Cattle Pheromones

Excerpt

The pheromone signals are known to have a potential role in animal reproduction and management (Archunan 2009; Buck 2000; Dominic 1991; Rekwot et al. 2001; Tirindelli et al. 2009). The sources of chemosignals are urine, feces, vaginal secretions, saliva, and specialized scent glands including the odor produced from hair and wool (Albone 1984; Aron 1979; Patra et al. 2012; Van den Hurk 2007). Communication of the timing of the physiological event of ovulation and coordination of sexual behavior are important for successful fertilization (Schams et al. 1977; Ziegler et al. 1993); the success rate of artificial insemination in cattle mainly depends on the time of estrus it is inseminated. If the female fails to conceive when it is inseminated in the nonestrus period, it is a great economic loss estimated around $300 million to the dairy industry in the United States and in India the approximate loss would be several crores. The detection of estrus and diagnosing early pregnancy are the major problems in farm animals, particularly in buffalo. The other problems like irregular or prolonging of the estrous cycle, anestrus, fighting behavior among young ones, mother-young bond, unmotivated males, and poor farm animal management including stress are considered as major issues in farm animals (Rekwot et al. 2001) that need to be addressed. Moreover, pheromones have not been exploited for the purpose of enhancing livestock production.

The animal releases volatile odors into the surrounding atmosphere, most of which are waste products of metabolism in which emission of some compounds closely related to reproductive activities are termed as chemical signals (Hradecky 1975). The estrus-related odors are present only during the preestrus and estrus stages. These chemical signals have been reported to be volatile and nonvolatile molecules that are perceived through the main or accessory olfactory system (Brennan and Keverne 1997; Tirindelli et al. 1998). In mammals, structurally and anatomically, the olfactory systems are classified into two types: the MOS and the accessory olfactory system (AOS), specialized for the detection and transmission of pheromonal information (Halpern and Marinez-Marcos 2003; Mucignat-Caretta et al. 2012).

In the last two decades, there has been a considerable increase in the knowledge of the chemistry of pheromones in cattle (Rajanarayanan and Archunan 2011; Rameshkumar et al. 2000; Sankar and Archunan 2004; Sankar et al. 2007), pig (Signoret 1970), horse (Kimura 2001), goat (Delgadillo et al. 2006), and sheep (Gelez and Fabre-Nys 2006). These findings suggest that cattle pheromones may act together for influencing precopulatory behavior and successful reproduction. It further indicates that cattle pheromones may be a single compound or a mixture of compounds and that each of the major fractions was faithfully involved in conveying specific signals related to reproductive and social behaviors. The pheromones have not been exploited as much as they can for farmer utility although they have a tremendous role in reproduction. The present review provides insights about the nature of the compounds, behavioral characterization, and practical utility of cattle pheromones that are available (Table 16.1).