Relationship between carcass composition and first oestrus in Romney ewe lambs.

Area of Science:

• Animal Science
• Reproductive Biology
• Sheep Husbandry

Background:

• Nutritional management is crucial for livestock reproduction.
• Understanding factors influencing sexual maturity in sheep is vital for optimizing breeding programs.

Purpose of the Study:

• To investigate the relationship between nutrition and sexual maturity in Romney ewe lambs.
• To identify reliable indicators of sexual maturity in female sheep.

Main Methods:

• Ewe lambs were subjected to two nutritional levels post-weaning.
• Estrus occurrence and timing were monitored after ram introduction.
• Organ weights and carcass composition (protein, fat) were analyzed.

Main Results:

• High nutrition significantly increased estrus occurrence (100%) compared to low nutrition (74%).
• Uterus weight, and a combination of lung, spleen, and stomach weights, effectively differentiated estrous from non-estrous ewes.
• Body fatness and protein content did not correlate with sexual maturity.

Conclusions:

• Nutritional plane influences the onset of sexual maturity in ewe lambs.
• Specific organ weights, particularly the uterus, are better indicators of sexual maturity than body composition in sheep.