Thesis (M. Tech. (Agriculture)) - Central University of Technology, Free state, 2013 / The objectives of the study were to find the relationship between live performance and testis traits of South African indigenous cockerels on Naked Neck, Ovambo and Potchefstroom Koekoek (Trial 1). Characterise Naked Neck, Ovambo and Potchefstroom Koekoek cockerels’ semen macroscopically and microscopically (Trial 2). To investigate the relationship between phenotypic and sperm traits of the South African indigenous cockerels Naked Neck, Ovambo and Potchefstroom Koekoek. (Trial 3). Quantification of indigenous cockerels sperm traits measured by Computer Assisted Sperm Analysis (CASA) technology and the relationship to fertility (Trial 4). The cockerels shank, comb and wattle length were recorded with a vernier calliper. A total of 198 ejaculates were collected from 33 cockerels; Ovambo (n=11), Potchefstroom Koekoek (n=11) and Naked Neck (n=11) by means of an abdominal massage technique. Following analysis, 0.25 ml undiluted semen dose from Naked Neck (NN, 11), Ovambo (OV, 11) and Potchefstroom Koekoek (PK, 11) cockerels were inseminated NN (30), OV (30) and PK (30) hens once per week for 6 weeks. Semen was analysed macroscopically and microscopically. The sperm motility rate was evaluated with the aid of the Computer Assisted Sperm Analysis (CASA) called Sperm Class Analyser (SCA) system. Breed significantly (P< 0.05) affected the body weight of Ovambo (2.5±0.4kg), Naked Neck (2.0±0.3kg) and Potchefstroom Koekoek (2.3±0.3kg) cockerels, OV was statistically heavier than NN and PK. The semen volume of Naked Neck (0.5±0.2ml) breed was significantly higher, when compared to Ovambo (0.4±0.2ml), but similar to Potchefstroom Koekoek (0.3±0.2ml) breed. The overall sperm motility rate of Ovambo (95.0±7.2%), Potchefstroom Koekoek (86.0±13.7%) Naked Neck (76.4±22.2%) group was significantly different. The normal sperm morphology in the Naked Neck (76.4±22.2%) was significantly lower when compared to Potchefstroom Koekoek (86.0±13.7%) and Ovambo (95.0±7.2%) cockerels. A positive correlation existed between body weight and semen volume for Potchefstroom Koekoek (r=0.1477) cockerels only. Moreover, there was a positive correlation between the body weight and total sperm motility for Naked Neck (r=0.3848), Ovambo (r=0.4871) and Potchefstroom Koekoek (r=0.2230) cockerels. However, a negative correlation existed between body weight and semen volume for Naked Neck (r=-0.4502) and Ovambo (r=-0.1244). There was no significant differences (P>0.05) on the shank length (SL), comb length (CL) and wattle length WL) of Naked Neck (8.4, 5.4 and 5.6 cm), Ovambo (8.3, 5.8 and 6.0 cm) and Potchefstroom Koekoek (7.7, 5.9 and 5.6). There was a positive correlation between shank length and wattle length, comb length, semen volume, sperm concentration, semen pH and live normal sperm, inversely, a negative correlation of body weight and total sperm motility was observed. Introspective a negative correlation existed between body weight and total motility. Ovambo (11.45±0.9 g) had the highest live weight of testis, it was significantly different from Naked Neck (9.2±0.8g) and Potchefstroom Koekoek (8.9±0.8 g). For average length of the testis there was a significant difference amongst all breeds, Ovambo (4.0±0.5 cm), Naked Neck (3.4±0.3 cm) and Potchefstroom Koekoek (3.7±0.4 cm). Following Al, significant differences were recorded in Potchefstroom Koekoek and produced eggs that had highest average egg weight (55.5 g), fertility (68.2 %), hatchability (78.6 %), percentage of normal chicks (80.1%) and chick weight (37.9 g) compared to Ovambo (40.4 g, 5 2.1 % , 70.2 %, 71.5 %, 32.8 g and Naked Neck (37.1 g, 50.6 %, 71.1 %, 75.8 % and 23.5 g). In order to achieve the highest level of fertility and hatched of fertile eggs, an adequate number of active males that are producing high quality semen should be maintained in the breeder house at all times. In conclusion, body weight positively affected semen volume and sperm motility rate but this was breed dependent. The Sperm of Potchefstroom Koekoek and Ovambo resulted in a better motility and morphology rate. The Sperm Class Analyser or CASA provided more precise, repeatable and objective information. Evaluation of the sperm motility rate of South African indigenous cockerels holds potential for future use in semen evaluation. Body weight of all three indigenous breeds was positively correlated with sperm concentration, semen pH, and total sperm motility. Shank and wattle length of all three indigenous breeds were positively correlated with semen volume, sperm concentration, and semen pH but not with total sperm motility. However, comb length was positively correlated with semen volume and pH, sperm concentration, and total motility. In conclusion, there is no correlation between live performance and testis traits. Though the study suggests that body weight and testicular length are good indicators of sperm production. Simple and indirect method of estimation is still needed to predict the fertility of the breeding cockerels. In order to achieve the highest level of fertility and hatch of fertile eggs, an adequate number of active males that are producing high quality semen should be maintained in the breeder house at all times. The Potchefstroom Koekoek, Ovambo and Naked Neck donated quality semen as well as in improving the fertility and hatchability traits of the indigenous chicken breeds. Chicken hatched from larger eggs had higher body weight, hatchability and fertility therefore breeders should select bigger egg sizes probably of 50-55g for breeding programmes. Consequently, the local cockerels have higher potential for use in natural mating and Al programmes since seminal traits could be a viable index for selection of breeding cockerels.

Institute for Rural Development / MRDV

Department of Animal Science / BSCAGR

The objective of this study was to compare the nutrient status of full scavenging and semi-scavenging village chicken production systems. The semi-scavenging chickens were given broiler finisher mash between 14-24 weeks of age, whilst the full scavenging relied on natural foraging. The study also sought to compare the quality of meat from chickens from the two systems. After slaughtering the chickens, the crop contents were physically separated and analysed for chemical composition. Meat pH and colour were measured on the breast muscle of individual carcasses and a consumer sensory evaluation was also done on the breast muscle. The mean crop content weights per day were significantly higher in full scavenging chickens (±16.7g/day biomass) than in semi-scavenging chickens (±9.14g/day). Dry matter, calcium, and phosphorus levels were higher in the crop contents of the full than in the semi-scavenging chickens but crude protein, crude fibre and metabolisable energy were higher in the latter system. Semi-scavenging (1.3 ± 0.05kg) carcasses were heavier (P<0.05) than full scavenging ones (1.0 ± 0.06kg). The ultimate pH (24h) (pHu) of meat from full scavenging chickens (6.0 ± 0.03) was higher (P<0.05) than that of meat from the semi-scavenging chickens (5.7 ± 0.04). Meat from the full scavenging chickens had higher L* values (60 ± 1.2) than meat from the semi-scavenging chickens (47 ± 0.8). The a* value of meat of full scavenging chickens was significantly (P<0.05) less (4 ± 0.4) than that of meat from semi-scavenging chickens (15 ± 1.3). There was a significant positive (0.60) correlation between pHu and L* of meat from village chickens across rearing systems. The semi-scavenging system meat had better sensory attributes than the meat from the full scavenging system. Female consumers scored the typical flavour of village chicken meat across rearing systems higher (P< 0.05) than male consumers. The Shona consumers scored the meat higher (P< 0.05) than the Xhosa, Zulu, Ndebele and other tribes for initial juiciness, first bite impression and muscle fibre and tenderness of the chicken across rearing systems. Consumers scored of the meat from the semi-scavenging system higher (P<0.05) on initial juiciness (4.3 ± 0.20), first bite impression (4.2 ± 0.197), muscle fibre tenderness (4.5 ± 0.217) than meat from the full scavenging chickens. There were positive correlations (0.46) between aroma intensity and overall flavour intensity across both rearing systems. The semi-scavenging system produced better carcass characteristics, lighter (L*) meat and more consumer acceptable meat than full scavenging chickens. Therefore the full scavenging rearing system had better nutrient composition in its scavenging feed resource base, although the semi-scavenging systems produced chickens with better carcass, meat pH, colour and sensory characteristics than the full scavenging chickens.