Effect of Saccharomyces cerevisiae fermentation product on oxidative status, inflammation, and immune response in transition dairy cattle.

Dairy cattle are subjected to oxidative stress, inflammation, and altered immune function during the transition to lactation. The objective of this study was to evaluate the effects of a dietary Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V) on oxidative status, inflammation, and innate and adaptive immune responses during the transition period. Holstein cows were blocked by parity, expected calving date, and previous milk yield and then randomly assigned to treatment within block. Treatment was a control total mixed ration (n = 30) or SCFP total mixed ration (n = 34) fed from -29 ± 5 to 42 d relative to calving (RTC). Blood was sampled during wk -4, -2, 1, 2, and 5 and liver tissue at wk -3 and 2 RTC. Oxidative status was evaluated in plasma by retinol, α-tocopherol, and malondialdehyde concentrations, glutathione peroxidase activity, and Trolox equivalent antioxidant capacity, and in liver by mRNA abundance of nuclear factor E2-related factor 2 (NFE2L2), metallothionein 1E (MT1E), and glutathione peroxidase 3 (GPX3). Inflammation was evaluated in plasma by haptoglobin (HP) and serum amyloid A (SAA) concentrations and in liver by mRNA abundance of HP, serum amyloid A3 (SAA3), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB1). Innate immune response was measured by stimulated oxidative burst of polymorphonuclear cells (neutrophils) isolated from blood. Ovalbumin (OVA) was administered with adjuvant on d 7 and 21 RTC, and adaptive immune response was evaluated by serum anti-OVA IgG content on d 28 and 35. Mixed models were used to assess effects of treatment, time, parity, and all interactions. We previously reported that SCFP had limited effects on productivity in this cohort, although milk fat yield was transiently increased and subclinical ketosis incidence was increased. Supplementation with SCFP did not affect overall oxidative, inflammatory, or immune parameters. The only treatment × week interaction detected was for plasma α-tocopherol concentration, which tended to be greater in control cows during wk 2 RTC. A tendency for a treatment × parity interaction was detected for serum anti-OVA IgG titer, which tended to be greater for SCFP than for controls among primiparous cows. Plasma inflammatory biomarkers were not affected by SCFP but, unexpectedly, plasma HP was elevated at both prepartum time points and plasma SAA was elevated during wk -2 RTC compared with the expected increases in both biomarkers postpartum. In this cohort of transition cows with low disease incidence, SCFP generally did not affect oxidative, inflammatory, or immune parameters.

Resynchronizing the first eligible estrus in dairy cattle after a prior insemination and fertility of the prior insemination after gonadotropin-releasing hormone and progesterone treatments.

The hypothesis of this study tested whether application of designed treatments to synchronize estrus in nonpregnant previously inseminated lactating dairy cows increased the proportion of nonpregnant cows in estrus before early pregnancy diagnosis on Day 32 after the previous insemination (Day 0) and increase fertility of the pretreatment insemination. A progesterone insert (CIDR) and GnRH were applied to cows after insemination to resynchronize the returning estrus of cows that failed to conceive on Day 0. The combination of GnRH (Day 14) and a CIDR insert (d 17 through 24) in experiment 1 (n = 347 cows) did not increase (P = 0.13) the proportion of nonpregnant cows returning to estrus before pregnancy diagnosis, but increased (P < 0.01) the synchrony of their return by 24.4% points, and delayed (P < 0.01) that return by 2.3 ± 0.3 d compared with controls. Ovulation risk after GnRH treatment on Day 14 was only 10%. For cows that failed to return to estrus before Day 32, progesterone concentration on Days 14 and 17 were less than that in cows that returned to estrus by Day 32 and in pregnant cows. Cows that returned to estrus had larger follicles and fewer numbers of CL on Day 21 than pregnant cows and cows that failed to return to estrus, but concentrations of pregnancy-associated glycoproteins on Day 28 indicated that cows failing to return to estrus were likely pregnant but suffered embryo death. In experiment 2 (n = 881), use of GnRH alone (Day 7), a CIDR insert alone (Days 14 through 21), or in combination, failed to increase the proportion of nonpregnant cows in estrus before pregnancy diagnosis on Day 32 compared with controls. Cows receiving the CIDR insert had increased (P < 0.01) synchrony of estrus by 24-34% points compared with cows that did not receive a CIDR insert. More cows receiving GnRH had 2 or more CL on Days 14 and 21 compared with controls. Ovulation risk after GnRH on Day 7 was greater than 66%. In both experiments combined, treatments with GnRH or GnRH + CIDR insert increased (P = 0.015) pretreatment pregnancy per AI by 7.1% points, but did not affect pregnancy loss. Although administering GnRH with or without a CIDR insert synchronized returns to estrus, treatments failed to increase the proportion of nonpregnant cows reinseminated before pregnancy diagnosis, but increased pretreatment pregnancy risk.

First postpartum ovulation, metabolites and hormones in follicular fluid and blood in transition dairy cows supplemented with a Saccharomyces cerevisiae fermentation product.

We hypothesized that feeding a Saccharomyces cerevisiae fermentation product (SCFP) from -4 through +7 wk (calving = Day 0) facilitates early first postpartum ovulation and alters blood and follicular fluid concentrations of glucose, beta-hydroxybutyrate (BHB), free fatty acids (FFA), and steroid hormones favorable to subsequent fertility. Holstein cows were fed individually a SCFP product (n = 24) or served as controls (n = 23). Blood samples were collected at wk -4 and -2 from expected calving and at 1, 2, 5, and 7 wk postpartum to determine plasma concentrations of FFA and BHB. Early spontaneous ovulation (progesterone > 1 ng/mL or corpus luteum presence by postpartum median Day 33) or late ovulation was determined. Plasma FFA in weekly samples was not affected by SCFP supplementation, but FFA was greater (P < 0.01; week by ovulation status) in late compared with early ovulating cows during and after postpartum wk 2. Plasma BHB in weekly samples was greater (P = 0.03) in SCFP than control cows and tended (P = 0.06) to be greater in late than early ovulating cows. Cows were exposed to ovulation synchronization (GnRH, PGF2α, and GnRH on Days 33, 40, and 43 ± 3, respectively). Transvaginal dominant follicle aspiration was conducted at Day 50, 7 d after GnRH on Day 43. Metabolites (FFA, BHB, and glucose) and steroid hormones (progesterone, androstenedione, and estradiol) measured in follicular fluid and blood samples collected at aspiration revealed that androstenedione in serum was numerically less (P = 0.11) in SCFP-treated compared with control cows, whereas androstenedione in serum was less (P < 0.05) in late than early ovulating cows. Concentrations of BHB (r = 0.75) and glucose (r = 0.52) in follicular fluid were positively correlated (P < 0.01) with those in blood. Body weight at calving and Day 42 was less (P ≤ 0.05), and energy balance through Days 28 and 42 was more positive (P < 0.05) in early than late ovulating cows and in SCFP-supplemented compared with control cows (P < 0.05). Dry matter intake, daily milk yield, and yields of fat, protein, lactose, and total solids were less (P < 0.01) in early compared with late ovulating cows, whereas milk fat percentage was increased (P < 0.01) by SCFP supplementation. We conclude that elevated postpartum BHB and FFA in plasma, greater negative energy balance, and greater milk yield and components were associated with later postpartum ovulation, but metabolites and steroid hormones in blood and follicular fluid were unaffected by SCFP treatment or ovulation status except for androstenedione.

Physiologic responses to feeding rumen-protected glucose to lactating dairy cows.

It was hypothesized that rumen-protected glucose (RPG) in diets of dairy cows increases concentrations of insulin resulting in greater blood progesterone concentrations because elevated insulin decreases activity of liver enzymes inactivating steroid hormones. Timing of ovulation was synchronized among 64 postpartum Holstein cows using GnRH and PGF2α (Day 0 = ovulation). Cows were milked thrice daily and assigned randomly a basal diet supplemented with 0, 1, 2, or 4 kg of an RPG product in place of corn grain, top-dressed in the diet beginning on Day -3. Blood was collected pre- and post-prandial on Days 0, 2, and 4 to determine plasma glucose and insulin concentrations and daily from Days 2 through 12. Intake of crude protein and energy-soluble carbohydrates increased linearly with dose, whereas starch intake decreased linearly with dose. Neither daily milk yield nor dry matter intake (DMI), energy-corrected milk (ECM), somatic cell count, or percentages of milk fat, protein and lactose on Day 8 differed among dietary treatments. Neither pre- nor post-prandial changes in plasma glucose differed among treatments. In contrast, post-prandial glucose decreased from Days 0 through 4. A change in plasma insulin (post-prandial minus pre-prandial) was detected. Milk urea nitrogen increased linearly with RPG dose. Concentrations of progesterone were unaffected by RPG dose. It is concluded that insulin response to RPG was decreased relative to the control and RPG supplementation linearly increased crude protein intake and milk urea nitrogen with increasing dose, but did not affect concentrations of progesterone, milk yield, or dry matter intake.

A shortened resynchronization treatment for dairy cows after a nonpregnancy diagnosis.

We hypothesized that a shortened version of a modified Ovsynch program (OVS: GnRH-1 - 7 d - PGF2α-1 - 24 h - PGF2α-2 - 32 h - GnRH-2 - 16 h - AI) that excluded GnRH-1 to resynchronize ovulation in cows bearing a corpus luteum (CL) after a non-pregnancy diagnosis (NPD) or including progesterone supplementation with the OVS treatment for cows without a CL would produce shorter inter-insemination intervals and pregnancy per AI (P/AI) not different from that of cows treated with the OVS treatment. Of the 1697 lactating Holstein cows enrolled in this experiment, complete data were available for only 1584 cows because the remainder was not treated, inseminated per treatment design, left the herd before pregnancy diagnosis, or some other outcome was missing. Cows were enrolled in the study and assigned to either of three treatments at NPD (32 ±â€¯3 d after AI [Day 0]). Cows with a detected CL were assigned randomly to: (1) a modified Ovsynch (OVS; GnRH-1 - 7 d - PGF2α-1 - 24 h - PGF2α-2 - 32 h - GnRH-2 - 16 h - AI) or (2) Short Synch (SS; PGF2α-1 - 24 h - PGF2α-2 - 32 h - GnRH-2 - 16 h - AI). Cows with no CL were assigned to OVS plus a progesterone insert (CIDR). Blood was collected at NPD to measure progesterone concentration and determine accuracy of treatment assignment (progesterone ≥ 1 ng/mL for a functional CL). Overall progesterone concentration at NPD was less in OVS + CIDR cows (1.5 ± 0.3 ng/mL) than in OVS (5.2 ± 0.2 ng/mL) or SS cows (3.7 ± 0.3 ng/mL). No differences in luteolytic risk (progesterone < 0.5 ng/mL at 72 h after PGF2α-1) were detected after PGF2α (>96.7%) and ovulation risk after GnRH-2 was 93.8, 91.7, and 86.2% for SS, OVS, and OVS + CIDR, respectively. Mean and median inter-insemination interval were less in SS (mean = 34.3 ± 0.05 d [median = 35 d] than OVS cows (40.2 ± 0.05 d [42 d]), but that in OVS cows did not differ from OVS + CIDR cows (41.4 ± 0.05 d [42 d]). Technicians were more accurate in visually detecting a functional CL than a non-functional CL (81.2 vs. 61.1%). Sensitivity of detecting a functional CL by technicians averaged 91.2%, but specificity was 39.8%. Pregnancy per AI at 32 ± 3 d after AI was less for SS (16.5% [n = 115]) than OVS (29.3% [n = 133] when a functional CL was inaccurately detected, but did not differ when a functional CL was detected accurately (27.6% [n = 561] vs 30.3% [508]). Pregnancy per AI did not differ between OVS and OVS + CIDR cows regardless of CL status. Short synch is an alternative to the entire modified Ovsynch program to produce similar P/AI when the CL status was detected accurately, and regardless of functional CL status, SS reduced inter-insemination intervals by 7 d.

Effect of Saccharomyces cerevisiae fermentation product on feed intake parameters, lactation performance, and metabolism of transition dairy cattle.

The transition period in dairy cattle is characterized by many stressors, including an abrupt diet change, but yeast product supplementation can alter the rumen environment to increase dairy cattle productivity. Saccharomyces cerevisiae fermentation product (SCFP) was fed from -29 ± 5 to 42 d relative to calving (RTC) to evaluate the effects on feed intake, milk production, and metabolism. Treatments were control (n = 30) or SCFP (n = 34) incorporated into a total mixed ration. Cows were individually fed 3×/d prepartum and 2×/d postpartum. Blood samples were collected once during each of the following time points RTC: d -28 to -24 (wk -4), d -14 to -10 (wk -2), d 3 to 7 (wk 1), d 12 to 16 (wk 2), and d 31 to 35 (wk 5). Liver biopsies were taken once between d -19 and d -12 (wk -3) and at 14 d in milk. Cows were milked 2×/d, and samples were taken 2 d/wk for composition analysis. Dry matter intake did not differ by treatment, but SCFP increased meals per day and decreased time between meals. Body weight (measured at enrollment, d 0, and d 42 RTC) and body condition score (scored weekly) were not affected by treatment. Milk, energy-corrected milk, and fat-corrected milk yields did not differ by treatment. Milk fat concentration was greater for SCFP, with significant differences in wk 4 and 5. Milk lactose concentration tended to be greater for the control and milk urea nitrogen tended to be lesser for the control, but there were no treatment effects on milk protein concentration or somatic cell count. Assuming equal digestibility, energy balance deficit was greater for SCFP than for the control (-6.15 vs. -4.34 ± 0.74 Mcal/d), with significant differences in wk 4 and 5. Plasma concentrations of free fatty acids, ß-hydroxybutyrate, glucose, and insulin did not differ with treatment, but cholesterol was greater for SCFP. Liver triglyceride increased and liver cholesterol decreased with time. Liver triglyceride did not differ by treatment, but liver cholesterol tended to be lesser in SCFP. Relative mRNA abundance of cholesterol-related genes (SREBF2, HMGCS1, HMGCR, MTTP, SPOB100, APOA1), FGF21, and CPT1A did not differ by treatment, but PCK1 tended to be greater for SCFP. The ketogenic transcript HMGCS2 was greater for SCFP, which aligns with SCFP increasing incidence of subclinical ketosis; however, BDH did not differ between treatments. In conclusion, SCFP supplementation increased meals per day with less time between meals, increased milk fat concentration, altered cholesterol metabolism, and increased incidence of subclinical ketosis, but early-lactation milk yield and metabolism were generally unaffected.