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Biomedical subjects

B D Lott

Publications and source records attributed to B D Lott.

At least 55 records · Page 3Linked to original sources
PubMed1983

The effect of dietary energy level and broiler body weight on abdominal fat.

Utilizing a moderate rearing temperature regimen, two trials were conducted to determine the effect of dietary energy level on the amount of abdominal fat deposited when broilers are grown to equal body weight by varying growth time. The most abdominal fat (2.29% average of live weight for male and females) was produced by broilers offered a diet calculated to contain 3325 ME kcal/kg. The least amount of abdominal fat (1.92% average of live weight for male and females) was produced by broilers offered diets calculated to contain 3100 and 3175 metabolizable energy (ME) kcal/kg. In one additional day (48 vs. 47 days) the growth of the broilers offered diets calculated to contain 3100 and 3175 ME kcal/kg equalled that of broilers offered diets calculated to contain 3250 and 3325 ME kcal/kg. Feed conversion (g feed/g live weight) significantly decreased as dietary energy level increased. Three additional trials were conducted to determine when abdominal fat is deposited in relation to age and weight. It was found that male broilers offered diets calculated to contain 3325 ME kcal/kg had as much abdominal fat when expressed as a percent of body weight at 40 days of age as they did at 53 days of age.

Abdomen↗
PubMed1982

The effect of environmental temperature on sensible and latent heat production of broiler chickens.

Sensible and latent heat (moisture) production data were obtained for broiler chickens grown from 3 to 7 weeks of age on litter at three environmental temperatures: 15.6, 21.1, and 26.7 C. Shape of the specific sensible and latent heat curves were similar for the 15.6 and 21.1 C temperatures, but the sensible heat production at 15.6 C was about 12% greater than for 21.1 C for chickens weighing between 500 and 1000 g; the different increased for heavier chickens. Heat production curves for 26.7 C were markedly different from the other two temperatures. Specific sensible heat at 26.7 C was 2.8 cal/hr (g) and was independent of body weight over the range 500 to 1800 g. The data were compared to those published since 1969 to determine if increased growth rates have affected heat production data. Results indicate no discernible effect for cool temperatures, but for warm temperatures it appears that increased growth rates may be accompanied by an approximately proportional increase in specific sensible heat production.

Animals↗
PubMed1982

Effect of atmospheric ammonia on laying hen performance.

In periods of extremely cold weather, energy conservation in a pit-type laying house usually results in a restricted ventilation rate and an increase in air pollutants particularly ammonia. Results show that 200 ppm ammonia for 17 days causes a significant loss in percent egg production and the hens lose a significant amount of weight with a reduced feed intake. Although not satisfactory, it appears that lesser amounts of ammonia (100 ppm) can be tolerated for short periods without an immediate drastic loss in laying performance if a choice has to be made between frozen waterers and cold stress versus atmospheric ammonia in the laying house.

Ammonia↗
PubMed1980

Effect of sex and Mycoplasma synoviae infection on chicken red blood cells used for hemagglutination-inhibition test.

A total of 10 male and 10 female 9-week-old commercial Mycoplasma-free broiler chickens was used in this test. Five males and 5 females were artificially infected by aerosol with a broth culture of Mycoplasma synoviae (MS) F10-2AS. The other 5 males and 5 females were used as noninfected controls. At 3, 9, and 12 weeks postinfection all birds were bled, and the blood was pooled into 4 groups: infected male, noninfected male, infected female, and noninfected female. Hemagglutination-inhibition (HI) tests for MS and Mycoplasma gallisepticum (Mg) were run on a selected group of known positive serums using the 4 pools as red blood cell (RBC) sources. The geometric mean HI titers of the 4 groups showed no significant differences between male and female or MS-infected and noninfected chickens as a source of RCB's for the MS or Mg HI test. These results indicate that if procedures are correct, there is no danger in using RBC's from MS-infected birds.

Animals↗
PubMed1980

Effect of carbon dioxide on broiler chicken performance.

Broiler chickens were exposed to 3,000, 6,000 and 12,000 ppm of CO2 for the 4-week brooding period, and their performance was compared to that of controls brooded where the CO2 level did not exceed 1,000 ppm. Exposure to 3,000 and 6,000 ppm did not significantly affect body weights at 4 or 7 weeks, but exposure to 12,000 ppm of CO2 depressed body weight at 4 weeks by about 60 g; the deficiency in weight persisted until 7 weeks of age. Feed conversions were not affected.

Animals↗
PubMedDate not supplied

The effects of 6/85 live Mycoplasma gallisepticum vaccine in commercial layer hens over a 43-week laying cycle on egg production, selected egg quality parameters, and egg size distribution when challenged before beginning of lay.

In each of two trials, 80 commercial leghorn-type pullets were separated into two treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation, whereas the remaining 40 pullets received the 6/85 vaccine strain of Mycoplasma gallisepticum (MG) at 10 wk of age. Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded weekly in each trial through an entire laying cycle of 43 wk. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. No significant difference was observed between the treatments for 43-wk means for hen-day egg production, for any of the monitored egg or eggshell quality parameters, or for the number of extra large, large, medium, small, pee wee, or undergrade egg sizes. A significant (P < or = 0.05) difference was observed for the number of jumbo-sized eggs between the two treatments. Results of this study suggest that vaccination of commercial layer chickens at 10 wk of age with 6/85 strain MG does not detrimentally impact egg production, egg size distribution, or ovary/oviduct function as evidenced by selected egg parameters monitored in this study.

Animals↗
PubMedDate not supplied

The effects of F strain Mycoplasma gallisepticum, Mycoplasma synoviae, and the dual infection in commercial layer hens over a 44-week laying cycle when challenged before beginning of lay. II. Egg size distribution.

In each of two trials, 160 commercial pullets were separated into four treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation; 40 pullets received F strain Mycoplasma gallisepticum (FMG); an additional 40 pullets received Mycoplasma synoviae (MS); and the final 40 pullets were inoculated with both FMG and MS (dual). All inoculations occurred at 10 wk of age. Eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. No significant difference was observed among the treatments for percentages of jumbo, extra-large, medium, small, peewee, or undergrade eggs. As a percentage of eggs laid for the 4 days of each week over the 44-wk laying cycle of each trial, the FMG hens laid significantly fewer large size eggs (43.2%) as compared with either controls (51.17%) or dual-infected hens (49.95%). No significant difference was found in percentage of large eggs laid by FMG hens when compared with MS hens.

Animal Husbandry↗
PubMedDate not supplied

Effects of age at inoculation and induced molt on the recovery of Mycoplasma gallisepticum from layer chickens.

An experiment was conducted to determine the effects of age at inoculation and induced molt on the reisolation of Mycoplasma gallisepticum (MG) from commercial leghorn hens that had been eyedrop-inoculated with F strain MG at either 10 or 66 wk of age. Chickens were maintained in biological isolation units from 10 wk of age through 78 wk of age. At 70 wk of age (premolt), hens were swabbed, cultured for MG, and molted. Swabs were taken both at the end of molt (postmolt [74 wk]) and again 4 wk later (postmolt+4 [78 wk]). A significant (P < or = 0.05) decrease in MG isolations was observed in the postmolt swabs as compared with the premolt swabs of hens inoculated at either 10 or 66 wk of age. A significant (P < or = 0.05) increase in isolations was observed in the postmolt+4 swabs as compared with the postmolt swabs of hens inoculated at either 10 or 66 wk of age. For the hens inoculated at 10 wk, no significant difference was found in premolt as compared with postmolt+4 MG isolations; however, for hens inoculated at 66 wk, a significant (P < or = 0.05) decrease was observed between premolt and postmolt+4 isolations. Significantly (P < or = 0.05) fewer MG isolations were obtained from the premolt swabs of hens inoculated at 10 wk as compared with hens inoculated at 66 wk. No significant difference in MG isolations was observed in either the postmolt or postmolt+4 swabs between hens inoculated at either 10 or 66 wk.

Aging↗
PubMedDate not supplied

The effects of ts-11 strain Mycoplasma gallisepticum vaccination in commercial layers on egg production and selected egg quality parameters.

Live Mycoplasma gallisepticum (MG) vaccines have been USDA approved and licensed for use in commercial layer chickens since 1988; however, egg production and egg quality data exist only for the F strain of MG. Information pertinent to the effects of ts-11 MG on egg and eggshell quality parameters, as well as egg size distribution, is lacking. In this study, pullets were inoculated at 10 wk of age with ts-11 strain MG and placed in biological isolation units at 10 birds/unit. Hen-day egg production, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded in each trial through a 45-wk production cycle. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. Results of this study indicate that no significant difference was observed between the treatments for the parameters measured or for egg size distribution. Therefore, these data should lessen producers' concerns pertaining to the impact of ts-11 strain MG on egg production, egg and eggshell quality parameters, and egg size distribution.

Animals↗
PubMedDate not supplied

F strain Mycoplasma gallisepticum vaccination of post-production-peak commercial Leghorns and its effect on egg and eggshell quality.

Forty-five-week-old commercial leghorns negative for antibodies to Mycoplasma gallisepticum (MG) and M. synoviae were vaccinated with high-passage F strain MG (FMG). Hens were confined in modified Horsfall-Bauer isolation units through 60 weeks of age. Egg production (% hen day) and parameters of egg and eggshell quality were monitored, including egg weight, eggshell strength, Haugh unit score, pimpling, and blood/meat spot incidence. Egg production was significantly lower (P less than 0.05) for FMG vaccinates than controls (down 5.76% and 5.80% in Trials 1 and 2, respectively). However, vaccinates and controls did not differ significantly in eggshell strength, shell thickness, pimpling, or blood/meat spot incidence. Haugh unit scores were significantly (P less than 0.05) greater for FMG vaccinates. At necropsy, all reproductive tracts appeared grossly normal. These studies suggest that high-passage FMG vaccination of post-production-peak hens does not adversely affect oviduct function.

Animals↗
PubMedDate not supplied

Fatty liver-hemorrhagic syndrome observed in commercial layers fed diets containing chelated minerals.

This study was originally conducted to determine the effect of various chloride levels and consumption of chelated versus non-chelated minerals on egg production and eggshell breaking strength. However, the focus of this report changed after fatty liver-hemorrhagic syndrome (FLHS) was observed in hens that consumed diets containing chelated minerals. No FLHS was observed in hens that consumed a diet that contained non-chelated minerals. Four hundred thirty-two 35-week-old commercial laying hens were housed in individual cages in groups of nine hens each. The treatments were factorially arranged (3 x 2) such that six experimental diets differing in chloride levels and in source of minerals were fed for six 28-day laying periods. A significantly higher mortality attributed to FLHS was observed in hens that consumed the diets having chelated minerals as compared with hens that consumed the diets with non-chelated minerals. No difference in mortality was observed among the hens fed the various chloride diets.

Animal Feed↗
PubMedDate not supplied

The effect of photoperiod and nutrition on ascites incidence in broilers.

Light restriction was used to restrict growth of male broilers up to 41 days of age. Dietary energy and lysine were also investigated for their interaction with slowed growth rate. A total of 1440 male broilers was used in each of two trials. Light restriction significantly reduced body weights at 22 days (P < or = 0.05) but not at 52 days. Restricting early growth by photoperiod for the 3-to-41-day period reduced deaths due to ascites. Neither dietary energy nor lysine affected mortality from ascites. These results suggest that manipulation of photoperiod for young broilers is a useful way to limit early growth and subsequent ascites mortality.

Aging↗
PubMedDate not supplied

Various blood parameters in commercial hens acutely and chronically infected with Mycoplasma gallisepticum and Mycoplasma synoviae.

Two trials were conducted to study the effects of acute (Trial 1) and chronic (Trial 2) mycoplasma infections on differential leukocyte counts in chickens. The trials initially included either 20 (Trial 1) or 40 (Trial 2) 6-wk-old commercial leghorn chickens negative for antibodies to Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS). Chickens were inoculated with F strain MG (FMG), MS (WVU 1853), or both. One group of chickens remained uninoculated and served as a negative control for both trials. Chickens were housed in fiberglass isolation units from 6 to 10 wk (Trial 1) or 6 to 70 wk of age (Trial 2). Differential leukocyte counts were examined from 6 to 10 wk (Trial 1) or 66 to 70 wk of age (Trial 2) in all chickens. Also, in Trial 2, packed cell volumes (PCVs) and plasma protein values were examined from 66 to 70 wk of age. In the acute study (Trial 1), differential leukocyte counts revealed statistically significant differences (P < 0.05) in heterophil, lymphocyte, monocyte, eosinophil, and basophil values among treatments. In general, the differential counts of FMG- and MS-infected birds were characterized by heterophilia, lymphopenia, monocytosis, eosinopenia, and basopenia. Histopathologic examination of the spleen, liver, kidney, and bone marrow revealed a high degree of lymphoid foci within the spleen and bone marrow of all infected chickens. In the chronic study (Trial 2), no statistically significant differences (P < 0.05) were observed in differential leukocyte counts, PCV, and plasma protein values among treatments. Histopathologic examination of spleen, liver, kidney, and bone marrow did not reveal any difference among treatments.

Acute Disease↗
PubMedDate not supplied

The effects of F strain Mycoplasma gallisepticum, Mycoplasma synoviae, and the dual infection in commercial layer hens over a 44-week laying cycle when challenged before beginning of lay. I. Egg production and selected egg quality parameters.

In each of two trials, 160 commercial pullets were separated into four treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation; 40 other pullets received F strain Mycoplasma gallisepticum (FMG); an additional 40 pullets received Mycoplasma synoviae (MS); and the final 40 pullets were inoculated with both FMG and MS (dual). Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded in each trial through an entire laying cycle. No significant difference was observed among the treatments for hen-day egg production, egg weight, eggshell strength, or Haugh unit scores. Significant differences were observed for pimpling incidence among controls (1.63%), Mycoplasma gallisepticum (MG)-infected (2.09%), and dual-infected hens (2.41%). A significant difference in blood/meat spot incidence was observed between MG-infected hens (0.27%) and dual-infected hens (0.45%). Histopathologic examination of the ovary and all segments of the oviduct revealed no significant differences among the treatments. These results suggest that the majority of the hen reproductive tract functions similarly in FMG-vaccinated, MS-infected, or dual-infected hens as compared with Mycoplasma-clean hens.

Animals↗