Field testing the influence of sperm competition based on sperm mobility in breeder turkey toms.

1. Commercial reproduction of turkeys relies on pooling of semen from multiple males for inseminations. Understanding how sperm characteristics influence paternity under commercial breeding conditions is important to improving production efficiency. 2. The objective of this study was to evaluate progeny production of individual toms following commercial practices of pooling semen to determine if sperm mobility influences progeny production in field conditions. 3. A total of 104 toms were evaluated for sperm mobility. A subset of 10 toms were housed together and semen was collected, pooled and used to inseminate hens (n = 28). Hens were inseminated at 30 weeks of age and weekly thereafter. 4. Ejaculates from each tom were evaluated on two separate days for sperm mobility. Semen from each tom was diluted and layered upon 6% (wt/vol) Accudenz solution. The sperm suspension was incubated at 41 degrees C for 5 min and absorbance was measured with a spectrophotometer. 5. Toms were ranked by absorbance and categorised as high or low if mobility score was +/- 1 SD from the flock mean (average). 6. For parentage determination, DNA was extracted from tom, hen and poult blood. Poult parentage (n = 276) was determined at one day of age or at 14 weeks by analysis of marker genotypes that were generated by polymerase chain reaction (PCR) amplification of genomic DNA with selected microsatellite markers. 7. Sperm mobility differed across males with absorbance values ranging from 0.147 to 0.366. 8. Findings demonstrate differences in poult production among individual toms when semen from multiple males was pooled and inseminated. Toms classified as high, average and low produced 55, 41 and 4% of the offspring, respectively. 9. It appears that sperm mobility is a trait that influences sperm competition among toms under field conditions where sperm numbers inseminated from individual toms are not controlled or constant and that toms with low sperm mobility produce few offspring.

Effect of physical feed restriction during rearing on large white turkey breeder hens: 2. Reproductive performance.

Large White turkey breeder hens were used to evaluate the effect of three different levels of physical feed restriction on subsequent reproductive performance. The feed treatments were: 1) fed ad libitum throughout the study (CC), 2) feed-restricted from 16 to 24 wk (CR), 3) feed-restricted from 3 to 16 wk (RC), and 4) feed-restricted from 3 to 24 wk (RR). Feed restriction was implemented so that restricted-fed hens (RC and RR) achieved a 45% reduction in BW as compared to CC hens at 16 wk. From 16 to 24 wk, feed was allotted to RR and CR hens to maintain a slight increase in BW. At the completion of the respective restriction periods, hens were gradually returned to ad libitum feeding. At 30 wk of age, hens were photostimulated for a 20-wk summer season egg production cycle. Hens receiving RC and RR treatments laid significantly more eggs than did CC and CR hens for the first 5 wk of lay. However, once the house temperature increased to 26.7 to 29.4 C during 6 to 10 wk of lay, egg production of all hens decreased, resulting in a significant decrease in cumulative egg production for RR and RC hens compared to CC and CR hens. Egg and poult weights were less for RC and RR hens compared to those from CC and CR hens. In conclusion, age of breeder, season of implementation, and length of physical feed restriction have significant effects on the reproductive performance of turkey breeder hens.

Effect of physical feed restriction during rearing on large white turkey breeder hens: 1. Growth performance.

Large White turkey breeder hens were fed ad libitum (CC), feed-restricted from 16 to 24 wk (CR), feed-restricted from 3 to 16 wk (RC), or feed-restricted from 3 to 24 wk (RR). Feed restriction was implemented so that RC and RR hens achieved a 45% reduction in BW compared to CC hens at 16 wk. From 16 to 24 wk, feed was allotted to RR and CR hens to maintain a slight increase in BW. At the completion of each restriction period, hens were gradually released back to ad libitum feeding. At 30 wk of age, hens were photostimulated for a 20-wk summer season egg production cycle. Mean BW for all treatments were different (P < or = 0.05) at 16 and 30 wk. At the end of lay, hens on treatment CR were not different in BW from treatment CC hens, and treatment RR hens were not different in BW from treatment RC hens. Hens on treatment RR had the greatest BW gain and feed consumption leading into the production cycle. All treatment hens lost BW from the time of first egg until 47 wk of age. Hens on treatment CC lost significantly (P < or = 0.05) more relative BW (%) than those in any other treatment. Coefficient of variation for flock uniformity was similar for all treatments at time of photostimulation. At the end of the study, cumulative feed consumption was significantly less for restricted treatments: 86.5, 83.1, 75.8, and 70.7 kg/hen for treatments CC, CR, RC, and RR, respectively.

Effect of physical feed restriction during rearing on Large White turkey breeder hens: 3. Body and carcass composition.

Large White turkey breeder hens were used to evaluate the effect of three different levels of physical feed restriction on subsequent body and carcass composition. The four feed treatments were 1) ad libitum fed throughout the study (CC), 2) feed restricted from 16 to 24 wk (CR), 3) feed restricted from 3 to 16 wk (RC), and 4) feed restricted from 3 to 24 wk (RR). Feed restriction was implemented so that RC and RR hens achieved a 45% reduction in BW compared to CC hens at 16 wk. From 16 to 24 wk, feed was allotted to RR and CR hens to maintain a slight increase in BW. At the completion of each restriction period, hens were gradually returned to ad libitum feeding. At 30 wk, hens were photostimulated for a 20-wk summer season egg production cycle. Restricted fed hens had increased moisture levels at 16 and 30 wk and decreased fat levels at 16, 30, 39, and 54 wk (P < or = 0.05). Absolute and relative weights of the pectoralis major muscle were greater in hens fed ad libitum through 43 wk (P < or = 0.05). There were no differences in the number of maturing yellow follicles due to treatment. However, restricted fed hens had higher peak egg production during early lay but decreased subsequent and cumulative egg production. Changes in egg production were associated with changes in breast muscle weight. Prolactin levels were greater in hens in-production compared to hens out-of-production; however, there were no differences due to feed treatment. In conclusion, further research on quantitative feed-restriction programs, which result in body weight reductions as described in this study, should address specific physiological and nutritional requirements and not be implemented as general programs.

Restriction of feed consumption and body weight in two strains of large white turkey breeder hens.

Large White female-line turkey breeder hen poults (576) of two strains (N, female line and B, male line) were brooded by strain in floor pens from day of hatch until 3 wk of age (WOA). At 3 WOA, all poults were randomly distributed by strain to 48 floor pens in a curtain-sided house. Poults were feed (calorie) restricted beginning at 3 (N3, B3) or 6 (N6, B6) WOA to obtain a 45% reduction in BW at 16 WOA compared to ad libitum controls (NC, BC). At 16 WOA, all hens were gradually returned to ad libitum feeding. At 18 to 30 WOA, all hens were subjected to 8 h light/d. At 30 WOA, all hens were photostimulated with 15.5 h/d. Hens were inseminated weekly with semen from same strain, male-line breeder males. Eggs were collected daily, and all settable eggs from weeks of lay (WOL) 5 to 6, 10 to 11, 15 to 16, 20 to 21, and 24 to 25 were incubated by pen in a common incubator for each set date. Measurements included BW, feed consumption, egg production, mortality, egg fertility, egg hatchability, and poult weight. Statistical analysis of means was performed by strain. Target BW were obtained for feed-restricted hens. Restricted hens increased their feed consumption upon re-alimentation but did not achieve the cumulative feed consumption or BW of control fed hens by 56 WOA. Egg production of N3 hens was greater than NC hens for WOL 2 and 3. Total and settable eggs per hen were greater for N3 hens than for NC for WOL 1 to 5. There were no differences observed for egg weight, egg fertility, hatch of all eggs set, hatch of fertile eggs, or offspring weight among N hen treatments. The B0 hens produced more eggs than B3 or B6 hens. The B6 hens produced lighter weight eggs than B0 hens. It was concluded that early severe feed restriction of female line breeder hens might improve subsequent reproductive performance.