Performance of pedigreed Lyallpur silver black (LSB) chicken selected for better comb size and body weight

The study was carried out at Poultry Research Centre (PRC), University of Agriculture, Faisalabad to determine the effect of male comb size and body weight on age at first lay and other productive and reproductive traits in a pedigreed Lyallpur Silver Black (LSB) flock. Sire variance for some of these traits was also determined. The pedigreed pullets reaching to the age of 16 weeks were confined in individual battery cages and were later randomly allotted to eight males, selected for better comb index (height of comb x length of comb) and body weight, for stud mating and collection, of eggs. Feed efficiency information on these 48 hens was collected at 37th, 38th, 39th and 40th weeks of age. One egg of individual female was weighed weekly (preferably around mid week) to calculate weekly egg mass per bird. For reproductive traits, 625 egg (identified by individual hen and cock) collected at 38th, 39th, 40th and 41st weeks of age were set for incubation and hatching in four separate hatches. Candling was performed on 18th day of incubation and eggs that were clear (infertile) or had dead germs were recorded. At the time of hatch, dead in shell eggs were also recorded for each hen. Day old chicks were weighed and wing banded for future identification and selection. A general linear model was used for statistical analysis while parental half-sib correlation technique was used to determine the sire variance. Body weight of hens at the age of 20 week, at first lay and at 40th week of age averaged 996.9 plus minus 81.14, 1327.4 plus minus 93.59 and 1359.4 plus minus 136.55 g, respectively. The body weight of cocks at 26 weeks of age averaged 1791.4 plus minus 82.42g and at 40th week of age 1825.7 plus minus 286.23g. Comb index of cocks at 25th week of age averaged 50.6+6.88 cm2 and at 39th weeks of age, average was 90.5 + 9.81 cm2. Average age at first lay was 179.5+11.35 days while weight of first egg averaged 32.0 plus minus 3.23g. Total number of eggs (per hen) up to 40 weeks of age was 63.4+9.64 and total egg number in the first 20 weeks of egg production averaged 81.0 plus minus 12.79 eggs. Average egg weight up to 40th week of age averaged 41.2+3.31g. Weekly egg mass at 37th, 38th, 39th, and 40th weeks averaged 200.7 plus minus 55.36, 203.4 plus minus 56.28, 196.4+61.30 and 179.3 plus minus 67.37g, respectively. Weekly feed intake per bird for these four weeks averaged 420.4 plus minus 73.32, 468.2 plus minus 88.20, 503.9 plus minus 59.77 and 519.0 plus minus 62.95 g, respectively. Feed consumed to produce one dozen eggs for the four weeks was thus 1198.4 plus minus 529.79, 1309.7 plus minus 491.20, 1570.3 plus minus 915.03, 1997.0 plus minus 505.62 g, respectively and FCR in terms of per kg of egg mass was 2.4 plus minus 1.16, 2.6 plus minus 1.08, 3.0 plus minus 1.72 and 3.8 plus minus 2.94 kg, respectively. Hatchability and fertility averaged 68.9 plus minus 18.57 and 88.5 plus minus 14.23%, respectively. Day old chicks weighed 30.7 plus minus 2.34g (n=425) on the average. Age at first lay and weight of egg at first lay were not affected by weight at first lay because of selected sample of birds under consideration. For egg- production up to the age of 40 weeks or in the first 20 weeks of production, none of the weight traits (weight at 8th, 16th, 20th, 26th, 29th, 38th week and at first lay) and even the age of the hen at first lay had any influence. Egg weight (up to 40th week of age) was however affected by weight of hen at 16th week (P less than 0.05), 20th week (P less than 0.05), first lay (P less than 0.01), 26th week (P less than 0.05), 29th week (P less than 0.01) and 38th week (P less than 0.05). Body weight of hens at 37th, 38th, 39th and 40th week of age significantly affected (P less than 0.01) the egg weight of that week at which body weight was recorded but not the egg weight of previous or next weeks. Feed intake, FCR and egg number were also not affected by the body weight. Number of infertile eggs, dead germs, dead in shell eggs, fertility (%) and hatchability (%) were also not affected by any of the weight traits or comb index of the cock. The day old chick weight in the subsequent generation was significantly affected (P less than 0.01) by weight of dam at first lay, at 26th, 29th, 38th, 39th and 41st week. Comb index of sire at 39th and 41st week of age also affected the day old chick weight (P less than 0.05). Comb index of sire at 25th and 29th week of age however, had no effect. Age at first, lay of dam weight of sire at 26th, 29th, 38th, 39th and 41st week of age also did not show any significant affect on the day old chick weight. Sire variance for body weight of hen at first lay, egg production up to 40 weeks of age and egg production in the first 20 productive weeks was close to zero while heritability estimate for egg weight and age at first lay was 0.45 plus minus 0.595 and 0.16 plus minus 0.352, respectively. For day old chick weight, number of observations was reasonable (n=425) and heritability estimate was 0.55 plus minus 0.195, which indicated good scope of improvement in the trait through mass selection.