Abstract
Many reports have been published on the restricted feeding of broiler breeding stock. Is it necessary to always keep layers full diet? The lower feed conversion ratio may bring the more economical profits by means of feed restriction.
This report deals with the effect of feed restriction on the performance of layers and the relationship between the breeds of feed restriction and the economical profit was discussed.
The experiment was carried out with strain cross of White Leghorn (No. 1), two crossbreds of Rhode Island Red _??_ _??_ x White Leghorn _??_ _??_ (No.2, 3) and strain cross of Rhode Island Red (No. 4) hatched on May 14, 1968. Numbers of layers used in this experiment were 162 of the two breeds and two crossbreds. The layers were full diet until 154 days of age. Layers were divided into control group and restricted group at 155 days of age.
Feed restriction was terminated at 519 days of age, and feed restriction rate was 90% of full diet of the control layers. Still more their layers were carried out force molting on account of investigation of effect of feed restriction on performance of two years of age. Their layers were fasted for 7 days from 520 to 526 days of age. Experimental period was for 365 days from 562 to 926 days age. In the both groups no feed restriction was carried out.
Feed consumption of the restricted groups was 88.4% of the control groups during the experimental period. Hen-day egg production of restricted groups was 96.7% of the control group. Samely, the ratio of average egg weignt and egg production per bird per day were 99.3%, and 96.0% of the control groups, respectively. These results were inferior a little to the control. However, the feed conversion ratio of restricted groups was improved 0.24 by feed restriction, therefore it was possible to saving of feed. Body weignt of the restricted groups was 88.6% of the control groups at 500 days of age. The restricted groups lost their body weight by the same ratio of feed intake. Grude profit of restriction in the restrieted groups was much more than that in the control group by 107 yen and that in No. 2, 3, and 4 was much more than that in the No. 1.
We compared with the egg production of both groups after force molting at 520 days of age. It was found that no effect by the treatment of feed restriction.
