K. W. Koelkebeck

Laying hen responses to acute heat stress and carbon dioxide supplementation: II. Changes in plasma enzymes, metabolites and electrolytes

Exposure of laying hens to an acute heat stress period (38 degrees C) produced a decrease (P < or = 0.05) in blood plasma magnesium compared with pre-heat stress (23 degrees C) levels. Blood plasma glucose, alkaline phosphatase, total protein, uric acid and creatinine were not changed (P > or = 0.05) by exposure to 38 degrees C compared with the first 23 degrees C exposure. Inorganic phosphorus, calcium, potassium and sodium levels were not affected by acute heat-stress exposure or carbon dioxide addition. These results suggest that acute heat stress had no dramatic effect on plasma enzymes, metabolites and electrolytes of laying hens.

Evaluation of limit feeding varying levels of distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens.

An experiment was conducted with 672 Hy-Line W-36 Single Comb White Leghorn hens (69 wk of age) to evaluate the effects of feeding varying levels of corn distillers dried grains with solubles (DDGS) with corn, wheat middlings, and soybean hulls on long-term laying hen postmolt performance. The control molt treatment consisted of a 47% corn:47% soybean hulls (C:SH) diet fed ad libitum for 28 d. Hens fed the other 7 treatments were limit fed 65 g/hen per day for 16 d, and then fed 55 g/hen per day for 12 d. Hens on treatments 2 and 3 were fed 49% C:35% wheat middlings (WM) or SH:10% DDGS diets (C:WM:10DDGS, C:SH:10DDGS). Hens on treatments 4 and 5 were fed 49% C:25% WM or SH:20% DDGS diets (C:WM:20DDGS, C:SH:20DDGS). Those on treatments 6 and 7 were fed 47% C:47% DDGS (C:DDGS) or 47% WM:47% DDGS (WM:DDGS) diets. Those on treatment 8 were fed a 94% DDGS diet. At 28 d, all hens were fed a corn-soybean meal layer diet (16% CP) and production performance was measured for 36 wk. None of the hens fed the molt diets went completely out of production, and only the C:SH and C:SH:10DDGS molt diets decreased hen-day egg production to below 5% by wk 4 of the molt period. Postmolt egg production was lowest (P < 0.05) for the C:WM:20DDGS treatment. No differences (P > 0.05) in egg weights were detected among treatments throughout the postmolt period. In addition, no consistent differences were observed among treatments for egg mass throughout the postmolt period. Overall results of this study indicated that limit feeding diets containing DDGS at levels of 65 or 55 g/hen per day during the molt period did not cause hens to totally cease egg production.

Use of adrenocorticotropin challenges to indicate chronic stress responses of laying hens in several housing alternatives

Abstract The use of adrenocorticotropin (ACTH) challenges was tested as an indicator of the level of physiological stress response of laying hens in several housing alternatives. Single Comb White Leghorn (SCWL) hens were challenged with intravenous ACTH injections (either .33, 1.0 or 3.0 IU/kg body weight). Plasma corticosterone (CORT) concentrations taken at intervals from 10 to 180 min following ACTH challenges revealed CORT response curves which peaked within 30 min at 34-, 54- and 60-fold increases over pre-challenge CORT levels with doses of .33, 1.0 and 3.0 IU/kg ACTH, respectively. Peak CORT levels for 1.0 and 3.0 IU/kg of ACTH did not differ; however, CORT levels for 1.0 IU/kg ACTH were significantly elevated above the peak for .33 IU/kg ACTH. Laying hens housed in cage and floor management alternatives were challenged with .33 and 1.0 IU/kg of ACTH after 10 months of lay. Cage management treatments were 3, 4 or 5 hens per cage and floor treatments with hens kept at 2 densities. Significant differences in the ACTH-induced CORT response between management alternatives could be detected following injection of .33 IU/kg ACTH, but not with the higher ACTH dose (1.0 IU/kg). These studies demonstrated that the CORT response to the lower dose of ACTH seemed to be more effective in assessing management differences, but further clarification may be necessary before ACTH challenges can be accurately used to evaluate physiological stress responses of laying hens housed in different conditions.

Plasma prostaglandin, LH, and progesterone levels during the ovulation cycle of the turkey (Meleagris gallopavo)

Abstract Single intrauterine injection of prostaglandins E 1 , E 2 , and F 2α induced premature oviposition in the turkey within a few minutes. Indomethacin (50 mg/bird) blocked spontaneous oviposition by several hours. Plasma levels of both PGE and PGF increased significantly around the time of oviposition and appeared not to be related to increasing levels of either progesterone or LH during the ovulation cycle. These data are consistent with the proposed physiological role for prostaglandins in the regulation of avian oviposition.

Evaluation of limit feeding corn and distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens

An experiment was conducted using 504 Hy-Line W-36 Single Comb White Leghorn hens (69 wk of age) randomly assigned to 1 of 7 treatments. These treatments consisted of a 47% corn:47% soy hulls diet (C:SH) fed ad libitum; a 94% corn diet fed at a rate of 36.3, 45.4, or 54.5 g/hen per day (CORN 36, CORN 45, and CORN 54, respectively); and a 94% corn distillers dried grains with solubles (DDGS) diet fed at the same rates as the previous corn diets (DDGS 36, DDGS 45, and DDGS 54, respectively) during the molt period of 28 d. The intent was to feed the DDGS diets for 28 d; however, all hens on these diets had very low feed intakes and greater than anticipated BW loss. Thus, they were switched to a 16% CP corn-soybean meal layer diet on d 19 of the molt period. At d 28, hens on all treatments were fed the same corn-soybean meal layer diet for 39 wk (73 to 112 wk of age). All DDGS diets and the CORN 36 diet resulted in total cessation of egg production during the molt period and egg production of hens fed the CORN 45, CORN 54, and C:SH diets had decreased to 3 and 4%, respectively, by d 28. Body weight loss during the 28-d molt period ranged from 14% for the CORN 54 diet to approximately 23% for the 3 DDGS diets. Postmolt egg production (5 to 43 wk) was higher for hens fed the DDGS molt diets than those fed the corn diets. There were no consistent differences in egg mass, egg-specific gravity, feed efficiency, or layer feed consumption among molt treatments for the postmolt period. These results indicate that limit feeding corn diet and DDGS diet in non-feed-withdrawal molt programs will yield long-term postmolt performance that is comparable to that observed by ad libitum feeding a C:SH diet.

Laying hen responses to acute heat stress and carbon dioxide supplementation: I. Blood gas changes and plasma lactate accumulation.

Exposure to heat stress lowered partial pressure of arterial blood carbon dioxide (paCO2), arterial blood bicarbonate ion (HCO3-), but increased arterial blood pH (pHa) and plasma lactate (LA). Increasing ambient carbon dioxide (CO2) to 1.5% increased paCO2 from hypocapnic levels to normocapnic levels, raised HCO3-, lowered pHa and plasma LA to pre-heat stress levels. Following CO2 treatment, respiratory alkalosis conditions returned. It was evident in this study that increasing ambient chamber CO2 to 1.5% was effective in ameliorating acid-base disturbances and reducing elevated levels of plasma LA which normally develops when laying hens are subjected to an acute heat stress exposure.

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.

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.

Evaluation of feeding various sources of distillers dried grains with solubles in non-feed-withdrawal molt programs for laying hens

An experiment was conducted using 588 Hy-Line W-36 hens (68 wk of age) to evaluate if laying hens can be successfully molted by ad libitum feeding various levels of 3 sources of distillers dried grains with solubles (DDGS). Treatment 1 consisted of a 47% corn (C):47% soy hulls (SH) molt diet (C:SH) fed for 28 d (positive control). Treatments 2, 3, and 4 were molt diets containing 94% DDGS from the 3 sources fed for 28 d. Treatments 5, 6, and 7 were 32% C: 42% SH: 20% DDGS, from each of the 3 DDGS sources, also fed for 28 d. At the end of the 28-d molt period, all hens were fed a 16% CP corn-soybean meal layer diet. Body weight loss during the molt period was significantly greater (P < 0.05) for hens fed the C:SH diet (26%) than hens fed the diets containing DDGS, and the reduction in BW loss varied among DDGS sources. Feed intake was lower (P < 0.05) for the C:SH control treatment compared with most DDGS treatments. Hens fed the C:SH diet had egg production near 0% during the last 3 wk of the molt period. Hens on the other treatments did not have mean egg production below 17% during the molt period (wk 1 to 4), and the reduction in egg production varied among DDGS sources. Postmolt hen-day egg production (5-41 wk) did not significantly differ among treatments; however, egg mass and egg specific gravity were generally reduced (P < 0.05) for hens fed the 94% DDGS molt diets compared with hens fed the C:SH diet. This study showed that molt and postmolt performance responses varied among DDGS sources; however, none of the molt diets containing 20 to 94% DDGS yielded molt period reductions in BW or egg production similar to a 47% C: 47% SH diet.

Effects of carbon dioxide on turkey poult performance and behavior

Abstract Appropriate ventilation of poultry facilities is critical for achieving optimum performance. Ventilation promotes good air exchange to remove harmful gases, excessive heat, moisture, and particulate matter. In a turkey brooder barn, carbon dioxide (CO2) may be present at higher levels during the winter due to reduced ventilation rates to maintain high temperatures. This higher CO2 may negatively affect turkey poult performance. Therefore, the objective of this study was to evaluate the effects of subjecting tom turkey poults (commercial Large White Hybrid Converters) to different constant levels of atmospheric CO2 on their growth performance and behavior. In three consecutive replicate trials, a total of 552 poults were weighed post‐hatch and randomly placed in 3 environmental control chambers, with 60 (Trial 1) and 62 (Trials 2 and 3) poults housed per chamber. They were reared with standard temperature and humidity levels for 3 wks. The poults were exposed to 3 different fixed CO2 concentrations of 2,000, 4,000, and 6,000 ppm throughout each trial. Following each trial (replicate), the CO2 treatments were switched and assigned to a different chamber in order to expose each treatment to each chamber. At the end of each trial, all poults were sent to a local turkey producer to finish growout. For each trial, individual body weight and group feed intake were measured, and mortality and behavioral movement were recorded. Wk 3 and cumulative body weight gain of poults housed at 2,000 ppm CO2 was greater (P < 0.05) than those exposed to 4,000 and 6,000 ppm CO2. Feed intake and feed conversion were unaffected by the different CO2 concentrations. No significant difference in poult mortality was found between treatments. In addition, no effect of CO2 treatments was evident in the incidence of spontaneous turkey cardiomyopathy for turkeys processed at 19 wk of age. Poults housed at the lower CO2 level (2,000 ppm) demonstrated reduced movement compared with those exposed to the 2 higher CO2 concentrations.