Two consecutive experiments were conducted to evaluate the influence of dietary composition, specifically protein and amino acid profile, on performance parameters, oocyst output, and lesion development in male and female replacement broiler breeders of two different genetic lines vaccinated with a live coccidiosis vaccine. Dietary formulations were based on either breeder specific recommendations or formulations of a broiler integrator. On day 28, males of each genetic line were added to female pens to evaluate the effect of co-mingling on male performance. Lesion assessment was performed on three separate occasions per each experiment. Fecal material was collected to determine oocyst cycling patterns. During experiment 1, flock uniformity was improved (P less than/equal to 0.05) in Line A males fed the integrator diet. Increased body weight and improved uniformity of Line B females was observed with the breeder recommended diet. Co-mingling negatively impacted (P less than/equal to 0.05) male body weight. Multiple oocyst peaks were observed in both genetic lines, with the first peak occurring at approximately 16 to 18 days post placement. This first peak tended to have the highest observed magnitude and corresponded with the highest level of intestinal lesions observed during the experiment. In experiment 2, diet impacted (P less than/equal to 0.05) average body weight in Line A males, Line B males, and Line B females. Line A males fed the breeder recommended diet had increased (P less than/equal to 0.05) body weight at the termination of the experiment. Line B males and females fed the breeder recommended diet had increased (P less than/equal to 0.05) body weights throughout the experiment beginning on day 7. Negative effects (P less than/equal to 0.05) on male body weight resulting from co-mingling were observed. Oocyst peaks were delayed and at a lower magnitude in both genetic lines compared to peaks observed in experiment 1. Dietary interactions were observed in both experiments where magnitude of peak, duration of oocyst output, and severity of lesion development was influenced by diet in both male and female genetic lines. These data indicate that co-mingling negatively impacts male performance and dietary composition can impact male and female performance, oocyst cycling, and lesion development during coccidiosis vaccination in replacement broiler breeders and should be taken into consideration when rearing replacement broiler breeders.

No description available.

This project researched the effects of pullet-phase feed restriction methodology or management and hen-phase diet fortification on female broiler breeder BW and carcass trait uniformity as well as on performance of the broiler offspring. Feed treatments had a significant effect on female BW and carcass trait uniformity at 22 wk of age, with sorting and scatter treatments having the highest uniformity estimates, compared to limited daily, skip-a-day and fibre-diluted programs. Feed and premix treatments did not affect traits after 22 wk of age as individual caging at 22 wk of age unified female BW uniformity across all treatments. Feed treatments did not affect the uniformity of age at sexual maturity, first egg characteristics or production parameters. Premix treatment resulted in decreased shell uniformity and increased uniformity of one of the production parameters, total egg mass. Feed treatments may have a greater effect on female broiler breeder efficiency than previously suggested. / Animal Science

Two experiments were performed to evaluate effects of amprolium administration at specific times and concentrations in replacement broiler breeders of three genetic lines vaccinated against coccidiosis. Effects on performance parameters including body weight and flock uniformity, and post-vaccination oocyst cycling patterns were evaluated in addition to development of immunity following clinical Eimeria challenge according to gross and microscopic lesion scoring, post-challenge body weight gain (BWG), and total oocyst output. Experiment one was conducted on fresh pine shavings while experiment two was conducted on used litter remaining in treatment pens from the first trial. No significant differences were seen among treatment groups with regard to body weight in either trial. Increased magnitude of oocyst shedding was observed in trial one, Line A with the group receiving amprolium on day 10. Trends in the data indicated increased uniformity in Line A related to amprolium administration following day 21. The group in Line A receiving amprolium at day 10 showed a significantly lower degree of total oocyst output following challenge than the other medicated groups. The group receiving amprolium on day 10 in Line B showed significant reduction in post-vaccination oocyst shedding following treatment in both trials while all shedding was delayed in trial two when compared to the first trial. Effects on uniformity in Line B pullets varied between trials with trends indicating it being advantageous when used litter was a factor. Higher post-challenge BWG was observed in Line B pullets administered the low concentration at day 16 than the controls. Reductions in gross lesion development were seen in Line B pullets in both trials. Line C pullets receiving the highest concentration of amprolium at day 16 showed significantly less uniformity in trial one while the controls appeared to perform better than all medicated groups in trial two. All medicated groups in Line C exhibited delayed and increased magnitudes of oocyst shedding in trial two. These data indicate that the effects of amprolium on performance and immunity development are variable according to genetic strain and indicated that administration may be influenced by litter condition.

No description available.

A preliminary test was conducted evaluating the effect of digestible lysine (dLys) on broiler breeder (BB) male semen quality from forty-one to forty-nine wk of age. Five dietary treatments: corn-soybean meal diet with 1,000 mg dLys/rooser/day (Soy1,000), distillers dried grains with solubles diet with 1,000 (DDGS1,000), 850 (DDGS850), 700 (DDGS700), and 550 (DDGS550) mg dLys/rooster/day. Semen quality was similar except percentage dead sperm which was higher in DDGS550. A second trail was conducted using the same dietary treatments as the preliminary test during twenty to thirty-nine wk of age. Semen quality was similar except percentage dead sperm which was higher in Soy1,000. Soy1,000 exhibited higher body weight (BW), breast weight, and plasma testosterone. In conclusion dLys levels from 1,000 to 700 mg/rooster/day will not adversely affect semen quality of BB males. Attention should be given to BW in BB as it could lead to an increased percentage dead sperm.

The effect of decreasing digestible lysine (dLys) intake by broiler breeder (BB) hens from 35 to 45 wk of age on their reproductive performance and performance of their progeny was evaluated. Two types of diets were fed: a diet from commercially available ingredients consisting of dLys intakes of 1,200 (IDL) and 1,010 mg/hen/day (ID) and a semi-purified diet with dLys intakes of 1,010 (SPL) and 600 mg/hen/day (SP). Hens fed the SPL and SP diets had lower hen-day egg production compared to BB hens fed the IDL and ID diets. Fertility and hatchability of eggs set were lowest (P <0.05) for hens fed the SPL diets. Chick weight at hatch was lower (P<0.05) for those that came from the SP and SPLed hens, but 42 and 56 day body weights (BW) were similar for all treatments. Marginal improvements (P<0.10) in FCR were seen at 42 and 56 days for chicks from IDed hens compared to IDL hens. A decrease in daily intake of dLys appeared to improve BB reproductive performance when hens were fed a semi-purified diet and the same response was not observed in hens fed a diet from commercially available ingredients. Furthermore, the progeny study revealed marginal improvements in some live performance parameters. In a second study, a diet based from corn-soybean meal and formulated to a dLys intake of 1,000 mg/hen/day (CS) and three diets composed primarily of corn, soybean meal, and DDGS with 1,000 (DDGS-1,000), 800 (DDGS-800), and 600 (DDGS-600) mg of dLys/hen/day were fed to evaluate the reproductive performance of BB hens from 24 to 42 wk of age. Feeding diets composed of commercially available ingredients with dLys intake levels below 1,000 mg/hen/day did not impact BB reproductive performance. Reduced BW, carcass and breast weight, and higher (P<0.05) back half weight at 42 days of age was observed from broilers that came from 26 wk old BB hens fed the DDGS-600 diet. Reducing dLys intake in later BB hen ages did not impact progeny performance or carcass characteristics. This suggests that Lys may be in dietary surplus concentrations for commercial breeders under current practical conditions.

A series of trials were conducted to determine the effect of feeding barley silage to laying hens and broiler breeder pullets on performance, stress and behaviour. In the first study, two trials were conducted each with 20 hens and 2 roosters (n=176) randomly assigned to one of 8 community cages. The birds in 4 cages were provided with a nutritionally balanced soy/wheatbased laying hen diet ad libitum, whereas the birds in another 4 cages were given free access to barley silage in addition to the regular laying hen diet. In both trials, the control birds consumed more feed (P < 0.05) than the birds given barley silage. Birds fed barley silage had significantly decreased (P < 0.05) aggressive and feather pecking behaviours as well as time spent in their nest boxes at different ages. Time spent drinking, resting, preening and eating a large particle calcium source was similar between the two treatments. No treatment effects (P > 0.05) were found in regards to egg quality, egg production and bird weights at various ages; however yolk colour was darker by silage treatment in each trial. At the end of each trial, the feather score was improved in silage-fed birds compared to the control birds. It was concluded that feeding barley silage as a supplement to laying hens can improve their welfare without negatively affecting the egg production and egg quality. <p>A second study was conducted to determine the effect of feeding barley silage on body weight, stereotypic behaviour, stress and fear on broiler breeder pullets during the brooding and rearing periods. The 3 week old broiler breeder pullets (n=180) were randomly allocated into 12 straw litter floor pens having 15 birds per pen. The birds in 6 pens were provided with a nutritionally balanced corn/oat-soybean/canola meal-based broiler breeder diet at recommended restricted levels, whereas the birds in another 6 pens were given free access to barley silage in addition to a regular broiler breeder diet. Total DM intake was significantly higher (P < 0.05) for silage-fed birds compared to their control counterparts without affecting mean body weights. Dietary treatment had no significant effect on bird behaviour with the exception of object pecking behaviour which was reduced with silage feeding. Aggressive and gentle feather pecking behaviour was consistently numerically higher in the control birds than the silage-fed birds, although not significantly. Age affected many of the behaviours recorded in this study. Silage feeding had no significant effect on heterophil to lymphocyte ratios and tonic immobility values indicating that birds in both treatments were not very stressed or fearful. It was concluded that feeding barley silage to broiler breeder pullets has potential to aid in improving their welfare.

A series of trials were conducted to determine the effect of feeding barley silage to laying hens and broiler breeder pullets on performance, stress and behaviour. In the first study, two trials were conducted each with 20 hens and 2 roosters (n=176) randomly assigned to one of 8 community cages. The birds in 4 cages were provided with a nutritionally balanced soy/wheatbased laying hen diet ad libitum, whereas the birds in another 4 cages were given free access to barley silage in addition to the regular laying hen diet. In both trials, the control birds consumed more feed (P < 0.05) than the birds given barley silage. Birds fed barley silage had significantly decreased (P < 0.05) aggressive and feather pecking behaviours as well as time spent in their nest boxes at different ages. Time spent drinking, resting, preening and eating a large particle calcium source was similar between the two treatments. No treatment effects (P > 0.05) were found in regards to egg quality, egg production and bird weights at various ages; however yolk colour was darker by silage treatment in each trial. At the end of each trial, the feather score was improved in silage-fed birds compared to the control birds. It was concluded that feeding barley silage as a supplement to laying hens can improve their welfare without negatively affecting the egg production and egg quality. <p>A second study was conducted to determine the effect of feeding barley silage on body weight, stereotypic behaviour, stress and fear on broiler breeder pullets during the brooding and rearing periods. The 3 week old broiler breeder pullets (n=180) were randomly allocated into 12 straw litter floor pens having 15 birds per pen. The birds in 6 pens were provided with a nutritionally balanced corn/oat-soybean/canola meal-based broiler breeder diet at recommended restricted levels, whereas the birds in another 6 pens were given free access to barley silage in addition to a regular broiler breeder diet. Total DM intake was significantly higher (P < 0.05) for silage-fed birds compared to their control counterparts without affecting mean body weights. Dietary treatment had no significant effect on bird behaviour with the exception of object pecking behaviour which was reduced with silage feeding. Aggressive and gentle feather pecking behaviour was consistently numerically higher in the control birds than the silage-fed birds, although not significantly. Age affected many of the behaviours recorded in this study. Silage feeding had no significant effect on heterophil to lymphocyte ratios and tonic immobility values indicating that birds in both treatments were not very stressed or fearful. It was concluded that feeding barley silage to broiler breeder pullets has potential to aid in improving their welfare.

This programme of research uses choice test methodologies to quantify hungry broiler breeder chickens’ preferences for qualitative or quantitative dietary restriction. It begins with an outline of quantitative dietary restriction, its severity and welfare implications before discussing methods of qualitative feed restriction and the difficulties ascertaining whether it represents a welfare improvement. Chapter two reviews the factors affecting diet preferences and discusses implications for feed restricted broiler breeder diet preferences. Chapter three outlines the use of a closed economy T-maze task to quantity the diet preferences of feed restricted broiler breeders. It concludes that broiler breeders can learn a food versus no food task but find it very difficult to learn a task in which both of the options are rewarded with food and this impeded diet preference quantification. Chapter four demonstrates that severity of feed restriction underlies these difficulties in learning. In Chapter five, a conditioned place preference task to identify the effects of diets on affective state (hunger versus satiety) is reported. A method validation group demonstrated that broilers show a state dependent preference for an environment associated with ad libitum access to food. However, birds failed to show a preference between an environment associated with quantitative dietary restriction and one associated with qualitative dietary restriction. Chapter six applies state- dependent learning (SDL) to quantifying the satiating effects of quantitative and qualitative dietary restriction. However, a validation group suggested that SDL preferences were probably an artefact of the test rather than a genuine state-led preference. Finally, the overall conclusion that no evidence was found that broiler breeders want, or that their welfare is improved by, qualitative feed restriction was drawn. However, the conditions under which a preference was reliably observed and the presence of hunger – state dependent effects on learning and expression of learnt preferences complicates the interpretation of any findings. Recommendations for further research are highlighted.