Effects of castration on grooming in goats

Programmed Grooming after 30 Years of Study: A Review of Evidence and Future Prospects

In 1992, an evolutionary model for the endogenous regulation of parasite-defense grooming was first proposed for African antelope by Ben and Lynette Hart. Known as the programmed grooming model, it hypothesized that a central control mechanism periodically evokes grooming so as to remove ectoparasites before they blood feed. The programmed grooming model contrasts with a stimulus-driven mechanism, in which grooming is stimulated by direct peripheral irritation from ectoparasite bites. In the 30+ years since the seminal 1992 paper, 26 studies have provided robust support for the programmed grooming model in ungulate hosts and ticks. In addition, multiple studies from unaffiliated investigators have evaluated the predictions of the model in different host systems (including rodents and primates) and in a variety of other ectoparasites (fleas, lice, and keds). I conducted a tricennial review of these studies to assess the current evidence and arrived at the following three conclusions: (1) tests of the programmed grooming predictions should use a similar methodology to the well-established protocol, so that the results are comparable and can be properly assessed; (2) the predictions used to test the model should be tailored to the biology of the host taxa under investigation; and (3) the predictions should likewise be tailored to the biology of the ectoparasites involved, bearing in mind that grooming has varying degrees of effectiveness, depending on the parasite. Further research is warranted to enhance our understanding of the role of grooming in maintaining the health of wild animals in the face of parasite attacks.

Evaluation of Pain Mitigation Strategies in Goat Kids after Cautery Disbudding

Simple Summary

Disbudding is a routine procedure performed in goat kids at an early age, especially the ones in the dairy industry. The procedure is mainly done to increase safety for other animals and workers in intensive dairy farms. Disbudding is a painful procedure that affects the welfare of the kids. Effective and practical pain mitigation strategies to reduce the suffering of goat kids due to disbudding have not yet been found. We studied two different pain mitigation strategies for this procedure and concluded that they were not entirely effective. Consumers are increasingly aware of animal farming practices, especially the ones that can lead to suffering and pain, such as disbudding. It is crucial that pain mitigation strategies as well as possible alternative solutions to disbudding continue to be investigated.

Abstract

Nowadays, most of the goat milk production in developed countries is done in intensive indoors production systems. In these systems, procedures such as disbudding are performed routinely. Disbudding is done in young goat kids and is a recognised as a painful procedure. Pain mitigation strategies have been extensively researched, but a method that is effective in mitigating pain as well as being safe and practical has not yet been found. In this paper we used three treatment groups: one control and two groups with pain mitigation strategies for cautery disbudding, one using local anaesthesia (lidocaine) and a second one using local anaesthesia (lidocaine) plus an analgesic (flunixin meglumine). The behaviour of twenty-seven goat kids was recorded for three hours after disbudding. Overall, the goat kids that received both pain mitigation treatments dedicated more time performing active and positive behaviours. Nevertheless, the incidence of behaviours related to pain and discomfort was not consistently reduced. Research is still needed to find a practical and effective pain mitigation strategy for disbudding. A solution to this challenge would improve animal welfare as well as address societal concerns linked to the suffering of farm animals.

How Can We Assess Positive Welfare in Ruminants?

Until now, most research has focused on the development of indicators of negative welfare, and relatively few studies provide information on valid, reliable, and feasible indicators addressing positive aspects of animal welfare. However, a lack of suffering does not guarantee that animals are experiencing a positive welfare state. The aim of the present review is to identify promising valid and reliable animal-based indicators for the assessment of positive welfare that might be included in welfare assessment protocols for ruminants, and to discuss them in the light of the five domains model, highlighting possible gaps to be filled by future research. Based on the existing literature in the main databases, each indicator was evaluated in terms of its validity, reliability, and on-farm feasibility. Some valid indicators were identified, but a lot of the validity evidence is based on their absence when a negative situation is present; furthermore, only a few indicators are available in the domains of Nutrition and Health. Reliability has been seldom addressed. On-farm feasibility could be increased by developing specific sampling strategies and/or relying on the use of video- or automatic-recording devices. In conclusion, several indicators are potentially available (e.g., synchronisation of lying and feeding, coat or fleece condition, qualitative behaviour assessment), but further research is required.

How mammals stay healthy in nature: the evolution of behaviours to avoid parasites and pathogens

Mammals live and thrive in environments presenting ongoing threats from parasites in the form of biting flies, ticks and intestinal worms and from pathogens as wound contaminants and agents of infectious disease. Several strategies have evolved that enable animals to deal with parasites and pathogens, including eliminating away from the sleeping-resting areas, use of an array of grooming techniques, use of saliva in licking, and consuming medicinal plant-based compounds. These strategies all are species-specific and reflect the particular environment that the animal inhabits.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.

Effects of sex and body size on ectoparasite loads in the northern flying squirrel (Glaucomys sabrinus)

Ectoparasites can have profoundly negative fitness consequences for host organisms. Sex differences in parasite load have been documented in many mammals, and have been attributed either to the allocation of energy to growth rather than the immune system in mammals exhibiting male-biased sexual size dimorphism or to the immunosuppressive qualities of testosterone. In addition, ectoparasites can have negative effects on body size and condition, as energy is allocated to the immune system rather than to growth and maintenance. Here, we used the northern flying squirrel (Glaucomys sabrinus (Shaw, 1801)) and its ectoparasites to test two predictions: (1) males are more heavily parasitized than females and (2) individuals with high ectoparasite loads will be in poorer condition and be smaller than individuals with low ectoparasite loads. Males were significantly more parasitized than females, and there was a nonsignificant trend for small males to be more parasitized than large males. Because the northern flying squirrel is not sexually dimorphic, the immunosuppressive qualities of testosterone may explain the sex differences in ectoparasite load. Ectoparasites may also influence skeletal growth rates, and males that are more susceptible to ectoparasites may simply be unable to allocate as much energy to growth and are thus structurally smaller.

Role of grooming in biological control of ticks

Although many species of wild bovids live in tick infested environments, tick loads are usually kept to very low levels, primarily by frequent self grooming. Evidence from numerous studies on antelope in Africa strongly support the concept that the delivery of bouts of grooming reflects programmed grooming rather than stimulus driven or reactive grooming. In other words, grooming occurs in response to an endogenous generator that produces grooming bouts at periodic intervals, resulting in removal of ticks before they attach and begin to feed. In the same tick exposure environment, animals that groom most have the fewest ticks. The rate of programmed grooming is modulated by a number of interspecific and intraspecific determinants. Interspecific determinants include adult body size and whether or not the evolutionary habitat is tick dense or tick sparse. Intraspecific determinants include developmental stage of growth, gender (e.g., territorial male vs. female), ectoparasite exposure, and stage of arousal. Some of the intraspecific determinants appear to be mediated by systemic physiological influences suggesting there may be ways to improve grooming activity in weak groomers, such as cattle.

Testing the interspecific body size principle in ungulates: the smaller they come, the harder they groom

Tick removal grooming may be centrally regulated by an internal timing mechanism operating to remove ticks before they attach and engorge (programmed grooming model) and/or evoked by cutaneous stimulation from tick bites (stimulus-driven model). The programmed grooming model predicts that organismic and environmental factors that impact the cost-benefit ratio of grooming (e.g. body size and habitat) will influence the rate of tick removal grooming. The body size principle predicts that smaller-sized animals, because of their greater surface-to-mass ratio, should engage in more frequent tick removal grooming than larger-bodied animals in order to compensate for higher costs of tick infestation. The body size principle may be tested intraspecifically between young and adult animals, or interspecifically among species of contrasting body sizes. To rigorously test the interspecific body size prediction, we observed the programmed grooming (oral and scratch grooming) of 25 species (or subspecies) of bovids at a tick-free zoological park in which stimulus-driven grooming was ruled out. Multiple correlation analysis revealed highly significant negative correlations between species-typical mass and mean species grooming rates when habitat was controlled for in the model. Species-typical habitat type (classified along a gradient from most open to most closed) was positively correlated with mean oral grooming rate, indicating that species tended to groom at a higher rate in woodland and forest habitats (where typical tick density would be high) compared with more open environments. Species mass accounted for up to two-thirds of the variation in grooming rate across species, whereas habitat accounted for ca. 20% of variation in oral grooming. Similar results were obtained when the analysis was expanded to include 36 species/subspecies of six different families. The body size principle can therefore account for a large proportion of species-typical differences in programmed grooming rate among ungulates. However, to understand the tick defence adaptations of very large mammals that rarely or never engage in oral or scratch grooming (e.g. elephants, giraffes, rhinoceros), alternative tick defence strategies must be considered, such as thick skin, wallowing, rubbing and tolerance of oxpeckers and other tick-eating birds. Copyright 2000 The Association for the Study of Animal Behaviour.