Behavioural responses related to increasing core body temperature of grazing dairy cows experiencing moderate heat stress

Exposure to direct solar radiation, high ambient temperature, lack of wind movement, coupled with own metabolic heat production, makes grazing dairy cows vulnerable to heat stress. In pastures, it would be beneficial to monitor heat stress by observable changes in behaviour. We hypothesised that grazing dairy cows exhibit behavioural changes due to increasing heat load in temperate climate. Over two consecutive summers, 38 full-time grazing Holstein dairy cows were investigated in 12 experimental periods of up to 3 consecutive days where the cows were repeatedly exposed to various levels of moderate heat load determined by the comprehensive climate index (CCI). The CCI defines the ambient climate conditions, combining air temperature, relative humidity, solar radiation and wind speed. Vaginal temperature (VT) was automatically measured as an indicator of heat stress. In addition, as a less invasive method, we investigated if reticular temperature (RET) can be indicative of heat stress on pastures. Walking activity, lying-, feeding, and ruminating durations were recorded continuously with sensors. Respiration rate (RR), proximity to and competition at the water trough, social licking, self-licking, inter-individual distance, and fly intensity were directly observed. Data were analysed in the morning (0900-1100 h) and during the hottest time of day when cows were on pasture (1230-1430 h). The VT and RET showed similar patterns in relation to the CCI, suggesting that RET can be suitable for continuous monitoring of heat stress on pastures. In the morning, the cow's VT and RET did not relevantly react to the CCI. During the period 1230-1430 h, the cow's mean VT (mean vaginal temperature (VTMEAN); range: 37.7-40.3 °C) and mean RET (mean reticular temperature; range: 37.0-41.1 °C) were positively related to the mean CCI (mean comprehensive climate index) in this period (mean ± SD: 25.9 ± 5.71 °C). For cows with greater VTMEAN, an increased mean RR and decreased durations of walking, lying, feeding, and ruminating were found. These cows were also more likely to be in proximity to the water trough and to have small inter-individual distances. Changes in these traits seem to reflect behavioural adaptations to heat stress in a temperate climate and could be used to detect the heat stress in individual dairy cows on pastures.

Agonistic behaviour of dairy goats and sheep during feeding - A pilot study on Swiss farms with mixed rations

INTRODUCTION

Feeding mixed rations is a widely used practice for cattle to ensure the intake of a balanced diet and to reduce competition for food. It is unknown, whether mixed rations have the same advantages for small ruminants because they differ from cattle in their feeding and social behaviour. In this observational pilot study, an array of feeding and social behaviour of dairy goats and sheep fed ad libitum with mixed rations on Swiss farms was investigated. Twelve dairy goat and 12 dairy sheep farms feeding mixed rations were visited once during the winter feeding period. Data on the feeding management, feeding place design and the composition of the mixed rations were collected. The number of animals feeding simultaneously and the number and type of agonistic interactions during feeding were assessed by direct observations for 6 hours after the morning feed-distribution. The feeding management and the composition of the mixed rations were very heterogeneous among farms. The feed rations were mostly well balanced in relation to energy and protein and covered the requirements for the daily production of about 2,5 kg of milk. In terms of feeding simultaneously, sheep were more synchronous than goats. The mean number of agonistic interactions per feeding place within 6 hours were 3,8 in goats and 1,8 in sheep; thus, the probability to observe agonistic behaviour is higher in goats than in sheep. Goats and sheep also differed in the frequency of types of agonistic interactions. Overall, the occurrence of agonistic interactions between animals during feeding decreased with higher numbers of feeding places per animal and longer periods of time since the feed distribution. To conclude, when feeding mixed rations, agonistic interactions related to feeding are more frequent in goats but also occur in sheep to a considerable extent. They can be decreased by offering more feeding places.

Effects of the anti-sucking device «SuckStop Müller» on calf behavior

INTRODUCTION

When cross-sucking persists beyond calf-hood, it represents an important problem in dairy heifers and cows. It can cause teat injuries and severe mastitis and lead to significant economic losses. The «SuckStop Müller,» a novel anti-sucking device, is designed to give the calf a negative feedback when cross-sucking on a conspecific. The aim of this study was to assess whether wearing a SuckStop would result in behavioral changes other than cross-sucking and thus, impair welfare in the short- and longer-term. Sixteen group-housed calves were observed in groups of four on five days, before and after fitting the SuckStop: day -2, day -1, day 0, day 1, and day 9. Maintenance behaviors (e.g., feeding, drinking, lying) were recorded using instantaneous scan sampling. In addition, the frequency of contact behaviors (e.g., exploring the feeding fence, touching own body) was recorded by means of continuous focal animal observations. Contact behaviors were classified as «impaired» or «normal» depending on whether or not the calf flinched in response to the contact. Finally, the number of visits to the milk and concentrate feeders was extracted from the computer-controlled feeding system. Fitting a SuckStop resulted in a higher proportion of observations spent lying and less exploration behavior on day 0 and day 1 than on day -2, day -1, and day 9. On day 0 and day 1, 6,3 % of exploration behaviors were classified as impaired, compared to 0,4 % (day -2, day -1) before and 0,2 % (day 9) after fitting the SuckStop. On day 9, all calves had superficial ulcerations on the nasal septum. In four calves, these ulcerations were moderately severe, whereas all other calves had slight ulcerations. In summary, the calves habituated quickly to this novel anti-sucking device. Follow-up studies are necessary to assess the long-term relevance of tissue alterations in the nasal septum for calf welfare as well as the effect of the SuckStop on cross-sucking behavior.

Influence of weaning method on health status and rumen development in dairy calves

In the artificial rearing of dairy calves, the same feeding plan is applied to all animals during the milk-feeding period, with individual differences attributable to development or health status rarely considered. The aim of this study was 1) to analyze whether the parameters of feeding behavior automatically recorded by a feeding computer and weight gain are suitable for predicting the health status and rumen development of male dairy calves, and 2) to compare a conventional weaning method (end of milk provision at 12 wk of age, n = 23 calves) with a concentrate-dependent weaning method (with reduction in the milk amount depending on the consumption of concentrate, n = 24). The health status of each animal was evaluated daily by a scoring list (health score), and body temperature was measured automatically during each milk intake. In addition, the number of veterinary treatments per calf was recorded. Rumen development was assessed by measuring rumen papillae in 8 rumen areas after slaughter (n = 24, half of each treatment group). During the milk-feeding period, body temperature was elevated (>/=39.5 degrees C) on 40.8 and 43.2% of all days for calves on the concentrate-dependent weaning method and the conventional weaning method, respectively. Hay and concentrate intake (but not milk intake) and weight gain were clearly affected by health status. In addition, health score and the probability of being treated by a veterinarian were significantly related to decreases in concentrate consumption. During the milk-feeding period, increased body temperature, an increased number of veterinary treatments, and decreases in milk consumption were all associated with reduced weight gain. Calves on the concentrate-dependent weaning method were weaned at an average age of 76 d, which was significantly shorter than the age at the end of milk provision for conventionally fed calves (84 d). Weight gain and health status did not differ between treatment groups. Weight gain was positively associated with papillae length. A treatment effect on rumen development could not be found. We conclude that the concentrate-dependent weaning method allows a faster physiological development without any negative impact on rumen development, weight gain, or health status; we therefore recommend its use in practice.

Effects of frequency and duration of outdoor exercise on the prevalence of hock lesions in tied Swiss dairy cows

Injuries around the tarsal joint are common in dairy cows kept in tie stalls. This study investigated the influence of the frequency and duration of outdoor exercise on the prevalence of hock lesions in tied Swiss dairy cows. Over a 1-year period (from January to December), cows on 66 farms were examined a total of six times (once every 2 months) for the number and severity of hock lesions (hairless patches, scabs and open wounds, swellings). The prevalence of scabs and wounds (mean 2.1 scabs per cow and farm, range 0.3-4.1) was negatively associated with the duration of outdoor exercise, and positively associated with its frequency. It was also significantly affected by the time of visit and the type of bedding (straw being better than other materials). With increasing length of the lying area, the prevalence of scabs and wounds decreased. Based on the interpretation of the final model, it is suggested that a minimum of 50h spent outdoors over a 4-week period is necessary to have a marked result on the prevalence of hock lesions.

Is intersucking in dairy cows the continuation of a habit developed in early life?

Intersucking, i.e., cattle sucking the udder of heifers or cows, is a frequent problem in dairy herds and may lead to udder damage, mastitis, milk loss, and culling of breeding animals. Using epidemiological methods, we conducted an observational cross-sectional study to investigate risk factors for intersucking in Swiss dairy cows. We asked 114 randomly selected dairy farmers about a broad spectrum of environmental factors possibly associated with intersucking, such as housing conditions, management, and feeding of calves, heifers, and cows. Thirty of the 114 farms were confronted with intersucking in cows. The mean proportion of intersucking cows per farm was 1.6%. From a total of 3077 cows (Swiss Brown Cattle, Simmental, and Holstein Friesian) we recorded 49 cows that had performed or were currently intersucking. In 69% of these cows, intersucking had been observed as heifers. Using path analysis and multivariable stepwise backward logistic and linear regression analyses, we revealed that the most important risk factor for intersucking cows was the presence of intersucking heifers on a farm (odds ratio = 7.8). The results suggest that intersucking in cows is the continuation of a habit that was already established in a cow's subadult life. This emphasizes the importance of looking not only at the animal's current environmental situation but also considering its entire life history for the prevention of behavioral problems.

Factors associated with intersucking in Swiss dairy heifers

Intersucking is a problem that may lead to udder damage, mastitis, milk loss, and culling of breeding animals. To analyse the risk factors for intersucking in dairy heifers in Switzerland, we asked 130 randomly selected dairy farmers about a broad spectrum of environmental factors that might be associated with intersucking (such as housing conditions, management, and the feeding of calves and heifers). In total, 2768 heifers (Swiss Brown Cattle, Simmental and Holstein Friesian) were included of which 303 had ever performed intersucking. Data at the farm level were analysed using path analysis (linear and logistic regression). Two outcome variables were considered: the occurrence of intersucking on the farm and the proportion of intersucking heifers above the cut-off of 7.2%. Farms where calves had no access to barnyard or pasture, where calves were reared in pens in enclosed buildings, where heifers after weaning were not restrained while feeding, where heifers after weaning received <0.5kg concentrate per day, and where heifers after weaning were fed > or =40% maize silage (dry-matter ratio) were most likely to have intersucking heifers.