| | Overfeeding broiler breeder pullets results in the development of excess large yellow follicles (yolks) at first egg. These extra large yellow follicles are related to decreased egg production. However, later in lay, follicle numbers decrease, and it is possible that there are too few follicles developing to sustain a high rate of lay. An experiment was conducted at the Poultry Research Centre to determine if the number of follicles late in lay could be increased by providing more feed to the hens.
Twenty Shaver Starbro hens were fed a standard amount of feed (STD = 122 g/day), twenty were given an extra 10 g (STD+10), and twenty were given an extra 20 g of feed daily (STD+20) from 54 to 62 weeks of age (see the table to the right if you prefer to think of feed allocations in lb/100 hens). The effect of these treatments on body weight, egg production, and ovary appearance were observed.
Birds fed the extra feed were significantly heavier by 62 weeks of age. The birds gained approximately 80, 160 and 300 g in the STD, STD+10 and STD+20 treatments, respectively. There was not a significant effect on follicle numbers due to overfeeding. Egg production was not significantly different between treatments, at 34, 37, and 32 eggs per bird in the STD, STD+10 and STD+20 treatments, respectively. Egg weight was also not significantly affected.
This work suggests that broiler breeder hens late in lay are not as sensitive to over feeding than pullets or young hens. The older hens in this trial did not respond to increased feed by developing more follicles on their ovaries, as young hens have been shown to do. Perhaps higher levels of overfeeding are necessary to stimulate follicle development later in lay.
The implication of this research is that feeding this strain of broiler breeders generously late in lay is not as detrimental for bird performance as overfeeding earlier in lay.
Summarized from: McGovern, R. H., and F. E. Robinson, 1996. Increased feed allocation does not stimulate
increased ovarian development or increased egg output in 54 wk old broiler breeder hens.
Source: Poultry Research Centre News - Vol. 5 No. 2, 1996 |
|