Relationships of thyroid hormones, IGF-I and testosterone in breeds of ram lambs with low and high prolificacies

Autor:	M. L. Connor, A. H. Fallah-Rad
Rok vydání:	1999
Předmět:	medicine.medical_specialty Endocrinology Food Animals Testicular histology Thyroid hormones Internal medicine medicine Animal Science and Zoology Semen Biology Testosterone
Zdroj:	Canadian Journal of Animal Science. 79:441-448
ISSN:	1918-1825 0008-3984
DOI:	10.4141/a98-080
Popis:	Ten Suffolk (Sfk) and 10 Outaouais (Out) ram lambs were selected to study the relationship between testosterone, thyroid hormones (T3, T4), IGF-I, glucose, semen production and testicular histology at the onset of puberty in lower prolific (Sfk) and higher prolific (Out) breeds. SC, BW, ADG, RG and DM consumption were recorded weekly. Semen was collected by electro-ejaculation from 32 to 35 wk of age and evaluated. Blood was collected weekly by indwelling jugular catheters, every 20 minutes from 0900 to 1520 h to measure the concentration of glucose, T4, T3, IGF-I and testosterone. At wk 35, histological sections of testes were evaluated. Number of spermatozoa in the semen of Out was higher than Sfk (P 0.1). However, there were negative correlations between levels of glucose, T4, T3 and age of the lambs. Testosterone concentrations and pulse frequencies were higher in Out than Sfk (P 4, T3 and IGF-I were higher in Out than Sfk throughout the sampling period (P 4, T3, IGF-I and testosterone pulses in Out may be associated with greater prolificacy in this breed. Key words: Ram lambs, prolificacy, thyroxin, IGF-I, tri-iodothyronine
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b423e33ca584135da7aea22e8e1eb628 https://doi.org/10.4141/a98-080 Zobrazit plný text záznamu