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Articles by R.D. Ekmay
Total Records ( 6 ) for R.D. Ekmay
  R.D. Ekmay and C.N. Coon
  A 40-wk study was conducted to assess the effects of limestone particle size on the production performance, skeletal integrity and Ca/P balance of three broiler breeder purelines. A flock of LINE A, LINE B and LINE C broiler breeders were reared according to Cobb 500 guidelines (Cobb-Vantress, 2005) and transferred to a production house at 21 wks of age. Each line was split into two groups consisting of 66, 68 and 62 hens for the LINE A, LINE B and LINE C lines, respectively and fed a diet that differed only in the inclusion of either large (3489.7 microns; 38.5% solubility) or small particle (185.5 microns; 58.8% solubility) limestone. Production performance, egg quality, breeder skeletal integrity, reproductive performance, progeny performance and Ca/P balance were monitored. LINE B produced the most eggs per hen housed and highest egg number, followed by LINE C and LINE A, respectively. Egg weight, specific gravity and shell weight were also superior in LINE B compared to the other purelines. The % P retention did not differ across purelines, but Ca retention was also highest in LINE B. Breeder skeletal integrity and progeny bone quality were higher in LINE C. The addition of large particle limestone in lieu of small particles did not provide a consistent effect in production performance but significantly improved shell quality (P = 0.0013), bone quality (P = 0.0341). The large genetic differences in purelines compared to parent stock may uniquely alter the effects of particulate calcium on production performance; yet large particle limestone provided the boost in shell quality and bone quality reported by others. In summary, LINE A, LINE B and LINE C purelines utilize Ca and P differently and have unique genetic potential for hatching egg production, egg shell quality, breeder bone ash and progeny bone ash.
  R.D. Ekmay and C.N. Coon
  A 40-wk study was performed to assess the effects of reduced dietary Non-Phytate Phosphorus (NPP) on broiler breeder performance, progeny quality and P balance. Seven hundred Cobb 500 chicks were reared according to Cobb guidelines (Cobb-Vantress, 2005) and transferred to a production house at 21 wk. At 24 wk, 285 birds were switched over to one of five experimental diets (5 groups of 57) that differed only in NPP. Phosphorus levels ranged from 0.2% to 0.4% NPP in 0.05% increments; and corresponded to a daily intake of 288, 360, 432, 504 and 576 mg at peak. Production performance, egg quality, breeder and progeny skeletal quality, hatchability, progeny weight and P retention were monitored throughout the experimental period. Results show that total egg production, egg number, age at sexual maturity and egg weight were not negatively effected by lowering NPP levels to 0.20% (288 mg/day). Shell quality, though statistically impacted by NPP level, remained at high levels for all treatments (above 1.081). Reproductively, reduced dietary NPP did not negatively impact hatchability or subsequent progeny performance. Day old progeny wt and progeny bone quality were not significantly different from the breeders fed different NPP intake. Breeder tibia ash and relative strength was impaired at 0.20% NPP. The % total P (TP) retention showed a negative linear response with increasing dietary NPP, although absolute P retained increased with increasing dietary NPP. The amount of P deposited into the egg was not different among the treatment groups. Results appear to indicate that 360 mg NPP/day at peak (0.25% NPP) is sufficient for breeder hen performance, progeny 1 d wt and progeny skeletal quality. Breeder hens are able to maintain their performance by mobilizing bone reserves to meet the demands of egg formation and utilize dietary sources to replenish these reserves.
  R.D. Ekmay and C.N. Coon
  A 2 x 5 factorial production and balance study with 90 broiler breeders was performed to assess the effects calcium particle size and NPP levels. Cobb 500 broiler breeders, 24 wk of age, were fed 4.68 g Ca intake at peak using 2 particle sizes of dietary calcium carbonate (185.5 microns; 58.8% solubility and 3489.7 microns; 38.5% solubility) and 5 levels of dietary %NPP (0.2% to 0.4% NPP in 0.05% increments; corresponding to a daily intake of 288, 360, 432, 504 and 576 mg at peak intake). Egg production, specific gravity and egg wt were monitored from 24 to 40 wk of age and tibia relative strength at 45 weeks. A retention study was performed at 31 wk of age to determine Ca and P balance. No differences were noted in breeder bone integrity due to NPP intake, though eggs per hen housed and egg shell quality were affected. The breeders fed 288 mg NPP produced the largest number of eggs. The % P retention showed a positive linear response to increasing dietary NPP for breeders fed large particle limestone; but no response in hens fed small particle limestone. The amount of P excreted was increased with P intake but was minimized for hens fed large particle limestone. The amount of Ca excreted was significantly increased with increasing P intake. There was a significant linear increase in excreta Ca and linear decrease in % Ca retention for breeders fed increasing P intake along with small particle calcium but the amount of Ca excreted and % Ca retention was not statistically impacted by particle size. Feeding breeders large particle calcium carbonate increased the egg weight but did not significantly improve shell quality or tibia bone strength. The increased egg weight response for breeders fed large particle calcium carbonate in this short term experiment may have reduced the opportunity for large particle Ca to significantly improve egg shell quality. It can be concluded that particulate Ca sources can improve breeder performance and that dietary levels as low as 0.20% NPP (288 mg/day NPP intake) can be fed without impacting breeder performance; however dietary levels of >0.25%NPP (360 mg/day NPP intake) ensure adequate skeletal integrity.
  J.A. England , C. Salas , R.D. Ekmay and C.N. Coon
  Most methods for evaluating shell quality and egg components are destructive and time consuming. Four trials were conducted to investigate the use of Dual Energy X-ray Absorptiometry (DXA) as a fast and non-destructive method for evaluating shell quality and measuring the components of broiler breeder eggs. In Trial 1, 180 eggs were scanned with a GE Lunar Prodigy DXA. The eggs were also evaluated by traditional methods that required breaking the eggs for shell quality evaluation and egg components (shell, albumen and yolk) weighed. Values obtained from the DXA scans were subjected to stepwise regression analysis to develop prediction equations. Prediction equations were developed for the weight of egg components (egg, yolk, albumen and shell) and parameters of shell quality (shell weight, thickness and calcium content). In Trial 1, the r2 values for the prediction equations using DXA values were 0.9961, 0.9692, 0.9843, 0.6891, 0.8499 and 0.5738 for the total egg weight, shell weight, shell calcium content, shell thickness, albumen weight and yolk weight, respectively (P>F, <0.0001). In Trial 2, 180 eggs were scanned to validate the prediction equations developed in Trial 1. Results from Trial 2 indicate that the prediction equations using DXA values are an effective method for predicting total egg weight, shell weight, shell calcium content, shell thickness, albumen weight and yolk weight (P>F, <0.0001). In Trial 3, 250 hatching eggs were scanned to determine the affect of scanning on hatchability. DXA scanning had no negative effect on hatchability, hatch chick weight or hatch residue breakout. In Trial 4, the specific gravity of 400 hatching eggs was determined by flotation in salt solutions. The eggs were then scanned with the DXA and values obtained from these scans were used to calculate SWUSA and shell:egg weight ratios. The SWUSA and shell:egg weight ratios determined by DXA scan were useful in predicting eggshell quality and correlated closely with actual specific gravity values (r = 0.7849, p<0.0001). A SWUSA of 75.1 and specific gravity of 1.081 corresponded to a shell:egg weight ratio of 0.0895 and 0.0924, respectively. Following the evaluation of egg shell quality by DXA and specific gravity, the 400 eggs were incubated to determine hatchability. Shell:egg weight ratios less than 0.0895 significantly increased the number of early dead (p = 0.02) during the hatchability study. By defining the scan area it is possible to scan and analyze 140 eggs per hour for all egg components and shell quality. DXA offers the primary breeder or researcher a method for selecting individual hens, based on egg component and shell quality profiles, which may improve the performance of the progeny.
  C. Salas , R.D. Ekmay , J. England , S. Cerrate and C.N. Coon
  Traditionally, body composition data for poultry is determined by grinding /homogenizing the whole bird and obtaining a sample for wet chemistry analysis. The overall process is slow, requires a large amount of freezer space and the time-lag required for determining body composition reduces the opportunity to use data in real- time situations. Two studies were conducted to evaluate Dual-energy X-ray Absorptiometry (DEXA) as a means of measuring body composition in broilers and broiler breeders. In Trial 1, two hundred and forty Cobb 500 broilers were reared from day-old to 60 days of age. Broilers were extracted from the flock every 3 days during the 60 day grow-out in order to obtain a variety of body weights and body composition for developing the body composition equations. The birds were weighed and scanned using the small animal software mode of the DEXA scanner (LunarProdigy, GE®). DEXA provides measurements in grams of Bone Mineral Content (BMC), Fat Mass (FM) and Lean Mass (LM). It was assumed that the sum of BMC+FM+LM represented the total body mass. After the scan was performed, the carcasses were frozen for further chemical analysis. Prior to chemical analysis, the carcasses were thawed, autoclaved at 110°C with 1 atm pressure for 1-5 h depending upon Body Weight (BW) and homogenized in a heavy duty blender (Waring Laboratory, Blender LBC15, Model CB15). Samples of the homogenized carcasses were freeze dried, weighed, ground and analyzed for total ash, ether extract and crude protein. The measurements obtained from the DEXA scans were compared with the whole body chemical analysis for each broiler. Regression analysis of DEXA values (BMC, FM, LM) and chemical analysis (ash, ether extract and protein) were utilized to determine possible correlations. Prediction equations were then developed to adjust the original DEXA results to more accurately predict BMC, fat tissue and lean mass. The R2 values for the prediction equations using DEXA values were 0.999, 0.99, 0.96 and 0.99 for total mass, BMC, fat and lean mass (P<0.0001). In Trial 2, 156 Cobb 500 broiler breeder hens were scanned to validate the equations developed in Trial 1. The results indicate that the prediction equations were adequate and a reliable alternative for measuring body composition in broilers and broiler breeders. The high degree of correlation for all the variables indicates that with proper calibration the DEXA values can be used to predict body composition for these birds (R2 = 0.99, 9.99, 0.84 and 0.94 for total mass, BMC, FM and LM, respectively, p<0.001).
  J.A. England , J.R. Moyle , D.E. Yoho , R.K. Bramwell , R.D. Ekmay , R. Kriseldi and C.N. Coon
  The effect of pullet growth curve on body conformation and subsequent reproductive performance and effect of breeder feed protein level on reproductive performance was determined. The cost effectiveness of the different programs was evaluated. Cobb 700e pullets were reared from day of age in floor pens. Each pen was assigned to one of two growth curves from 16 weeks of age to housing at 21 weeks of age. One growth curve followed a standard (SD) body weight curve and a second followed a lighter (LI) body weight curve. At 23 weeks of age, half of the hens from each of the growth curves were assigned to one of two breeder diets. Half of the hens were fed a low (LO)-protein (14%) breeder diet and half were fed a higher (HI)-protein breeder diet (16%) during the production phase. Pullet growth curve significantly affected body weight through 30 weeks of age. The protein level of the breeder feed significantly affected body weight at 35 and 40 weeks of age. Pullet growth curve affected body conformation, but did not affect age of first egg. Pullet growth curve did not affect egg weight. Protein level of the breeder feed significantly affected egg weight; hens fed the HI-protein diet laid heavier eggs. Egg production was not affected by pullet rearing growth curve (p = 0.0845) or protein level (p = 0.7348) of the breeder feed. Feeding a LO-protein diet resulted in feed cost savings. The feed cost of SD reared hens fed LO-protein diet was $0.03227 per hen less than for those fed HI-protein diets. The feed cost of LI reared hens fed LO-protein diet was $0.3616 per hen less than for those fed HI-protein diet.
 
 
 
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