Search results for "productive life"
showing 4 items of 4 documents
Delayed Fatherhood in Mice Decreases Reproductive Fitness and Longevity of Offspring1
2009
Abstract This study aims to analyze, in mice, the long-term effects of delayed fatherhood on reproductive fitness and longevity of offspring. Hybrid parental-generation (F0) males, at the age of 12, 70, 100, and 120 wk, were individually housed with a randomly selected 12-wk-old hybrid female. The reproductive fitness of first-generation (F1) females was tested from the age of 25 wk until the end of their reproductive life. In F1 males, the testing period ranged from the age of 52 wk until death. Breeding F1 females from the 120-wk group displayed interbirth intervals longer than females from the 12-, 70-, and 100-wk groups. Furthermore, F2 pups begotten by F1 studs exhibited weaning weight…
Effect of somatic cell count level on functional longevity in Valle del Belice dairy sheep assessed using survival analysis.
2009
The objectives of this study were to evaluate the effect of somatic cell count (SCC) on functional longevity and to estimate the heritability of functional longevity using survival analysis in Valle del Belice dairy sheep. A total of 4,880 lactations of 2,190 ewes from 11 flocks were used. In this study, SCC was considered as an indication of subclinical mastitis. In case of clinical cases, identified by the technicians at milking time, test-day weights and milk samples of those ewes were not considered. Somatic cells were analyzed as counts, without any transformation, and were grouped in 3 classes based on the observed SCC maximum (mxSCC). The mxSCC classes, expressed as 103 cells/mL, wer…
Menopause: The Concepts and the Biological Background
2017
The exhaustion of the follicular endowment in the ovary defines the biological basis of menopause. The clinical implications are the loss of menses and fertility. Menopause is preceded by a series of clinical phases, reflected in the Staging of Reproductive Aging Workshop (STRAW). STRAW includes the different reproductive stages, with the clinically impacting menopausal transition and the end of the reproductive life, represented by the late post-menopausal period. Epidemiological studies show that the age at menopause, globally considered at around 50 years, undergoes significant differences across the world regions. High socio-economic conditions may prolong the age at menopause, but othe…
Long-term effects of delayed motherhood in mice on postnatal development and behavioural traits of offspring
2003
BACKGROUND: Some epidemiological evidence tentatively suggests that children born to older parents may have lower intellectual development and maturity than children whose parents are younger. This study aims to analyse the long-term effects of delayed motherhood in mice on postnatal development and behavioural traits later in life. METHODS: Hybrid females, either at the age of 10 weeks or 51 weeks, were individually housed with a randomly selected 12-14 week old hybrid male. After a postweaning resting period of 1 week, dams were caged again with a new randomly selected 12-14 week old male. This sequence of events was repeated until old females reached the end of their reproductive life. R…