Mortality associated with avian reovirus infection in a free-living magpie (Pica pica) in Great Britain

Avian reoviruses (ARVs) cause a range of disease presentations in domestic, captive and free-living bird species. ARVs have been reported as a cause of significant disease and mortality in free-living corvid species in North America and continental Europe. Until this report, there have been no confirmed cases of ARV-associated disease in British wild birds

Vitamins for livestock

Cover title.Includes bibliographical references

Physiological and nutritional interrelationships of mineral elements to growth and reproduction in turkeys

Experiments involving poults were conducted with the primary objective of studying the effects of sodium chloride on field rickets. A second objective was to study the effects of mineral elements on reproduction of turkey breeder males and females. Three experiments were conducted with poults. A comparison of added dietary sodium chloride at levels of 0, .075, .10, .25, and .45% showed that there were significant differences in body weight gains, blood calcium, magnesium and sodium, feed conversion and adrenal gland weights among the treatments. Mortality and abnormal bone scores decreased with increasing sodium chloride levels. Vitamin D-like bone defects caused a rib-beading effect and the tibia/femur showed an abnormally round, large growth. The bones were soft and failed to calcify. In a second experiment with sodium chloride at levels of 0, .025, .05, .10, .20, and .40%, significant differences were found in weight gains, feed conversion and thyroid gland weight between the two highest and four lowest treatments. Feed conversion, mortality and bone abnormalities decreased with increasing sodium chloride levels. When sodium was fed to the poults at levels of either 0, .09, .10, .11, and .12% or chloride at levels of 0, .009, .01, .02, and .03%, in comparison to a control group with sodium chloride levels of .50%, significant difference were found in weekly weight gains, bone ash, bone breaking strength, tibia weight/body weight and serum alkaline phosphatase levels between the sodium, chloride and control groups. Microscopic lesions were variable and more marked in the groups fed the low sodium and chloride diets. Medullary spaces of the proximal metaphysis contained undifferentiated mesenchymal cells, Collagen and osteoclasts lined the trabeculae. Tibiatarsi from affected poults were soft to the knife and nervous symptoms accompanied by extended legs and semi-paralysis were observed in the three duplicate lots fed the lowest chloride feed levels. Bone abnormality scores decreased with increasing levels of both sodium and chloride diets. Four experiments were completed on mineral effects on breeder hens performance. When a calcium level of .45% was fed intermittently to turkey hens for 3.5, 7, and 14 days respectively, and 2.2% calcium level fed as control, significant differences were found in egg production, shell thickness and shell breaking strength between the groups fed the control and low calcium at 3.5 days interval compared to those fed .45% dietary calcium for 7 and 14 days. No significant differences were found in egg shape index, hatchability and feed per dozen eggs. An experiment with three added dietary levels of salt (0, .25, and .50%) in holding rations fed to turkey hens showed significant differences in subsequent egg production and shell thickness between the three groups. There were no significant differences in egg weight and egg shape index. When rations with three dietary levels of added salt (0, .25, and .50%) were fed to turkey hens, significant differences were found in egg production, shell thickness and egg weights between the lowest and two highest levels. There were numerical but non-significant differences in percent fertility and hatchability. When dietary salt levels of 0, .10, and .50% were fed to turkey hens and the chloride levels balanced by calcium chloride, significant differences were found in egg production, shell thickness, egg weights and blood sodium levels between the three treatments. Pimpling of egg shell and abnormal embryonic development with petechiae hemorrhages were seen in hens fed the two lowest levels of dietary salt. Four experiments were completed with turkey breeder males. Significant differences were found in semen and spermatozoa packed cell volumes between the treatments when three rations with dietary calcium levels of either .15, .45 or 2.2% were fed to the turkey males. Numerical differences were seen in dead spermatozoa and fertility. An experiment with a high zinc oxide level (0 and 3,000 ppm) in the diet fed to turkey males showed significant differences in semen and spermatozoa packed cell volumes and haemocytometer spermatozoa count between the two groups. When the feed was supplemented with four levels of zinc oxide (0, 3,000, 15,000 and 30,000 ppm) semen and packed cell volumes, feed consumption and body weights were significantly different between the two lowest levels and the two highest dietary zinc oxide levels. Numerical differences were seen in the percent live-dead spermatozoa. When rations with three dietary salt levels (0, .25, and .50%) were fed to turkey males, significant differences were found in semen and spermatozoa packed cell volumes between the lowest and the two highest salt levels. The finding in these investigations showed that with a rapidly growing strain of poults .25 to .55% total dietary salt is required for maximum growth and prevention of field rickets. Also .18% and .07% total dietary sodium and chloride were found inadequate for maintaining maximum growth as compared to .50% dietary salt, but reduced incidence of field rickets. The intermittent feeding of low dietary calcium levels to turkey layers reduced egg production intensity, shell thickness and shell breaking strength. The feeding of low dietary sodium levels to layers reduced egg production, caused egg shell pimpling, and adversely affected embryonic development. Total dietary salt levels of .30 to .58% fed to layers positively affected egg production and egg quality. In turkey males levels of 3,000 ppm zinc oxide or higher were found detrimental to both efficiency and semen quality. The feeding of total dietary salt levels of .37 to .60%, and .15% calcium were found adequate for ensuring good semen quality and other physiological functions

The impact of stocking density on the performance, health and welfare of turkey hens

The impact of graded levels of stocking density (SD) on the performance, health, and welfare, of Nicholas Select turkey hens raised from day 0 to 11 weeks of age were evaluated in this study. Poults (n=3550/block; randomized complete design with block as trial) were randomly placed into one of four final estimated SD treatments of 30, 40, 50, or 60 kg/m2 based on final predicted body weight at 11 weeks of age. Birds were housed in open rooms (67.5m2) with a total of four replications per treatment. Feeder and drinker space were equalized on a per bird basis. Based on CO2 and ammonia measures, ventilation was adjusted to equalize air quality across all treatments. Productivity was evaluated by measuring group body weight and feed consumption on day 0 and in weeks 3, 5, 8, and 11. Body weight gain and feed-to-gain ratio were calculated. At week 8 and 11, flock uniformity was evaluated on 30 birds/replicate. A brief economic analysis utilizing 2019 and 2020 poult and feed costs was performed. At week 8 and 11, footpad lesions, mobility (subjective gait scores) and feather cover and cleanliness were evaluated on 30 birds/replicate and litter samples were collected to determine moisture content (block 1 only). Incidences of aggressive pecking were recorded daily. Heterophil/lymphocyte (H/L) ratios were evaluated at 3, 5, 8, and 11 weeks of age (20 birds/replicate). Behavioural activity was recorded, and scan sampled (field of view observations) at 8 and 11 weeks of age. Data were analyzed using regression analysis in SAS 9.4 (Proc Reg and Proc RSReg; SD as independent variable). An analysis of variance was performed for all data (Proc Mixed; SAS 9.4) and a Tukey’s range test was used to separate means. Differences were considered significant when P0.05, and trends were noted when P0.10. Ammonia and CO2 were consistent across treatments for both blocks. Body weight (week 11) decreased linearly as SD increased. Feed consumption was lowest at high SD (linear for week 8-11; quadratic for week 0-11). Overall body weight gain tended to decrease as SD increased. Feed-to-gain ratio, percent mortality, and uniformity were not affected by SD. Total aggression related mortality and culls linearly increased with decreasing SD. Net room income linearly increased as SD increased. Average footpad scores worsened at week 8 as SD increased. Mobility was poorer in the 60 kg/m2 treatment at week 11. Feather cover and cleanliness scores were poorer in the high SD treatment at week 8 and 11. Incidence of aggressive damage was highest at low SD (30 kg/m2). The H/L ratios increased linearly with increasing SD at 5 weeks of age. At 8 weeks, H/L ratios were highest in the 40 kg/m2 treatment (quadratic) and at 11 weeks, were highest in the 50 and 60 kg/m2 treatments (quadratic). Behaviour was impacted with increasing SD as the percentage of birds resting, feather pecking, and total disturbances increased. The percentage of birds standing, walking, litter pecking, environmental pecking, and performing aggressive behaviours increased with decreasing SD. Litter moisture tended to increase with increasing SD at week 11. Overall, turkey hen performance, health, and welfare were negatively affected at higher SD although economic returns were greater. Conversely, the lowest SD (30 kg/m2) also negatively affected welfare as more aggression occurred

The impact of daylength on turkey productivity, health and behaviour

The impact of graded levels of daylength on the productivity, health and behaviour of hens and toms was studied in two experiments to 18 wk of age. Daylength treatments (trt) were 14 (14L), 17 (17L), 20 (20L) and 23 (23L) h and were started at 10 d of age. Turkeys (720 hens and 480 toms) were randomly allocated to 8 rooms (2 rooms per lighting trt) with six pens (3 hen and 3 tom) per room in each experiment. Body weight (BW) and feed consumption (FC) were assessed throughout the trial and feed efficiency (G:F; g of gain/g of feed) calculated from BW and FC values. Birds were checked daily for mortality and culls, and affected birds sent for necropsy. Bird well-being was evaluated by gait score (GS), the incidence of foot pad dermatitis (FPD), breast buttons and blisters, ocular size and pressure, and tom behavioural observations. Data were analyzed using SAS 9.3 based on a completely randomized design nested within four daylengths. Regression analysis established relationships between response criteria and daylength. Differences were considered significant at P≤0.05 and trends noted at P≤0.10. At 21 and 42 d, body weight increased linearly with daylength, but by 84 d tom weights decreased in a quadratic fashion and hen weights were unaffected by daylength. At 126 d, both male and female weights decreased linearly with increasing daylength, with the magnitude of the response gender dependent. Feed consumption corresponded to body weight changes, increasing for d 10-21 and 21-42, and decreasing for d 63-84, 84-105, and 105-126 with increasing daylength. Feed efficiency (G:F) was not affected by daylength for 10-84, 10-105 and 10-126 d periods. The incidence of mortality and culling was not affected by daylength for the 10-84 d period, but increased in a quadratic manner with increasing daylength for the 10-105 and 10-126 d periods. The incidence of skeletal disorders (valgus-varus and rotated tibia), injurious pecking and pendulous crops (females only) increased linearly with increasing daylength. Average GS increased linearly with daylength at 11 and 17 wk for both hens and toms, but the effect was larger in toms. Daylength did not affect FPD, but more lesions and more severe scores were found for hens than toms. The presence of breast buttons and blisters increased linearly with daylength (11 wk) with the effect on blisters predominately seen in toms. Eye weight increased and corneal diameter decreased linearly with increasing daylength at 12 and 18 wk. Dorso-ventral and media-lateral diameter, and anterior to posterior depth exhibited a quadratic relationship with the highest values seen for the 23L trt. Ocular pressure was not affected by daylength. Over 24 h of behavioural observation (both photo- and scotoperiod), resting increased, and walking, and environmental and feather pecking decreased with increasing daylength. During the photoperiod, inactive resting increased and feeding, drinking, standing, walking, preening, and environmental and feather pecking behaviours decreased as daylength increased. To conclude, daylength affects the growth and feed intake of turkeys in an age and gender specific manner, and mortality and culling increase with longer daylength. Health and welfare parameters are also affected by daylength with 23L demonstrating poorest overall bird well-being

The effect of early nutrient restriction on subsequent compensatory growth in market turkeys

Experiment one was a factorial arrangement of diets containing two levels of protein (P) (100% (HP) or 70% (LP) of National Research Council (1984) (N.R.C.)) and two levels of energy (E) (100% (HE) or 90% (LE) of N.R.C.), which were fed ad libitum to Nicholas toms from 10 days to 6 weeks (wks) of age. Subsequently, the four treatment groups were fed diets containing either 4% or 8% fat (F) to 20 wks of age. LP or LE reduced weight gain (WG) and increased feed/gain (F/G) until 6 weeks (P \u3c.005). After 6 wks of age, LP toms had consistently lower body weight (BW) and F/G than HP toms until 20 wks (P \u3c.005). In comparison, LE and HE toms had the same BW at 20 wks. WG increased and F/G decreased as the level of F increased (P \u3c.005), irrespective of P and E. Percentage carcass fat at 6 wks was increased by LP, and decreased by LE (P \u3c.005). LP also increased leg length relative to 6-wk BW and reduced breast meat yield. Carcass composition and structural proportionality of LP and LE toms were restored at 12 and 20 wks with the exception of breast yield, which was still adversely affected by LP at 12 wks. At 12 and 20 wks, % carcass fat increased as the level of F increased. Results show that toms responded more favorably to early P than E restriction, regardless of fat content of the realimentation diet;In experiment two, four levels of dietary protein (P) (100%, 80%, 70%, or 60% of N.R.C.) were fed to toms from 1-6 wks and subsequently the toms were fed according to N.R.C. until 20 wks of age. As the level of P decreased 6-wk BW decreased and 1-6 wk F/G increased. P did not influence 6-20-wk WG, but F/G was improved (P \u3c.005). Furthermore, 60-70% P reduced the incidence of severe leg weakness observed at 18 wks by more than 60%. Percentage carcass fat at 6 wks increased linearly and breast and thigh meat yields decreased as P decreased, but other carcass components were unaffected by P. Carcass composition and meat yield were restored to normal proportions at 12 and 20 wks, irrespective of the level of P; however, breast yield at 20 wks was reduced by 60% P. Results show that large toms do not exhibit compensatory WG, irrespective of the level of P; however, significant savings in feed costs and reduced incidence of leg weakness without adverse effects on carcass quality may be economically beneficial if toms are fed at 70-80% of N.R.C. protein recommendations from 1-6 wks of age;Reference. National Research Council. 1984. Nutrient Requirements of poultry. 8th ed. Natl. Acad. Sci., Washington, DC

Performance and physiological impacts of branched-chain amino acid and tryptophan ratio variations in turkey starter diets utilizing concentrated corn proteins

In Chapter 2, a study was designed to evaluate the effects of varying dietary branched-chain amino acids (BCAA) ratio in corn and soybean meal-based turkey starter diets. The BCAA leucine, isoleucine, and valine are considered indispensable amino acids needed for energy and stimulation of muscle protein synthesis via the mammalian target of rapamycin (mTOR) pathway. Imbalanced BCAA ratios can lead to antagonism and degradation of limiting BCAA, particularly in diets with excess leucine. Concentrated corn proteins contain high levels of leucine and can alter BCAA requirements; however, crystalline BCAA may be added to correct these ratios. This study aimed to determine the effects of varying dietary BCAA ratio using corn gluten meal (CG), L-isoleucine, and L-valine on performance, mTOR activation, and apparent ileal AA digestibility (AIAAD) in commercial turkey hens from 0-21days of age. A 38.4% corn and 49.8% soybean meal diet served as the Control, and CG was serially increased to create an uncorrected low- and high-leucine diet. The high-leucine diet was then used to create partially or fully corrected diets by inclusion of L-isoleucine and/or L-valine. In uncorrected high-leucine treatments, feed intake, bird weight, and live weight gain decreased (P \u3c 0.05), and feed conversion ratio (FCR) increased relative to the Control at day 14 (P \u3c 0.05). Performance equivalent to the Control was induced by adding both L-isoleucine and L-valine at day 14 (P \u3e 0.05), and FCR decreased relative to the Control at day 21 (P \u3c 0.05). Relative mTOR activation numerically increased in high-leucine diets compared to the Control (P = 0.13). BCAA digestibility was maximized in high-leucine diets with additional L-isoleucine and L-valine (P \u3c 0.05). These results demonstrate that diets containing excess leucine from concentrated corn proteins can decrease poult hen performance, but concomitant additions of crystalline isoleucine and valine may restore performance. In production settings, nutritionists should assess the costs associated with BCAA supplementation at practical levels versus corn and soybean meal-based diets. In Chapter 3, a follow-up study was designed to investigate the influence of dietary branched chain amino acid (BCAA) and tryptophan ratio in turkeys. Larger inclusions of concentrated corn proteins in corn and soybean meal-based diets can increase leucine levels above requirement, leading to potential deficiency of limiting isoleucine and valine. Excess leucine may also inhibit tryptophan absorption and transport, influencing serotonin synthesis. Hence, high-leucine diets corrected with supplementary isoleucine, valine, and tryptophan could prevent performance reductions associated with imbalanced BCAA and tryptophan ratios. This study evaluated the effects of varying dietary BCAA and tryptophan ratios using corn gluten meal (CG), L-isoleucine, L-valine, and L-tryptophan on performance, plasma serotonin concentration, immune organ weight, and tibia mineralization in commercial turkey hens from 0-28 days of age. A 34.8% corn and 54.0% soybean meal diet served as the Control. An uncorrected high-leucine diet was formulated with a high inclusion of CG and the subsequent high-leucine diets contained partial or total correction with L-isoleucine, L-valine, and L-tryptophan. Diets were fed to 15 replicate cages of 6 poults using a randomized complete block design. Uncorrected high-Leu diets (1.6 Leu:Lys) reduced feed intake (FI), body weight (BW), and live weight gain (LWG) relative to the Control at day 14 (

Animal hygiene and sustainable livestock production: impact of ground water contamination with arsenic

There is a growing concern all over the world about contamination of ground water with Arsenic. One of the major repercussions of arsenic contamination is degradation of animal hygiene that ultimately affects sustainable livestock production. The reports suggest that concentration of Arsenic in ground water of twenty one countries is well above the guideline values. Use of such contaminated water for animal husbandry and livestock production compromises with the hygienic value of animal products. Therefore, there is an urgent need to develop low cost treatment technologies for reducing the level of arsenic in ground water to maintain the hygiene and sustainability of livestock production. Most of the traditional treatment technologies are costly and less effective in reducing arsenic concentration to safer limits. Therefore, during present study, an attempt was made to design a low-cost algal adsorbent based filtration unit consisting of polyurethane columns with entrapped algal adsorbents. The column was made of adsorbents of algal origin like agar-agar, alginic acid, calcium alginate and Spirulina platensis biomass entrapped in polyurethane foam matrix. The performance of the column was assessed in terms of removal efficiency and the quantity of metal sequestered in unit time interval. The results from the study the show that algal biosorbents and S. platensis biomass combination has a capacity to adsorbed arsenic from aqueous solution. The simple design, easy fabrication and no energy requirement for the operation of the filtration unit developed under the present study is suitable to rural areas where arsenic contamination of ground water is adversely affecting the animal hygiene and sustained livestock production

Assessing the Effects of Stocking Density on Turkey Tom Health and Welfare to 16 Weeks of Age

Four levels of turkey tom stocking density (SD) (30, 40, 50, 60 kg/m2) were evaluated in two 16 week trials (n = 2,868 Nicholas Select). Poults were allocated to one of eight independently ventilated rooms per trial (6.71 × 10.06 m) based on final predicted body weight (two replicates per SD per trial). Room temperature, humidity, carbon dioxide and ammonia concentration were recorded throughout the trial; ventilation was adjusted to equalize air quality across treatments. Mobility (gait score, scale 0–5) was recorded at 12 and 16 weeks (20 birds per replicate). Footpad lesion score (scale 0–4), feather condition (scale 1–4), and cleanliness scores (scale 1–4) were recorded at 10 (Trial 2), 12, and 16 weeks of age (20 birds per replicate). Aggressive injury incidence was recorded daily for Trial 2. Stress (heterophil/lymphocyte ratio) was evaluated at 4, 12, and 16 weeks of age (15 birds per replicate). Behavior was recorded and scan sampled (field of view) at 12 (Trial 1), 14, and 16 weeks. Data were analyzed using regression analysis (linear, Proc Reg; quadratic, Proc RSReg) for relationships between the variables and SD. Differences were considered significant when p ≤ 0.05. Mobility and footpad lesions were negatively affected by increasing SD (linear) at 16 weeks only. Feather condition and cleanliness decreased linearly as SD increased at week 10, 12, and 16. The incidence of aggressive damage was higher as SD increased during week 4–8 (quadratic). Heterophil/lymphocyte ratios increased linearly at 4 weeks (similar trend at 12 weeks). Behavior was impacted at 12 weeks of age with standing behavior showing a quadratic response, and walking and total disturbance showing a linear decrease as SD increased. Resting, preening, and comfort behaviors increased linearly (14 weeks), while walking and strutting decreased linearly with increasing SD. Finally, at 16 weeks of age resting, standing, walking, feeding, and total disturbance responded quadratically while preening behavior increased linearly with increasing SD. Results suggest that increasing SD negatively impacts bird health and wellbeing through decreased mobility, increased footpad lesions, poorer feather condition and cleanliness, and behavioral changes, but that very low SD (30 kg/m2) may result in increased aggressive damage

The effects of stocking density on heavy turkey tom productivity, health, and wellbeing to 16 weeks of age

The impacts of increasing stocking density (SD) were observed on Nicholas Select turkey toms (n=2,868) to 16 wk of age. In two trials, birds were allocated to 8 independently controlled rooms (6.7x10.0 m = 67.5 m2) based on final predicted body weight, resulting in a total of 4 room replicates per treatment. Air quality was monitored via carbon dioxide and ammonia and was equalized across treatments. The number of birds placed differed by density to reach a final predicted density (based on Aviagen, 2015a Performance Objectives) of 30, 40, 50, and 60 kg/m2. Productivity was evaluated using body weight and feed consumption at 0, 4, 8, 12, and 16 wk of age, and feed efficiency was calculated at 4 wk intervals. A brief economic analysis was conducted based on productivity. At 12 and 16 wk of age, a sample of 20 birds per replicate were weighed for determination of flock uniformity, feather condition and cleanliness, footpad lesions, and mobility. The heterophil/lymphocyte ratio (H/L) was evaluated at 4, 12, and 16 wk (15 birds per replicate) and core body temperature was evaluated at 16 wk (3 birds per replicate). Behavioural expression was analyzed at 12, 14, and 16 wk using a scan sampling technique. Data were analyzed using regression analyses (Proc Reg for linear and Proc RSReg for quadratic relationships; SAS®9.4). Differences were significant when P≤0.05, and trends were noted when P≤0.10. Overall body weight and body weight gain decreased linearly as SD increased. Feed consumption decreased linearly as SD increased within the last 4 wk (12-16). Mortality corrected feed-to-gain ratio demonstrated an increasing linear relationship with SD beginning at 4 wk and continuing throughout the trial. Body weight uniformity and total percentage mortality and culls showed no impact in relation to increasing SD. Footpad lesion severity and frequency and bird mobility were negatively impacted in relation to increasing SD. Feather condition and cleanliness decreased linearly with increasing SD over the course of the trial. The H/L ratio demonstrated an increasing linear relationship with increasing SD at 4 wk of age. Core body temperature increased with increasing SD. Behaviour was altered in relation to increasing density with increases in comfort behaviours, decreases in nutritive behaviours, and quadratic effects on mobility behaviours. The economic analysis, based on production parameters alone, supported increased monetary return with increasing SD. High levels of SD negatively impact bird performance, health and wellbeing, although the economic return continues to improve with increasing density