The objectives in these four experiments were to observe the effectiveness of sodium bisulfate and clinoptilolite and different methods of application of sodium bisulfate, ferrous sulfate heptahydrate and Micro Aide® on atmospheric ammonia level in the broiler house and on broiler performance. The first experiment was conducted to determine the optimum effective level of the litter application of sodium bisulfate. Atmospheric ammonia at 4 weeks and litter moisture at 3 weeks treated-pens were significantly lower in sodium bisulfate (488 g/m²) than in the untreated control pens. However, broiler performance was not significantly affected with any treatment. Litter application of sodium bisulfate at 244 g/m² and 488 g/m² were comparable and better than the 122 g/m² and untreated control. In Experiments 2 and 3 comparisons of litter chemical treatments of liquid Micro Aid® (8.75 ml/L H₂O) applied at 0, 2, 4,and 6 weeks; granular Micro Aid® (0.5 mg/g of feed) fed continuously throughout the experiment, and litter application of ferrous sulfate (732 g/m²); clinoptilolite (2443 g/m²), sodium bisulfate (244 g/m²) and ferrous sulfate (732 g/m²) were made for 7 week periods. Ferrous sulfate-treated pens (732 g/m²) had significantly lower litter pH at 2, 4 and 6 weeks than untreated control and significantly lower atmospheric ammonia levels at 3 and 6 weeks than the clinoptilolite (2443 g/m²), sodium bisulfate (244 g/m²) and untreated control in the other experiment. In the fourth experiment, sodium bisulfate was applied twice (244 g/m²/application) at 0 and 4 weeks, sodium bisulfate applied once (488 g/m²) and ferrous sulfate applied once (732 g/m²) prior to the experiment. At 4 weeks mean body weights and feed conversion were significantly better with one sodium bisulfate application than the untreated control. At 7 weeks feed conversion (P<0.08) and male body weights (P<0.1) were slightly better in one sodium bisulfate application than in the untreated control while mortality was significantly lower in the untreated control pens. Most mortality occurred after 4 weeks and were due primarily to Sudden Death Syndrome. Atmospheric ammonia levels at 0, 1, 2, 3 and 4, weeks and litter pH levels at 0, 1, 2, 3, and 4 weeks were significantly lower in pens with one application of sodium bisulfate than in pens untreated. Litter application of sodium bisulfate once (488 g/m²) seemed to be the best litter treatment in reducing atmospheric ammonia. / Graduation date: 1991

This study was conducted to examine the potential of plastic slats as flooring material for maintenance of broiler breeders. Although plastic slats are more expensive than wood slats, plastic slats are more durable and easier to clean. Wood and plastic slats were tested as full and partial flooring to determine the ideal proportion of slats for broiler breeder floors. Space allotment was 2040 cm²/bird on all floor treatments. . Arbor Acres broiler breeders, one of the more common strains in British Columbia, were raised to 58 weeks of age to monitor the influence of slat material and slat coverage on egg production and progeny growth over one production cycle. Since the pens were not set up to determine the number of eggs lost through slats, "egg production" values were actually egg recovery values. Over-all egg recovery was significantly higher on partial wood (PWS) and partial plastic slats (PPS) than on either of the full slat treatments. Breeders on full wood slats (FWS) had higher over-all egg production than those on full plastic slats (FPS). Differences were significant for three biweekly periods, but slats did not influence the over-all incidence of floor eggs and cracked floor eggs. The incidence of cracked nest eggs was significantly higher in FWS and FPS than in PWS and PPS pens during four lay periods and overall. The proportion of non-cracked nest eggs, which was taken as an approximation of the proportion of settable eggs, was higher for partial slat pens than full slat pens, and FWS pens had a higher proportion of non-cracked nest eggs than FPS pens. To monitor fertility and hatchability, eggs were incubated at 37, 42, 46, 50 and 56 weeks of breeder age. Fertility, hatchability of total eggs set and hatchability of fertile eggs was not affected by type of slats. Progeny from the hatch at 37, 46 and 56 week of breeder age were grown in Petersime battery cages to three weeks of age. The progeny of breeders on FPS had lower first week weight gain than the other progeny groups due to moisture loss when 7 FPS progeny were lost during the second growth trial. Weekly and over-all feed conversion of progeny was not affected by types of slats used by parents. The 56th week progeny were grown in Petersime battery cages to market age (six weeks). PWS and FPS progeny had higher third week weight gain than PPS progeny. During the sixth week, FWS and PWS progeny had higher weight gain than FPS and PPS progeny. The sixth week feed conversion of FPS progeny was higher than that of the other three progeny groups. No other differences were seen. As long as slats were used as partial flooring, there were no differences in egg production on wood or plastic slats. The proportion of "settable" eggs, fertility, and hatchability of eggs of plastic slat breeders were comparable with that of wood slat breeders regardless of slat coverage. There were significant differences in the 3-week growth of 37th, 46th and 56th week progeny and the 6-week growth of 56th week progeny on the different slat types, but the differences were not due to slat treatments. There was no interaction between breeder age and slat material, therefore the influence of slat material on egg production and progeny growth did not vary with breeder age. Although egg recovery and the number of settable eggs were lower for FPS breeders, breeders on plastic slats performed as well as those on wood slats in the present study. / Land and Food Systems, Faculty of / Graduate

The expression of photorefractoriness, a feature of seasonal breeding in birds, is important in production species, where egg production and fertility are affected by the photoperiod. Years of selection in meat-type birds have reduced the potential reproductive function, and the environmental manipulation of such genotypes is essential to maximise productivity. While it is known that egg-type pullets no longer exhibit photorefractoriness, and that female broiler breeders do, there is not much information about the response of male broiler breeders to photoperiod. Such information is important when designing lighting programmes for breeding stock, and this study aimed to gain more insight into the male response to photoperiod. A series of experiments was designed in order to achieve this. In the first the response of male broiler breeders to rearing on constant photoperiods was measured, and in the second the effects of age at photostimulation on age at sexual maturity were assessed. The response to an increase in photoperiod during the production cycle was investigated in the third trial. Evidence of photorefractoriness in males was observed, but this was not the case in all birds, possibly due to high variation in some of the fertility traits measured. It seems possible that males do not respond to photoperiod to the same extent as females. Unexpected observations of a response in some birds to early photostimulation, and the high variation observed prompted another experiment in which the heritability of the response to early photostimulation was measured as a potentially revolutionary method of selection, whilst checking that this response is not negatively linked to broiler growth rates. Left and right testis weight data, collected in the above experiments, were analysed for asymmetry. There was no consistent response in testes asymmetry to photoperiod, or evidence that asymmetry in testis weights is as a result of the imposition of genetic or environmental stress. The strong correlation found between testes dimensions and weight suggests that predictions of testis weights could be made through ultrasonics or laparoscopy. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

There are negative influences of selection for broiler growth on the reproductive ability of broiler breeder parents. This is mostly due to problems related to excessive body weight, such as an inability to achieve successful cloacal contact during natural mating. There is also an age-related decline in fertility of broiler breeders. In attempts to prolong the fertile period of the breeders, various forms of management techniques have been employed. These include tools such as feed restriction, photoperiod management, spiking, and possibly even using artificial insemination. The first objective of this thesis was to investigate the possible benefits of feeding broiler breeder males diets containing lower crude protein levels, than given to the females, as a means of possibly tempering growth rate or improving semen quality and fertility. There was a definite improvement in the ability of the spermatozoa of the males on a lower crude protein diet to survive in the female reproductive tract. Males that received higher levels of crude protein were at a disadvantage in that fewer males yielded semen in response to abdominal massage. The second objective of this thesis was to assess the possible benefits in semen quality and fertility, when supplementing the male diets with additional vitamin E or Se in the form of Sel-Plex®. No significant effect of treatment was observed on egg fertility or semen quality. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.