Two kinds of the fat-soluble dye, Sudan black and red, were intravenously injected on alternate days into layers aged from 5 to 23 months to study the growth pattern of the ovarian follicle in relation to aging. Results indicated: 1) the length of the rapid growth period showed a tendency to shorten during 5 to 11 months, then to lengthen from 15 to 23 months of age; 2) there was a continuous increase in follicular volume at ovulation with the progress of age; 3) the growth rate (degree of curvature of the growth line calculated in each follicle) was low at 5 months, increased from 8 to 11 months, and remained constant thereafter; 4) during the first year of age, the number of growing follicles in the ovary decreased gradually, whereas the total amount of daily yolk deposition increased. During the second year of age, both the number of growing follicles and total yolk deposition remained constant.

Two experiments were conducted to investigate egg weight, fertility, hatchability, and embryonic mortality in relation to time of oviposition of young and old broiler breeder flocks. In experiment 1, eggs were collected from 2 flocks (34 and 59 wk) for 2 d at hourly intervals between 0700 and 1900 h. Most eggs were laid between 0700 and 1300 h, but eggs were laid later in the day by the old flock. Weights of early laid (C1) eggs were significantly greater than middle laid (Cs) and the late laid (Ct) eggs in the young flock, whereas late laid eggs (Ct) were significantly smaller than early laid (C1) and middle laid (Cs) eggs in the old flock. In experiment 2, eggs from experiment 1 were categorized as early laid first-in-sequence (C1) eggs (0700 to 0800 h), the mid-sequence (Cs) eggs (0900 to 1200 h), and the late laid terminal-in-sequence (Ct) eggs (1300 to 1700 h). These eggs were incubated to determine fertility, hatchability, and stage of embryonic mortality relative to oviposition time and flock age. Fertility declined with flock age, but there were no differences due to time of oviposition. There were no differences in hatchability of fertile eggs or embryonic mortality relative to time of oviposition (sequence position) or flock age. These results suggested that although there were differences in egg weight among eggs at different times of the day (different sequence positions), there were no differences in fertility, fertile hatchability, or embryonic mortality in naturally mated broiler breeders.

An experiment was conducted to determine the effect of time of oviposition, generally representing different positions in the normal egg laying sequence, on egg weight loss during storage and incubation, and on fertility and fertile hatchability of eggs from mid-lay (42 wk) and old (67 wk) broiler breeders. A total of 1,800 eggs (900 eggs per flock age) were collected during 10 consecutive days between 0830 and 1830 h each day. The eggs were individually marked, weighed, and stored for 1 to 10 d before incubation was initiated. Egg weight remained less from collection through incubation for eggs from the mid-lay flock than those from the old flock. Fresh weight of early laid (first-in-sequence; C1) eggs was significantly greater than that for the middle-of-day laid (mid-sequence; Cs), or late-in-day laid eggs (terminal-in-sequence; Ct). Percentage of egg weight loss during storage did not differ significantly between the mid-lay and old flocks but percentage of weight loss in the mid-lay flock was greater during incubation. Egg weight loss during storage of eggs from the middle-of-day laid (Cs) eggs was significantly greater than for early laid (C1) eggs, which was greater than for the late-in-day laid (Ct) eggs. Fertility was significantly decreased due to flock age but not due to oviposition time. Fertile hatchability was also significantly decreased due to flock age, but there was no significant effect of oviposition time. Early and late dead embryos increased with flock age, but there was no significant effect of oviposition time. It was concluded that there was no effect of oviposition time on fertility or fertile hatchability even though there were significant differences in egg weight and egg weight loss during storage due to oviposition time.

No abstract

To analyze characteristics of follicular rapid growth patterns in relation to clutch length and egg position in various clutch lengths, Sudan black and red were alternately injected intravenously into laying hens. The average growth period tended to decrease as clutch size increased, and this was accompanied by an increase in growth rate. The number of growing follicles and the total amount of daily yolk deposition in layers with short clutches were less than in layers exhibiting long clutches. The growth period tended to decrease as egg position advanced in clutches of 2 to 6 eggs. Follicular volume at ovulation also tended to be less in terminal (Ct) follicles in clutches of 2 to 5 eggs. Follicular growth rate was generaly reduced in the first egg of a clutch (Cl) and increased in the Ct follicles. Comparison of growth patterns between Ct and Cl follicles led to the detection of two growth patterns. In the first pattern, the growth period of the Ct follicle was equal to that of the Cl follicle and a one day skip was found between the transformation days of the two follicles; in the second pattern, Ct and Cl follicles entered into the rapid growth phase on consecutive days, but the Cl follicle took one day longer than the Ct follicle to reach ovulation.