Prevention of fatal cage-layer osteoporosis.

Regular necropsy of samples of laying hen mortality at a large cage-layer ranch revealed significant loses due to osteoporosis. The feeding program consisted of feeding a pullet-growing diet until egg production commenced followed by a change to a laying diet. Literature review and experimental results have demonstrated a requirement for 2% dietary calcium for about 2 wk before first egg is anticipated followed by transfer to a higher calcium level during lay. A nutritional regimen of this design was tested on two paired sister flocks of hens. Necropsy of mortality during the tests showed a striking reduction in mortality due to osteoporosis.

Temperature sequence of eggs from oviposition through distribution: production--part 1.

During Egg Safety Action Plan hearings in Washington, DC, many questions were raised concerning the egg temperature (T) used in the risk assessment model. Therefore, a national study was initiated to determine the T of eggs from oviposition through distribution. In part 1; researchers gathered data on internal and surface egg T from commercial egg production facilities. An infrared thermometer was used to rapidly measure surface T, and internal T was determined by probing individual eggs. The main effects were geographic region (state) and season evaluated in a factorial design. Egg T data were recorded in the production facilities in standardized comparisons. Regression analysis (P < 0.0001) showed that the R(2) (0.952) between infrared egg surface T and internal T was very high, and validated further use of the infrared thermometer. Hen house egg surface and internal T were significantly influenced by state, season, and the state x season interaction. Mean hen house egg surface T was 27.3 and 23.8 degrees C for summer and winter, respectively, with 29.2 and 26.2 degrees C for egg internal T (P < 0.0001). Hen house eggs from California had the lowest surface and internal T in winter among all the states (P < 0.0001), whereas the highest egg surface T were recorded during summer in North Carolina, Georgia, and Texas, and the highest internal T were recorded from Texas and Georgia. Cooling of warm eggs following oviposition was significantly influenced by season, state, and their interaction. Egg internal T when 3/4 cool was higher in summer vs. winter and higher in North Carolina and Pennsylvania compared with Iowa. The time required to 3/4 cool eggs was greater in winter than summer and greater in Iowa than in other states. These findings showed seasonal and state impacts on ambient T in the hen house that ultimately influenced egg surface and internal T. More important, they showed opportunities to influence cooling rate to improve internal and microbial egg quality.

Temperature sequence of eggs from oviposition through distribution: processing--part 2.

The Egg Safety Action Plan released in 1999 raised questions concerning egg temperature used in the risk assessment model. Therefore, a national study was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, shell egg processing, and distribution facilities. The experimental design was a mixed model with 2 random effects for season and geographic region and a fixed effect for operation type (inline or offline). For this report, internal and external egg temperature data were recorded at specific points during shell egg processing in the winter and summer months. In addition, internal egg temperatures were recorded in pre- and postshell egg processing cooler areas. There was a significant season x geographic region interaction (P < 0.05) for both surface and internal temperatures. Egg temperatures were lower in the winter vs. summer, but eggs gained in temperature from the accumulator to the postshell egg processing cooler. During shell egg processing, summer egg surface and internal temperatures were greater (P < 0.05) than during the winter. When examining the effect of shell egg processing time and conditions, it was found that 2.4 and 3.8 degrees C were added to egg surface temperatures, and 3.3 and 6.0 degrees C were added to internal temperatures in the summer and winter, respectively. Internal egg temperatures were higher (P < 0.05) in the preshell egg processing cooler area during the summer vs. winter, and internal egg temperatures were higher (P < 0.05) in the summer when eggs were (3/4) cool (temperature change required to meet USDA-Agricultural Marketing Service storage regulation of 7.2 degrees C) in the postshell egg processing area. However, the cooling rate was not different (P > 0.05) for eggs in the postshell egg processing cooler area in the summer vs. winter. Therefore, these data suggest that season of year and geographic location can affect the temperature of eggs during shell egg processing and should be a component in future assessments of egg safety.

Temperature sequence of eggs from oviposition through distribution: transportation--part 3.

The Egg Safety Action Plan released in 1999 raised many questions concerning egg temperature used in the risk assessment model. Therefore, a national study by researchers in California, Connecticut, Georgia, Iowa, Illinois, North Carolina, Pennsylvania, and Texas was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, processing, and distribution facilities. The experimental design was a mixed model with random effects for season and a fixed effect for duration of the transport period (long or short haul). It was determined that processors used refrigerated transport trucks (REFER) as short-term storage (STS) in both the winter and summer. Therefore, this summary of data obtained from REFER also examines the impact of their use as STS. Egg temperature data were recorded for specific loads of eggs during transport to point of resale or distribution to retailers. To standardize data comparisons between loads, they were segregated between long and short hauls. The summer egg temperatures were higher in the STS and during delivery. Egg temperature was not significantly reduced during the STS phase. Egg temperature decreases were less (P < 0.0001) during short delivery hauls 0.6 degrees C than during long hauls 7.8 degrees C. There was a significant season x delivery interaction (P < 0.05) for the change in the temperature differences between the egg and ambient temperature indicated as the cooling potential. This indicated that the ambient temperature during long winter deliveries had the potential to increase egg temperature. The REFER used as STS did not appreciably reduce internal egg temperature. These data suggest that the season of year affects the temperature of eggs during transport. Eggs are appreciably cooled on the truck, during the delivery phase, which was contrary to the original supposition that egg temperatures would remain static during refrigerated transport. These data indicate that refrigerated transport should be a component in future assessments of egg safety.

Evaluation of low-phytate corn and barley on broiler chick performance.

Grains produced by low-phytate barley and corn isolines homozygous for each species' respective low phytic acid 1-1 allele were compared to grain produced by near-isogenic normal or wild-type barley and corn in broiler chick feeds. Cobb x Cobb (384) chicks were used in a 10-d study. A randomized complete block design with a factorial arrangement of 2 x 2 x 3 was used with 4 replicates (8 chicks / replicate) per treatment. Twelve isocaloric and isonitrogenous treatment diets were formulated to contain 2 types of grain (barley and corn), 2 levels of grain (40% and 60%), and 3 sources of available P (wild-type grain, wild-type P-supplemented grain, and low-phytate grain). Growth parameters, bone parameters, total bone mineral, and apparent digestibilities were measured. The mean growth and bone responses were 1) higher for barley diets compared to corn diets, 2) higher for 60% grain inclusion compared to 40%, 3) higher for low-phytate compared to wild-type grains, and 4) not different for low-phytate compared to P-supplemented wild-type grain diets. Chicks fed low-phytate-based diets excreted 33 and 43% less P than chicks fed wild-type and P-supplemented wild-type diets, respectively. Correlations between percentage bone ash, total bone ash, and bone strength indicated a strong relationship and appear to support the use of bone strength analysis as a simpler method than ash content determination as an indication of P status. Feeding low-phytate grains will reduce the need for supplemental P in chick diets.

Lyophilized bovine hemoglobin as a possible reference material for the determination of hemoglobin derivatives in human blood.

We investigated the suitability of a lyophilized bovine hemoglobin (LBH) preparation containing various fractions of oxyhemoglobin (O2Hb), carboxyhemoglobin (COHb), and methemoglobin (MetHb) for quality assessment in multicomponent analysis (MCA) of hemoglobin derivatives. It was demonstrated that a stable preparation of these components after reconstitution yields a hemoglobin solution that is spectrophotometrically equivalent with a fresh bovine hemoglobin solution. The preparation was found to be stable for at least 1 year when it is kept at 2-8 degrees C and for 1 h after reconstitution. We determined the fractions of O2Hb, COHb, and MetHb of several LBH preparations, using the complete spectra of 480-650 nm with 2-nm intervals and absorptivities as determined for pure LBH solutions. A field trial involving various types of multiwavelength hemoglobin photometers showed the suitability of LBH as a quality-control material. Computer models of the various common multiwavelength hemoglobin photometers may be useful for establishing more accurate target values of LBH preparations for each type of photometer and for studying the importance of the influence of specific factors such as wavelength selection, absorptivity values, and interfering dyes.

Effect of halofuginone (Stenorol) on Chukar partridge (Alectoris chukar).

This study was conducted to assess the effect of the coccidiostat halofuginone (Stenorol) on growth, feed consumption, and survival of Chukar partridge. Halofuginone was fed to three replicates (14 chicks per replicate) of chukar chicks from 2 to 7 d of age at levels of 0, 1.5, 3.0, 6.0 and 12 ppm. Mortality from 2 to 7 d was 0, 0, 0, 11, and 21 birds, respectively, by treatment. Seven-day body weight showed a significant linear decrease with increasing halofuginone level (P < 0.01). On the 7th d, replicates receiving 6.0 and 12.0 ppm halofuginone were transferred to unmedicated feed for the remainder of the test due to excessive mortality. The other groups were continued until 6 wk of age. At 6 wk, chicks fed 6 or 12 ppm halofuginone from 2 to 7 d and then unmedicated feed did not differ in body weight from those fed the unmedicated control diet. A significant difference in mortality was not observed among the other three treatment groups to 6 wk of age. A linear depression in 3-, 4-, 5-, and 6-wk body weight with increasing halofuginone level was observed within the first three treatment levels (P < 0.05). It was concluded that 1.5 ppm halofuginone depressed growth of young chukars and that 6 ppm resulted in increased mortality.

The effect of cyclic and constant ambient temperatures on feed consumption, egg production, egg weight, and shell thickness of hens.

Groups of 18 hens, 230 days of age, were housed in each of three climatic chambers with light schedules of 14L:10D. One was maintained at a constant temperature of 23.9 C, the second was cycled between 15.6 and 37.7 C (mean, 26.7 C), and the third was cycled between 21.1 and 37.7 C (mean, 29.4 C). In Experiment 1, the high temperature peaked during the dark period at 0200 hr and in Experiment 2, the high temperature peak was at 1400 hr during the light period. The birds had free access to a commercial breeder feed in these two experiments. The results from three 2-week observation periods indicated no significant differences in percent hen-day production, grams of feed per gram of egg mass, or overall body weight change but feed intake per day, egg weight, and shell thickness were significantly reduced by mean temperatures of 26.7 and 29.4 C in cycling chambers. The pair-feeding of birds in the 23.9 C constant chamber compared with those in the cycling 29.4 C chamber resulted in production of significantly heavier eggs with thicker shells without significantly influencing any of the other parameters. The reductions in egg weight and shell thickness observed at cyclic temperatures were not simply a result of a reduction in nutrient intake at high temperatures but also the direct effect of heat stress on the hens. In the 23.9 C constant temperature chambers, a reduction in AME of the feed for the hens fed ad libitum was observed but not for hens pair-fed to hens in the 29.4 C cyclic chamber.

Effects of heat stress on day-old broiler chicks.

Short-term heat stress can occur when chicks are transported from the hatchery to growing facilities. Two experiments were conducted to determine the possible effects of short-term heat stress on growth and feed conversion of broiler (Hubbard X Hubbard) chicks. The heat stress was accomplished by placing chicks in Jamesway 252 incubators at dry bulb temperatures ranging from 40 to 45 C for variable times. Growth, feed consumption, and mortality were measured for 16 days following the heat stress. Short sublethal heat stress significantly reduced growth rate to 16 days in these experiments without any effect on feed conversion ratio. The results indicate that the hatchery industry should avoid overheating chicks even for periods as short as 1 hr.

The effect of a low energy diet on the concentration of DDT in the adipose tissue of turkeys.

Turkey hens which had completed a breeding season and contained DDT in their fat were divided into 2 groups of 20 hens each. One group was fed a high wheat control diet throughout a 6 week period while another group was fed a low energy diet for 3 weeks and then the control diet for 3 weeks. Biopsy samples of adipose tissue taken initially and at 3 weeks and carcass adipose tissue samples of 6 weeks were analyzed for DDT and DDE. Total DDT concentration in adipose tissue increased when the hens were fed the low energy diet but decreased again when fed the control diet so that the overall change in DDT concentration over the 6 week period was not different for the two groups. The biopsy technique used in this study was successful in greatly reducing variability and improving precision.