The effects of stocking density on turkey tom performance and environment to 16 weeks of age

Stocking density effects on turkey hen performance to 11 weeks of age

Stocking density (SD) affects economic return for turkey production and can impact performance parameters. In this study (2 experimental blocks), Nicholas Select hens (n = 3,550 poults/block) were randomly placed in 1 of 4 SD treatments of 30, 40, 50, or 60 kg/m2 in open rooms (67.5 m2) with 4 replications per treatment. Feeder and drinker space were equalized on a per bird basis. Air quality was measured, and ventilation was adjusted to equalize ammonia and carbon dioxide levels across all rooms. Group BW and feed consumption were measured on d 0 and wk 3, 5, 8, and 11. BW gain and mortality corrected feed-to-gain ratio were calculated. Mortality and culls were recorded daily and necropsied for cause of death. At wk 8 and 11, flock uniformity was evaluated (30 birds/replicate). Data were analyzed using regression analyses in SAS 9.4 (Proc Reg for linear regression and Proc RSReg for quadratic regression; SD as independent variable). An ANOVA was performed for air quality (Proc Mixed; SAS 9.4) and a Tukey's range test was used to separate means. Differences were considered significant when P ≤ 0.05. Carbon dioxide and ammonia were consistent across treatments for both blocks. At wk 11, BW decreased linearly as SD increased (P = 0.05). There was a tendency for overall BW gain to decrease linearly as SD increased (P = 0.06). Feed consumption decreased as SD increased during wk 8 to 11 (linear; P < 0.01) and from wk 0 to 11 (quadratic; P = 0.04). SD had no impact on feed efficiency, mortality, or uniformity. Total aggression related mortality and culls were highest in the 30 kg/m2 treatment (linear; P = 0.02). A brief economic analysis was performed utilizing commercial poult and feed costs and income at marketing. Net room income increased as SD increased (linear; P < 0.01). The results indicate that high SD negatively impacted turkey hen final BW and feed consumption, but no effect was observed on feed-to-gain ratio, percent mortality, or uniformity.

The potential post-hatching growth of domestic birds is sufficiently described by the Gompertz function

It has been hypothesised that, for post-hatching domestic birds reared under good conditions, the relative growth rate R = (dW/dt)/W = dlnW/dt is a linear function of lnW; W is body weight. It followed that dW/dt = B.W.ln(A/W), where A is mature weight, and, by integration, that weight by time is described by a Gompertz function: W_t = A.exp.(-exp(-(G₀ - B.t)), where W_t is weight at time t d, B is the rate parameter d^-1, and G₀ = -ln(-ln(W₀/A)).Where growth data published in the literature did not show this relationship, it was likely to be caused by sub-optimal conditions for maximum growth, such as inadequate nutrition or other factors.Published data, which have been diligently examined from both sexes and nine species, over 400-fold range of degree of maturity was seen, collected over nearly a century of data from four continents, which strongly corroborated the hypothesis.The data were not in agreement with other functions using three parameters and made functions with four or more parameters superfluous. The relationship between R and lnW should be carefully examined before subjecting any data set to further analysis.

Evaluating the effects of stocking density on the behavior, health, and welfare of turkey hens to 11 weeks of age

Nicholas Select hens (n = 3,550 poults in each of 2 experimental trials) were randomly placed in 1 of 4 stocking density (SD) treatments of 30, 40, 50, or 60 kg/m² until 11 wk. Birds were housed in open rooms (67.5 m²) with 4 replications per treatment. Ventilation was adjusted in each room independently to ensure air quality measures did not differ across replicate rooms. At wk 8 and 11, footpad lesions, mobility, feather cover and cleanliness, behavior (recorded), and litter moisture were evaluated. Incidences of aggressive pecking were recorded daily. Heterophil/lymphocyte (H/L) ratios were evaluated at 3, 5, 8, and 11 wk. Data were analyzed using regression analyses in SAS 9.4 (Proc Reg and Proc RSReg; SD as independent variable). Differences were considered significant when P ≤ 0.05. Gait scores were not affected by SD. Average footpad scores worsened with increasing SD at wk 8 (linear) but were not affected at wk 11. Total feather cover scores and average feather cleanliness were poorer at high SD (linear) at wk 8 and 11. The incidence of aggressive pecking and culls for aggressive damage decreased linearly as SD increased. At 5 (linear) and 11 (quadratic) wk, H/L ratios increased as SD increased. At 8 wk, H/L ratios were highest in the 40 kg/m² treatment (quadratic). At 8 wk, the percentage of birds at the feeder, resting, and total disturbances linearly increased as SD increased. The percentage of birds standing, walking, and litter pecking decreased linearly with increasing SD, while total aggressive behaviors (sum of fighting and aggressive pecking) decreased (quadratic). At 11 wk, the percentage of birds at the drinker, and decreased with increasing SD while resting, feather pecking, and severe disturbances increased as SD increased. Litter moisture increased linearly with increasing SD (wk 11). Turkey hen health and welfare were negatively impacted by higher SD. At low SD, there was notably more aggression which may also impact welfare.

The influence of stocking density on behaviour, health, and production in commercial fattening turkeys - a review

Worldwide, there are various regulations and recommendations on the maximum stocking density. While stocking density can be determined based on the space covered by the body, a more appropriate method considers space requirements for natural behaviour.Turkeys are less likely disturbed at low stocking density as seen by increased sitting, lying, and preening behaviours, compared to animals housed at high stocking density. Furthermore, lower stocking density, together with smaller group size, species-appropriate light conditions and suitable structuring of barn housing, have been repeatedly mentioned as good strategies to prevent injurious pecking.Increased stocking density - in terms of weight and animal number per floor area - is related to increased litter moisture, which can have negative impact on animal welfare. High stocking density can lead to poor body mass gain and increased mortality, which are indicators of impaired welfare and economic losses.Based on the available scientific literature and economic aspects with regard to the above criteria, maximum stocking density for turkeys appears to be 40 kg live weight per m² of usable floor space. However, the number of animals per square space should be limited to avoid increased litter moisture and reduced health and welfare.

Effects of stocking density on large white, commercial tom turkeys reared to 20 weeks of age: 1. growth and performance

Industry standards for turkey stocking densities are variable and may not represent the more rapidly growing strains currently available. Therefore, a study was completed to evaluate 4 stocking densities: a nominal density (0.3525 m²/bird), 10% tighter density (0.3169 m²/bird), 10% looser density (0.3882 m²/bird), and 20% looser density (0.4238 m²/bird) on the effects on large white, commercial male turkeys with regard to performance from 5 to 20 wk of age. Brooding stocking density was fixed for all pens of birds with 60 birds per replicate pen at 0.46 m²/bird to 5 wk of age. Density treatments were applied from 5 to 20 wk by altering pen size with pen population held constant at 60 per pen. There were 4 pens of birds per density treatment. Birds were weighed individually at 0, 5, and 20 wk of age and performance parameters were calculated. There were no differences in bird performance at 5 wk, which was expected because stocking density was fixed. From 5 to 20 wk and at 20 wk, birds that were reared at the nominal standard (0.3525 m²/bird) and 10% tighter density (0.3169 m²/bird) had significantly lower body weight compared with the 10% looser density (0.3882 m²/bird) and 20% looser density (0.4238 m²/bird) (P = 0.03 and 0.01, respectfully). The feed conversion ratio (FCR) tended (P = 0.08) to be improved for birds reared at looser density. In addition, based on linear regression, as stocking density decreased (i.e., m²/bird increased), BW (P < 0.05) increased, and FCR (P = 0.10) tended to decrease (improve) at 20 wk. It was concluded that birds reared at looser density had improved performance.

Analysis of risk factors for dermatitis and cellulitis in turkeys using abattoir post mortem data

1. Cellulitis and dermatitis are often seen in turkeys at slaughter and are, in many cases, reasons for rejection at meat inspection. Using the results of meat inspections and information about the housing conditions of the animals may provide information on causative factors in the development of cellulitis and dermatitis. 2. A census of two years of turkey production in a company including both fattening farms and an abattoir in the north of England was used to study the relationship between the prevalence of cellulitis/dermatitis and mechanical versus natural ventilation in the poultry house, litter type (long straw, short straw and wood shavings) and stocking density. 3. The overall prevalence of cellulitis and dermatitis in this population was 0.12 %, which was extremely low compared to reports in the literature. In mechanically ventilated houses, the odds of developing cellulitis and/or dermatitis was significantly higher than in naturally ventilated houses (Odds Ratio 3.18). Long straw had a protective effect compared to wood shavings (Odds Ratio 0.18). 4. The study showed that using slaughter data can be helpful in studying on-farm risk factors for disease development.