Field Implementation of Buserelin-Supplemented Boar Semen Protocol at the First Insemination: Farrowing Rate and Litter Size in Gilts and Sows Under Tropical Conditions.
Buserelin supplementation at the first insemination may improve farrowing rates in commercial swine herds, but it does not appear to significantly affect litter size.
Where it sits
this study against the rest of the buserelin corpusSummary and findings
This study evaluated the impact of buserelin acetate supplementation on farrowing rate and litter size in 2780 Landrace × Yorkshire females. The females received either standard extended semen or extended semen supplemented with 4-8 µg of buserelin acetate at the first insemination. The overall farrowing rate was 88.5%, with buserelin supplementation resulting in a statistically significant increase in farrowing rate compared to the control group.
Abstract
Maximizing farrowing rate and litter size is essential for improving reproductive efficiency and profitability in swine production. Both outcomes depend on the timing of artificial insemination (AI) relative to ovulation; however, predicting ovulation is challenging because estrus duration and the interval from estrus onset to ovulation vary considerably among females. Therefore, this study aimed to determine whether supplementing extended boar semen with 4-8 µg of buserelin acetate at the first insemination improves the reproductive performance of gilts and sows under tropical commercial conditions. A randomized controlled field trial was conducted involving 2780 Landrace × Yorkshire females across five commercial herds in tropical regions (herds A-E). The females (parity 3.0 ± 2.1) comprised gilts (<i>n</i> = 412), sows (<i>n</i> = 2280), and repeat-service females (<i>n</i> = 88). They were randomly assigned to receive either standard extended semen (control; <i>n</i> = 1438) or extended semen supplemented with 4 μg (1.0 mL; <i>n</i> = 121), 5 μg (1.25 mL; <i>n</i> = 1052), or 8 μg (2.0 mL; <i>n</i> = 169) of buserelin acetate per 90 mL insemination dose (treatment; <i>n</i> = 1342). The overall farrowing rate was 88.5% and ranged from 84.5% to 90.0% among herds. Buserelin supplementation increased the farrowing rate compared with the control (90.1% vs. 86.9%, <i>p</i> = 0.009), representing an improvement of 3.2 percentage points. In Herd C, supplementation increased the farrowing rate from 86.5% to 90.1% (<i>p</i> = 0.036). The overall total number of piglets born was 14.1 ± 3.2 per litter. Litter size did not differ significantly between groups in any herd (all <i>p</i> > 0.05), although buserelin-treated females generally had numerically more total-born and live-born piglets. Among gilts, buserelin tended to increase the total number born (12.7 ± 0.4 vs. 11.8 ± 0.4 piglets, <i>p</i> = 0.083), but not the number born alive (11.3 ± 0.4 vs. 10.6 ± 0.4 piglets, <i>p</i> = 0.258). No significant effects were observed in sows for total-born or live-born piglets (+0.3 and +0.4 piglets, <i>p</i> = 0.380 and 0.376, respectively), or in repeat-service females (-0.4 and +0.2 piglets, <i>p</i> = 0.735 and 0.883, respectively). These findings indicate that supplementing extended semen with buserelin acetate at the first insemination is a practical, non-invasive strategy for improving farrowing success in commercial swine herds under tropical conditions. Further studies should clarify the underlying endocrine and reproductive mechanisms and identify the physiological or reproductive characteristics of females most likely to benefit from additional hormonal stimulation.
Background
This paper addresses the challenge of maximizing farrowing rates and litter sizes in swine production, which are critical for reproductive efficiency and profitability. Previous studies have indicated that the timing of artificial insemination relative to ovulation is crucial, yet predicting ovulation remains difficult due to variability among females. This study aims to evaluate whether supplementing boar semen with buserelin acetate can enhance reproductive performance under tropical conditions.
Methods
A randomized controlled field trial was conducted with 2780 Landrace × Yorkshire females across five commercial herds. The females were randomly assigned to receive either standard extended semen (control; n=1438) or extended semen supplemented with 4 µg (n=121), 5 µg (n=1052), or 8 µg (n=169) of buserelin acetate per 90 mL insemination dose (treatment; n=1342). The primary outcome measure was the farrowing rate, while secondary measures included litter size and the number of piglets born.
Results
The overall farrowing rate was 88.5%, with buserelin supplementation resulting in a farrowing rate of 90.1% compared to 86.9% for the control group (p=0.009). In Herd C, the farrowing rate increased from 86.5% to 90.1% (p=0.036). The total number of piglets born was 14.1 ± 3.2 per litter, but litter size did not differ significantly between groups (all p > 0.05). Among gilts, there was a tendency for buserelin to increase the total number born (12.7 ± 0.4 vs. 11.8 ± 0.4 piglets, p=0.083).
Interpretation
The findings indicate that buserelin supplementation can improve farrowing rates, which aligns with some previous literature suggesting hormonal stimulation can enhance reproductive outcomes. However, the effect size for litter size was not statistically significant, suggesting limited clinical relevance. The study's confounds include the lack of significant findings in sows and repeat-service females, which may limit the generalizability of the results to broader populations. Further research is needed to explore the mechanisms and identify which females may benefit most from this approach.
Key findings
- Overall farrowing rate was 88.5%, ranging from 84.5% to 90.0% among herds.
- Buserelin supplementation increased the farrowing rate compared with the control (90.1% vs. 86.9%, p=0.009).
- In Herd C, supplementation increased the farrowing rate from 86.5% to 90.1% (p=0.036).
- Total number of piglets born was 14.1 ± 3.2 per litter.
- Buserelin-treated gilts tended to have more total-born piglets (12.7 ± 0.4 vs. 11.8 ± 0.4, p=0.083).
- No significant effects were observed in sows or repeat-service females for total-born or live-born piglets.
Limitations
- No long-term effects reported.
- Lack of significant findings in litter size.
- Did not identify specific female characteristics that may benefit.
- Study conducted under tropical conditions may limit generalizability.