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Bedding source and stocking density affect turkey hen performance and footpad health

By: Gabriella Furo, Ph.D. student
Department of Animal Science, University of Minnesota

What is footpad dermatitis (FPD) and why should I care?

Footpad dermatitis is a skin inflammation, and a frequently occurring problem in turkey production worldwide, which can affect the turkey performance, including body weight and feed intake. The signs of FPD include thickened scales (hyperkeratosis), discoloration, dark brown and black lesions, ulcers which develop on the footpads and toes of poultry. Footpad dermatitis is associated with potential pain, therefore it is an animal welfare issue, and FPD can affect turkeys at any age.

There are many contributing factors in the development of FPD, such as nutrition, past and existing diseases, but the most important factor is litter moisture. Research studies recommend to keep litter moisture under 30% in order to minimize the incidence of FPD. The lesion develops quickly with early signs seen 24-48 hr after exposing the birds to high litter moisture. Even severe lesions healed in 14-15 days if turkeys were transferred to dry litter.

What are UMN scientists learning about how the bedding source and stocking density affect FPD, turkey performance and welfare?

Researchers at UMN and Pennsylvania State University collaborated to study factors, such as bedding source and stocking density influence on turkey hen performance, and footpad dermatitis. In a pen study, over 1000 turkey hens were kept on one of two bedding materials (pine shavings or Giant miscanthus grass), and one of three stocking densities (1.5, 2.0, or 2.5 bird/ft2 to 14 wk of age. The final stocking density when expressed as lb/ft2 was 8.8, 10.1, and 13.4 lb/ft2 and referred to as low (LD), medium (MD), and high density (HD), respectively). Giant miscanthus grass is an alternative bedding material, can be grown by farmers in MN and Canada.

At market, no differences existed between bedding materials for body weight, feed intake, and feed conversion ratio (FCR). During the last two weeks of the study, feed intake was reduced by 4.65% for hens on miscanthus grass as compared to pine shavings, perhaps due to more severe footpad dermatitis observed at 14 wk of age.

Improved performance was observed in hens kept at LD compared to HD. Higher BW (by 6.5%) was observed at 14 wk, and lower FCR (by 6.1%) overall (Figure 1). Higher litter moisture was associated with use of miscanthus bedding or HD.
Figure 1. The effects of stocking density on turkey hen body weight (BW, lb) and feed conversion ratio (FCR) at 14 wk of age. Hens were housed at low, medium, and high stocking densities (1.5, 2.0, and 2.5 bird/ft2) referred to LD, MD, and HD, respectively). FCR (feed/gain) was calculated on a pen basis between 2-14 wk of age, and adjusted for mortality. a,ab,b Different superscripts indicate the significant differences (P<0.05) in body weight among density. 

x, xy, y Different superscripts indicate the significant differences (P<0.05) in FCR among density. 

The bedding and the stocking density affected the footpad scores of 14 wk old turkeys. Hens raised on miscanthus bedding developed more severe lesions compared to pine shavings (1.43 vs. 0.71, P<0.001) on a 3 point footpad scoring scale (Berg, 2015), ranging between 0 (no lesions) to 2 (severe lesions). Lower footpad scores were observed in hens housed at LD (0.77) as compared to either MD or HD (1.16 and 1.27, P = 0.006).

The correlation between pen average footpad scores and body weight revealed a moderate negative relationship (r = -0.46, P = 0.034) indicating that FPD influenced the turkey performance inversely at 14 wk of age. Litter moisture and footpad scores were positively correlated (r = 0.67, P = 0.001), indicating that as litter moisture increased, foot pad scores became more severe.
Figure 2. The effects of stocking density on the prevalence and severity of footpad lesions in turkey hens at 14 wk of age. Hens were housed at low, medium, and high stocking densities (1.5, 2.0, and 2.5 bird/ft2 referred to LD, MD, and HD, respectively). Footpad lesions were evaluated (Berg, 2015) on a 3 point footpad scoring scale, ranging between 0 (no lesions) to 2 (severe lesions). The percentage of hens with footpad score 0, 1, or 2 are illustrated as FS 0, FS 1, or FS 2, respectively on the left vertical axis. Average footpad score is presented on the right vertical axis.

Different superscripts indicate the significant differences in pen average footpad scores at 14 wk of age. 

What can farmers do?

1. Check the litter moisture, as it is a key component in the FPD development. An easy way is to grab a handful of litter, and if it is friable, the moisture is most likely low. If the litter sample compacts, the moisture is most likely in excess.

2. Keep litter moisture low:
  • Use heat and the ventilation to remove excess moisture form turkey houses
  • Select bedding material which has a better water absorption capacity
  • Check drinkers for leakage or signs of flood
  • Check the roof, floors and, sidewalls for excess rain and water coming into the turkey house
  • Eliminate wet spots to minimize bedding addition
3. Know the footpad status of your turkey flocks.

American Humane recommends to sample 300 turkeys in the processing plant, and the goal is to have fewer than 30 turkeys with score of 3, 4 or 5 on the 5 point footpad scoring scheme according to Clark et al (2002). The processing plants usually keep records of the footpad scores, please ask for assistance.
Figure 3. Turkey five point footpad scoring scheme ranging from 0 (no lesion) to 5 (severe lesions) developed by Clark et al. (2002). Image source: Clark et al. (2002). 

The author acknowledges the Project Investigators: Drs. Sally Noll, Michael Hulet, Kevin Janni, Carol Cardona, Yuzhi Li, Tim Johnson, Zheng Xing, Darrin Karcher, Michael Hulet, Marisa Erasmus, and collaborators Lisa Kitto, Brian Hetchler, Jeanine Brannon. The experiment was funded by the Agriculture and Food Research Initiative Competitive Grant no. 2016-67015-24457 from USDA National Institute of Food and Agriculture.
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