One thousand one hundred and fifty-two dual-purpose improved chickens (576 Kuroiler and 576 Sasso) of mixed sexes were reared in two diverse agro-ecological zones, i.e., highland and lowland in ...Mvomero district, Eastern Tanzania, to determine the effects of agro-ecological zones on growth performance, egg production, and survivability under farmer management conditions. Two villages per zone were purposively selected, and from each village, 16 farmers were included in the study; a particular farmer received 18 birds of mixed sexes of the same breed. Data on body weight, egg production trait, and mortality were taken at different ages from week 6 up to 52. General Linear Models fitting breed, agro-ecological zone, and interactions between breed and zone were used to analyze the data. Results show that breed had no significant effects on body weight and body weight gain. However, the effects of the agro-ecological zone and interaction between breed and zone on body weight and body weight gain were significant at the 16th and 20th week of age. The highland zone had heavier chickens than the lowland. While Sasso performed better than Kuroiler chickens in the highland zone, the opposite was observed in the lowland. Significant breed × agro-ecology interactions were observed only for age at first egg whereby Sasso matured earlier than Kuroiler in the highland zone but much later than Kuroiler in the lowland. Birds raised in the highland zone survived better than those chickens in the lowland during both growing and laying periods. Thus, knowledge of breed performance in relation to agro-ecological differences is critical when distributing improved chicken breeds to farmers.
The experiment was conducted to evaluate the effect of breed, diet, and level of feed supplementation on growth performance, feed conversion ratio, and survivability of Sasso and Kuroiler chicken. ...The study was conducted in two separate phases, i.e., the starter phase (0–6 weeks of age) and grower phase (6–20 weeks of age). One thousand sixty–day-old Sasso and Kuroiler chicks were raised until 6 weeks under intensive management system with three dietary treatments. At the age of 6 weeks, a total of 960 birds (480 Sasso and 480 Kuroiler) were randomly selected from each treatment diet and assigned to four feed supplementation levels, i.e., 25%, 50%, 75%, and 100% with two replicates each having 20 birds. Beginning week 7, birds were allowed to semi-scavenge from 6:00 am in the morning to 6:00 pm in the evening with free access to open grass area of 1 bird/4 m
2
. Grower rations based on the three categories, i.e., commercial, medium-cost, and low-cost formulation, were fed from 7th to the 20th week of age. During 0 to 6 weeks of the growing phase, the breed and diet significantly (
p
< 0.05) influenced 6-week live weight, live weight gain, and feed conversion ratio. Birds given commercial diet (D1) excelled in live weight, total live weight gains, and feed conversion ratio followed by medium-cost (D2) and low-cost (D3) diet respectively. During the 7th to 20th weeks of the growing phase, the breed, diet, and supplementation levels had a significant influence (
p
< 0.05) on the live weight and weight gain at 20 weeks of age. Feed cost per kilogram gain increased with an increase in the level of supplementation. Days taken by birds to reach market weight (2 kg) with 100%, 75%, 50%, and 25% level of dietary supplementation were 16, 18, 20, and more than 20 weeks respectively. The survival rate for Sasso and Kuroiler was 99.80% and 97.13% respectively. It is concluded that appreciable growth performance can be attained for semi-scavenging Sasso and Kuroiler chickens when supplemented with medium- or low-cost diets at the level of 50 to 75% of their daily feed requirements.
The productivity of local chickens under village management conditions was studied in six villages situated in three climatic zones within Morogoro District in Tanzania. Two villages were picked in ...each climatic zone (warm and wet, warm and dry, cool and wet) for the study. The data were obtained by actual measurement, qualitative observations and interview of members of the households directly responsible for the care of chickens. In addition, data sheets were given to selected farmers to record the performance of their chickens. The mean flock size for the three zones was 16.2, with a range of 2 to 58. The overall mean clutch size, egg weight and hatchability were 11.8, 44.1 g and 83.6%, respectively. The overall mean chick survival rate to 10 weeks of age was 59.7%. The mean live weights for cocks and hens were 1948 g and 1348 g, respectively. The mean growth rates to the age of 10 weeks were 4.6 g/day and 5.4 g/day, while those from 10 to 14 weeks of age were 8.4 g/day and 10.2 g/day for female and male birds, respectively. The age at first lay ranged between 6 and 8 months, and the average hen had three laying cycles per year. Most of the chickens were left to scavenge during the day and were provided with simple housing at night (95.2% of the owners). Only small amounts of supplementary feeds were occasionally given and minimal health care was provided. It was concluded that the low productivity of chickens was partly due to the prevailing poor management practices, in particular the lack of proper health care, poor nutrition and housing.
1. A total of 144 chickens purchased from peasants in Morogoro, Tanzania were slaughtered, their crops dissected and the contents analysed. The birds consisted of 48 chickens from each of three ...climatic zones (warm and wet, warm and dry, cool and wet). Seventy-two chickens were slaughtered in each season, that is short rainy and long rainy season. 2. Cereal grains, bran, green forages, insects/worms and kitchen food wastes were the main crop contents and their composition varied significantly with season and climate. 3. The overall mean chemical compositions (g/kg) of the crop contents were: 430.8 ± 107.78 dry matter (DM), 104.4 ± 43.47 crude protein (CP), 61.2 ± 36.48 ether extract (EE), 58.2 ± 26.29 crude fibre (CF), 125.4 ± 58.27 ash, 6.3 ± 5.19 calcium (Ca) and 3.6 ± 2.41 phosphorus (P). 4. CP, EE, ash and P contents varied significantly ( P < 0.05) with season but contents of DM, CF and Ca were not significantly different. 5. CP content was significantly higher ( P < 0.05) in growers than in adults while the reverse was true for Ca content. Other variables did not differ significantly. 6. Significant differences ( P < 0.05) in chemical composition were observed among the zones in all parameters except for CP content. 7. The study showed that the chemical composition of feeds eaten by rural scavenging chickens was below the nutritional requirements and varied with season, climate and age of birds.
DETERMINATION GENETIQUE DES REACTIONS IMMUNITAIRES AU VACCIN CONTRE LE VIRUS DE LA MALADIE DE NEWCASSTLE CHEZ LES POULETS Résumé Une étude a été menée à l'Université Sokoine afin d'examiner le ...contrôle génétique de la réaction immunitaire des poulets au vaccin contre le virus de la maladie de Newcastle. L'étude portait sur les poulets locaux de la Tanzanie (LL), les hybrides Rhode Island Red (EE) et leurs croisements réciproques (LE et EL). L'écotype local avait les titres d'anticorps moyens les plus élevés suite à une première vaccination, puis avant et après une deuxième vaccination ; tandis que la race exotique avait les titres les plus faibles pour toutes les trois périodes susmentionnées. Quant aux poulets croisés, ils étaient entre les deux génotypes parentaux, mais les différences entre l'écotype local et les croisements n'étaient pas significatives à l'exception du titre d'anticorps de la première vaccination. Les estimations de l'héritabilité pour le titre d'anticorps variaient entre 0,27 ± 0,06 et 0,39 ± 0,09 ; 0,17 ± 0,03 et 0,32 ± 0,11 ; 0,18 ± 0,08 et 0,28 ± 0,08 pour le titre d'anticorps après la première vaccination, puis avant et après la deuxième vaccination respectivement. Il n'y avait pas de coefficients de corrélation importants entre les titres d'anticorps pour les trois périodes précitées, et entre les titres d'anticorps et les poids vifs des poulets. D'après ces résultats, il est conclu qu'une nette amélioration de l'état immunologique d'une bande de poulets contre la maladie de Newcastle pourrait être obtenue par le biais de la sélection et du croisement. Summary A study was conducted at Sokoine University of Agriculture to investigate the genetic control of immune response of chickens against Newcastle disease virus (NDV) vaccine. The study involved local chickens from Tanzania (LL), Rhode Island Red derivative hybrids (EE), and their reciprocal crosses (LE and EL). The local ecotype had the highest mean antibody titres following primary vaccination, as well as prior to (residual) and after secondary vaccination, while the exotic breed had the lowest titres in all three measuring periods. The crossbred chicks were found to be intermediate between the two parental genotypes, but the differences between the local ecotype and the crosses were not significant except for the primary vaccination antibody titre. Heritability estimates for antibody titre ranged from 0.27 ± 0.06 to 0.39 ± 0.09, 0.17 ± 0.03 to 0.32 ± 0.11, and 0.18 ± 0.08 to 0.28 ± 0.08 for antibody titre following primary vaccination, prior to, and after secondary vaccination, respectively. There were no significant correlation coefficients between antibody titres at different periods of measurement, nor between antibody titres and body weights of chickens. From these results it is concluded that substantial improvement in immunological status of a stock against Newcastle disease could be achieved through both selection and crossbreeding. Bull Anim. Hlth. Prod. Afr. Vol.52(3) 2004: 186-197
A 2-phase crossbreeding study was undertaken to explore prospects of improving the performance of chickens under extensive production conditions in Tanzania. The first phase was carried out under ...reasonably good feeding and housing conditions and involved one imported meat and egg type each as well as a local breed and their crosses. In the second phase, 15 genetic groups with graded proportions of inheritance from the 3 parental breeds were compared for their performance under relatively poor conditions of feeding and general management. The results revealed that under good production conditions the performance in a particular trait increased with increasing levels of inheritance from the exotic breed which had been developed mainly for that trait. Under poor management conditions, the trend was rather obscure, with the superiority of germ plasma from the exotic breeds expressed in the crosses rather than in the parental breeds. The disparity between the results obtained in the two phases is attributed to genotype x environmental interaction, heterosis, heterosis x environment interaction, and maternal and sex-linked influences. It is concluded that the genetic disposition of the high performers should be adapted to the local production conditions by forming synthetic breeds based on crossbreeding.
