Estudo da Puberdade no cavalo puro sangue Lusitano em condições de maneio tradicional

• Author(s): Fernandes, Rita Sofia Costa
• Date: 2009
• Persistent ID: http://hdl.handle.net/10400.5/1648
• Origin: Repositório da UTL
• Subject(s): Lusitano horse; puberty; progesterone; testosterone; leptin; cavalo; puro sangue Lusitano; puberdade
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Dias, Graça Maria Leitão Ferreira; Fradinho, Maria João Martelo
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia

The objective of this work was to study puberty in Lusitano foals and to evaluate the role of leptin. One-year-old fillies (n=14) and colts (n=19), and two-year-old fillies (n=5) were kept under extensive management. Blood was collected from the jugular every 11 days from females for progesterone and leptin analyses. Monthly blood samples were obtained from males for testosterone and leptin determinations. Between April and June, 57.1% of the fillies, aged from 12.7 to 16.0 months (13.6±0.7), displayed ovarian activity. Among these, 75% ovulated twice, and 25% ovulated only once. In pubertal fillies, plasma leptin concentration tended to decrease between pre-puberty and cyclicity, and further decreased during anestrus (p<0.01). Plasma leptin levels decreased in all fillies between April and September. Fillies’ body weight increased from the pre-puberal period to cyclicity (p<0.05) and to anestrus (p<0.01). However, their body condition decreased throughout the experiment, which might explain leptin fall. Only one colt (5.3%) had testosterone concentrations above the puberty threshold (0.5ng/ml). Plasma leptin was higher in males than in females (p<0.01). This study suggests that puberty might be influenced by leptin. These results should be seen as preliminary, suggesting the need for further research in this area.