| Summary: | 碩士 === 國立臺灣大學 === 畜產學研究所 === 94 === The survey was conducted to investigate layer production performance in Taiwan from March, 2003 to October, 2005. The production parameters including egg mass, cracked egg rate, mortality rate, cumulative mortality rate, feed consumption and feed conversion ratio were collected daily from 42 layer farms. There were 1,248,586 laying hens, and 37,324 daily-record data in 116 different flocks were analyzed by week. The major commercial white Leghorn strains in Taiwan were Hy-Line W-36, Hy-Line W-98, Hendrix Dekalb White, Hendrix Hisex White and Lohmann LSL-Lite.
Results showed that egg mass and cracked egg rate in the first laying cycle (18 wk old to molted) and the second laying cycle (molted to 120 wk old) were 46.33 g vs. 43.89 g and 2.81 % vs. 4.34 % (p<0.05), respectively. Significant difference existed in the mortality rate between the two cycles (0.19 % vs. 0.28 %). The production of egg mass from strain E and strain D were significantly (p<0.05) higher than those of other strains. Strain C, strain B, and strain D had the highest average cracked egg rate. However, mortality was highest in strain B when compared with others (p<0.05). Hens in the 1st (Jan.-Mar.) season had the best egg mass and the lowest cracked egg rate, with the 3rd (Jul.-Sep.) season the worst. The average mortality rate of 3rd and 1st season was worse than 2nd (Apr.-Jun.) and 4th (Oct.-Dec.) seasons of the year (p<0.05). Feed consumption was significantly different between cold and hot season, but there was no significant in feed conversion ratio. Hens in north and south Taiwan had different mortality rate, cracked egg rate, and feed consumption. Hens had the highest production of egg mass when raised in closed-house system, however, cracked egg rate, mortality rate, and feed consumption were also higher than those in open-house system. There were various interactions of strain, season, location, and type of house on egg mass, mortality rate, and feed consumption.
The data described above gave an indication of production performance commercial laying hens raised Taiwan, this should provide useful information for egg layer industry.
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