Brenda McCowan
As Program Head of Primate Behavioral Management at California National Primate Research Center, McCowan has published numerous studies regarding the behavioral management of primates used for laboratory testing, predominantly rhesus macaques ("Macaca mulatta"). Many of these studies examine methods for reducing aggression and injury and improving well-being. It is a widespread practice in the poultry industry to induce molting in egg-laying chickens, which maximizes both egg production and hen health. However, the effects of induced molting on hen well-being are poorly understood. The most common method for inducing molting is via forced fasting (fast-induced), and there is growing concern that hen well-being is negatively affected by fast-induced molting. A less popular but promising method of induced molting involves feeding of low-caloric density feed (nonfasting-induced). McCowan et al. (2006) examined the behavior of chickens subjected to different induced molting styles and found that cage pecking, aggression, and calling increased in fast-induced chickens. McCowan et al. (2006) concluded that nonfast-induced molting appears to be a more appropriate method, minimizing discomfort during a physiologically stressful time. The data also support vocalization as an indicator of stress/discomfort in chickens, which are notoriously stoic and therefore have been hard to assess for well-being, historically. Cows, as with many mammals, use vocal communication to mediate and strengthen strong mother-infant bonds. Calves often call to their mothers in times of need (hunger, danger), and it is believed that certain calls are used to solicit nursing. McCowan et al. (2002) found that playback of calf vocalizations caused a statistically significant increase (1-2%) in milk production in dairy cows. The cows most responsive to the vocalizations were those cows whose actual infants were closest in age to the calves used for the recordings (less than 1 week old); therefore, it is possible that milk production within a dairy herd could be increased further if multiple playbacks of calf vocalizations were used, varying by age as appropriate for the cows (McCowan 2002). (Young calf playbacks to cows with young calves; older calf playbacks to cows with older calves, etc.) These results highlight an innovative non-chemical method for increasing milk production in dairy cows, and are especially important findings for use on organic dairy farms, as the demand for organic products grows. Belding's ground squirrels ("Spermophilus beldingi") are social squirrels living in the western United States which exhibit kin altruism by making alarm calls commonly referred to as ‘chirps’ to warn other individuals of terrestrial or aerial predators. Belding's ground squirrels live in colonies of related females and their dependent offspring, with the older sons dispersing to find other less-related females’ burrows, and the daughters staying to expand upon their mother's current burrow system. McCowan et al. (2002) hypothesized that there is an acoustic variability in these chirps dependent on individual identity, sex, and social group membership which is subsequently important in kin and social group recognition. McCowan et al. (2002) recorded the alarm chirps of eight adult female Belding's ground squirrels from four lakes in the High Sierra Nevada mountain range, analyzed the acoustic structure of these chirps, and found the chirps to be individually distinctive, yet with similarity among individuals that may correspond to genetic similarity. McCowan et al. (2002) concluded that analysis of acoustic variation may then be a reliable, noninvasive tool for tracking dispersal patterns and other population dynamics in this species, as well as in other more threatened and endangered vocal mammalian species. The effects of anthropogenic noise caused by ships, sonar, and other manmade systems on marine mammals have received increasing attention in recent years by environmental organizations, governmental agencies, and the general public. Such noise is potentially disrupting the feeding and mating behavior of marine mammals which rely on vocal communication and echolocation. After recording over 50 hours of vocalizations from 100 humpback whales ("Megaptera novaeangliae") in Glacier Bay National Park over 5 years, McCowan et al. (2008) introduced a quantitative tool, based on information theory, that can characterize and
quantify humpback whale responses to environmental boat noise. The researchers conclude that use of this new tool has the potential to help determine the effects of boat noise on humpback whale vocal communication and population dynamics, and may also be used to evaluate anthropogenic noise effects on other wildlife populations. Mastitis, a potentially fatal inflammatory infection of the mammary glands, is a common health problem in dairy cows in the United States and causes great economic losses for the dairy industry each year due to reduced milk production in cows with mastitis. While the influence of contagious gram-positive bacteria (e.g. "Staphylococcus" and "Streptococcus") – which used to be the primary cause for mastitis in dairy cows – has been significantly reduced in recent years, environmental pathogens such as coliform bacteria (e.g. E. coli) and noncontagious "Streptococcus" now play a larger role in the infection of dairy cows. This is cause for concern as environmental bacteria, noncontagious Streptococcus especially, are becoming increasingly resistant to antimicrobial intramammary therapy. McCowan et al. (2005) set out to determine if certain housing facilities, husbandry practices, and/or use of antimicrobial agents caused higher levels of resistant environmental bacteria. The researchers sampled the bulk tank milk of nearly 100 California dairies and conducted a face-to-face on-site questionnaire for approximately 50 of the dairies found to have at least 3 environmental bacteria isolates. McCowan et al. (2005) analyzed the results and found that not drying udders before attaching the milk units significantly increased chances of antimicrobial resistance, as did the use of some antimicrobial agents (ceftiofur, Sulfadimethoxine) for treatment of non-mastitis diseases. Surprisingly, no antimicrobial agents used to treat mastitis were found to cause increased resistance. Squirrel monkeys ("Saimiri sciureus") are highly social New World monkeys found in Central and South America which exhibit various alarm calls to warn other individuals of potential predators. McCowan et al. (2000) researched the role of learning in the development of chuck call recognition in squirrel monkeys, hypothesizing that monkeys at different developmental stages (ages) respond preferentially to the chuck calls of familiar – yet genetically unrelated – companions as compared to those of unfamiliar individuals. The researchers conducted a controlled playback experiment on four different age classes of squirrel monkeys and found that infants did not appear to have any preference for the chuck calls of close social associates or other social group members, concluding that learning plays a role in chuck call recognition in squirrel monkeys and that infants gradually learn to acoustically recognize social companions within their group. To warn others in highly threatening situations, squirrel monkeys use an alarm call known as an alarm peep. In a later study, McCowan et al. (2001) examined the role of learning in the development of response to alarm peeps. The researchers again conducted a controlled playback experiment on four different age classes of squirrel monkeys, and found that adult females were more discerning in their responses to alarm peeps, preferring to trust the peeps of other adult females as opposed to the peeps of infants or juveniles. The researchers concluded that squirrel monkeys do learn more appropriate responses to alarm peeps over their first year of development.
Research Interests ; Animal Welfare
Dr. McCowan is the Program Head of Primate Behavioral Management at California National Primate Research Center, a position she has held since 2004.