Administering carbetocin before electroejaculation in bulls improves semen quality and increases the number of insemination doses.
Carbetocin may slightly improve semen quality and yield in bulls, but the clinical significance of these findings remains uncertain.
Where it sits
this study against the rest of the carbetocin corpusSummary and findings
The study measured the effects of carbetocin on semen yield and quality in 29 Braford bulls. Carbetocin was administered at a dose of 0.2 mg/100 kg body weight intravenously 15 minutes before electroejaculation. Results indicated slight enhancements in semen quality and quantity compared to control treatments.
Abstract
It was recently reported that administering carbetocin before electroejaculation in rams improves quantitative and qualitative characteristics of fresh semen; therefore, the hypothesis was that its use in bulls improves collection conditions in the field. The aim of the study was to determine whether administering carbetocin 15 min before electroejaculation improves semen yield in bulls, and whether these effects are associated with post-thaw sperm quality and sperm cryoresistance. Semen was collected from 29 Braford bulls in a two-period crossover study. Semen was collected from each bull after administering carbetocin (0.2 mg/100 kg body weight, IV) 15 min before electroejaculation, or without carbetocin (control treatment). The treatments were rotated so that all bulls received both. Carbetocin administered 15 min before electroejaculation slightly enhanced semen mass motility (P = 0.05) and moderately increased the number of calculated insemination doses (P = 0.05) compared to control bulls. In addition, it tended to increase the total number of sperm in the ejaculate, the total number of motile sperm, the number of sperm with functional membranes, and the number of sperm without bent tails in fresh semen, as well as the number of effective insemination doses in thawed semen (P = 0.09, P = 0.07, P = 0.06, P = 0.09, and P = 0.08, respectively). Carbetocin administration before electroejaculation in bulls marginally improved fresh semen quality and quantity, including motility and the number of fresh semen insemination doses. This may support routine use in artificial insemination programs by making the collection process more efficient.
Background
This paper investigates whether carbetocin can enhance semen quality and yield in bulls during electroejaculation, building on previous findings in rams. Prior studies indicated that carbetocin improved semen characteristics, but its effects in bulls had not been thoroughly examined. Understanding these effects could have implications for improving artificial insemination practices in cattle.
Methods
The study utilized a two-period crossover design with 29 Braford bulls. Each bull received either carbetocin (0.2 mg/100 kg body weight, IV) or a control treatment before electroejaculation, with treatments rotated. The primary outcome measures included semen yield and quality parameters assessed post-collection.
Results
Carbetocin administration resulted in a slight enhancement in semen mass motility (P = 0.05) and a moderate increase in the number of calculated insemination doses (P = 0.05). Additionally, there were trends towards increased total sperm count (P = 0.09), total motile sperm (P = 0.07), and other quality metrics, although these did not reach statistical significance.
Interpretation
While the findings suggest a potential benefit of carbetocin in improving semen quality and yield, the effect sizes are modest and may not be clinically meaningful. The results are consistent with previous research on rams but should be interpreted cautiously due to the small sample size and the presence of several outcomes that only approached significance. These limitations may affect the applicability of the findings in practical settings.
Key findings
- Slightly enhanced semen mass motility (P = 0.05).
- Moderately increased the number of calculated insemination doses (P = 0.05).
- Tended to increase total number of sperm in the ejaculate (P = 0.09).
- Tended to increase total number of motile sperm (P = 0.07).
- Tended to increase number of sperm with functional membranes (P = 0.06).
- Tended to increase number of sperm without bent tails (P = 0.09).
Limitations
- Small sample size of 29 bulls.
- Several outcomes only trending towards significance.
- Crossover design may introduce carryover effects.
- Single-site study limits generalizability.
- No long-term follow-up on semen quality.