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Plasma prolactin concentration in gilts reared in confinement
K L Esbenshade1, B N Day, A L Mulloy
1Dept. of Anim. Husb., University of Missouri, Columbia, MO 65211, USA.
Theriogenology
|January 1, 1981
Summary
Plasma prolactin levels in gilts did not correlate with puberty onset, regardless of boar exposure or relocation to pasture. Environmental changes did not significantly alter these hormone concentrations in growing pigs.
Area of Science:
- Reproductive endocrinology in livestock
- Swine physiology and behavior
Background:
- Puberty onset in gilts is influenced by environmental and social factors.
- Plasma prolactin is a hormone implicated in reproductive processes.
Purpose of the Study:
- To investigate the relationship between plasma prolactin concentrations and puberty in confinement-reared gilts.
- To determine the effects of boar exposure and relocation to pasture on prolactin levels.
Main Methods:
- Surgically implanted vascular cannulas in 28 gilts (average age 181 days) for blood sampling.
- Assigned gilts to control (confinement) or treatment (pasture) groups, with boar exposure in both.
- Quantified plasma prolactin using radio-immunoassay procedures across different sampling times and seasons (April vs. September).
Main Results:
- Post-surgical prolactin levels were significantly higher than pre-surgical levels in most gilts.
- No significant effect of confinement versus pasture relocation on overall prolactin concentrations.
- Boar exposure showed a trend towards reducing prolactin in relocated gilts, and higher prolactin levels were observed in September compared to April, particularly in control gilts.
Conclusions:
- Plasma prolactin levels do not appear to be a reliable indicator for delayed puberty in confinement-reared gilts.
- Environmental factors like relocation and boar exposure, or seasonal changes, did not significantly impact prolactin levels in a way that reflects puberty induction or delay.