The Effect Of Various Types And Intensities Of Electric Lights On The Egg Production Of Pullets And The Effect Of Light Rationing On The Egg Production Of Pullets

Author : Robert James Spiller
Publisher :
ISBN 13 :
Total Pages : 388 pages
Book Rating : 4.E/5 ( download)

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Download or read book Sexual Maturity and Performance of White Leghorn Pullets Subjected to Intermittent Watering, Lighting Regimes, and Nutrient Restrictions written by Robert James Spiller and published by . This book was released on 1975 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of 8 experiments was conducted to investigate various methods of delaying the sexual maturity of developing White Leghorn (W.L.) pullets grown during a period of increasing day length and to control the feed intake of W.L. layers. In the first five experiments W.L. pullets were fed low-lysine (0.54%) and low-protein (10.36%) developer rations from 8 to 20, and 8 to 20 or 12 to 20 weeks of age, respectively. Other groups were subjected to watering regimes in which water was cycling on 24 hr.--off 24 hr. and on 24 hr.--off 48 hr. from 8 to 20, and 8 to 20, 12 to 20, or 14 to 20 weeks of age, respectively. Additional groups were reared using two lighting programs; the first featured a gradual decline of 15 min./week in the day length from 0 to 22 weeks of age. The second provided a constant amount of light from 0 to 12 weeks of age, a sudden 5-hr. drop at 12 weeks, and then a constant level from 12 to 20 weeks of age. In Exp. 6 to 8, W.L. layers were provided water concurrent with light (15.0--16.25 hr./day), 15 min. each hour, three or five 15-min. periods/day or two 2-hr. periods per day. An additional group had access to feed for two 2-hr. periods per day. The low-lysine developer had no effect on body weights, sexual maturity, or feed intake during the growing period. These pullets tended to lay fewer, but heavier, eggs during 40 weeks of lay. Cannibalism tended to be higher in the pullets fed low lysine. Feeding the low-protein developer from 8 or 12 to 20 weeks of age resulted in significantly lower body weights and feed consumption in the developing period. Fed from 8 to 20 weeks of age, this diet led to 14 and 11-day delays in reaching 25 and 50% production, respectively. Lay house performance was satisfactory in three of four comparisons, but brooder house mortality was slightly higher in pullets fed the low-protein diets. Providing water every other day after 8 weeks of age did not significantly alter feed intake, body weights, or sexual maturity. Feed intake in the subsequent lay period was significantly lower for dwarf W.L. pullets, but unaffected in normal W.L. pullets. Hen-day production tended to be slightly lower and lay house mortality slightly higher for these pullets. Providing water every third day from 8, 12, or 14 to 20 weeks of age significantly reduced body weights and feed intake, and delayed 25 and 50% production. The degree of growth retardation was proportional to the duration of the water restriction regime. These pullets tended to lay at a higher rate, require less feed per egg, and lay larger eggs. Pullets subjected to either of the lighting programs ate more and were heavier in the first 12 weeks of life, but consumed less from 12 to 20 weeks and weighed less than the control group at 20 weeks of age. Both lighting programs increased average egg weights in the laying period. A 5-hr. light reduction at 12 weeks of age delayed 25 and 50% production as much as 11 and 14 days, respectively. There were no significant differences in egg production, feed per hen-day, per egg, or per gram of egg. Providing hens two 2-hr. or three 15-min. waterings after 5 months of lay significantly reduced egg production, reduced feed intake and weight gain, but had no effect on average egg weights. When the three 15-minute regime was initiated prior to lay, egg production was not altered, but feed per hen-day, per egg and per gram of egg, and average egg weight were reduced by 3.0, 11.0, 0.1, and 2.6 g., respectively. The number of large eggs was significantly reduced. Egg production tended to be higher when pullets were provided five 15-min. waterings each day. No adverse effects were observed on average egg weights or mortality. In two comparisons, feed per henday, per egg, and per gram of egg were reduced by 0.3 and 3.0, 7.7 and 9.0, and 0.14 and 0.17 g., respectively. Providing layers water 15 min. each hour had no effect on egg production, feed intake, or weight gain during lay. In one comparison egg size was significantly increased and the number of medium eggs significantly reduced. These hens required slightly less feed to produce a gram of egg. Providing laying hens two 2-hr. feedings significantly reduced egg production and weight gain during lay, reduced egg mass per henday, increased mortality, but had no effect on average egg weights. Feed per hen-day was decreased by 4.7 g., but feed per egg and per gram of egg were increased by 3.9 and 0.07 g., respectively.