Three trials involving 251 crossbred pigs were conducted to establish response surfaces for effects of Ca/P levels (70, 85, 100, 115 and 130% of NRC [1979] estimated requirements) and time (weaning to market) on bone criteria and to compare bending and shear bone testing. Nine replicates, each consisting of five pigs, were used over the three trials. One pig per replicate was slaughtered every 4 wk following the start of the trials. Third metacarpals and metatarsals (3M) and fourth metacarpals and metatarsals (4M) were collected at slaughter; the bone length, bending or shear stress, and dry, fat-free ash percentage (DFF%) were determined. Most bone criteria increased (P less than .01) at a decreasing rate (P less than .05) in response to increasing dietary Ca/P intake and increased linearly (P less than .01) with time on test, although bone length and stress increased at a decreasing rate with time on test. Asymptotic models relating continuous effects of total Ca + P intake ratio (CAP; expressed as a percentage of NRC) and number of days on test before slaughter to bone measurements were fit to least squares slaughter time by diet means. Bone length and DFF% reached 98% maximum at or near 100% the NRC estimated CAP level; however, to reach 98% of maximum bone shear and breaking stress higher CAP levels were required. Shear testing of bones was more desirable than bend testing as a method of determining bone strength due to reduced variability, better discrimination of Ca/P and time effects and ease of calculation.

No abstract

The study presented was designed to determine the effects of laying cages and conventional litter floors, pen temperatures of 12.8 degrees, 21.1 degrees and 29.4 degrees C., and chelated (EDTA-Zn) vs. nonchelated trace mineral mixes on the reproductive performance of yearling force-molted and young Large White female turkeys. Reproductive performance, as measured by egg production, settable eggs, fertility and hatchability of fertile eggs, was not significantly different between young and yearling hens. Females fed a chelated trace mineral mix had a higher percentage of settable eggs, greater feed consumption and thicker egg shells. Females in laying cages laid at a higher rate, ate more feed, and weighed more than those on conventional floors. Significant differences were not observed between the two pen environments for hatchability of fertile eggs or egg weight. The percentages of settable eggs and of fertile eggs were lower when females were maintained in cages. A constant temperature of 29.4 degrees C. reduced egg production below that obtained from females maintained at 12.8 degrees and 21.1 degrees C. The high pen temperature also caused lower body and egg weights, more birds out of production and an increased incidence of molting. Feed consumption decreased with increasing pen temperatures. Fertility, hatchability, percentage of settable eggs and egg shell thickness were unaffected by the imposed temperature environments. Temperatures of 12.8 degrees and 21.1 degrees C. yielded comparable results for all reproductive parameters measured. Within the range of temperatures studied, results obtained suggest that optimum reproductive performance can be obtained with breeder turkeys when environmental temperatures are maintained between 12.8 degrees and 21.1 degrees C.

The study presented was designed to determine the effects of light intensities of 5.4 and 86.1 lux, of laying cages versus conventional litter floors and of constant environmental temperatures of 12.8°, 21.1° and 2°.4°C. on the reproductive performance of Large White female turkeys.A light intensity of 5.4 lux yielded comparable results to that of 86.1 lux when 16 hours of light were provided.Turkey females in laying cages laid at a higher rate over the first 12 weeks of production and showed an increase in feed consumption and body weight over those maintained in conventional litter pens. No significant differences were observed between the two pen environments for total egg production, hatchability of fertile eggs and egg weights. Percentage settable eggs and percentage fertility were lower from females maintained in cages. The percentage of cracked and broken, and soft-and thin-shelled eggs from cage birds increased over the production period.A constant pen temperature of 29.4° C. dramatically reduced egg production below that obtained from females maintained at 12.8° and 21.1 °C. The high pen temperature also reduced feed consumption, body weights, egg weights, the effectiveness of broodiness control and increased the incidence of birds molting and mortality. Fertility, hatchability, percentage settable eggs and shell thickness were unaffected by the imposed temperature environments. Pen temperatures of 12.8° and 21.°C. yielded comparable results for all reproductive parameters studied.It is concluded that reproductive potential of turkeys in the present study was maximized on conventional litter floors with constant temperatures between 12.8° and 21.1°C. and light intensities between S.4 and 86.1 lux.

No abstract