Growth Dependent Changes in Pressure Sensing Walkway Data for Turkeys

Abstract

Genetic selection for rapidly growing turkeys has created an unfavorable consequence impacting the skeletal system resulting in long bone distortions. These distortions have resulted in locomotor problems, gait abnormalities, leg weakness, or lameness issues. These effects raise welfare concerns along with animal agriculture inefficiency in the form of lost product. The purpose was to determine baseline gait and force distribution in visibly unimpaired growing turkey hens. Hendrix commercial turkey hen poults (n = 100) were placed on pine wood shavings providing 0.78 m2 per bird with ad libitum access to feed and water at the MSU Poultry Farm. Fifty hens were randomly selected at 5 weeks and identified with a leg band to ensure longitudinal data collection. The turkeys were walked across a pressure-sensing walkway (PSW, Tekscan, Boston, MA) and weighed at 5, 6, 8, and 10 weeks of age. PSW collected data on gait length, gait time, step force and step length, and the statistics were analyzed with SAS. Both temporospatial data, including step time and step length, and kinetic data, including peak downward force, and vertical impulse, were recorded. Body weight increased linearly with age (P < 0.001), demonstrating a typical growth pattern. Gait cycle time and peak vertical force (PVF) all displayed no difference between right and left sides, indicating that the hens had no detectable gait abnormalities. Gait velocity increased with age (P = 0.02) suggesting hens' growth impacted their gait velocity. The gait cycle time (P < 0.01) did not correspond with age. PVF increased linearly with age (P < 0.01) from 6 weeks (2.23 kg) to 10 weeks of age (5.91 kg). PVF/kg body weight (P < 0.01) increased from 6 weeks of age (96.9% BW) to 8 weeks of age (106%BW). Overall, the birds were not lame and some data was influenced by the hen's adjustment to the materials or stage of growth; in contrast, some temporospatial data did not coincide with age. The PSW could be used to detect locomotor issues in commercially produced turkey hens providing another tool for assessing well-being.

Validity of Micro-Data Loggers to Determine Walking Activity of Turkeys and Effects on Turkey Gait

“…Cadence is the number of steps taken per minute (27), which was lower at 16 weeks of age compared to 8 and 12 weeks. Cadence had not been previously shown to decrease with age in turkey hens (24). Differences due to turkey sex may be a factor as hens displayed a longer step length with age (24), while no changes were observed for male turkeys (25).…”

“…Descriptions of gait parameters are provided in Table 1. Gait parameters were selected for analysis based on previous leg heath studies with the Tekscan system in turkey hens (24) and Pekin ducks (30).…”

“…In addition to the gait parameters derived from the Tekscan, we calculated the duty factor [derived from (25, 28, 29)] to incorporate previous avian gait dynamics known to change with age (24, 25, 28). Duty factor is a measure of the total stride cycle when the foot is in contact with the ground (Table 1).…”

“…These changes in body conformation can have effects on how turkeys walk, but limited research has investigated changes in turkey gait. Recently, Kremer et al demonstrated that as female turkeys age, certain gait parameters such gait velocity, peak vertical force, and step length increased with age while other parameters such as gait cycle time were not affected (24). Similarly, Oviedo-Rondón et al demonstrated that in male turkeys, certain gait dynamic change due to leg health and age.…”

“…These age-related studies indicate that both age and leg health play crucial roles in turkey gait dynamics, so introducing an unfamiliar accelerometer on the leg may further complicate how a bird walks. Male vs. female gait changes may also be a factor as hens displayed a longer step length with age, while males showed no change (24, 25).…”