Capture of the vicuña (Vicugna vicugna) for sustainable use: Animal welfare implications - PDF

BIOLOGICAL CONSERVATION xxx (2006) xxx xxx available at journal homepage: Capture of the vicuña (Vicugna vicugna) for sustainable use: Animal welfare

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BIOLOGICAL CONSERVATION xxx (2006) xxx xxx available at journal homepage: Capture of the vicuña (Vicugna vicugna) for sustainable use: Animal welfare implications C. Bonacic a,b, R.E. Feber b, D.W. Macdonald b, * a Department of Animal Science, Faculty of Agriculture and Forestry Science, Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago, Chile b Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Tubney House, Abingdon Road Tubney, Abingdon, Oxon OX13 5QL, United Kingdom ARTICLE INFO ABSTRACT Article history: Received 31 March 2005 Received in revised form 5 November 2005 Accepted 18 November 2005 Keywords: Capture Stress Camelids Sustainable use Andean communities Animal welfare The current program of vicuña conservation includes their live-capture for wool harvest in the Andes Region in northern Chile. Here, we describe studies that assess the impacts on the species of different variables relating to the capture process. The immediate physical and physiological effects on vicuña of contrasting capture methods, chase distances and restraint were measured. Comparisons between two methods of capture showed that cortisol concentrations were higher in animals herded using vehicles alone compared to those herded using a combination of vehicles and local people on foot. Blood glucose levels, heart rate and respiratory rate showed an immediate but ephemeral response to herding into a corral. The range of distances over which animals were herded caused less noticeable changes in blood and physical parameters. The most marked changes were associated with restraint, during which there were significant increases in creatin kinase, packed cell volume and rectal temperature. The implications of changes in these parameters on vicuña welfare and conservation are discussed. Ó 2005 Elsevier Ltd. All rights reserved. 1. Introduction The vicuña (Vicugna vicugna), a South American wild camelid, has been captured, handled and sheared since the 15th century, when the Inca Empire conducted the chaku throughout the Andes of South America (Hurtado, 1987; Torres, 1992). The chaku consisted of herding thousands of vicuña into stone corrals for shearing. Local people surrounded large areas and walked behind the animals towards large corrals. Although large numbers of animals were sheared by this method, associated morbidity and mortality probably had little effect on their populations because the process was conducted only once in every 4 years in any given region. When Europeans arrived in South America, the traditional chaku was replaced by indiscriminate hunting (Hoffmann et al., 1983; Cueto et al., 1985; Hurtado, 1987; CONAF, 1991). This, as well as livestock competition and possibly disease brought by domestic European livestock, led to a drastic decline in vicuña numbers over the last hundred years (Koford, 1957). Now, after 30 years of protection, the vicuña has recovered from its previous endangered status and a program of sustainable use is now in place (Bonacic et al., 2003). This sustainable use program is intended to provide economic benefits to local indigenous communities, thereby fostering the species conservation. The sustainability of this programme is being questioned (Lichtenstein and y Vilá, 2003) although it seems * Corresponding author: Tel.: ; fax: address: (D.W. Macdonald) /$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi: /j.biocon 2 BIOLOGICAL CONSERVATION xxx (2006) xxx xxx that capturing and releasing back to the wild is not detrimental to vicuna in the ways that it is in many other cases in South America (i.e. other ungulates, see Altrichter, 2005). However, several aspects of the effects of capture for shearing on wild vicuña are yet unknown. There are more than a quarter of a million animals in 5 countries and more than 43 tons of fibre have been sold over the last 10 years. Hence, many small enterprises are starting to capture animals for shearing (Lichtenstein and y Vilá, 2003). Yet there are no animal welfare recommendations available to practitioners, and physiological and ecological findings are not linked in previous studies (Bonacic et al., 2002). Current policies for vicuña management include practices such as capture and shearing of wild animals, farming, ranching, and translocation and reintroduction (Cueto et al., 1985; Torres, 1987, 1992; Urquieta and Rojas, 1990; Rebuffi, 1993; Urquieta et al., 1994; Wheeler and Hoces, 1997; Galaz, 1998). Despite the importance of handling in the management of vicuña populations, little is known about their response to handling and captivity. However, it is likely that vicuña become stressed by human contact in a similar way to other wild ungulates (Wesson et al., 1979). Poor welfare may add a new mortality factor and increase the risk of less efficient captures in the future, affecting population and economic viability of the utilisation programme. Therefore, this paper addresses the potential animal welfare consequences of capturing and shearing wild vicuñas. Animal welfare is determined by the degree of adaptation that animals can achieve in human-designed environments, without experiencing any suffering. Since wild vicuñas are driven into human made facilities, restrained, handled and sheared, it is likely that animal welfare problems may occur. Capture and transportation can cause significant stress in wild ungulates, as well as in carnivores and birds (Bailey et al., 1996; DeNicola and Swihart, 1997; Grigor et al., 1998; Little et al., 1998). In ungulates, such as red deer (Cervus elaphus) and white-tailed deer (Odocoileus virginianus), capture and immobilisation are known to cause stress, as indicated by changes in haematological and biochemical blood constituents (Wesson et al., 1979; Vassart et al., 1992; Beringer et al., 1996; DeNicola and Swihart, 1997; Marco et al., 1998). Specifically, capture and restraint can cause capture myopathy, also known as exertional myopathy, a syndrome observed in wild and domestic animals (for a review see Wesson et al., 1979; Beringer et al., 1996; Williams and Thomas, 1996; DeNicola and Swihart, 1997). Capture myopathy is caused by complex metabolic changes that may result in per-acute (immediate, within seconds or minutes) fatal acid base and electrolyte imbalances (Fowler, 1989). Changes in biological and haematological parameters vary according to the capture method, species and previous capture experience of the animals (Morton et al., 1995). However, some general trends can be described. Several physiological variables are affected by capture stress in a manner similar to stress induced by exercise. The variables likely to respond immediately are core body temperature (as reflected by rectal temperature), cathecholamine levels, heart rate, respiratory rate and packed cell volume, as is the case in other species (Eckert and Randall, 1983; Radostits et al., 1994; Schmidt-Nielsen, 1997; Harris et al., 1999). A less acute response (i.e. from minutes to hours) should be observed in blood glucose, plasmatic cortisol concentrations and creatin kinase (Coles, 1980; Kaneko et al., 1997; Bateson and Wise, 1998; Harris et al., 1999). Finally, some parameters may change within hours to days, such as aspartate aminotransferase, total protein and blood urea nitrogen as well (Kaneko et al., 1997; Harris et al., 1999). Against this background, we would expect different methods of capture to have different effects on vicuña, and studying these could reveal ways to substantially reduce stress before shearing. Several capture methods for shearing are currently used for vicuñas in South America (Bonacic and Macdonald, 2003). The simplest capture method, which emulates the ancient chaku and is currently used in Perú (Wheeler and Hoces, 1997), involves people slowly herding groups of vicuña into a wire-fenced corral (Bonacic and Gimpel, 2001; Bas and Bonacic, 2003). An alternative method uses vehicles (motorbikes and pick-up trucks) to chase small groups of animals for up to 5 km into fenced corrals (Bonacic, 2000). This is the most common system used in Chile (Bonacic and Gimpel, 2001). These two methods differ in the speed of the chase and the amount of time for which animals are held in captivity (Bonacic and Macdonald, 2001, 2003). An intermediate method, which combines vehicles and people, has also been used in Chile and Argentina. Vehicles herd groups from the perimeter of the capture site and people help to enclose the animals when they approach the corral (Bonacic et al., 2001). Once animals have been enclosed there, they are either restrained (tied up by ropes in sternal recumbency) before shearing begins or, alternatively, held unrestrained in an adjacent corral (Bonacic, 2000). This study investigated how these last two contrasting capture systems (using vehicles only or a combination of vehicles and people walking on foot), distance over which vicuñas were herded, and whether or not they were restrained affected their physiology. We conducted a clinical examination and measured blood parameters immediately after capture. As a consequence of the capture assessment, a series of animal welfare recommendations are suggested in order to minimise any negative consequences of the capture of this wild species for shearing. 2. Materials and methods The studies were conducted on sub-sets of free-living animals and involved the observation of capture and handling events for shearing organised by local people and the Chilean Government. Captures were carried out in Las Vicuñas National Reserve (Chile), Parinacota Province in Northern Chile (209,131 ha; South and West ). Rainfall there (annual mean mm) is concentrated in summer, between December and March. Winter is dry and cold between May and August. July is the coldest month of the year with 0.04 C and January is the warmest month of the year with a mean of 8 C(Bonacic and Macdonald, 2003). A total of 407 vicuñas were captured between March 1997 and November 1998 in 41 unrelated capture events. The effect of capture on the animals was assessed for all subjects pooled together and compared to reference values from captive vicuña (see Bonacic and Macdonald, 2003 for details of captive BIOLOGICAL CONSERVATION xxx (2006) xxx xxx 3 in situ stress studies). The studies were conducted on 3 subsets of animals, concerning, respectively, the effects of (1) capture method, (2) herding distance and (3) restraint, on a range of physiological variables. Blood samples were taken by jugular venepuncture and details of each laboratory test are available in studies conducted by the same authors (Bonacic and Macdonald, 2003; Bonacic et al., 2003). Each physical and blood parameter was checked for normality and homocedasticity (Gurevitch and Scheiner, 1993; Underwood, 1997). Blood parameters from captured animals were compared with reference values from habituated captive vicuña held in the same study area, captive-born vicuña taken from private collections and reference values in the published literature for the vicuña and other South American camelids (Bonacic, 2000; Bonacic et al., 2003) The effect of capture method Two contrasting capture methods were compared within the same location and season, in October 1997 and 1998, to evaluate how physical and physiological variables were affected by the procedure of capture. The capture methods differed regarding the herding system. One method used vehicles only, while the other employed a combination of vehicles and people. The capture of vicuña with vehicles consisted only of a small team of professional rangers using vehicles to herd animals into a corral where they were held, unrestrained, until shearing. Vehicles were Chevrolet Luv pick ups and motorbikes with noise levels below 80 db each (European Parliament fact sheet: Noise, 2001). The second method, capture with vehicles and people, involved vehicles chasing the animals until they reached the entrance of the funnel formed by the fences leading to the corral, followed by local communities (30 40 people) and rangers herding the animals into the corral by walking behind them (in silence) while holding a rope with coloured plastic strips used as visual barriers. Both methods used a corral that was divided into four sub-corrals: reception, enclosure, shearing area and pre-release corral. Gates connected sub-corrals and plastic covers prevented sight between them. The capture parameters recorded were herding distance (m), herding time (min) and mean speed (km/h). Herding distances were recorded for each capture event using motorbike speedometers. Herding time was recorded from a vehicle behind the motorbikes from the moment the animals started to run (start time) until the chase ended with the animals enclosed in the capture corral. The mean speed of herding was determined on the basis of distance and time or, where distance could not be measured, by means of repeated records of the vehicle speedometer. To evaluate the effects of herding distance and herding time, a linear regression model was used, with physical parameters (rectal temperature, heart rate and respiratory rate) and blood parameters (blood glucose, packed cell volume, creatin kinase, cortisol and white blood cell count) as dependent variables, and herding time or herding distance as the independent factor. The two capture methods were compared within age categories using a mixed random nested model (SPSS, 1997). The model was nested because individuals belonged to social groups, and were herded from the total population into the capture facilities. This approach also took account of the fact that individuals were sampled at different times within each group. A mean for each group was compared with the mean of other groups and reflected the effect of capture method. Twenty-three groups of vicuña were sampled to study the effect of capture with vehicles alone (n = 167 vicuña) in October 1997and October 1998 and compared with six groups that were captured by vehicles and people in October 1997 (n = 56 vicuña) The effect of herding distance The effect of the herding distance was studied by comparing blood samples from the first animal captured from independent groups that were herded for different distances The effect of restraint The effect of restraint on vicuña was studied in March A sample of vicuñas, captured by herding with vehicles into a semi-circular corral, was restrained with ropes for different lengths of time and the effects on physical and blood parameters were measured. The first animal captured in each group was sampled immediately, therefore it was considered to have no effect of restraint and was used to compare against the other subjects. A second group of animals that was restrained for less than 15 min were considered the short restraint time group and a third group that was restrained for more than one hour constituted the long restraint time group. The animals remained restrained throughout the period of handling and sampling and were released back to the wild on the same day. A second group of animals, held in a corral prior to blood collection without the use of ropes (unrestrained) for a variable period of time, was also studied and the same parameters were measured. These animals were also released back to the wild on the same day of capture. Restrained animals were compared with unrestrained animals correcting by restraint time (covariance). This allowed the comparison of the effect of restraint for both groups and eliminating the confounding effect of different sampling times since captivity and restraint began. 3. Results Overall, capture events were characterised by a mean herding time of 10 min: 52 s ± 45 s (n = 29 groups) with a mean herding distance of 3999 m ± 270 m (n = 28 groups) and a mean speed of 25.7 km/h ± 1.7 km/h (n = 29 groups). The mean time that each animal was held in the corral before sampling and shearing was 16 min ± 2 s. In total, 33 independent groups of vicuña were rounded up, captured and sampled. The mean group time in captivity was 1:38 h ± 8 min (n = 33). Capture with vehicles alone was the fastest method, with a mean speed of 34.4 km/h ± 3.1(s.e.) compared to capture by vehicles and people on foot (4.9 km/h ± 6.6 s.e.). Captures with vehicles (n = 23 groups) also covered greater distances (range m) than vehicles and people on foot (range m; n = 6 groups). Overall, there was no significant difference in herding time between the two herding methods used 4 BIOLOGICAL CONSERVATION xxx (2006) xxx xxx (F 1,3 = 0.6, p = 0.5). This can be explained by the significant difference in herding distance between methods (F 3,32 = 3.3, p = 0.03). Vehicles had a larger range allowing more rapid herding and capture than could be achieved by people on foot. Total time that the animals were maintained in captivity was positively related to group size captured (R 2 : 0.71, F 1,41 = 103, p 0.001). Larger groups remained for longer periods of time in captivity because they were not released until the last animal of their group had been sampled. Individual mean waiting time (total group time/group size) to be sampled and sheared was similar between capture methods (16 ± 2 min; F 1,38 = 1.2, p = 0.2; range: 1 6 h). That is, larger groups did not cause an efficiency loss in each individual handling time, considering the range of group sizes captured in this study (range 1 19 animals). Less than 1% of all captured animals presented trauma and nose bleeding as a consequence of crushing against posts of the corral. No mortality was recorded during the capture and handling. Crias (less than 1 year old animals) were immediately removed from the group and kept separately to avoid physical damage by crushing between adults The effects of capture Five variables were affected by capture when compared with baseline values from captive animals (Bonacic and Macdonald, 2003; Bonacic et al., 2003). Rectal temperature, heart rate, respiratory rate, creatin kinase, and plasmatic cortisol concentration all increased as a result of capture, beyond the normal range described for vicuña and other South American camelids (Bonacic and Macdonald, 2003). For example, plasmatic cortisol was 41% higher than baseline values, suggesting an active response to capture. In contrast, blood glucose, packed cell volume, aspartate amino transferase, plasma protein, blood urea nitrogen, blood cell count, differential white blood cell counts and N:L ratio were within normal ranges suggested for the species The effects of herding distance There was no significant effect of herding distance on any of the physical and blood variables measured. The effect of herding was studied in 37 vicuña with a mean herding distance of 3917 ± 281 m (range m) and a mean herding time of 10 min: 39 s ± 43 s (range 2 22 min). Only rectal temperature, heart rate and respiratory rate reached values outside the normal range for the species, indicating a short agitation response to exercise (Table 2) The effects of restraint Animals that were restrained in the enclosures had significantly higher creatin kinase levels, increased neutrophil: lymphocyte (N:L) ratio, packed cell volume and blood glucose (Table 1) compared to unrestrained animals. Longer restraint times also caused significant changes in the blood parameters, indicating excessive exertion. Longer restraint time was significantly correlated with an increase in blood enzyme values (creatin kinase and aspartate aminotransferase) and blood parameters (packed cell volume, N:L ratio). Animals with higher creatin kinase also showed higher levels of blood glucose and higher rectal temperature. The N:L ratio tripled in animals restrained for longer periods (Fig. 1) and creatin kinase rose ten times above values recorded from unrestrained animals (Fig. 2). Comparison with the mean of the first ani
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