Effects of provision of drinking water on the behavior and growth rate of group-housed calves with different milk allowances.

Despite the clear importance of drinking water, calves are not always provided water on farm for the first few weeks of life. The main objective of this study was to investigate the effects of water provision (access or no access) and milk allowance (high or low) on the behavior and growth rate of calves. Fifty mixed-breed calves were each assigned to 1 of 4 treatments: (1) water and high (10 L/d) milk allowance (n = 13), (2) no water and high milk allowance (n = 12), (3) water and low (5 L/d) milk allowance (n = 12), or (4) no water and low milk allowance (n = 13). Visits to the water trough, water intake, milk drinking behavior (visits and drinking speed), proportion of observations eating hay and calf starter, and lying behavior were recorded from when the calves were, on average, 5 d of age (standard deviation: 2 d) for 4 consecutive weeks. Calves were weighed weekly. Some calves began to visit the water trough from the start of the recording period, as early as 4 d of age, and water intake increased with age for all calves that had access to it. This increase was greater for calves provided a high milk allowance. Water intake increased with ambient temperature, which highlights the importance of providing drinking water in warm conditions. Overall, calves spent a greater proportion of observations eating hay and calf starter with age. The provision of drinking water was associated with a greater proportion of observations eating hay but less eating calf starter. The increase in the proportion of observations eating calf starter with age was greater for calves on a low milk allowance than of those provided a high milk allowance; this is likely due to calves on a low milk allowance searching for nutrients and energy. Calves on a high milk allowance grew faster and spent more time lying compared with calves with a low milk allowance, thus suggesting greater satiety of well-fed calves. Our results suggest that calves should have free access to drinking water from birth and that access to drinking water may aid in hay (fiber) intake and possibly rumen development.

Physiological and behavioral responses as indicators for early disease detection in dairy calves.

This study investigated physiological and behavioral responses associated with the onset of neonatal calf diarrhea (NCD) in calves experimentally infected with rotavirus and assessed the suitability of these responses as early disease indicators. The suitability of infrared thermography (IRT) as a noninvasive, automated method for early disease detection was also assessed. Forty-three calves either (1) were experimentally infected with rotavirus (n = 20) or (2) acted as uninfected controls (n = 23). Health checks were conducted on a daily basis to identify when calves presented overt clinical signs of disease. In addition, fecal samples were collected to verify NCD as the cause of illness. Feeding behavior was recorded continuously as calves fed from an automated calf feeder, and IRT temperatures were recorded once per day across 5 anatomical locations using a hand-held IRT camera. Lying behavior was recorded continuously using accelerometers. Drinking behavior at the water trough was filmed continuously to determine the number and duration of visits. Respiration rate was recorded once per day by observing flank movements. The effectiveness of inoculating calves with rotavirus was limited because not all calves in the infected group contracted the virus; further, an unexpected outbreak of Salmonella during the trial led to all calves developing NCD, including those in the healthy control group. Therefore, treatment was ignored and instead each calf was analyzed as its own control, with data analyzed with respect to when each calf displayed clinical signs of disease regardless of the causative pathogen. Milk consumption decreased before clinical signs of disease appeared. The IRT temperatures were also found to change before clinical signs of disease appeared, with a decrease in shoulder temperature and an increase in side temperature. There were no changes in respiration rate or lying time before clinical signs of disease appeared. However, the number of lying bouts decreased and lying bout duration increased before and following clinical signs of disease. There was no change in the number of visits to the water trough, but visit duration increased before clinical signs of disease appeared. Results indicate that milk consumption, IRT temperatures of the side and shoulder, number and duration of lying bouts, and duration of time spent at the water trough show potential as suitable early indicators of disease.

Pain sensitivity and injury associated with three methods of disbudding goat kids: Cautery, cryosurgical and caustic paste.

Pain sensitivity and skull/brain injury associated with cautery, cryosurgical and caustic paste disbudding were evaluated in goat kids. Kids (reared for meat; n=280) were randomly assigned to one of four treatments (n=70 per treatment): (1) sham-handling (SHAM) or (2) cautery (CAUT), (3) cryosurgical (CRYO) or (4) caustic paste (CASP) disbudding. A pain sensitivity test was carried out 15min pre-treatment and 1h post-treatment. Skull/brain injury was assessed at post-mortem examination. Kids with evidence of injury to the skull/brain, as well as a random sample of kids (n=15 per treatment) without evidence of skull/brain injury, were selected for histological examination of brain tissue. Average daily gains (ADG) were calculated from body weight measurements taken 10min pre-treatment and then at 2, 7 and 14days post-treatment as a measure of the potential effects of pain or injury on growth. CASP and CRYO kids displayed higher pain sensitivity post-treatment than CAUT or SHAM kids, suggesting that they experienced more acute pain 1h post-treatment. One of 70 CAUT kids had a perforated skull, but there was no histological evidence of brain injury in this animal; a further nine CAUT kids exhibited hyperaemia of the skull. The other treatments did not result in injury to the skull/brain. There was no evidence of a difference in ADG across treatments. Caustic paste and cryosurgical disbudding resulted in greater acute pain sensitivity than cautery disbudding; however, cautery disbudding has the potential to cause skull injury if performed incorrectly.

Measurement of dairy calf behavior prior to onset of clinical disease and in response to disbudding using automated calf feeders and accelerometers.

We determined if feeding and lying behavior, recorded by automatic calf feeding systems (ACFS) and accelerometers, could be used to detect changes in behavior before onset of neonatal calf diarrhea (NCD) or in response to disbudding pain in dairy calves. At 4 d of age, 112 calves had accelerometers attached to their hind leg and were housed in pens with ACFS. Calves were examined daily for signs of illness or injury. Of the 112 calves monitored, 18 were diagnosed with NCD; activities of calves with NCD were then compared with those of 18 healthy controls (calves that had no symptoms of NCD, other illnesses, or injury). Feeding (milk consumption and the number of rewarded and unrewarded visits to the feeder) and lying behavior during the 5 d leading up to calves displaying clinical signs of NCD were analyzed. Calves with NCD performed fewer unrewarded visits and consumed less milk than healthy calves during the 2- and 4-d periods before diagnosis with NCD, respectively. Calves with NCD tended to perform fewer lying bouts than healthy calves over the 5-d period before diagnosis with NCD. At 3 wk of age, a subset of 51 healthy calves were allocated to 1 of 5 treatment groups: (1) sham handling (SHAM, n = 10), (2) cautery disbudding (DB, n = 11), (3) administration of local anesthetic (LA) and DB (LA+DB, n = 11), 4) administration of a nonsteroidal anti-inflammatory drug (NSAID) and DB (NSAID+DB, n = 9), and (5) administration of LA, NSAID and DB (LA+NSAID+DB, n = 10). Feeding and lying behavior were recorded continuously for 24 h pre- and postdisbudding. We found no effect of treatment on the number of rewarded or unrewarded visits to the feeder and milk volume consumed 24 h before administration of treatments. During the 24-h postdisbudding period, SHAM calves performed more unrewarded visits than DB, LA+DB, and NSAID+DB calves, but the number of unrewarded visits did not differ between SHAM and LA+NSAID+DB calves. During the first hour of the posttreatment period we noted a difference in lying times among treatments, with DB and NSAID+DB calves spending less time lying than SHAM calves and lying times being similar between SHAM, LA+DB, and LA+NSAID+DB calves. The ACFS and accelerometers have the potential to automatically gather valuable information regarding health status and pain in calves. Therefore, it may be advantageous to combine both of these measures (ACFS and accelerometers) when evaluating NCD on farm or pain in calves in future research.

Oxytocin Acting in the Nucleus Accumbens Core Decreases Food Intake.

Central oxytocin (OT) promotes feeding termination in response to homeostatic challenges, such as excessive stomach distension, salt loading and toxicity. OT has also been proposed to affect feeding reward by decreasing the consumption of palatable carbohydrates and sweet tastants. Because the OT receptor (OTR) is expressed in the nucleus accumbens core (AcbC) and shell (AcbSh), a site regulating diverse aspects of eating behaviour, we investigated whether OT acts there to affect appetite in rats. First, we examined whether direct AcbC and AcbSh OT injections affect hunger- and palatability-driven consumption. We found that only AcbC OT infusions decrease deprivation-induced chow intake and reduce the consumption of palatable sucrose and saccharin solutions in nondeprived animals. These effects were abolished by pretreatment with an OTR antagonist, L-368,899, injected in the same site. AcbC OT at an anorexigenic dose did not induce a conditioned taste aversion, which indicates that AcbC OT-driven anorexia is not caused by sickness/malaise. The appetite-specific effect of AcbC OT is supported by the real-time polymerase chain reaction analysis of OTR mRNA in the AcbC, which revealed that food deprivation elevates OTR mRNA expression, whereas saccharin solution intake decreases OTR transcript levels. We also used c-Fos immunohistochemistry as a marker of neuronal activation and found that AcbC OT injection increases activation of the AcbC itself, as well as of two feeding-related sites: the hypothalamic paraventricular and supraoptic nuclei. Finally, considering the fact that OT plays a significant role in social behaviour, we examined whether offering animals a meal in a social setting would modify their hypophagic response to AcbC OT injections. We found that a social context abolishes the anorexigenic effects of AcbC OT. We conclude that OT acting via the AcbC decreases food intake driven by hunger and reward in rats offered a meal in a nonsocial setting.

Effect of previous handling experiences on responses of dairy calves to routine husbandry procedures.

The nature of human-animal interactions is an important factor contributing to animal welfare and productivity. Reducing stress during routine husbandry procedures is likely to improve animal welfare. We examined how the type of early handling of calves affected responses to two common husbandry procedures, ear-tagging and disbudding. Forty Holstein-Friesian calves (n = 20/treatment) were exposed to one of two handling treatments daily from 1 to 5 weeks of age: (1) positive (n = 20), involving gentle handling (soft voices, slow movements, patting), and (2) negative (n = 20), involving rough handling (rough voices, rapid movements, pushing). Heart rate (HR), respiration rate (RR) and behaviour (activity, tail flicking) were measured before and after ear-tagging and disbudding (2 days apart). Cortisol was measured at -20 (baseline), 20 and 40 min relative to disbudding time. There were no significant treatment differences in HR, RR or behaviour in response to either procedure. However, the following changes occurred across both treatment groups. HR increased after disbudding (by 14.7 ± 4.0 and 18.6 ± 3.8 bpm, positive and negative, respectively; mean ± s.e.m.) and ear-tagging (by 8.7 ± 3.1 and 10.3 ± 3.0 bpm, positive and negative, respectively). After disbudding, there was an increase in RR (by 8.2 ± 3.4 and 9.3 ± 3.4 breaths/min, positive and negative, respectively), overall activity (by 9.4 ± 1.2 and 9.9 ± 1.3 frequency/min, positive and negative, respectively) and tail flicking (by 13.2 ± 2.8 and 11.2 ± 3.0 frequency/min, positive and negative, respectively), and cortisol increased from baseline at 20 min post procedure (by 10.3 ± 1.1 and 12.3 ± 1.1 nmol/l positive and negative, respectively). Although we recorded significant changes in calf responses during ear-tagging and disbudding, the type of prior handling had no effect on responses. The effects of handling may have been overridden by the degree of pain and/or stress associated with the procedures. Further research is warranted to understand the welfare impact and interaction between previous handling and responses to husbandry procedures.

Motivation to obtain a food reward of pregnant ewes in negative energy balance: behavioural, metabolic and endocrine considerations.

Low food availability often coincides with pregnancy in grazing animals. This study investigated how chronic reductions in food intake affected feeding motivation, and metabolic and endocrine parameters in pregnant sheep, which might be indicative of compromised welfare. Ewes with an initial Body Condition Score of 2.7±0.3 (BCS; 0 indicates emaciation and 5 obesity) were fed to attain low (LBC 2.0±0.0,), medium (MBC 2.9±0.1) or high BCS (HBC 3.7±0.1) in the first trimester of pregnancy. A feeding motivation test in which sheep were required to walk a set distance for a palatable food reward was conducted in the second trimester. LBC and MBC ewes consumed more rewards (P=0.001) and displayed a higher expenditure (P=0.02) than HBC ewes, LBC ewes also tended to consume more rewards than MBC ewes (P=0.09). Plasma leptin and glucose concentrations were inversely correlated to expenditure (both P<0.05) and appear to be associated with hunger in sheep. LBC ewes were in negative energy balance, with lower muscle dimensions, plasma glucose, leptin, insulin, cortisol, and insulin-like growth factor-1 concentrations and higher free fatty acids concentrations compared to HBC ewes; metabolic and endocrine parameters of the MBC ewes were intermediate. The high feeding motivation and negative energy balance of low BCS ewes suggested an increased risk of compromised welfare. Imposing even a small cost on a food reward reduced motivation substantially in high BCS ewes (despite high intake when food was freely available). Assessment of a willingness to work for rewards, combined with measures of key metabolic and endocrine parameters, may provide sensitive barometers of welfare in energetically-taxed animals.

Environmental influences on Adelie penguin breeding schedules, endocrinology, and chick survival.

To understand how the social and physical environment influences behaviour, reproduction and survival, studies of underlying hormonal processes are crucial; in particular, interactions between stress and reproductive responses may have critical influences on breeding schedules. Several authors have examined the timing of breeding in relation to environmental stimuli, while others have independently described endocrine profiles. However, few studies have simultaneously measured endocrine profiles, breeding behaviour, and offspring survival across seasons. We measured sex and stress hormone concentrations (oestrogens, testosterone, and corticosterone), timing of breeding, and chick survival, in Adelie penguins (Pygoscelis adeliae) at two colonies in two different years. Clutch initiation at Cape Bird South (CBS; year 1, ~14,000 pairs) occurred later than at Cape Crozier East (CCE; year 2, ~ 25,000 pairs); however, breeding was more synchronous at CBS. This pattern was probably generated by the persistence of extensive sea ice at CBS (year 1). Higher corticosterone metabolite and lower sex hormone concentrations at CBS correlated with later breeding and lower chick survival compared to at CCE - again, a likely consequence of sea ice conditions. Within colonies, sub-colony size (S, 50-100; M, 200-300; L, 500-600; XL, >1000 pairs) did not influence the onset or synchrony of breeding, chick survival, or hormone concentrations. We showed that the endocrine profiles of breeding Adelie penguins can differ markedly between years and/or colonies, and that combining measures of endocrinology, behaviour, and offspring survival can reveal the mechanisms and consequences that different environmental conditions can have on breeding ecology.

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae.

Physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. Different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure that they correlate. We directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the Adelie penguin (Pygoscelis adeliae). Blood and faecal samples were simultaneously collected from individual penguins for comparison and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher mean corticosterone concentrations than females, but the difference was only statistically significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males, perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Our data indicate that faecal sampling appears more suitable for assessing baseline hormone concentrations, whilst plasma sampling may best define immediate responses to environmental events. Consequently, future studies should ensure that they select the most appropriate matrix and method of hormone measurement to answer their research questions.

Bill colour and correlates of male quality in blackbirds: an analysis using canonical ordination.

Carotenoid-dependent plumage displays are widely assumed to be honest indicators of individual health or quality, which are used as cues during mate choice and/or agonistic signalling. Despite the fact that red, yellow and orange pigmentation of bills is common, and also variable between individuals, comparatively little is known about bill colouration as a condition-dependent trait. Furthermore, many studies of avian colouration are confounded by the lack of objective colour quantification and the use of overly simplistic univariate techniques for analysis of the relationship between the condition-dependent trait and individual quality variables. In this study, we correlated male blackbird bill colour (a likely carotenoid-dependent sexually selected trait) with body/condition variables that reflect male quality. We measured bill colour using photometric techniques, thus ensuring objectivity. The data were analysed using the multivariate statistical techniques of canonical ordination. Analyses based on reflectance spectra of male blackbird bill samples and colour components (i.e. hue, chroma and brightness) derived from the reflectance spectra were very similar. Analysing the entire reflectance spectra of blackbird bill samples with Redundancy Analysis (RDA) allowed examination of individual wavelengths and their specific associations with the body/condition variables. However, hue, chroma and brightness values also provided useful information to explain colour variation, and the two approaches may be complimentary. We did not find any significant associations between male blackbird bill colour and percent incidence of ectoparasites or cloaca size. However, both the colour component and full spectral analyses showed that culmen length explained a significant amount of variation in male blackbird bill colour. Culmen length was positively associated with greater reflectance from the bill samples at longer wavelengths and a higher hue value (i.e. more orange-pigmented bills). Larger males may have larger territories or be better at defending territories during male-male interactions, ensuring access to carotenoid food sources. Future studies should elucidate the relationship between bill colour and behavioural measures such as aggressiveness, territory size, song rate and nest attendance.

Laboratory and field evaluation of predator odors as repellents for kiore (Rattus exulans) and ship rats (R. rattus).

Predator odors may serve to stop rats from entering conservation areas or to decrease predation, food consumption, and other damage by rats in areas tainted with predator odor. We compared the efficacy of real predator odors and synthetic odors (derived from the urine and feces of carnivores) as rat repellents with real herbivore odors as controls in a Y maze. We tested six predator odors: cat (Felis catus) urine and feces, mongoose (Herpestes auropunctatus) feces, n-propylthietane, S-methyl, methyl butanol, and isopentyl-methyl sulphide. The herbivore odors we used were: red deer (Cervus elaphus) urine, guinea pig (Cavia porcellus) feces, and white rabbit (Oryctolagus cuniculus) urine. Ship rats (Rattus rattus) and kiore or Polynesian rats (R. exulans) showed no aversion to any of the six predator odors when compared with herbivore odors. Ship rats, however, may have avoided synthesized odors more than real ones. We applied two odors (S-methyl, methyl butanol and n-propylthietane) to purpose-built feeders in native forest but recorded no change in either visitation rate or duration of visits for rodents [rats and mice (Mus musculus)] or possums (Trichosurus vulpecula). The consumption of maize at feeders was correlated with the number and duration of possum visits, but only weakly correlated with the number of visits by rodents. Consumption of maize was unaffected by the odor associated with the feeder. It is unlikely that the odors we tested will be useful in deterring rodents or possums from areas where they have been removed for economic, public health or conservation reasons.

Transmission of Leptospira interrogans serovar Balcanica infection among socially housed brushtail possums in New Zealand.

Leptospira interrogans serovar balcanica is a potential vector being investigated for spreading a biological control agent among introduced brushtail possums (Trichosurus vulpecula) in New Zealand. As previous studies have shown that possums are unlikely to contract leptospirosis through a contaminated environment alone, the objective was to determine whether L. interrogans serovar balcanica could be transmitted between sexually mature, socially housed possums. Possums were infected experimentally with L. interrogans serovar balcanica and housed in pairs or groups with uninfected possums for either 70 or 140 days, during the breeding or non-breeding seasons. No transmission occurred between any infected and uninfected possums during the non-breeding season. However, transmission occurred between females that had been socially housed in pairs or groups in the breeding season. Mixed sex transmission also occurred in pairs and groups, both from males to females and from females to males. Mixed sex transmission usually occurred rapidly (< 44 days) and was not associated with the production of offspring. No transmission occurred between males during the breeding or the non-breeding seasons. Transmission probably occurs as a result of affiliative or sexual behaviour, but is unlikely to occur through fighting. The social transmission pathways determined in this study suggest that L. interrogans serovar balcanica may have the transmission attributes desired in a vector for biological control.

Physiological responses of red deer (Cervus elaphus) to conditions experienced during road transport.

Remote heart rate and blood sampling devices were attached to transported red deer stags to assess the effects of several road transport parameters on physiological responses associated with welfare. Stocking density had a significant influence on heart rates and plasma lactate concentrations. Heart rates of deer transported at a high density (0.38 m2 per 84 kg animal) were 10-13% higher than those of deer transported at medium (0.62 m2) or low densities (0.85 m2). Lactate concentrations of animals transported at a high or medium density were 30-40% higher than those of deer transported at a low density. Heart rates of deer transported in the back or middle pens were 7-8% higher than those of deer transported at the front, and lactate concentrations were 30-40% higher. Because elevated heart rates and lactate concentrations are indicative of physiological or psychological challenges, it may be best to transport deer at densities below the currently recommended limit (0.40 m2/100 kg animal) and to keep deer nearer the front of the crate. Although hematocrit, sodium, and cortisol concentrations were not sensitive to variation in stocking density or the animal's position within the crate, cortisol and sodium concentrations increased significantly with time in transit; heart rates and lactate concentrations decreased significantly during the journey. A 2-fold increase in cortisol during the 2-h trip suggests that the length of journeys should be minimized to avoid welfare problems.

Leptospirosis in brushtail possums: is Leptospira interrogans serovar balcanica environmentally transmitted?

In New Zealand, the biological control of introduced brushtail possums (Trichosurus vulpecula) may be the only affordable option for achieving a significant long term reduction in pest numbers on a national scale. Leptospira interrogans serovar balcanica is among the potential biocontrol agents and vectors currently being investigated for this purpose. As the transmission pathways of L. interrogans serovar balcanica between possums are poorly understood, the objective of the study was to determine whether infection could result from exposure to contaminated environments. Sixteen individually housed, uninfected possums, in three groups, were regularly exposed over a period of 32 days to contaminated cages or grass enclosures of 16 other experimentally infected possums all shedding leptospires in their urine. None of the 16 challenged possums developed serological evidence of L. interrogans serovar balcancia infection. These results suggest that this organism is unlikely to be transmitted environmentally, supporting previous circumstantial evidence that social contact may be required for transmission of L. interrogans serovar balcanica between possums.

Effects of experimental infection with Leptospira interrogans serovar balcanica on the health of brushtail possums (Trichosurus vulpecula).

Data on changes in the condition and feeding behaviour of captive brushtail possums (Trichosurus vulpecula) following an experimental infection with Leptospira interrogans serovar balcanica are presented. The daily food intake of nine experimentally infected possums was recorded for 47 days before and 24 days after balcanica inoculation (0.5 ml intraperitoneally containing about 10(8) organisms). Body weight was recorded seven times between 42 days before and 96 days after inoculation. The mean daily food intake of infected possums decreased significantly throughout the 24-day recording period after infection with balcanica. The mean body weight of infected possums had decreased significantly by day 26 after inoculation but had fully recovered by day 96 after inoculation. Uninfected and control possums showed no significant changes in mean daily food intake or mean body weight over the experimental period. These data suggest that the health of possums is temporarily affected by infection with balcanica, but that overt disease caused by balcanica is unlikely. These findings support previous research suggesting that balcanica has only subclinical effects on possums.

Chemical cues associated with visually elaborate aggressive displays of three-spine sticklebacks.

A two-choice chamber was used to determine if three-spine sticklebacks could distinguish between water conditioned by a displaying male and water conditioned by a male that was active but not displaying. Both nonterritorial males and gravid females appeared to recognize which male was displaying; i.e., males and females were more likely to bite or bump the substrate in front of a chamber receiving water from a displaying male. Nonterritorial males were more likely to enter the chamber receiving water from a male that was not displaying; gravid females entered the chamber that received water from the displaying male more often than males but not more often than expected by chance. The aggressive displays of male sticklebacks may have both visual and chemical components; alternatively, the fish may have been capable of detecting chemical by-products associated with different rates of physical activity.