@article{zakaria_plumstead_romero-sanchez_leksrisompong_brake_2009, title={The effects of oviposition time on egg weight loss during storage and incubation, fertility, and hatchability of broiler hatching eggs}, volume={88}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2009-00069}, abstractNote={An experiment was conducted to determine the effect of time of oviposition, generally representing different positions in the normal egg laying sequence, on egg weight loss during storage and incubation, and on fertility and fertile hatchability of eggs from mid-lay (42 wk) and old (67 wk) broiler breeders. A total of 1,800 eggs (900 eggs per flock age) were collected during 10 consecutive days between 0830 and 1830 h each day. The eggs were individually marked, weighed, and stored for 1 to 10 d before incubation was initiated. Egg weight remained less from collection through incubation for eggs from the mid-lay flock than those from the old flock. Fresh weight of early laid (first-in-sequence; C1) eggs was significantly greater than that for the middle-of-day laid (mid-sequence; Cs), or late-in-day laid eggs (terminal-in-sequence; Ct). Percentage of egg weight loss during storage did not differ significantly between the mid-lay and old flocks but percentage of weight loss in the mid-lay flock was greater during incubation. Egg weight loss during storage of eggs from the middle-of-day laid (Cs) eggs was significantly greater than for early laid (C1) eggs, which was greater than for the late-in-day laid (Ct) eggs. Fertility was significantly decreased due to flock age but not due to oviposition time. Fertile hatchability was also significantly decreased due to flock age, but there was no significant effect of oviposition time. Early and late dead embryos increased with flock age, but there was no significant effect of oviposition time. It was concluded that there was no effect of oviposition time on fertility or fertile hatchability even though there were significant differences in egg weight and egg weight loss during storage due to oviposition time.}, number={12}, journal={POULTRY SCIENCE}, author={Zakaria, A. H. and Plumstead, P. W. and Romero-Sanchez, H. and Leksrisompong, N. and Brake, J.}, year={2009}, month={Dec}, pages={2712–2717} }
 @article{romero-sanchez_plumstead_leksrisompong_brannan_brake_2008, title={Feeding broiler breeder males. 4. Deficient feed allocation reduces fertility and broiler progeny body weight}, volume={87}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2007-00285}, abstractNote={Two experiments were conducted to evaluate the effects of male broiler breeder feed intake on broiler progeny performance. In experiment 1, a low cumulative nutrition program supplied 29,580 kcal of ME and 1,470 g of CP, whereas a high cumulative nutrition program supplied 33,500 kcal of ME and 1,730 g of CP to photostimulation at 21 wk of age. Two diets (HiDiet and LoDiet) were formulated, and a single feeding program was used to achieve the selected nutrient intakes. The HiDiet group of males in experiment 1 achieved greater BW and exhibited lower fertility when fed as the LoDiet males from the onset of egg production. The HiDiet breeder males subsequently produced male broilers from eggs laid at 29 wk of age that exhibited lower BW at 42 d. This was due to the heaviest 50% of the breeder males in this treatment not gaining BW consistently due to less-than-adequate ME intake relative to their greater BW requirements. Two feeding programs during the production period (constant or increasing) were compared in experiment 2. Broilers were hatched from eggs laid at 32 and 48 wk of age to evaluate the vertical effect of male treatments on progeny performance. No difference in fertility or broiler performance was found at 32 wk. However, the constant feeding program produced lower fertility from 36 to 55 wk of age, and this resulted in a lower male and female broiler progeny BW at 42 d of age from eggs collected at 48 wk of age. Adequate breeder male feed allocation during the production period improved fertility and favorably affected broiler progeny performance in both experiments. However, broiler progeny effects were observed only when there were differences in fertility, which suggests that the males with the greatest genetic potential were not mating at these times.}, number={4}, journal={POULTRY SCIENCE}, author={Romero-Sanchez, H. and Plumstead, P. W. and Leksrisompong, N. and Brannan, K. E. and Brake, J.}, year={2008}, month={Apr}, pages={805–811} }
 @article{plumstead_romero-sanchez_maguire_gernat_brake_2007, title={Effects of phosphorus level and phytase in broiler breeder rearing and laying diets on live performance and phosphorus excretion}, volume={86}, ISSN={["1525-3171"]}, DOI={10.1093/ps/86.2.225}, abstractNote={The effects of a reduced dietary nonphytate phosphorus (NPP) level and inclusion of phytase on broiler breeder performance and P concentrations in the litter and manure were investigated. Ross 308 broiler breeder pullets and Ross 344 cockerels were placed sex-separate in a blackout growing house and fed standard starter and grower diets to 9 wk of age. At 10 wk of age, 4 treatments (A, B, C, D) were assigned to each of 4 floor pens of 68 pullets and 1 pen of 50 cockerels. From 10 to 21 wk, treatments A to D contained 0.37, 0.27, 0.27, and 0.17% NPP, respectively, with 300 phytase units (FTU)/kg of phytase added to treatments B and D. At 21 wk of age, birds were photostimulated and transferred to a two-thirds slat-litter breeder house with 16 pens of 60 pullets and 6 cockerels. A laying diet was fed from 22 to 64 wk and NPP levels of treatments A to D were adjusted to 0.37, 0.27, 0.19, and 0.09%, respectively, and phytase addition to treatments B and D was increased to 500 FTU/kg. Analysis of the litter from growing pens showed no effect on litter total P when phytase replaced 0.1% of NPP. However, decreasing the dietary NPP by 0.1% without phytase reduced the litter total P by 18%. Water-soluble P (WSP) and the WSP:total P ratio decreased when the grower dietary NPP level was reduced to 0.17% with added phytase and was correlated with litter moisture levels in growing pens. During the laying period, a reduction in NPP from 0.37 to 0.09% with added phytase reduced both the manure total P and WSP by 42%. Hen-day egg production was highest on the lowest NPP diet with phytase, but fertility decreased when the dietary NPP was reduced below 0.37%. Results showed that phytase inclusion in a broiler breeder laying diet at the expense of all added P from dicalcium phosphate reduced the manure total P and WSP concentrations by 42%, with no effect on the number of chicks produced per hen housed.}, number={2}, journal={POULTRY SCIENCE}, author={Plumstead, P. W. and Romero-Sanchez, H. and Maguire, R. O. and Gernat, A. G. and Brake, J.}, year={2007}, month={Feb}, pages={225–231} }
 @article{romero-sanchez_plumstead_brake_2007, title={Feeding broiler breeder males. 3. Effect of feed allocation program from sixteen to twenty-six weeks and subsequent feed increments during the production period on body weight and fertility}, volume={86}, ISSN={["1525-3171"]}, DOI={10.1093/ps/86.4.775}, abstractNote={Two experiments were conducted to compare different feed allocation programs from 16 to 26 wk of age and during the subsequent production period on broiler breeder male BW and fertility. In experiment 1, Ross 344 males were randomly assigned to 3 rates (slow, medium, or fast) of weekly feed increase from 16 to 26 wk of age that provided a gradual increase from 85 to 110 g/male/d. Feed allocation was also increased 5 g/ male/d in a single increment at 55 wk of age after fertility had declined. In experiment 2, a 2 x 2 factorial design was used to evaluate the interaction between the slow and fast feeding programs described in experiment 1 in combination with 2 feeding programs (constant or increasing) during the subsequent production period. In experiment 1, the males on the fast feed program exhibited higher mortality after 32 wk of age and lower fertility after 46 wk of age. However, fertility recovered in all treatments after the feed allocation was increased at 55 wk of age. In experiment 2, the constant program elicited lower fertility from 36 to 55 wk. Males that received the slow feed program from 16 to 26 wk of age gained BW more slowly and apparently required less feed to sustain their BW throughout the production period. Increasing male feed allocation during the production period improved fertility.}, number={4}, journal={POULTRY SCIENCE}, author={Romero-Sanchez, H. and Plumstead, P. W. and Brake, J.}, year={2007}, month={Apr}, pages={775–781} }
 @article{zakaria_plumstead_romero-sanchez_leksrisompong_osborne_brake_2005, title={Oviposition pattern, egg weight, fertility, and hatchability of young and old broiler breeders}, volume={84}, ISSN={["1525-3171"]}, DOI={10.1093/ps/84.9.1505}, abstractNote={Two experiments were conducted to investigate egg weight, fertility, hatchability, and embryonic mortality in relation to time of oviposition of young and old broiler breeder flocks. In experiment 1, eggs were collected from 2 flocks (34 and 59 wk) for 2 d at hourly intervals between 0700 and 1900 h. Most eggs were laid between 0700 and 1300 h, but eggs were laid later in the day by the old flock. Weights of early laid (C1) eggs were significantly greater than middle laid (Cs) and the late laid (Ct) eggs in the young flock, whereas late laid eggs (Ct) were significantly smaller than early laid (C1) and middle laid (Cs) eggs in the old flock. In experiment 2, eggs from experiment 1 were categorized as early laid first-in-sequence (C1) eggs (0700 to 0800 h), the mid-sequence (Cs) eggs (0900 to 1200 h), and the late laid terminal-in-sequence (Ct) eggs (1300 to 1700 h). These eggs were incubated to determine fertility, hatchability, and stage of embryonic mortality relative to oviposition time and flock age. Fertility declined with flock age, but there were no differences due to time of oviposition. There were no differences in hatchability of fertile eggs or embryonic mortality relative to time of oviposition (sequence position) or flock age. These results suggested that although there were differences in egg weight among eggs at different times of the day (different sequence positions), there were no differences in fertility, fertile hatchability, or embryonic mortality in naturally mated broiler breeders.}, number={9}, journal={POULTRY SCIENCE}, author={Zakaria, AH and Plumstead, PW and Romero-Sanchez, H and Leksrisompong, N and Osborne, J and Brake, J}, year={2005}, month={Sep}, pages={1505–1509} }