Physiological and behavioural changes in Holstein calves during and after dehorning or castration.

Posted in: Welfare by admin on January 1, 2005 | No Comments

The behavioural and physiological effects of hot-iron dehorning or dehorning followed by scalpel castration were compared to control and sham procedures and to each other. Twenty-nine calves (17 bull and 12 heifer dairy) were studied. Each animal served as its own control. The control procedure for dehorning and castration involved collecting blood samples with minimal handling. The sham dehorning procedure involved restraint with a halter and being held immobile against a wall, and holding an unheated hot-iron dehorner around the horn bud for between 13-33 s. The actual dehorning procedure used the same method of restraint, but used a heated dehorner placed on the horn bud for between 19 and 52s. The control, sham and actual procedures were all performed on the same day by the same person without anaesthetic. The sham castration procedure was done to mimic the actual procedure except no incision was made. The tail was held upright and the scrotal area was disinfected. This procedure took between 13 and 70 s. The actual procedure was similar to the sham procedure, except there was an incision made into the scrotum and the testes were exposed and removed by manually applied traction. This procedure took between 21 and 79 s. For at least two hours after castration and for 30 minutes after dehorning, cortisol levels remained higher than controls. Initially, the cortisol responses did not differ between castration and dehorning. However, two to four hours after the procedure, cortisol levels were greater for castration than dehorning. Animals kicked and vocalized more during actual castration and dehorning procedures compared to sham procedures. More struggling occurred during actual dehorning than the sham procedure, but occurred less during castration than the sham. There was greater struggling and kicking among dehorned calves compared to castrated calves. Both sham and dehorned calves had higher heart rates compared to the control values. Dairy calves showed greater physiological and behavioural responses, with higher heart rates, cortisol concentrations, greater kicking, vocalizations and struggling compared to responses during the control and sham procedures. Handling differences and prior experience of dehorning could have caused the differences in responses to each procedure.

Impact of male-male competition and morphological traits on mating strategies and reproductive success in broiler breeders

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The goal of this experiment was to determine the effect of male-male competition on broiler breeder mating strategies and reproductive success and to identify behavioral and morphological traits associated with high fertility. Males were kept in groups with no competition (one male and 10 females; 1M), or high male-male competition (three males and 10 females; 3M). For each male we recorded the frequency of matings, forced matings, cloacal contacts and morphological traits (body weight, comb, wattle, tarsus and spur size), together with sperm quality and the reproductive success. Mating frequency consistently increased towards the end of the light phase. Significantly, higher mating activity occurred in 1 M groups compared to 3M groups. Mating frequency of 1M males, however, did not differ from the frequencies of the males with the highest mating frequency in 3M groups. After reducing the number of males from 3M to 1M in the second experimental phase we found significant increase in the mating frequency. This probably was a consequence of the reduction in the level of male-male competition or due to female response to a lower number of males. DNA fingerprinting results indicated that the males with the highest mating frequency did not always sire the most offspring within the group. The males with the highest sperm mobility or largest ejaculate volumes were equally successful. Frequency of forced mating was not affected by the level of competition, but was more likely used by heavier males or those with larger combs and wattles. We did not find any of the studied morphological traits to be reliable indicators of males reproductive potential, although this lack of association may have been affected by relatively low number of males available for this study.

Comparing two concentrate allowances in an automatic milking system

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In automatic milking systems, cows are attracted to concentrate food that is contained in a robot. This not only increases the number of milkings, but also the amount of concentrate food consumed. An increase in concentrate food consumption can affect the cow’s appetite, feeding behaviour and digestion and subsequent milk production. Therefore, this study investigated the effect of two concentrate allowances: 1) the ‘candy concept’ with a minimum amount of concentrate (1.2 kg) to attract the cow, and 2) the maximum of 7 kg of food concentrate per day. Cows in the first treatment consumed approximately 3.5 kg of concentrate per day, and cows in the second treatment consumed approximately 5 kg of concentrate per day. However, the number of voluntary milkings did not differ between the two treatments.

The role of the image of a conspecific in the regulation of stereotypic head movements in the horse

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Mirrors have been shown to decrease the weaving in horses. This study investigated whether it was the horse’s reflected image that caused the reduction or if it was some other property of the mirror. In order to answer this question, six weaving horses were shown three different posters and their responses were recorded. The posters included a life-size image of a horse’s face, the same image cut into 54 squares, which were randomly rearranged (pixilated image) and a white poster with no image. The results indicated that when horses were shown the poster of the horse’s face, weaving was significantly reduced compared to when they were shown the other two posters. Exposure to the poster of the horse’s face also resulted in a reduction of nodding compared to when they were shown the pixilated image. Horses were more alert and spent more time looking at the poster, when the poster of the horse’s face was presented. Greater activity and anticipation of specific events, which may or may not be associated with increased social contact, caused an increase in the intensity of stereotypic head movement. The authors concluded that the timing of stereotypic head movements might be associated with acute frustration as opposed to boredom/lack of stimulation.

Does the use of a device to measure heart rate affect the behavioural responses of lambs to humans?

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Devices used to measure cardiac activity in standardised behavioural tests could be stressful for the animals and therefore affects their responses. However, to date, the impact of carrying such devices has been poorly evaluated. The present experiment examined the impact of a device used to measure cardiac activity on the behavioural responses of handled and non-handled lambs in a standard human test. Furthermore this study evaluated the variations in heart rate in response to human presence and separation. Twenty-one lambs were separated from their dam 12 h after birth. 11 of them received no additional human contact (non-handled) and 10 received additional contact for 1 week and then 1 day a week until 6 weeks. At 6.5 weeks of age, each lamb was submitted twice to a behavioural test. The procedure comprised three phases: the lamb stayed alone for 2 minutes, then for 2 minutes with the familiar stockperson, and then alone for 2 minutes again. The tested lambs were equipped or not with a cardiac device. The results of this study showed that the device used to measure cardiac activity led to a decrease in vocalisations and locomotion. It had only a limited impact on the behavioural differences between handled and non-handled lambs. It reduced slightly the time spent near the stockperson for the non-handled lambs but no effect on the handled lambs. In summary, the device used to measure cardiac activity led to a general decrease in activity but did not affect the difference between handled and non-handled lambs. Consequently, this method seems to be appropriate for further exploring artificially reared lambs’ perception of humans, with few risks of behavioural alteration.

Impact of dried skim milk in production diets on Lactobacillus and pathogenic bacterial shedding in growing-finishing swine

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The test-retest reliability of four behavioural tests of fearfulness for quail: A critical evaluation.

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In order to understand the reliability of tests of fearfulness, Japanese quail were tested and retested in four different tests: an emergence test, a novel object test, a novel food test, and a predator surprise test. The results indicated that some of the measures were not reliable. Some examples of inconsistencies included: 1) there was a low correlation between the two tests for latency to extend head into emergence arena during the emergence test, but the number of times they extended there heads into the arena was more consistent; and 2) latency to try a novel food had inconsistent results, but the amount of novel food eaten was more reliable. The use of partial correlations was found to be more useful when attempting to determine test-retest reliability, than Pearson’s coefficient. It appears that the common behavioural indicators of fearfulness do not always have consistent results.

Resting behaviour and displacements in ewes–effects of reduced lying space and pen shape

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Lying space and pen shape were altered in order to determine the effects on resting behaviour and displacements in ewes. Lying space was 0.5, 0.75, of 1.0 m2/ewe and pen shape was either deep or wide. Six groups of four adult sheep were exposed to all of the treatments for a period of 7 days. Total lying time was reduced fro 70 to 63 % when the lying area was reduced from 1.0 to 0.5 m2, and lying time in the deep pens (67.0 %) was longer than in the wide pens (64.5 %). The occurrence of all four ewes lying simultaneously was reduced from 45.4 to 5.9 % as the lying area was reduced. The number of times a ewe displaced a lying ewe (per ewe and 24 hours) increased from 6.4 to 28.9 as the lying area was reduced. Low ranking ewes were lying less often and were more active than the other ewes. Pen shape did not have a significant effect on the behaviour of the ewes, except for lying time. There was a lower lying time for ewes in wide pens compared with ewes in deep pens. Reducing lying space from 1.0 to 0.5 m2/ewe resulting in a reduction in lying time, less synchronized resting, and a large increase in the number of displacements. There were no significant effects of pen shape, except for lying time.

The effect of flooring type and social grouping on the rest and growth of dairy calves.

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The effect of housing calves and pairs and flooring on growth and rest behaviours of one week old calves was examined. The calves were housed individually or in pairs on concrete floors or were housed individually with rubber mats on the floors for 20 weeks. All treatments were provided with wood shavings for bedding. The total daily duration, bout frequency and mean duration of total resting, resting on the side or resting on the stomach were noted through video recordings taken at 2, 4, 6, 7, 11, 14 and 21 weeks of age. The effect of time of day was analyzed on week 4, 7, 14 and 21. Mean daily growth was positively correlated with the total time the calves spent resting over the 20-week experimental period. As the calves grew older, the amount of time they spent resting remained the same, however the amount of time they spent resting on their side decreased. The time spent resting around feeding decreased after solid feed was introduced. Housing didn’t affect daily growth or resting behaviour. The daily duration and bout frequency for resting on the side was higher in pairs than individuals (both housed on concrete). There was also no difference in growth or resting behaviour between calves housed on concrete or on rubber mats. However, the provision of wood shavings may have made the concrete flooring comfortable. Adequate rest is needed to maximize growth and the longer a calf rests, the better it will grow. Housing calves in pairs provided them with more space, and they were observed resting on their side more often and for longer.

A note on reaction to novel stimulus and restraint by therapeutic riding horses.

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In this study, therapeutic riding horses (TRH) and jumping horses (JH) were exposed to acute, novel stressors to objectively measure individual reactivity and chronic stress. The responses of TRH and JH were compared when exposed to a restraint and startling stimulus. The restraint involved covering the horse’s head with a hood for one hour, and the startling stimulus (40 cm long red and white synthetic holiday garland shaken with a rustling noise inside the box). During the challenges, horses spent most of their time immobile. During the challenges, a higher average basal HR was found in TRHs compared to JH. During the restraint, average heart rate during pawing was higher than during other behaviours. Lymphocytes decreased in samples taken after the removal of the hood. Overall, there were no differences between TRHs and JHs in their reactions to novel stimuli.