Supplementation of Saccharomyces cerevisiae fermentation product to beef cows grazing fescue-based pastures and its impact on reproductive performance

Abstract

The study aimed to evaluate the effects of Saccharomyces cerevisiae fermentation product (SCFP) supplementation during the breeding season on reproductive performance of beef cows grazing fescue-dominated pastures (Festuca arundinacea). A total of 883 multiparous suckled beef cows across eight locations were stratified by age and days postpartum (DPP) and randomly assigned to one of two treatments: 1) CON-mineral supplementation at 90 g/hd/d (n = 439 cows; 13 experimental units), or 2) SCFP-mineral with 9 g SCFP (NaturSafe, Diamond V, Cedar Rapids, IA; n = 444 cows; 13 experimental units). Supplementation began 21 d pre-breeding and continued through the breeding season (approx. 171 d). Cows grazed tall-fescue pastures and followed a fixed-time artificial insemination (TAI) protocol (7-d CO-Synch + CIDR) with natural service and clean-up bulls for a 70-d breeding season. Pregnancy diagnoses were performed by ultrasonography at 55 d post-TAI and 40 d after the breeding season. Cow body weight (BW) and body condition score (BCS) were recorded at TAI (day 0) and weaning (day 150). Mineral disappearance was measured weekly. Data were analyzed using GLIMMIX for binomial data and MIXED for continuous data. Cow age and DPP did not differ (P > 0.10) between treatments (6.0 ± 1.0 yr and 79.7 ± 2.6 d, respectively). Mineral disappearance was similar (P = 0.97) between treatments (99.2 and 99.8 ± 8.76 g/hd/d for CON and SCFP, respectively). No differences were observed (P > 0.10) in BW and BCS between treatments on days 0 and 150. SCFP supplementation did not affect estrus expression (63.2% vs 63.7% ± 2.6% for CON and SCFP, respectively; P = 0.91), but TAI pregnancy rates were higher (P = 0.025) in SCFP (65.9% ± 2.5%) compared to CON (57.9% ± 2.5%). Final pregnancy rates tended to be higher (P = 0.057) for SCFP (92.9% ± 1.4%) vs CON (89.0% ± 1.4%), with no effect on calf performance (P > 0.10). In conclusion, SCFP supplementation during the breeding season did not influence BW or BCS but improved TAI pregnancy rates in beef cows grazing endophyte-infected tall fescue.

Keywords: artificial insemination; bovine; breeding; postbiotic; synchronization; tall-fescue.

Figure 1.

Endophyte infection level of tall-fescue (Festuca arundinacea) based pastures grazed by beef cows supplemented with a mineral product (CON) or a mineral product containing Saccharomyces cerevisiae fermentation product (SCFP). Pasture samples were collected by hand grabs on 6 locations for each treatment group in May, June and July. CON—supplementation of a mineral product at 90 g⁻¹hd⁻¹d (n = 439 cows; 13 experimental units); SCFP—supplementation of mineral product at 90 g⁻¹hd⁻¹d containing Saccharomyces cerevisiae fermentation product (9 g, NaturSafe™, Diamond V, Cedar Rapids, IA; n = 444 cows; 13 experimental units). Treatments were offered from day −21 to 150. Within month: *Denotes differences within time point, Treatment × Month P = 0.03; Treatment P = 0.713; Month P = 0.004.

Figure 2.

Temperature-humidity index (THI) and vaginal temperature of beef cows grazing tall-fescue (Festuca arundinacea) based pastures and supplemented with a mineral product (CON) or a mineral product containing Saccharomyces cerevisiae fermentation product (SCFP). CON—supplementation of a mineral product at 90 g⁻¹hd⁻¹d (n = 439 cows; 13 experimental units); SCFP—supplementation of mineral product at 90 g⁻¹hd⁻¹d containing Saccharomyces cerevisiae fermentation product (9 g, NaturSafe™, Diamond V, Cedar Rapids, IA; n = 444 cows; 13 experimental units). Treatments were offered from day −21 to 150. Vaginal temperature was determined during the month of June in a subset of cows (n = 111, at 3 locations; 6 experimental units) using a vaginal probe consisting of a CIDR (Zoetis) depleted of hormone and containing a digital temperature logger. Probes were equally distributed between treatments within location, probes remained in place for a total of 136 hours, and temperature loggers were programmed to record once every 5 min and were set at a resolution of 0.0625 °C. Zero hour is at 10 a.m. Within hour: *Denotes vaginal temperature differences within time point, Treatment × Time P < 0.0001; Treatment P = 0.613; Time P < 0.001.

Figure 3.

Pregnancy rate to fixed-time artificial insemination (TAI) by location and overall, of beef cows grazing tall-fescue (Festuca arundinacea) based pastures and supplemented with a mineral product (CON) or a mineral product containing Saccharomyces cerevisiae fermentation product (SCFP). CON—supplementation of a mineral product at 90 g⁻¹hd⁻¹d (n = 439 cows; 13 experimental units); SCFP—supplementation of mineral product at 90 g⁻¹hd⁻¹d containing Saccharomyces cerevisiae fermentation product (9 g, NaturSafe™, Diamond V, Cedar Rapids, IA; n = 444 cows; 13 experimental units). Treatments were offered from day −21 to 150. Cows were assigned to a TAI regimen from day − 10 to 0 (Larson et al., 2006). Pregnancy status was verified at day 70 by detecting a viable fetus using ultrasound (5.0 MHz linear transducer, Ibex Pro, E.I. Medical Imaging, Loveland, CO). *Treatment P = 0.02; Location P = 0.02; ‡ Trt × Loc P = 0.07.