear effect of OA inclusion in the supplemental FA blend, and (3) the quadratic effect of OA inclusion in the supplemental FA blend. There was no effect of treatment on DM intake, but the replacement of soyhulls in the FA treatments decreased neutral detergent fiber intake. Overall, compared with CON, FA treatments increased DM and neutral detergent fiber digestibility, and increasing OA within FA treatments quadratically increased digestibility of DM and neutral detergent fiber. Overall, FA treatments increased the intake of total, 16-carbon, and 18-carbon FA, decreased the digestibility of total and 18-carbon FA, but increased absorption of total, 16-carbon, and 18-carbon FA. Within FA treatments, increasing OA linearly increased the digestibility of total, 16-carbon, and 18-carbon FA, as well as the absorption of total, 16-carbon, and 18-carbon FA. Overall, FA treatments increased the yields of milk, energy-corrected milk, and milk fat, and tended to increase milk protein yield. Compared with CON, FA treatments had no effect on the yield of de novo milk FA and increased the yields of mixed and preformed milk FA. Within FA treatments, increasing OA did not affect the yields of milk or milk components, linearly decreased the yield of de novo FA, and quadratically affected the yield of mixed and preformed milk FA. Overall, FA treatments increased plasma nonesterified fatty acids but did not affect ß-hydroxybutyrate or insulin. Within FA treatments, increasing OA quadratically affected plasma nonesterified fatty acids, and tended to linearly increase ß-hydroxybutyrate and quadratically affect insulin. In conclusion, supplemental FA blends containing different ratios of SA and OA did not affect DM intake but increased the yields of milk and milk components. Supplemental FA blends also increased digestibility of DM and neutral detergent fiber and decreased digestibility of total and 18-carbon FA compared with CON. Although increasing OA within FA supplements did not alter milk production, increasing OA within FA supplements increased total, 16-carbon, and 18-carbon FA digestibility and FA absorption. Further research is required to determine longer term effects of SA and OA on nutrient digestion and partitioning and opportunities for maintaining or improving FA digestibility with increasing SA intake and availability in the small intestine.

Effects of commercially available palmitic and stearic acid supplements on nutrient digestibility and production responses of lactating dairy cows.

We evaluated the effects of commercially available fatty acid (FA) supplements containing palmitic (C16:0) and stearic acid (C18:0) on nutrient digestibility and production responses of dairy cows. Thirty-six mid-lactation (146 ± 55 d in milk) multiparous Holstein cows were randomly assigned to twelve 3 × 3 balanced truncated Latin squares, with 3 treatments and 2 consecutive 35-d periods, with the final 5 d used for sample and data collection. Treatments were (1) a control diet containing no supplemental FA (CON), (2) a control diet supplemented with a commercially available C16:0 supplement (PA), and (3) a control diet supplemented with a commercially available C16:0 and C18:0 supplement (MIX). Supplements were fed at 1.5% dry matter and replaced soyhulls in CON. The statistical model included the random effect of cow nested within square and the fixed effects of treatment, period, square, and their interactions. Preplanned contrasts were (1) overall effect of FA treatments [CON vs. the average of the FA treatments (FAT); 1/2 (PA + MIX)], and (2) effect of FA supplement (PA vs. MIX). Treatment had no effects on dry matter intake, body weight, or body weight change. Compared with CON, FAT decreased digestibilities of total FA and 18-carbon FA but did not affect dry matter and neutral detergent fiber digestibility. Compared with MIX, PA increased dry matter and neutral detergent fiber digestibilities by 3.6 and 4.8 percentage units, respectively. The PA also increased total FA and 18-carbon FA digestibilities but did not alter 16-carbon FA digestibility compared with MIX. Using a Lucas test, we estimated apparent digestibility coefficients of 0.768 and 0.553 for the PA and MIX supplements, respectively. Compared with CON, FAT increased milk yield and tended to increase energy-corrected milk, but did not affect yield of milk fat or milk protein. The PA increased energy-corrected milk and milk fat yield but had no effect on milk protein yield compared with MIX. Our results indicate that dairy cows producing around 45 kg of milk respond better to a FA supplement enriched in C16:0 compared with a supplement containing both C16:0 and C18:0, which is likely due in part to PA increasing FA and neutral detergent fiber digestibility compared with MIX.

Effects of timing of palmitic acid supplementation on production responses of early-lactation dairy cows.

The objective of our study was to evaluate the effects of timing of palmitic acid (C16:0) supplementation on production responses of early-lactation dairy cows. Fifty-two multiparous cows were used in a randomized complete block design experiment. During the fresh period (FR; 1-24 d in milk) cows were assigned to either a control diet containing no supplemental fat (CON) or a diet supplemented with C16:0 (palmitic acid, PA; 1.5% of diet dry matter). During the peak (PK) period (25-67 d in milk) cows were assigned to either a CON diet or a PA (1.5% of diet dry matter) diet in a 2 × 2 factorial arrangement of treatments considering the diet that they received during the FR period. During the FR period, we did not observe treatment differences for dry matter intake or milk yield. Compared with CON, PA increased the yield of 3.5% fat-corrected milk by 5.30 kg/d, yield of energy-corrected milk (ECM) by 4.70 kg/d, milk fat content by 0.41% units, milk fat yield by 280 g/d, and protein yield by 100 g/d. The increase in milk fat associated with the PA treatment during the FR period occurred due to an increase in yield of 16-carbon milk fatty acids (FA) by 147 g/d (derived from both de novo synthesis and extraction from plasma) and preformed milk FA by 96 g/d. Compared with CON, PA decreased body weight (BW) by 21 kg and body condition score (BCS) by 0.09 units and tended to increase BW loss by 0.76 kg/d. Although PA consistently increased milk fat yield and ECM over time, a treatment × time interaction was observed for BW and BCS due to PA inducing a greater decrease in BW and BCS after the second week of treatments. Feeding PA during the PK period increased milk yield by 3.45 kg/d, yield of 3.5% fat-corrected milk by 4.50 kg/d, yield of ECM by 4.60 kg/d, milk fat content by 0.22% units, milk fat yield by 210 g/d, protein yield by 140 g/d, and lactose yield by 100 g/d but tended to reduce BW by 10 kg compared with CON. Also, during the PK period we observed an interaction between diet fed in the FR and PK periods for milk fat yield due to feeding PA during the PK period increasing milk fat yield to a greater extent in cows that received the CON diet (+240 g/d) rather than the PA diet (+180 g/d) during the FR period. This difference was associated with the yield of preformed FA because feeding PA during the PK period increased the yield of preformed milk FA only in cows that received the CON diet during the FR period. In conclusion, feeding a C16:0 supplement to early-lactation cows consistently increased the yield of ECM in both the FR and PK periods compared with a control diet. For some variables, the effect of feeding C16:0 was affected by timing of supplementation because milk yield increased only during the PK period and BW decreased to a greater extent in the FR period. Regardless of diet fed in the FR period, feeding a C16:0 supplement during the PK period increased yields of milk and milk components.

Effect of fat supplementation on physiological and reproductive performance of Holstein Friesian bulls during summer.

The objective of current study was to determine the effect of fat supplement on physiological and reproductive performance of Holstein Friesian bulls during subtropical summer in Pakistan. Eighteen bulls were randomly divided into 3 treatment groups: (1) CTL, basal diet without fat supplementation; (2) FS100, basal diet with 100 g fat supplementation (Energizer-RP-10®, IFFCO, Johor, Malaysia); (3) FS200, basal diet with 200 g fat supplementation. Basal diet consisted of 50% green fodder (corn silage), 25% wheat straw, and 25% concentrate on dry matter basis. Diets were offered for 14 weeks from May to August 2016. The average daily temperature-humidity index ranged from 85 to 88 for the experimental period. The results indicated that there was no difference in dry matter intake, water intake, rectal temperature, pulse rate, and respiration rate among the treatment groups. Fat supplementation did not influence semen traits including sperm motility, progressive motility, amplitude of lateral head displacement, live-to-dead ratio, normal acrosomal ridge, plasma membrane integrity, and DNA integrity. The interaction of season with fat revealed that FA200 significantly increased post thaw semen motility and progressive motility during hot humid summer (P < 0.05). Analysis of blood metabolites showed that blood urea nitrogen was higher in FS200 compared with CTL and FS100 groups (P < 0.05). There was no effect of fat supplementation on blood testosterone level. Glucose showed quadratic trend in response to fat supplementation. It could be concluded that addition of fat only improved motility and progressive motility of sperms during hot humid summer.

Effects of fat supplementation on plasma glucose, insulin and fatty acid analysis in ponies maintained on a forage-based diet.

The objective of this study was to observe how fat incorporated into an equine forage-based diet through supplementation altered levels of plasma glucose, insulin and fatty acids. Five Shetland/Hackney cross pony mares were fed alfalfa pellet diets top dressed with commercially available vegetable oil (blend of soya bean, canola and corn oils) at 0%, 5%, 10% or 15% of diet. Ponies were randomly assigned one of four diets to start, with a 14-day adjustment period between transitioning to another one of the four diets. Ponies were gradually adapted to the new diet within the 14-day period before a five-day trial period. Each pony received all four diets by the end of the study. Each trial was a five-day period with a three-day sample collection. Blood samples for each collection week were taken 0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 min and at 5, 6, 7, 8, 9 and 10 hr post-feeding. Excess fat did not impact plasma glucose (p > .1), nor did it affect blood plasma insulin concentration. While there was no time alteration found for plasma fatty acid concentration (p > .1), C14:0 increased when ponies were fed 0% fat and C18:2 decreased when ponies were fed 0% fat. Plasma fatty acids (% of total FA) were higher in C18:0, C18:1, C18:2 and C20:1 in the added fat diets (p < .1). These findings suggest the amounts reported in this study of fat supplementation on a forage-based diet did influence the fatty acid analysis within the pony, but did not negatively impact blood glucose and insulin concentrations.

Short communication: Effects of prill size of a palmitic acid-enriched fat supplement on the yield of milk and milk components, and nutrient digestibility of dairy cows.

The objective of our experiment was to evaluate the effects of prill size of a palmitic acid-enriched fatty acid supplement (PA; 85% C16:0) on feed intake, nutrient digestibility, and production responses of dairy cows. Twenty-four primiparous and multiparous Holstein cows were assigned based on parity and production level to replicated 4×4 Latin squares balanced for carryover effects with 21-d periods. Treatments were a control diet (no added PA), or 2.0% PA added as a small prill size (PA-SM; 284±12.4µm), a medium prill size (PA-MD; 325±14.7µm), or a large prill size (PA-LG; 600±17.4µm) supplement. Overall, PA treatments increased milk fat content (4.25 vs. 3.99%), milk fat yield (1.48 vs. 1.39kg/d), 3.5% fat-corrected milk (39.2 vs. 37.7kg/d), and improved feed efficiency (fat-corrected milk:dry matter intake; 1.51 vs. 1.42) compared with control. Compared with control, PA treatments did not affect dry matter intake, body weight, body condition score, or yields of milk, protein, and lactose. The PA treatments increased neutral detergent fiber digestibility (44.8 vs. 42.4%) and reduced the digestibility of 16-carbon fatty acids (72.3 vs. 79.1%) and total fatty acids (76.6 vs. 80.3%). Compared with control, PA treatments reduced the contents of de novo synthesized milk fatty acids (23.0 vs. 25.8g/100g of fatty acids) and preformed milk fatty acids (36.3 vs. 39.1g/100g of fatty acids), but did not affect their yields. In contrast, PA treatments increased the content (40.8 vs. 35.1g/100g of fatty acids) and yield (570 vs. 436g/d) of 16-carbon milk fatty acids compared with control. The PA prill size had no effect on dry matter intake, yield of milk and milk components, or feed efficiency. However, PA-LG tended to increase milk fat content compared with PA-SM (4.28 vs. 4.22%), and it increased 16-carbon fatty acid digestibility compared with PA-MD (74.2 vs. 71.0%) and PA-SM (74.2 vs. 71.7%). Additionally, PA-LG increased total fatty acid digestibility compared with PA-MD (78.1 vs. 75.6%) and PA-SM (78.1 vs. 76.0%). Results demonstrate that PA increased milk fat content and yield, and feed efficiency. Reducing prill size decreased fatty acid digestibility, but it had no effect on animal performance under the dietary conditions and prill sizes evaluated.

Short-term effects of soybean oil supplementation on performance, digestion, and metabolism in dairy cows fed sugarcane-based diets.

We aimed to quantify the productive and metabolic responses, and digestive changes in dairy cows fed various concentrations of soybean oil (SBO) in high-concentrate, sugarcane-based diets. Eight rumen-cannulated multiparous Holstein cows in mid lactation (574 ± 19.1 kg of body weight and 122 ± 6.9 d in milk), averaging 22.5 ± 1.22 kg/d of milk were assigned to replicated 4 × 4 Latin squares. The experimental period lasted 21 d as follows: 14 d for adaptation, followed by a sampling period from d 15 to 21. The diets were formulated with increasing concentrations of SBO [% of dry matter (DM)]: control (0%), low (LSBO; 1.57%), medium (MSBO; 4.43%), and high (HSBO; 7.34%). Dry matter intake decreased quadratically in response to SBO addition. The greatest decrease in DM intake was observed in MSBO and HSBO diets. Both milk and energy-corrected milk yield were quadratically affected by the SBO inclusion, with a slight decrease up to MSBO and substantial decrease in the HSBO diet. The milk fat concentration linearly decreased from 3.78% in the control to 3.50% in the HSBO diet. The potentially digestible neutral detergent fiber digestibility in the rumen decreased from 55.7% in the control to 35.2% in the HSBO diet. The fractional rate of digestion of potentially digestible neutral detergent fiber in the rumen decreased linearly from 3.13 to 1.39%/h from the control to HSBO diet. The fractional rate of indigestible neutral detergent fiber passage in the rumen was quadratically affected, with the lowest value (2.25%/h) for the HSBO diet. Rumen pH increased from 6.42 to 6.67, and ammonia nitrogen decreased from 28.1 to 21.4 mg/dL, in the control and HSBO diets, respectively. Rumen volatile fatty acids decreased quadratically, with the greatest decrease observed in MSBO and HSBO diets. Serum concentrations of glucose, fatty acids, and ß-hydroxybutyrate were unaffected by SBO inclusion. However, serum concentrations of total cholesterol and high- and low-density lipoproteins linearly increased with increasing concentrations of SBO in the diet. Inclusion of SBO at concentrations from 4.43 to 7.34% of the diet DM decreased DM intake, energy-corrected milk production, fiber digestibility, and rumen fermentation and was thus not recommended. Soybean oil supplementation at 1.57% of the diet DM proved to be a safe concentration for dairy cows fed high-concentrate diets with sugarcane as the sole forage.

Short communication: Lactational responses to palmitic acid supplementation when replacing soyhulls or dry ground corn.

The objective of this study was to evaluate the response of mid-lactation dairy cows to a palmitic acid (C16:0)-enriched fatty acid supplement when replacing soyhulls or dry ground corn in the diet. Twenty-four multiparous Holstein cows (182 ± 60 d in milk; mean ± SD) were blocked by preliminary 3.5% fat-corrected milk and randomly assigned to treatment sequence in a replicated 3 × 3 Latin square design with 21-d periods. Treatments consisted of a control diet containing no supplemental fat (CON), and 2 C16:0-enriched fatty acid-supplemented treatments (PA; BergaFat F100, Berg & Schmidt, Hanover, Germany) as a replacement for either soyhulls (PA-SH) or dry ground corn (PA-CG). The C16:0-enriched supplement was fed at 1.5% of diet dry matter. The PA treatments did not affect dry matter intake, but PA-SH increased dry matter intake by 1.4 kg/d compared with PA-CG. The PA treatments did not affect milk yield; however, PA-SH increased milk yield by 2.4 kg/d compared with PA-CG. The PA treatments tended to decrease milk protein content (3.12 vs. 3.15%). In contrast, PA-SH increased milk protein content (3.14 vs. 3.10%) and milk protein yield (1.27 vs. 1.19 kg/d) compared with PA-CG. The PA treatments increased milk fat concentration (3.68 vs. 3.55%) and milk fat yield (1.46 vs. 1.38 kg/d). The increase in milk fat yield with PA treatments was due to the increase in the yield of 16-carbon fatty acid in milk fat. Furthermore, PA-SH tended to increase yield of de novo fatty acids and yield of 16-carbon fatty acids compared with PA-CG. The PA treatments tended to increase feed efficiency (3.5% fat-corrected milk/dry matter intake) compared with CON (1.51 vs. 1.46). The PA-SH treatment tended to increase insulin concentration compared with PA-CG (1.58 vs. 1.49 µg/L) and PA treatments increased nonesterified fatty acids compared with CON (110 vs. 99 µEq/L). Overall, PA treatments improved feed efficiency and increased milk fat yield and the response to the C16:0-enriched fatty acid supplement was greater when it replaced soyhulls compared with when it replaced dry ground corn in the diet.

Milk production responses to dietary stearic acid vary by production level in dairy cattle.

Effects of stearic acid supplementation on feed intake and metabolic and production responses of dairy cows with a wide range of milk production (32.2 to 64.4 kg/d) were evaluated in a crossover design experiment with a covariate period. Thirty-two multiparous Holstein cows (142±55 d in milk) were assigned randomly within level of milk yield to treatment sequence. Treatments were diets supplemented (2% of diet dry matter) with stearic acid (SA; 98% C18:0) or control (soyhulls). The diets were based on corn silage and alfalfa and contained 24.5% forage neutral detergent fiber, 25.1% starch, and 17.3% crude protein. Treatment periods were 21 d with the final 4 d used for data and sample collection. Compared with the control, SA increased dry matter intake (DMI; 26.1 vs. 25.2 kg/d) and milk yield (40.2 vs. 38.5 kg/d). Stearic acid had no effect on the concentration of milk components but increased yields of fat (1.42 vs. 1.35 kg/d), protein (1.19 vs. 1.14 kg/d), and lactose (1.96 vs. 1.87 kg/d). The SA treatment increased 3.5% fat-corrected milk (3.5% FCM; 40.5 vs. 38.6 kg/d) but did not affect feed efficiency (3.5% FCM/DMI, 1.55 vs. 1.53), body weight, or body condition score compared with the control. Linear interactions between treatment and level of milk yield during the covariate period were detected for DMI and yields of milk, fat, protein, lactose, and 3.5% FCM; responses to SA were positively related to milk yield of cows. The SA treatment increased crude protein digestibility (67.4 vs. 65.5%), tended to increase neutral detergent fiber digestibility (43.6 vs. 42.3%), decreased fatty acid (FA) digestibility (56.6 vs. 76.1%), and did not affect organic matter digestibility. Fatty acid yield response, calculated as the additional FA yield secreted in milk per unit of additional FA intake, was only 13.3% for total FA and 8.2% for C18:0 plus cis-9 C18:1. Low estimated digestibility of the SA supplement was at least partly responsible for the low FA yield response. Treatment did not affect plasma insulin, glucagon, glucose, and nonesterified FA concentrations. Results show that stearic acid has the potential to increase DMI and yields of milk and milk components, without affecting conversion of feed to milk, body condition score, or body weight. Moreover, effects on DMI and yields of milk and milk components were more pronounced for higher-yielding cows than for lower-yielding cows.

Cost-effectiveness of feeding strategies to reduce greenhouse gas emissions from dairy farming.

The objective of this paper was to evaluate the cost-effectiveness of 3 feeding strategies to reduce enteric CH4 production in dairy cows by calculating the effect on labor income at the farm level and on greenhouse gas (GHG) emissions at the chain level (i.e., from production of farm inputs to the farm gate). Strategies included were (1) dietary supplementation of an extruded linseed product (56% linseed; 1kg/cow per day in summer and 2kg/cow per day in winter), (2) dietary supplementation of a nitrate source (75% nitrate; 1% of dry matter intake), and (3) reducing the maturity stage of grass and grass silage (grazing at 1,400 instead of 1,700kg of dry matter/ha and harvesting at 3,000 instead of 3,500kg of dry matter/ha). A dairy farm linear programing model was used to define an average Dutch dairy farm on sandy soil without a predefined feeding strategy (reference situation). Subsequently, 1 of the 3 feeding strategies was implemented and the model was optimized again to determine the new economically optimal farm situation. Enteric CH4 production in the reference situation and after implementing the strategies was calculated based on a mechanistic model for enteric CH4 and empirical formulas explaining the effect of fat and nitrate supplementation on enteric CH4 production. Other GHG emissions along the chain were calculated using life cycle assessment. Total GHG emissions in the reference situation added up to 840kg of CO2 equivalents (CO2e) per t of fat- and protein-corrected milk (FPCM) and yearly labor income of €42,605. Supplementation of the extruded linseed product reduced emissions by 9kg of CO2e/t of FPCM and labor income by €16,041; supplementation of the dietary nitrate source reduced emissions by 32kg of CO2e/t of FPCM and labor income by €5,463; reducing the maturity stage of grass and grass silage reduced emissions by 11kg of CO2e/t of FPCM and labor income by €463. Of the 3 strategies, reducing grass maturity was the most cost-effective (€57/t of CO2e compared with €241/t of CO2e for nitrate supplementation and €2,594/t of CO2e for linseed supplementation) and had the greatest potential to be used in practice because the additional costs were low.

Feeding a C16:0-enriched fat supplement increased the yield of milk fat and improved conversion of feed to milk.

Previous work has indicated that dietary palmitic acid (C16:0) may increase milk fat yield. The effect of a dietary C16:0-enriched fat supplement on feed intake, yield of milk and milk components, and feed efficiency was evaluated in an experiment with a crossover arrangement of treatments with 25-d periods. A fermentable starch challenge on the last 4d of each period was utilized as a split-plot within period. Sixteen mid-lactation Holstein cows (249 ± 33 d in milk) were assigned randomly to treatment sequence. Treatments were either a C16:0-enriched (~85% C16:0) fat supplement (fatty acid treatment, FAT, 2% dry matter) or a control diet (CON) containing no supplemental fat. Diets containing dry ground corn grain were fed from d 1 through 21 of each period. On the last 4d of each period, dry ground corn was replaced by high-moisture corn grain on an equivalent dry matter basis to provide a fermentable starch challenge. Response variables were averaged for d 18 to 21 (immediately before the fermentable starch challenge) and d 22 to 25 (during the fermentable starch challenge). We observed no treatment effects on milk yield or milk protein yield. The FAT treatment increased milk fat concentration from 3.88 to 4.16% and fat yield from 1.23 to 1.32 kg/d compared with CON. The FAT treatment decreased dry matter intake by 1.4 kg/d and increased conversion of feed to milk (3.5% fat-corrected milk yield/dry matter intake) by 8.6% compared with CON. The increase in milk fat yield by FAT was entirely accounted for by a 27% increase in 16-carbon fatty acid output into milk. Yields of de novo and preformed fatty acids were not affected by FAT relative to CON. The fermentable starch challenge did not affect milk fat concentration or yield. Results demonstrate the potential for a dietary C16:0-enriched fat supplement to improve milk fat concentration and yield as well as efficiency of conversion of feed to milk. Further studies are required to verify and extend these results and to determine whether responses are similar across different diets and levels of milk production.

Palmitic acid increased yields of milk and milk fat and nutrient digestibility across production level of lactating cows.

The effects of palmitic acid supplementation on feed intake, digestibility, and metabolic and production responses were evaluated in dairy cows with a wide range of milk production (34.5 to 66.2 kg/d) in a crossover design experiment with a covariate period. Thirty-two multiparous Holstein cows (151 ± 66 d in milk) were randomly assigned to treatment sequence within level of milk production. Treatments were diets supplemented (2% of diet DM) with palmitic acid (PA; 99% C16:0) or control (SH; soyhulls). Treatment periods were 21 d, with the final 4 d used for data and sample collection. Immediately before the first treatment period, cows were fed the control diet for 21 d and baseline values were obtained for all variables (covariate period). Milk production measured during the covariate period (preliminary milk yield) was used as covariate. In general, no interactions were detected between treatment and preliminary milk yield for the response variables measured. The PA treatment increased milk fat percentage (3.40 vs. 3.29%) and yields of milk (46.0 vs. 44.9 kg/d), milk fat (1.53 vs. 1.45 kg/d), and 3.5% fat-corrected milk (44.6 vs. 42.9 kg/d), compared with SH. Concentrations and yields of protein and lactose were not affected by treatment. The PA treatment did not affect dry matter (DM) intake or body weight, tended to decrease body condition score (2.93 vs. 2.99), and increased feed efficiency (3.5% fat-corrected milk/DM intake; 1.60 vs. 1.54), compared with SH. The PA treatment increased total-tract digestibility of neutral detergent fiber (39.0 vs.35.7%) and organic matter (67.9 vs. 66.2%), but decreased fatty acid (FA) digestibility (61.2 vs. 71.3%). As total FA intake increased, total FA digestibility decreased (R(2) = 0.51) and total FA absorbed increased (quadratic R(2) = 0.82). Fatty acid yield response, calculated as the additional FA yield secreted in milk per unit of additional FA intake, was 11.7% for total FA and 16.5% for C16:0 plus cis-9 C16:1 FA. The PA treatment increased plasma concentration of nonesterified FA (101 vs. 90.0 µEq/L) and cholecystokinin (19.7 vs. 17.6 pmol/L), and tended to increase plasma concentration of insulin (10.7 vs. 9.57 µ IU/mL). Results show that palmitic acid fed at 2% of diet DM has the potential to increase yields of milk and milk fat, independent of production level without increasing body condition score or body weight. However, a small percentage of the supplemented FA was partitioned to milk.

Nutritional Quality of Milk Fat from Cows Fed Full-Fat Corn Germ in Diets Containing Cactus Opuntia and Sugarcane Bagasse as Forage Sources.

We evaluated the performance, milk composition, and milk fatty acid profile of cows fed diets composed of cactus cladodes (Opuntia stricta [Haw.] Haw), sugarcane bagasse and increasing levels of full-fat corn germ (FFCG). We hypothesized that ground corn can be effectively replaced by FFCG when cactus cladodes and sugarcane bagasse are used as forage sources. The cows were randomly distributed into two 5 × 5 Latin Squares and fed five diets in which ground corn was progressively replaced with full-fat corn germ (FFCG; 0%, 25%, 50%, 75%, or 100% of substitution). Adding FFCG to the diet increased milk production and milk fat content and reduced milk protein content. Overall, FFCG reduced the proportion of saturated FAs and increased mono- and polyunsaturated FAs in milk, including CLA isomers. In addition, activity indices of stearoyl-CoA desaturase were reduced by increasing levels of FFCG. We conclude that the substitution of corn for FFCG in diets based on cactus cladodes and sugarcane bagasse positively modifies the FA profile of milk and could add commercial value to milk products (e.g., CLA-enriched milk). In addition, the milk fat response indicates that the basal diet was favorable to the rumen environment, preventing the trans-10 shift commonly associated with milk fat depression.

The Effect of Fat Supplementation on the Appearance of Symptoms Associated With Dumping Syndrome in Patients Having Undergone Gastric Surgery: Preliminary Results.

BACKGROUND/OBJECTIVES: Data on the effect of dietary fat on dumping syndrome (DS) symptoms are limited. The aim of this study was to assess the effect of the addition of fat to a carbohydrate meal on the appearance of DS symptoms and glycemic response, in patients who had undergone gastric surgery. SUBJECTS/METHODS: This was an interventional crossover study. Patients scheduled for gastric surgical procedures related to DS at two surgical units of two public hospitals (General University Hospital of Larissa and General Hospital of Larissa) were considered for study inclusion. Patients presenting symptoms suggestive of diagnosis (n = 12), after the ingestion of a carbohydrate meal, were used as both intervention and control groups. During the intervention process, a fat supplement was added to the carbohydrate meal that was previously used for diagnosis. Glycemic response and the amount and intensity of DS symptoms provoked by the two meals were assessed at both appointments. RESULTS: Blood glucose levels were significantly lower in the group that consumed the added fat meal compared with the group that consumed the carbohydrate meal 60 minutes after ingestion (p = 0.028). Furthermore, a significant reduction was noted in the amount of late dumping symptoms (p = 0.021) and the intensity of both early and late dumping symptoms (p = 0.007 and p = 0.012 respectively), after fat addition.  Conclusions: Incorporating fat into a carbohydrate meal seems to attenuate postprandial blood glucose rises and reduce the amount and intensity of DS symptoms, in patients who had undergone gastric surgery.

Effects of Linseed Supplementation on Milk Production, Composition, Odd- and Branched-Chain Fatty Acids, and on Serum Biochemistry in Cilentana Grazing Goats.

The purpose of this study was to investigate the effects of linseed supplementation on milk yield and quality, serum biochemistry and, in particular, to evaluate its possible effects on the production of odd- and branched-chain fatty acids (OBCFA) in the milk of Cilentana grazing goats. Twelve pregnant Cilentana dairy goats were divided into two groups (CTR, control, and LIN, linseed supplementation group). After kidding, the goats had free access to the pasture and both groups received a supplement of 400 g/head of concentrate, but the one administered to the LIN group was characterized by the addition of linseed (in a ratio of 20% as fed) to the ingredients. During the trial, milk samples were taken from April to August in order to evaluate milk production, composition, and fatty acid profile. In addition, blood samples were taken for evaluating the effects of linseed supplementation on goats' health status. The health status of the goats was not influenced by the linseed supplementation, as confirmed by blood analyses. Concerning the effects on milk, the supplementation positively affected (p < 0.001) milk production and fat percentage and the fatty acid profile was markedly influenced by the lipid supplementation. In particular, milk from the LIN group was characterized by significantly lower concentrations of saturated fatty acids (FA; p < 0.001) and higher proportions of monounsaturated FA, polyunsaturated FA, and conjugated linoleic acids (CLAs) than milk from the CTR group (p < 0.001). In contrast, the OBCFA were negatively influenced by the linseed supplementation (p < 0.0001). Further studies are needed to test the effects of different fat sources and other nutrients on the diets.

The Effects of High-Fat Diets from Calcium Salts of Palm Oil on Milk Yields, Rumen Environment, and Digestibility of High-Yielding Dairy Cows Fed Low-Forage Diet.

Instability in grain prices led to continuing worldwide growth in the proportion of fat supplements in lactating cows' rations. However, fat supplementation was associated with decreases in feed intake, rumen fermentation, and feed digestibility. The present objectives were to test the effects of high-fat diets from calcium salts of palm oil fatty acids (CS-PFA) in lactating cow rations containing high proportions of concentrate, on feed intake, milk yields, rumen environment, and digestibility. Forty-two multiparous mid-lactation dairy cows were assigned to three treatments, designated as low fat (LF), moderate fat (MF), and high fat (HF) that contained (on DM basis), respectively, (i) 4.7% total fat with 1.7% CS-PFA, (ii) 5.8% total fat with 2.8% CS-PFA, and (iii) 6.8% total fat with 3.9% CS-PFA. Rumen samples were collected for pH, ammonia, and volatile fatty acid (VFA) measurements, and fecal grab samples were collected for digestibility measurements. A numerical trend of decreasing dry matter intake with increasing CS-PFA in diet was observed: 28.7, 28.5, and 28.1 kg/day in LF, MF, and HF, respectively (p < 0.20). No differences between treatments were observed in milk yields and milk-fat percentages, but protein percentage in milk tended to fall with increasing dietary CS-PFA content (p < 0.08), which resulted in 6.4% smaller protein yields in the HF than in the LF group (p < 0.01). Milk urea nitrogen was 15.3% higher in HF than in LF cows (p < 0.05). Rumen pH was higher at all sampling times in the MF and HF than in the LF cows. Concentrations of propionic acid and total VFA were higher in LF than in MF and HF cows. The apparent total-tract digestibility of dry matter was higher with LF than with HF (p < 0.002), and that of organic matter was lowest with the HF diet (p < 0.005). The apparent NDF digestibility declined with increasing dietary fat content, and it was 8.5 percentage points lower in HF than in LF cows (p < 0.009). Apparent fat digestibility increased with increasing dietary fat content, and it was higher by 10.4 percentage points in the HF than in the LF group (p < 0.004). In conclusion, diets with high concentrate-to-forage ratios, containing up to 6.8% total fat and 3.9% CS-PFA, negatively affected rumen fermentation and NDF digestibility in high-yielding dairy cows; however, the effects on yields were minor, indicating that, under specific circumstances, the inclusion of large amounts of CS-PFA in dairy cows' rations with low fiber content is feasible.

The Effects of Age at Weaning and Length of Lipid Supplementation on Growth, Metabolites, and Marbling of Young Steers.

The objective of this study was to determine how weaning age, days on supplements, and lipid supplementation affected the growth and marbling deposition of steers. Steers from a single sire were early weaned (n = 24) at 150 ± 11 days of age or traditionally weaned (n = 24) at 210 ± 11 days of age. Steers were assigned to control (n = 12/weaning group) or an isocaloric, isonitrogenous rumen by-pass lipid (RBL, n = 12/weaning group) for either 45 (n = 6/treatment) or 90 (n=6/treatment) days then harvested. Steer body weight (BW) was recorded on days -14 and -7, then BW and blood samples were collected on days 0, 22, 45, 66, and 90. The right rib section of each animal was collected for proximate analysis. Longissimus dorsi from RBL steers had increased lipids compared with control steers (3.6 ± 0.2 vs. 2.4 ± 0.2% on a wet basis; p < 0.0001). Steers fed for 90 days had greater (p = 0.02) concentrations of Longissimus dorsi lipid (3.3 ± 0.2%) than those fed for 45 days (2.7 ± 0.2%). There was a weaning age by treatment by days on feed interaction for intramuscular adipocyte diameter (p = 0.02) in which early weaned RBL fed for 90 days steers had an increased adipocyte diameter compared to the early weaned control fed for 90 and early weaned fed for 45 days steers with all other treatment groups as intermediates. Supplementation of RBL increased concentrations of C18:2, C20:4, and total fatty acids on days 45 and 90 (p ≤ 0.05). Data show that RBL supplementation increased the marbling content of the Longissimus dorsi. Furthermore, a longer period of supplementation resulted in increased adipose diameter.

Effects of maternal dietary omega-3 polyunsaturated fatty acids and methionine during late gestation on fetal growth, DNA methylation, and mRNA relative expression of genes associated with the inflammatory response, lipid metabolism and DNA methylation in placenta and offspring's liver in sheep.

BACKGROUND: Omega-3 PUFA or methionine (Met) supply during gestation alters offspring physiology. However, the effect of both nutrients on fetal development has not been explored. Our objective was to determine the effects of supplementation of these two nutrients during late gestation on fetal growth, DNA methylation, and mRNA expression of genes associated with the inflammatory response, and DNA methylation. Ewes (n = 5/treatment) were fed from day 100 to 145 of gestation one of the following treatments: 1) basal diet (NS) without fatty acids (FS) or methionine (MS) supplementation; 2) FS (10 g/kg Ca salts, source omega-3 PUFA); 3) MS (1 g/kg rumen protected methionine); and 4) FS and MS (FS-MS). On day 145, ewes were euthanized, and data from dams and fetus was recorded. Placenta (cotyledon), fetal liver, and blood samples were collected. RESULTS: A treatments interaction on fetal liver weight, ewe body weight and body condition score (BCS) was observed; FS-MS were heavier (P <  0.01) than FS and MS, and FS-MS ewes had a better (P = 0.02) BCS than NS. Methionine increased (P = 0.03) ewe plasma glucose concentration. Fetal liver global DNA methylation increased (P <  0.01) in FS and MS. Dietary treatments modify the mRNA relative expression on some of the genes evaluated. In the fetal liver, FS increased (P = 0.04) the mRNA relative expression of arachidonate-5-lipoxygenase-activating-protein and tended to decrease (P = 0.06) methionine-adenosyltransferase-1A. Moreover, MS decreased (P = 0.04) DNA-methyltransferase-1 and tended to decrease (P = 0.08) free-fatty-acid-receptor-1 mRNA relative expression. Furthermore, FS-MS decreased mRNA relative expression of tumor-necrosis-factor-alpha (P = 0.05), peroxisome-proliferator-activated-receptor-delta (P = 0.03) and gamma (P = 0.04), tended to decrease (P ≤ 0.09) interleukin-6, fatty-acid-transport-protein-1, and delta-5-desaturase, and increased adenosylhomocysteinase (P = 0.04) mRNA relative expression. In cotyledon, FS tended to decrease fatty acid binding protein 4 (P = 0.09) mRNA relative expression. CONCLUSION: Omega-3 PUFA and Met supplementation improves dam's performance in late gestation, which was positively correlated with an increase in offspring's liver development. Moreover, FS-MS decreased mRNA relative expression of proinflammatory cytokines, and lipogenic genes, and increased the expression on an enzyme that has an important role in methylation.