We examined the effects of light intensity (LI) from photostimulation to 45 wk of age on egg production parameters and egg size characteristics and on ovarian and carcass morphology at sexual maturity and 45 wk of age in four layer strains. Floor housed pullets were raised in a light-tight facility from 1 d of age until housing in individually illuminated cages at 17 wk of age. Two white egg st...

Most Brazilian dairy production is conducted by small holders whose general management skills and feeding programs are often deficient. One common problem directly attributed to underfeeding is that heifers rarely reach sexual maturity before 15 months of age. Groups of growing heifers were treated to detect the effects of protein supplementation and antihelmintic treatment on sexual maturity. ...

Hon-Tsen Yu and Yao-Sung Lin (1999) Age, reproduction, and demography of the spiny rat (Muridae: Niviventer coxingi) in subtropical central Taiwan. Zoological Studies 38(2): 153-163. Annual reproductive cycles and demographic changes in a wild population of the spiny rat (Niviventer coxingi) in central Taiwan were studied. Reproductive status of the rat was investigated by autopsy and histologi...

________________________________________________________________________________ Abstract Male broiler breeders were photostimulated at different ages (56, 77, 98, 119, 147 and 161 d) during the period of growth prior to achieving sexual maturity to observe their response to photoperiod stimulation. Birds were sampled at regular intervals to measure the average testis weight these values respon...

data related to yazd native fowls (obtained during 2000-2008) yazd native fowls were made use of in the present study. the investigated traits consisted of body weight at 8 (bw8) and 12 weeks (bw12), age at sexual maturity (asm), egg number during the first three months of production period (en) and the mean egg weight at 28, 30 and 32 weeks of age (ew). the genetic and phenotypic parameters we...

Size and age estimates at sexual maturity were determined for 162 male and 273 female little skates Leucoraja erinacea collected from the western Gulf of Maine. Maturity ogives suggest that 50% maturity in females occurs at age 9.5 years and 480 mm total length (LT), whereas 50% maturity in males occurs at a slightly younger age of 7.7 years and smaller size of 460 mm LT. Age estimates were mad...

The harbour porpoise is the only cetacean species native to German waters. Since human pressures are suggested to shorten their reproductive lifespan, basic knowledge on reproduction is strongly required. One parameter is the onset of sexual maturity in female harbour porpoises. Therefore, we investigated the first signs of sexual maturity for a period of almost two decades (1990-2016). Ovaries...

From studies of both wild and captive animals, gibbons are thought to reach sexual maturity at about 6 to 8 years of age, and the siamang (Hylobates syndactylus) at about 8 to 9 years. However, a review of the literature reveals that in most cases the exact age of the maturing animals was not known and had to be estimated. This study presents seven case reports on captive gibbons of known age. ...

Twenty four farmed great sturgeon, Huso huso (including 8 males and 16 females) over 6 years old were used to develop a method for determination of sex and maturity stages. Seasonal gonadal tissue and blood samples were collected from farmed great sturgeon for three years. The sex and stages of maturity were determined by histology and laparoscopy at the beginning and end of experiment. Plasma ...

Egg-laying strains of chickens are highly susceptible to osteoporosis, a noninfectious disease characterized by a decrease in structural bone as hens age. To minimize the onset of osteoporosis, it was hypothesized that a delay in sexual maturity may allow a pullet to develop a stronger skeletal frame before egg laying, leading to improved skeletal mineralization at end of lay. One management to...