Combined biotin,folic acid,and vitamin B12 supplementation given during the transition period to dairy cows: Part I. Effects on lactation performance,energy and protein metabolism,and hormones

Biotin (B₈), folates (B₉), and vitamin B₁₂ (B₁₂) are involved and interrelated in several metabolic reactions related to energy and protein metabolism. We hypothesized that a low supply of one of the latter vitamins during the transition period would impair metabolic status. The purpose of this study was to evaluate the effect of B₈ supplementation on the response of lactation performance and selected energy and protein metabolites and hormones to a combined supplementation of B₉ and B₁₂ given to periparturient dairy cows, from d ?21 to 21 relative to calving. A total of 32 multiparous Holstein cows housed in tie stalls were randomly assigned, according to their previous 305-d milk yield, to 8 incomplete blocks of 4 treatments: (1) a 2-mL weekly i.m. injection of saline (0.9% NaCl; B₈?/B₉B₁₂?); (2) 20 mg/d of dietary B₈ (unprotected from ruminal degradation) and 2-mL weekly i.m. injection of 0.9% NaCl (B₈+/B₉B₁₂?); (3) 2.6 g/d of dietary B₉ (unprotected) and 2-mL weekly i.m. injection of 10 mg of B₁₂ (B₈?/B₉B₁₂+); and (4) 20 mg/d of dietary B₈, 2.6 g/d of dietary B₉, and weekly i.m. injection of 10 mg of B₁₂ (B₈+/B₉B₁₂+) in a 2 × 2 factorial arrangement. Milk yield and dry matter intake were obtained daily and milk components weekly. Blood samples were taken weekly from d ?21 to calving and 3 times per week from calving to 21 d following parturition. Prepartum plasma concentrations of glucose, insulin, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), and adiponectin were unaffected by treatments. Biotin, B₉, and B₁₂ supplements increased their respective concentrations in plasma and milk. Cows fed the B₈ supplement tended to have lower dry matter intake, but only cows in B₈+/B₉B₁₂? had greater plasma concentrations of NEFA compared with B₈?/B₉B₁₂?. Milk and total solid yields were greater by 13.5 and 13.9%, respectively, for B₈?/B₉B₁₂+ [45.5 (standard error, SE: 1.8) and 5.81 (0.22) kg/d, respectively] compared with B₈?/B₉B₁₂? [40.1 (1.9) and 5.10 (0.23) kg/d, respectively], but these effects were suppressed when combined with the B₈ supplement. Cows in the B₈?/B₉B₁₂+ group had decreased plasma insulin and tended to have increased NEFA concentrations, but postpartum plasma concentrations of glucose, BHB, leptin, and adiponectin were not affected. These cows also mobilized more body fat reserves, as suggested by a tendency to increased plasma NEFA and more milk total solids compared with B₈?/B₉B₁₂? cows. However, plasma concentrations of BHB and adiponectin were similar among treatments. This suggests that the B₉ and B₁₂ supplements enhanced efficiency of energy metabolism in early lactation cows. Folic acid and B₁₂ supplementation increased postpartum plasma Cys and homocysteine concentrations but did not affect plasma Met concentration, suggesting an upregulation of the transsulfuration pathway. In summary, our results showed that, under the current experimental conditions, increasing B₈ supply did not improve responses to the B₉ and B₁₂ supplementation.     

Response to a glucose tolerance test in early-lactation Holstein cows receiving a supplementation of biotin,folic acid,and vitamin B12

The aim of the study was to evaluate glucose and insulin metabolism of cows receiving a supplementation of biotin (B₈), folic acid (B₉), and vitamin B₁₂ (B₁₂) during the transition period. According to a 2 × 2 factorial arrangement, 32 cows were randomly assigned to 9 incomplete blocks according to their previous 305-d milk yield. Within each block, cows were randomly assigned to 1 of the following levels of biotin from ?27 to 28 d relative to the parturition: (1) no biotin supplement (B₈?) or (2) 20 mg/d of dietary biotin (B₈+). Within each level of biotin, the cows received either (1) 2-mL weekly intramuscular injections of saline 0.9% NaCl (B₉B₁₂?) or (2) 2.6 g/d of dietary folic acid and 2-mL weekly intramuscular injections of 10 mg of vitamin B₁₂ (B₉B₁₂+). An intravenous glucose tolerance test was performed at 25 d in milk. Baseline plasma glucagon, glucose, and nonesterified fatty acid concentrations did not differ among treatments. For B₉B₁₂+ cows, baseline plasma insulin concentration and maximal glucose concentration after glucose administration were greater when also combined with biotin compared with no biotin combination, whereas there was no effect in B₉B₁₂? cows. There was no treatment effect on time to reach half-maximal glucose and insulin concentrations, glucose positive incremental area under the curve, and glucose and insulin clearance rates. Regarding insulin results, maximal plasma concentration and positive incremental area under the curve were respectively 51 and 74% greater for cows receiving the B₈ supplement than for cows who did not. Moreover, plasma nonesterified fatty acid concentration nadir tended to be reached later for B₈ cows. Insulin peak was reached earlier for cows in the group B₉B₁₂+ than cows in B₉B₁₂?, regardless of B₈ supplementation. Under the current conditions, our results suggested that cows receiving a B₈ supplement had a reduced insulin sensitivity in early lactation. Insulin response was faster for B₉B₁₂+ cows, but this was not translated into further improvements following the glucose administration challenge.     

Effect of cobalt supplementation during late gestation and early lactation on milk and serum measures

Thirty-six multiparous cows were assigned to a study to determine the effects of dietary Co supplementation during late gestation and early lactation on concentrations of Co in serum and liver, vitamin B₁₂ concentrations in serum and milk, and milk yield. Nonlactating cows received diets containing 0.15, 0.89, or 1.71 mg/ kg of Co (dry matter basis) from 55 d before parturition, and lactating cows received diets containing 0.19, 0.57, or 0.93 mg/kg of Co (dry matter basis) from parturition through 120 d postpartum. Serum vitamin B₁₂ concentrations declined sharply in all cows between 55 and 20 d prepartum. Dietary Co supplementation tended to cause an increase in the concentration of vitamin B₁₂ in colostrum and milk. Cobalt intake did not affect concentrations of Co in liver or serum, but increased the Co concentration of milk (0.089, 0.120, and 0.130 μg of Co/mL) at 120 days in milk. There was no effect of Co supplementation on dry matter intake or yield of milk and milk components. In conclusion, serum concentrations of vitamin B₁₂ are reduced in the early dry period, and added dietary Co may increase ruminal synthesis of vitamin B₁₂ as indicated by a tendency for increased vitamin B₁₂ concentrations in colostrum and milk of cows supplemented with dietary Co.     

Production,milk fatty acid profile,and nutrient utilization in grazing dairy cows supplemented with ground flaxseed

Flaxseed has been extensively used as a supplement for dairy cows because of its high concentrations of energy and the n-3 fatty acid (FA) cis-9,cis-12,cis-15 18:3. However, limited information is available regarding the effect of ground flaxseed on dry matter intake (DMI), ruminal fermentation, and nutrient utilization in grazing dairy cows. Twenty multiparous Jersey cows averaging (mean ± standard deviation) 111 ± 49 d in milk in the beginning of the study were used in a randomized complete block design to investigate the effects of supplementing herbage (i.e., grazed forage) with ground corn-soybean meal mix (control diet = CTRL) or ground flaxseed (flaxseed diet = FLX) on animal production, milk FA, ruminal metabolism, and nutrient digestibility. The study was conducted from June to September 2013, with data and sample collection taking place on wk 4, 8, 12, and 16. Cows were fed a diet formulated to yield a 60:40 forage-to-concentrate ratio consisting of (dry matter basis): 40% cool-season perennial herbage, 50% partial total mixed ration, and 10% of ground corn-soybean meal mix or 10% ground flaxseed. However, estimated herbage DMI averaged 5.59 kg/d or 34% of the total DMI. Significant treatment by week interactions were observed for milk and blood urea N, and several milk FA (e.g., trans-10 18:1). No significant differences between treatments were observed for herbage and total DMI, milk yield, feed efficiency, concentrations and yields of milk components, and urinary excretion of purine derivatives. Total-tract digestibility of organic matter decreased, whereas that of neutral detergent fiber increased with feeding FLX versus CTRL. No treatment effects were observed for ruminal concentrations of total volatile FA and NH₃-N, and ruminal proportions of acetate and propionate. Ruminal butyrate tended to decrease, and the acetate-to-propionate ratio decreased in the FLX diet. Most saturated and unsaturated FA in milk fat were changed. Specifically, milk proportion of cis-9,cis-12,cis-15 18:3, Σn-3 FA, and Σ18C FA increased, whereas that of cis-9,cis-12 18:2, Σn-6 FA, Σ odd-chain FA, Σ<16C FA, and Σ16C FA decreased with feeding FLX versus the CTRL diet. In conclusion, feeding FLX did not change yields of milk and milk components, but increased milk n-3 FA. Therefore, costs and industry adoption of premiums for n-3-enriched milk will determine the adoption of ground flaxseed in pasture-based dairy farms.     

Effects of chitosan and whole raw soybeans on ruminal fermentation and bacterial populations,and milk fatty acid profile in dairy cows

The objective of this study was to evaluate whether providing chitosan (CHI) to cows fed diets supplemented with whole raw soybeans (WRS) would affect the nutrient intake and digestibility, ruminal fermentation and bacterial populations, microbial protein synthesis, N utilization, blood metabolites, and milk yield and composition of dairy cows. Twenty-four multiparous Holstein cows (141 ± 37.1 d in milk, 38.8 ± 6.42 kg/d of milk yield; mean ± SD) were enrolled to a 4 × 4 Latin square design experiment with 23-d periods. Cows were blocked within Latin squares according to milk yield, days in milk, body weight, and rumen cannula (n = 8). A 2 × 2 factorial treatment arrangement was randomly assigned to cows within blocks. Treatments were composed of diets with 2 inclusion rates of WRS (0 or 14% diet dry matter) and 2 doses of CHI (0 or 4 g/kg of dry matter, Polymar Ciência e Nutrição, Fortaleza, Brazil). In general, CHI+WRS negatively affected nutrient intake and digestibility of cows, decreasing milk yield and solids production. The CHI increased ruminal pH and decreased acetate to propionate ratio, and WRS reduced NH₃-N concentration and acetate to propionate in the rumen. The CHI reduced the relative bacterial population of Butyrivibrio group, whereas WRS decreased the relative bacterial population of Butyrivibrio group, and Fibrobacter succinogenes, and increased the relative bacterial population of Streptococcus bovis. No interaction effects between CHI and WRS were observed on ruminal fermentation and bacterial populations. The CHI+WRS decreased N intake, microbial N synthesis, and N secreted in milk of cows. The WRS increased N excreted in feces and consequently decreased the N excreted in urine. The CHI had no effects on blood metabolites, but WRS decreased blood concentrations of glucose and increased blood cholesterol concentration. The CHI and WRS improved efficiency of milk yield of cows in terms of fat-corrected milk, energy-corrected milk, and net energy of lactation. The CHI increased milk concentration [g/100 g of fatty acids (FA)] of 18:1 trans-11, 18:2 cis-9,cis-12, 18:3 cis-9,cis-12,cis-15, 18:1 cis-9,trans-11, total monounsaturated FA, and total polyunsaturated FA. The WRS increased total monounsaturated FA, polyunsaturated FA, and 18:0 to unsaturated FA ratio in milk of cows. Evidence indicates that supplementing diets with unsaturated fat sources along with CHI negatively affects nutrient intake and digestibility of cows, resulting in less milk production. Diet supplementation with CHI or WRS can improve feed efficiency and increases unsaturated FA concentration in milk of dairy cows.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 16% and 27% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 42% higher in PP cows throughout the milking period, as well as 15% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 13% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 23% higher in colostrum than mature milk and 25% higher in MP cows. Linoleic acid was also 13% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 63% higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 25% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Whole-body propionate and glucose metabolism of multiparous dairy cows receiving folic acid and vitamin B12 supplements

This study was undertaken to evaluate the effect of supplementation of folic acid and vitamin B₁₂ on glucose and propionate metabolism. Twenty-four multiparous cows were assigned according to a complete block design in a 2 × 2 factorial arrangement to one of the following treatments: (1) saline 0.9% NaCl, (2) 320 mg of folic acid, (3) 10 mg of vitamin B₁₂, or (4) 320 mg of folic acid and 10 mg of vitamin B₁₂. Intramuscular injections were given weekly from 3 wk before the expected calving date until 9 wk postpartum. At 63 d in milk, d-[6,6-²H₂]-glucose (16.5 mmol/h; jugular vein) and [1-¹³C]-sodium propionate (13.9 mmol/h; ruminal vein) were simultaneously infused for 4 h; blood samples were collected from 2 to 4 h of the infusion period. Liver biopsies were carried out the following day. Supplements of folic acid and vitamin B₁₂ respectively increased folate and vitamin B₁₂ concentrations, both in milk and liver. Although dry matter intake was unaffected by treatments, milk and milk lactose yields tended to be lower by 5.0 and by 0.25 kg/d, respectively, for cows receiving the folic acid supplement. Plasma β-hydroxybutyrate concentration with the folic acid supplement followed the same tendency. Hepatic gene expression of methylmalonyl-CoA mutase and S-adenosylhomocysteine hydrolase was higher for cows receiving the combined folic acid and vitamin B₁₂ supplement compared with cows receiving only the supplement of folic acid, whereas no treatment effect was noted for cows not receiving the folic acid supplement. Whole-body glucose rate of appearance and the proportion of whole-body glucose rate of appearance secreted in milk lactose decreased by 229 g/d and 5%, respectively, for animals receiving the folic acid supplement, concomitant with the lower milk lactose synthesis in these cows, indicating that supplementary folic acid may alter energy partitioning in cows. The absence of treatment effect on plasma concentrations of methylmalonic acid as well as on the proportion of glucose synthesized from propionate, averaging 60%, supports the fact that vitamin B₁₂ supply was sufficient in control cows in the current study. Our results suggest that the folic acid supplement reduced glucose-derived lactose synthesis by redirecting glucose for other metabolic activity in the mammary gland or in other tissues.     

Effect of lauric acid and coconut oil on ruminal fermentation, digestion, ammonia losses from manure, and milk fatty acid composition in lactating cows

This experiment (replicated 3 × 3 Latin square design) was conducted to investigate the effects of lauric acid (LA) or coconut oil (CO) on ruminal fermentation, nutrient digestibility, ammonia losses from manure, and milk fatty acid (FA) composition in lactating cows. Treatments consisted of intraruminal doses of 240 g of stearic acid/d (SA; control), 240 g of LA/d, or 530 g of CO/d administered once daily, before feeding. Between periods, cows were inoculated with ruminal contents from donor cows and allowed a 7-d recovery period. Treatment did not affect dry matter intake, milk yield, or milk composition. Ruminal pH was slightly increased by CO compared with the other treatments, whereas LA and CO decreased ruminal ammonia concentration compared with SA. Both LA and CO decreased protozoal counts by 80% or more compared with SA. Methane production rate in the rumen was reduced by CO compared with LA and SA, with no differences between LA and SA. Treatments had no effect on total tract apparent dry matter, organic matter, N, and neutral detergent fiber digestibility coefficients or on cumulative (15 d) in vitro ammonia losses from manure. Compared with SA, LA and CO increased milk fat 12:0, cis-9 12:1, and trans-9 12:1 content and decreased 6:0, 8:0, 10:0, cis-9 10:1, 16:0, 18:0, cis 18:1, total 18:2, 18:3 n-3 and total polyunsaturated FA concentrations. Administration of LA and 14:0 (as CO) in the rumen were apparently transferred into milk fat with a mean efficiency of 18 and 15%, respectively. In conclusion, current data confirmed that LA and CO exhibit strong antiprotozoal activity when dosed intraruminally, an effect that is accompanied by decreases in ammonia concentration and, for CO, lowered methane production. Administration of LA and CO in the rumen also altered milk FA composition.     

Effects of bacterial direct-fed microbials on ruminal characteristics,methane emission,and milk fatty acid composition in cows fed high- or low-starch diets

This study investigated the effects of bacterial direct-fed microbials (DFM) on ruminal fermentation and microbial characteristics, methane (CH₄) emission, diet digestibility, and milk fatty acid (FA) composition in dairy cows fed diets formulated to induce different ruminal volatile fatty acid (VFA) profiles. Eight ruminally cannulated dairy cows were divided into 2 groups based on parity, days in milk, milk production, and body weight. Cows in each group were fed either a high-starch (38%, HS) or a low-starch (2%, LS) diet in a 55:45 forage-to-concentrate ratio on a dry matter (DM) basis. For each diet, cows were randomly assigned to 1 of 4 treatments in a Latin square design of (1) control (CON); (2) Propionibacterium P63 (P63); (3) P63 plus Lactobacillus plantarum 115 (P63+Lp); (4) P63 plus Lactobacillus rhamnosus 32 (P63+Lr). Strains of DFM were administered at 10¹⁰ cfu/d. Methane emission (using the sulfur hexafluoride tracer technique), total-tract digestibility, dry matter intake, and milk production and composition were quantified in wk 3. Ruminal fermentation and microbial characteristics were measured in wk 4. Data were analyzed using the mixed procedure of SAS (SAS Institute Inc., Cary, NC). The 2 diets induced different ruminal VFA profiles, with a greater proportion of propionate at the expense of acetate and butyrate for the HS diet. Greater concentrations of total bacteria and selected bacterial species of methanogenic Archaea were reported for the HS diet, whereas the protozoa concentration in HS decreased. For both diets, bacterial DFM supplementation raised ruminal pH (+0.18 pH units, on average) compared with CON. Irrespective of diet, P63+Lp and P63+Lr increased ruminal cellulase activity (3.8-fold, on average) compared with CON, but this effect was not associated with variations in ruminal microbial numbers. Irrespective of diet, no effect of bacterial DFM on ruminal VFA was observed. For the LS diet, supplementing cows with P63+Lr tended to decrease CH₄ emission (26.5%, on average, when expressed per kilogram of milk or 4% fat-corrected milk). Only P63 supplementation to cows fed the HS diet affected the concentration of some milk FA, such as cis isomers of 18:1 and intermediates of ruminal biohydrogenation of polyunsaturated FA. Overall, bacterial DFM could be useful to stabilize ruminal pH. Their effects on CH₄ production mitigation and milk FA profile depended on DFM strain and diet and should be confirmed under a greater variation of dietary conditions.     

Effect of dietary supplements of biotin,intramuscular injections of vitamin B12, or both on postpartum lactation performance in multiparous dairy cows

The current study was conducted to investigate the effects of dietary supplementation of biotin, intramuscular injections of vitamin B₁₂ (VB₁₂), or both beginning at the prepartum period on feed intake and lactation performance in postpartum dairy cows. Forty-eight dairy cows were allocated into 12 blocks, based on parity and milk yield of the previous lactation cycle, and randomly assigned to 1 of 4 treatments. Supplementation of VB₁₂ (weekly intramuscular injections of 0 or 10 mg) and biotin (dietary supplements of 0 or 30 mg/d) were used in a 2 × 2 factorial arrangement in a randomized complete block design of 12 blocks with repeated measures. The study started at 3 wk before the expected calving date and ended at 8 wk after calving. Feed intake and lactation performance (milk yield and composition) were recorded weekly after calving. Blood variables were measured on d ?10, 0, 8, 15, 29, 43, and 57 relative to calving. When VB₁₂ was given, the cows had greater feed intake, better lactation performance and lower body weight loss in the postpartum period compared with animals without injection of VB_12. The VB₁₂-injected cows had lower plasma nonesterified fatty acids and β-hydroxybutyrate concentrations but higher plasma superoxide dismutase activity compared with cows without VB₁₂. Cows fed a biotin supplement had higher milk protein yield (6 and 8 wk) and lactose yield (6–8 wk), compared with animals without biotin. However, under the present experimental conditions, we found no additive effect of a combined supplement of biotin and vitamin B₁₂ on lactation performance of dairy cows.     

Effect of dietary quebracho tannin extract on milk fatty acid composition in cows

The aim of this study was to examine the capacity of quebracho tannin extract (QTE) to modulate the fatty acid (FA) profile in the milk fat of cows. Fifty Holstein cows yielding 33.2 ± 8.2 kg/d of milk were divided into 2 groups. The cows were fed a basal diet with a forage-concentrate ratio of 66:34 on a dry matter (DM) basis. Diets tested were control (CON, basal diet without QTE) and basal diet plus 15 or 30 g of QTE/kg of DM (QTE₁₅ and QTE₃₀, respectively). Two treatments could be tested simultaneously and were arranged along 6 periods. The milk FA profile was characterized by increments in the proportion of linoleic (LA) and α-linolenic acid (α-LNA) (QTE₁₅ = 10 and 6.1%; QTE₃₀ = 28 and 25%, respectively) compared to CON, which might indicate reduced ruminal biohydrogenation (BH) of both dietary LA and α-LNA. Vaccenic acid (VA) in the milk fat was reduced (QTE₁₅ 8.9% and QTE₃₀ 12%) compared to CON, which may be linked to inhibited BH of LA and α-LNA. Rumenic acid (RA), a conjugated LA (cis-9,trans-11 conjugated linoleic acid) and an important human health promoter, was unfortunately decreased (QTE₁₅ 8.3% and QTE₃₀ 16%) in the milk compared with CON, probably because of inhibited ruminal BH of LA. However, reduced RA in the milk was probably due to reduced availability of VA produced in the rumen and the consequently low VA available to be desaturated to RA in the mammary gland by Δ⁹-desaturase. The proportions of total polyunsaturated FA were increased with QTE₁₅ and QTE₃₀ by 4.7 and 15% compared to CON, respectively, and the long-chain FA proportions were also increased (QTE₁₅ 2.0% and QTE₃₀ 8.2%). Moreover, myristic and palmitic acid were reduced by QTE₃₀ (9.6 and 3.3%, respectively) compared to CON, which also contributed to increasing the nutritional quality of milk because they are recognized to increase high-density lipoprotein in humans. Branched-chain FA in milk was reduced with QTE treatments, which indicates inhibited ruminal BH and microbial activity. In general, our findings suggest that dietary QTE have the potential to modulate FA profile of milk fat, and this effect is dosage dependent. Because QTE influenced the FA profile of milk fat both positively and negatively, further research is needed before concluding that QTE may improve the nutritional quality of cow milk fat in human diets.     

Ruminal fermentation, milk fatty acid profiles, and productive performance of Holstein dairy cows fed 2 different safflower seeds

A lactation trial was conducted to determine the effects of supplementing whole safflower seeds (SS) on ruminal fermentation, lactational performance, and milk fatty acid (FA) profiles. Nine multiparous Holstein cows (days in milk = 110 ± 20) were used in a replicated 3 × 3 Latin square design. Each period lasted 21 d, with 14 d of adaptation and 7 d of data collection. Within square, cows were randomly assigned to a sequence of 3 dietary treatments as follows: cottonseed total mixed ration (TMR; CST), conventional SS (variety S-208) TMR (CSST), and NutraSaff SS (Safflower Technologies International, Sidney, MT) TMR (NSST). Diets contained approximately 63% forage (36% alfalfa hay, 4% grass hay, and 23% corn silage) and 37% concentrate supplemented with 2% cottonseed to the CST and 3% conventional or NutraSaff SS to the CSST or the NSST, respectively. Intake of dry matter (DM) averaged 21.8 kg/d and did not differ across diets, but feeding the NSST decreased intake of neutral detergent fiber (NDF) due to lower dietary concentration of NDF in the NSST. Digestibilities of DM and nutrients were similar among treatments. No differences in yields of milk or milk components were observed in response to supplementing SS. Dietary treatments did not affect ruminal pH, total or molar proportions of ruminal volatile FA, and ammonia-N. However, cows fed SS had a higher molar proportion of isobutyrate than those fed the CST diet. Ruminal C16:0 FA concentration increased with the CST, whereas C18:1 cis-9 and C18:2 n-6 tended to increase with SS supplementation, indicating that conventional and NutraSaff SS were partially protected from microbial biohydrogenation. Supplementing SS decreased milk C16:0 concentration, whereas it increased C18:1 cis-9 and C18:1 trans-9. Milk FA C18:1 trans-11 and cis-9, trans-11 conjugated linoleic acid increased and tended to increase with feeding the NSST, respectively, but not the CSST diet. In conclusion, supplementing diets with whole SS at 3% of dietary DM can be an effective strategy of fat supplementation to lactating dairy cows without negative effects on lactational performance and milk FA profiles.     

Short communication: Effects of dietary 5,6-dimethylbenzimidazole supplementation on vitamin B12 supply,lactation performance,and energy balance in dairy cows during the transition period and early lactation

The current study was conducted to investigate the effects of 5,6-dimethylbenzimidazole (DMB) supplementation to the feed during the transition period and early lactation on the vitamin B₁₂ supply, lactation performance, and energy balance in postpartum cows. Twenty-four prepartum Holstein dairy cows were divided into 12 blocks based on their parity and milk yield at the last lactation and were then randomly allocated to 1 of 2 treatments: a basal diet without DMB (control) or a treatment diet that contained 1.5 g of DMB/d per cow. The study started at wk 3 before the expected calving day and ended at wk 8 postpartum. The feed intake and the lactation performance were measured weekly after calving. Blood parameters were measured on d ?10, 0, 8, 15, 29, 43, and 57 relative to the calving day. Body weight was measured on the calving day and on d 57 after calving. The yields of milk, protein, and lactose in cows fed DMB were higher than in the control throughout the whole postpartum stage. On wk 8 postpartum, the vitamin B₁₂ content in the milk and sera was greater in cows fed DMB than in the control. The overall body weight loss from wk 1 to 8 postpartum was less in cows fed DMB than in the control. The plasma content of nonesterified fatty acids and β-hydroxybutyric acid was significantly lower in cows fed DMB than in the control throughout the whole experimental stage. In conclusion, dietary DMB fed during the transition period and early lactation improved the vitamin B₁₂ supply, milk production, and energy balance of postpartum dairy cows.     

Effects of berry seed residues on ruminal fermentation,methane concentration,milk production,and fatty acid proportions in the rumen and milk of dairy cows

Strawberry (SB), black currant (BC), and raspberry seed (RB) residues were used in 3 experiments to study their effects on ruminal fermentation, methane concentration, and fatty acid (FA) proportions in the ruminal fluid and milk of dairy cows. Initially, a batch fermentation in vitro study (experiment 1) was performed to investigate the effects of the 3 berry residues on basic ruminal fermentation parameters. Total volatile fatty acid concentrations, including acetate, propionate, and butyrate, increased in the BC group compared with other treatments. Based on the preliminary in vitro results, 2 consecutive in vivo experiments were conducted using 4 Polish Holstein-Friesian cows fitted with rumen cannulas (experiment 2) and 30 lactating Polish Holstein-Friesian dairy cows (experiment 3) in a replicated 2 × 2 crossover design. Cows in both experiments received a partial mixed ration (PMR) in 2 variants: (1) a control diet of PMR + 2 kg of concentrate (control); (2) PMR + 2 kg of BC seed residues (BC). The BC diet did not mitigate ruminal methane production. Ruminal fermentation (experiment 2) was not affected by the BC diet; however, the concentrations of C18:1 trans-11 and C18:2 cis-9,trans-11 increased significantly by 91 and 131%, respectively. Likewise, concentrations of total trans C18:1 and total monounsaturated FA in ruminal fluid were increased significantly by BC seed residues. In experiment 3, BC significantly increased milk fat C18:1 trans-11, C18:2 cis-9,trans-11, n-3, n-6, and polyunsaturated FA concentrations without affecting milk production performance. In conclusion, the amount (2 kg/d) of BC used in this study did not adversely affect ruminal fermentation or milk production and composition. However, using BC increased proportions of unsaturated FA and conjugated linoleic acid in milk. Although dietary BC did not exert a strong methane inhibition effect, it could represent an inexpensive alternative concentrate to improve beneficial FA in milk without negative effects on rumen fermentation and production parameters in dairy cows. Incorporation of berry seed residues in diets would be profitable economically and nutritionally for dairy cattle production.     

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.     

Effects of ground,steam-flaked,and super-conditioned corn grain on production performance and total-tract digestibility in dairy cows

This study aimed to evaluate the effects of feeding ground, steam-flaked, or super-conditioned corn on production performance, rumen fermentation, nutrient digestibility, and milk fatty acid (FA) profile of lactating dairy cows. Twenty-four lactating Holstein cows (130 ± 12 d in milk) in a completely randomized block design experiment were assigned to 1 of 3 treatments that contained 31% of one of the following corn types: (1) ground corn; (2) steam-flaked corn; and (3) super-conditioned corn. Actual milk yield was greater in the super-conditioned corn diet than in the steam-flaked and ground corn diets. Dry matter intake, 3.5% fat-corrected milk and energy-corrected milk remained unaffected by treatments; however, milk fat concentration decreased in the super-conditioned corn diet compared with the ground and steam-flaked corn diets. The molar proportion of ruminal acetate decreased in the super-conditioned corn diet compared with the ground and steam-flaked corn diets, whereas the molar proportion of propionate spiked in the super-conditioned corn diet. Ruminal pH dropped in cows fed super-conditioned corn compared with the other 2 diets. A similar pattern was observed for ruminal NH₃-N and acetate-to-propionate ratio. Total-tract starch digestibility increased the most in the super-conditioned corn diet followed by the steam-flaked and ground corn diets (96.8, 95.1, and 92.5%, respectively). The neutral detergent fiber digestibility declined in cows fed the super-conditioned corn diet as opposed to other diets (~3.9%). The concentrations of 16:0 and mixed-FA in milk fat dropped in the super-conditioned corn-based diet compared with the ground corn diet. Milk trans-10 18:1 FA increased, whereas trans-11 18:1 FA decreased in cows fed the super-conditioned diet. We concluded that super-conditioned corn has the potential to increase milk yield and starch digestibility in lactating dairy cows; however, reduced milk fat output caused by altering ruminal pH and ruminal FA biohydrogenation pathways may not be desirable in certain markets. Future research is warranted to investigate how super-conditioned corn affects feed efficiency.     

The effect of rumen digesta inoculation on the time course of recovery from classical diet-induced milk fat depression in dairy cows

Ten ruminally cannulated cows were used in a crossover design that investigated the effect of rumen digesta inoculation from non-milk fat-depressed cows on recovery from classical diet-induced milk fat depression (MFD) characterized by reduced fat yield, reduced de novo milk fat synthesis, and increased alternate trans isomers. Two additional cows fed a high-fiber and low-polyunsaturated fatty acid (FA) diet (31.8% neutral detergent fiber, 4.2% FA, and 1.2% C18:2) were used as rumen digesta donors. Milk fat depression was induced during the first 10 d of each period by feeding a low-fiber and high-polyunsaturated FA diet (induction; 26.1% neutral detergent fiber, 5.8% FA, and 1.9% C18:2), resulting in a 30% decrease in milk fat yield. A recovery phase followed where all cows were switched to the high-forage, low-polyunsaturated FA diet and were allocated to (1) control (no inoculation) or (2) ruminal inoculation with donor cow digesta (8 kg/d for 6 d). Milk yield and composition were measured every 3 d. Milk yield progressively decreased during recovery. Milk fat concentration increased progressively during the recovery phase and no effect of treatment existed at any time point. Also, no treatment effect of milk fat yield was detected. The concentration of milk de novo FA increased progressively during recovery for both treatments and was higher for inoculated compared with control cows on d 6. In agreement, milk fat concentration of trans-10,cis-12 conjugated linoleic acid decreased progressively in both treatments and was lower in inoculated cows on d 3 and 6. Ruminal inoculation from non-milk fat-depressed cows did not change milk fat yield, but slightly accelerated the rate of recovery of de novo FA synthesis and normal ruminal FA biohydrogenation, demonstrating a possible opportunity for other interventions that improve the ruminal environment to accelerate recovery from this condition.     

Effects of lauric and myristic acids on ruminal fermentation, production, and milk fatty acid composition in lactating dairy cows

The objectives of this experiment were to investigate the effects of lauric (LA) and myristic (MA) acids on ruminal fermentation, production, and milk fatty acid (FA) profile in lactating dairy cows and to identify the FA responsible for the methanogen-suppressing effect of coconut oil. The experiment was conducted as a replicated 3 × 3 Latin square. Six ruminally cannulated cows (95 ± 26.4 DIM) were subjected to the following treatments: 240 g/cow per day each of stearic acid (SA, control), LA, or MA. Experimental periods were 28 d and cows were refaunated between periods. Lauric acid reduced protozoal counts in the rumen by 96%, as well as acetate, total VFA, and microbial N outflow from the rumen, compared with SA and MA. Ruminal methane production was not affected by treatment. Dry matter intake was reduced 35% by LA compared with SA and MA, which resulted in decreased milk yield. Milk fat content also was depressed by LA compared with SA and MA. Treatment had no effect on milk protein content. All treatments increased milk concentration of the respective treatment FA. Concentration of C12:0 was more than doubled by LA, and C14:0 was increased (45%) by MA compared with SA. Concentration of milk FA < C16 was 20% lower for LA than MA. Concentrations of trans 18:1 FA (except trans 12) and CLA isomers were increased by LA compared with SA and MA. Overall, the concentrations of saturated FA in milk fat were reduced, and that of > C16 FA and MUFA were increased, by LA compared with the other treatments. In this study, LA had profound effects on ruminal fermentation, mediated through inhibited microbial populations, and decreased DMI, milk yield, and milk fat content. Despite the significant decrease in protozoal counts, however, LA had no effect on ruminal methane production. Thus, the antimethanogenic effect of coconut oil, observed in related studies, is likely due to total FA application level, the additive effect of LA and MA, or a combination of both. Both LA and MA modified milk FA profile significantly.     

Effect of a high-palmitic acid fat supplement on milk production and apparent total-tract digestibility in high- and low-milk yield dairy cows

The effect of a high-palmitic acid fat supplement was tested in 12 high-producing (mean = 42.1 kg/d) and 12 low-producing (mean = 28.9 kg/d) cows arranged in a replicated 3 × 3 Latin square design. Experimental periods were 21 d, with 18 d of diet adaptation and 3 d of sample collection. Treatments were (1) control (no supplemental fat), (2) high-palmitic acid (PA) supplement (84% C16:0), and (3) Ca salts of palm fatty acid (FA) supplement (Ca-FA). The PA supplement had no effect on milk production, but decreased dry matter intake by 7 and 9% relative to the control in high- and low-producing cows, respectively, and increased feed efficiency by 8.5% in high-producing cows compared with the control. Milk fat concentration and yield were not affected by PA relative to the control in high- or low-producing cows, although PA increased the yield of milk 16-C FA by more than 85 g/d relative to the control. The Ca-FA decreased milk fat concentration compared with PA in high-, but not in low-producing cows. In agreement, Ca-FA dramatically increased milk fat concentration of trans-10 C18:1 and trans-10, cis-12 conjugated linoleic acid (>300%) compared with PA in high-producing cows, but not in low-producing cows. No effect of treatment on milk protein concentration or yield was detected. The PA supplement also increased 16-C FA apparent digestibility by over 10% and increased total FA digestibility compared with the control in high- and low-producing cows. During short-term feeding, palmitic acid supplementation did not increase milk or milk fat yield; however, it was efficiently absorbed, increased feed efficiency, and increased milk 16-C FA yield, while minimizing alterations in ruminal biohydrogenation commonly observed for other unsaturated fat supplements. Longer-term experiments will be necessary to determine the effects on energy balance and changes in body reserves.