Relationship between reproductive indicators and sound structure in broiler breeder roosters

Abstract

Domestic chickens commonly have two types of calls: loud calls (e.g., crowing) for attracting attention effectively over a long distance, and soft or light calls (e.g., squawking) for communication over a short distance. The emergence of secondary sexual characteristics, such as vocalization at the time of sexual maturation, is due to testicular hormone (i.e., testosterone) secretion. Luteinizing hormone (LH) and follicle-stimulating hormone are gonadotropins. These hormones along with semen parameters are essential reproductive indicators of reproductive health and performance of broiler breeder roosters. The objective of this study was to investigate the relationship between the reproductive indicators and sound structure for broiler breeder roosters. Seventy Ross 308 broiler breeder roosters at 50 weeks of age were divided into two groups (high or low), based on the performance of two sexual hormones of testosterone and LH and four semen parameters of semen volume, sperm concentration, sperm viability, and sperm total motility. Two types of rooster sounds (crowing and squawking) were recorded separately from the two groups. Acoustic signals were decomposed by wavelet transformation and correlated with the reproductive indicators. The results indicate that certain features (e.g., entropy and standard deviation) of crowing and squawking sounds from the roosters were significantly correlated with the testosterone and LH concentrations (P<0.05). Crowing roosters had significantly lower values of sperm viability (P<0.01) and sperm total motility (P<0.05) compared with non-crowing ones. Therefore, sound signals can be direct and noninvasive indicators of the reproductive performance of individual broiler breeder roosters.