Pre-slaughter factors linked to variation in responses to carbon dioxide gas stunning in pig abattoirs.

The stunning process is an important component of slaughter with implications for animal welfare due to the potential distress and pain in the case of a sub-effective or lengthy stun. This study examined the factors correlated with variation in responses to carbon dioxide (CO2) stunning of pigs in five Australian commercial abattoirs. A total of 1 769 pigs (199-492 focal pigs per abattoir) were individually followed from lairage to post-stunning. A standardised observation protocol was used based on a literature review of the pre-slaughter factors that may influence the reaction to CO2 stunning, such as animal background, lairage conditions, handling, stunning system and conditions. Pigs lost posture 22.5 ±â€¯0.2 s after commencement of descent of the gondola into the CO2 chamber. Latency to loss of posture was associated with farm of origin and time of day, which could be linked to various factors. Pigs that crawled or attempted to escape while in the gondola within the CO2 chamber took longer to lose posture. Crawl and escape attempts differed between abattoirs (0.6-46.2% of the pigs observed) as well as mounting other pigs (1.0-24.3%). Greater amounts of forceful contacts during handling in the race were related to more mounting in the gondola, but to less pigs crawling or attempting to escape. Mounting in the gondola was more frequent for pigs from lairage pens of mixed sexes, followed by pens of entire males and finally pens of females. Males were also twice as likely to show crawl and escape attempts than females. Gasping in the gondola was relatively frequent (63.1-81.8%) and was associated with higher activity in the lairage pen and higher skin injuries. Convulsions (60.1-69.6%) were generally observed after loss of posture. The type of CO2 system (group-wise vs single-file loading) had no significant effect on behaviour in the gondola. Nevertheless, pigs slaughtered in abattoirs with group-wise loading systems and automatic gates had lower cortisol concentrations post-stunning, which may be linked to minimal handling by stockpeople, other factors related to the systems, or differences in timing of when blood samples were taken. In conclusion, substantial variation in the reaction of pigs to CO2 stunning was observed between and within abattoirs using a uniform protocol for data collection. This variation in outcomes between abattoirs and stunning systems and the relationships between handling and behavioural outcomes indicates that improvements can be made to reduce aversive responses to CO2 stunning. In particular, avoiding mixing pigs of different sexes in lairage and aversive handling in the race may reduce aversive response to CO2 stunning.

Transitioning from conventional to automatic milking: Effects on the human-animal relationship.

There are several differences in how an automatic milking system (AMS; milking equipment not requiring human intervention for the milk harvesting process) and a conventional milking system (CMS) are managed, where the effect of milking system type on the human-animal relationship has remained unexplored. A survey and observations from 5 Australian dairy farms transitioning from CMS to AMS were taken twice, 1 yr apart, before and after transition to an AMS. The farmers completed a survey and had all farmer-cow interactions documented for 3 d. In addition, a random selection of lactating cows had their avoidance distance (the distance at which they move away from an approaching person) recorded and were involved in a handling test during both visits. The survey findings indicated that basic management practices remained mostly unchanged, whereas records of farmer-cow interactions showed 4 out of 5 farms had less interaction time after AMS transition. This was caused by a reduction in milk harvesting tasks, where a small portion of this time was re-invested into time that farmers spent around the cows without directly interacting with them and into tasks involving close cow contact. Overall, an approximate 27% decline was observed in avoidance distances of cows from an AMS compared with the CMS. A handling test was performed on 4 of the 5 farms before and after AMS transition, where the farmers were asked to move a selection of cows through a gate one at a time. In the AMS more vocal effort was required to move the cows, and the cows responded with a reduced occurrence of running past the farmer and reduced occurrence of slipping in an attempt to avoid the farmers compared with the CMS. Overall, results show that farmers spent less time interacting with cows in the AMS, and that cows were less fearful around people as seen by reduced avoidance distances and reduced stress responses to close handling.

The effects of herd size on the welfare of dairy cows in a pasture-based system using animal- and resource-based indicators.

Animal welfare assessments were conducted on 50 Australian pasture-based dairy farms of varying herd sizes: 16 small (<300 cows), 15 medium-sized (300-500 cows), 11 large (501-750 cows), and 10 very large (751+ cows). A protocol based on elements of Welfare Quality adapted for Australian conditions was developed to assess the broad categories of good feeding, housing, health, and appropriate behavior. Farm records, body condition scores, integument injuries, fecal plaques, avoidance distance of humans, and fecal pat scoring for acidosis assessment were undertaken. The mean maximum kilograms of grain fed per day significantly increased with herd size, from 5.2 ± 0.38 (small), 7.7 ± 0.29 (medium-sized), 8.8 ± 0.45 (large), to 10.1 ± 0.80 kg (very large). Acidosis was not related to herd size based on either farm records or fecal pat scoring. All cows had access to water for more than 12 h in a 24-h period. More larger farms had water points on the farm tracks or at the dairy. Very large farms (90%) were more likely than others (36-39%) to provide water suitable for human consumption. Integument lesions were not related to herd size and were uncommon; 56 and 84% of farms had no cows with lesions or hairless areas, respectively, and no farm had >6% integument lesions. Heat stress is an important welfare risk in Australia. All farms had some form of cooling strategy; shade in all paddocks was more common on smaller farms (>90%) than others (<75%). Sprinklers were more common on large or very large farms (>80%) than others (<65%). Mastitis and lameness were the most common health conditions, followed by dystocia, downer cows, and gastrointestinal diseases. Prevalence of lameness, mastitis, downer cows, dystocia, and gastrointestinal disease were not related to farm size. Larger farms were more likely to have electronic infrastructure to monitor or electronically draft cows for inspection. We found wide variation in the avoidance distance of humans, but this was not related to farm size. Larger farms had longer walking distances to pasture and longer time away from pasture, which could affect the time available for behaviors such as lying down. Animal welfare risks differ on Australian farms compared with housed cattle. As animal welfare is multidimensional, both animal- and resource-based indicators can be useful. Animal-based indicators have strengths in that, when measured accurately, they genuinely reflect the outcome being measured, but they also have weaknesses in that the point-estimate of a disease prevalence on a given day may not be representative of other times of year or differences in case definition may exist when farm records are used. Similarly, resource-based indicators have strengths in that they may be applicable to longer periods, but weaknesses because the fact a resource is present does not guarantee it is being used. Identifying the major risks to animal welfare on individual farms and ensuring a plan is in place to effectively manage them should be an important element of any on-farm animal welfare assessment protocol.

Lame cows on Australian dairy farms: A comparison of farmer-identified lameness and formal lameness scoring, and the position of lame cows within the milking order.

On Australian pasture-based farms, where cows may often walk several kilometers and stand for several hours per day in a crowded concrete yard while they wait to be milked, the potential for lameness to negatively affect animal welfare is of ongoing concern. Several studies have shown that farmers tend to underestimate the incidence of lameness. Further, improving farmer diagnosis/identification of lameness is likely to result in more prompt treatment, which in turn will improve clinical and animal welfare outcomes. We scored 19,154 cows over 50 farms for lameness, in herd groups ranging from approximately 100 to 1,000 cows, as they left the milking parlor. We compared these results with farmer-diagnosed lameness records on the same day. We used a scoring system of 0, walks normally; 1, walks unevenly; 2, lame; and 3, very lame. All very lame cows had been detected by the farmer, but overall, farmers detected only 24% of cows identified by lameness scoring. An analysis of the position of lame cows within the milking order showed that lameness scoring of the entire herd was necessary to detect all the lame cows as only 60% of lame cows appeared in the last 30% of cows to be milked. However, lameness scoring only the last 200 cows to be milked could be used as a screening test to identify herds with a lameness prevalence below a given threshold.

Implications of prolonged milking time on time budgets and lying behavior of cows in large pasture-based dairy herds.

In large Australian pasture-based dairy herds, it is common for the time taken to milk a herd of cows to be up to 4 h. Cows are collected from the paddock as a group, wait in turn in the dairy yard to be milked, and then return individually to the paddock or feed pad immediately after leaving the milking parlor. In such herds, we previously found a consistent milking order, resulting in some cows being regularly away from pasture for several hours per day more than others. Increased time away from pasture may affect the time budgets of cows because of decreased opportunity for grazing or lying down. Lying behavior is a high-priority behavior for cows, and the duration of lying has been used as an important measure of their welfare. We applied activity monitors for 7 d to 15 cows toward the beginning and 15 cows toward the end of the milking order in 10 dairy herds milking 500 to 730 cows as a single group to understand the effect of extra time spent in the dairy on lying behavior. Study cows typically produced 6,000 to 8,000 L in a 300-d lactation on rotary dairy platforms with 40 to 80 units, being fed 2.5 to 6 kg of grain mix in the milking parlor daily, with the rest of the diet being supplied as pasture or forage provided in the pasture or close to the exit of the dairy. Over the 10 farms, 1,948 cow-days were available for analysis. The furthest paddocks on each farm were 1.8 to 3.5 km walking distance from the dairy. A wide range of steps were taken each day, ranging from 1,705 to 15,075 (mean = 5,916). The main predictor of the number of steps was the farm on which the cows were located. Cows that spent less than an hour waiting to be milked (and would be unlikely to have their ability to lie down affected by the milking process) laid down for a mean of 9.8 h/d. Steps walked and delay in the dairy waiting to be milked were both significantly associated with lying time, but the effect was not large. A regression model accounting for the waiting time at the dairy, steps taken, cow age, and farm was used to investigate the relationship with daily lying time. For every 1,000 steps, lying time reduced by 0.49 h; however, the number of steps explained only 1% of the variation in lying time. For every hour increase in waiting time at the dairy, lying decreased by approximately 14 min, but this explained only 14% of the variation in lying. We concluded that milking time durations of 2 to 4 h, common in large Australian pasture-based dairy herds, did not significantly affect the time budget for lying of individual cows in our study herds. Whereas the effect of long milking times does not appear to be a major risk to animal welfare in terms of lying time, the effect on cow health and production warrants further investigation.

Short communication: Milking order consistency of dairy cows in large Australian herds.

We used on-farm records from dairy infrastructure to examine the consistency of the milking order over 150 d in 5 Australian dairy herds that were milking more than 500 cows as a single group. Within a single day the difference in milking order rank position was less than 20 percentage points for 72% of cows. The correlation coefficient comparing milking rank position in the morning and afternoon was 0.72, with the position of cows at the beginning and end of the milking order being more consistent than cows toward the middle of the milking order. Over a period of 150 d, cows with a mean position in the first and last 20% of the milking order maintained their position more consistently than cows in the middle of the milking order. Milking position of cows between one month and the next was highly correlated (r = 0.88). In large herds, subpopulations of cows are regularly milked toward the beginning and the end of the milking order. It is common for cows to be collected from the paddock as a group, to wait as a group in the dairy yard to be milked, and to return individually to the paddock or feed pad immediately after they have been milked. Thus, cows milked later in the milking order are likely to be away from the paddock for several hours longer than cows milked earlier in the milking order. This may affect their welfare though differences in time available for lying down, equality of pasture eaten, and time spent standing in the dairy yard.

A survey of Australian dairy farmers to investigate animal welfare risks associated with increasing scale of production.

Although large herds (more than 500 cows) only represent 13% of Australian dairy farms, they represent more than 35% of the cows milked. A survey of Australian dairy farmers was conducted to assess relationships between herd size and known or proposed risk factors for adverse animal welfare outcomes in Australian dairy herds in relation to increasing scale of production. Responses from 863 Australian dairy farms (13% of Australian dairy farms) were received. Increasing herd size was associated with increases in stocking density, stock per labor unit, and grain fed per day-all of which could reasonably be hypothesized to increase the risk of adverse welfare outcomes unless carefully managed. However, increasing herd size was also associated with an increased likelihood of staff with formal and industry-based training qualifications. Herd size was not associated with reported increases in mastitis or lameness treatments. Some disease conditions, such as milk fever, gut problems, and down cows, were reported less in larger herds. Larger herds were more likely to have routine veterinary herd health visits, separate milking of the main herd and the sick herd, transition diets before calving, and written protocols for disease treatment. They were more likely to use monitoring systems such as electronic identification in the dairy, computerized records, daily milk yield or cell count monitoring, and pedometers or activity meters. Euthanasia methods were consistent between herds of varying sizes, and it was noted that less than 3% of farms make use of captive-bolt devices despite their effectiveness and ready availability. Increasing herd size was related to increased herd milking time, increased time away from the paddock, and increased distance walked. If the milking order of cows is consistent, this may result in reduced feed access for late-milking-order cows because of a difference in time away from the paddock. More than 95% of farmers believed that their cows were content most of the time, and cows were reported as well behaved on more than 90% of farms. Although the potential animal welfare issues appear to be different between herd sizes, no evidence existed for a relationship between herd size and adverse welfare outcomes in terms of reported disease or cow contentment levels.

Space allowance and barriers influence cow competition for mixed rations fed on a feed-pad between bouts of grazing.

The objective of this experiment was to evaluate how feeding space allowance and provision of feed barriers interact to affect feeding and social behavior of dairy cows fed a partial mixed ration on a feed-pad. The treatments were factorial with 3 feeding space allowances (0.6, 0.75, or 1.0m of trough space per cow) and feed troughs that were either open or had head barriers that physically separated adjacent cows to reduce interactions during feeding. One hundred and forty-four Holstein-Friesian cows in mid lactation were allocated into 12 groups of 12 cows, with 1 of 6 treatments (3 × 2) randomly assigned to 2 groups out of 12. Treatments were changed weekly over 3 wk according to a row-column, crossover design, with week corresponding to rows and group corresponding to columns. Thus, the design included 2 replicated groups per treatment in each week. Grazed pasture intake was approximately 6.1 kg of dry matter (DM)/cow per day, supplemented with 3.5 kg of DM/cow per day of wheat (Triticum aestivum) grain fed during milking and 10.7 kg of DM/cow per day of a mixed ration offered on the feed-pad after each milking. The experiment comprised a 7-d pre-experimental period followed by a 21-d experimental period. The social hierarchy within each group was determined before the experiment commenced. Feeding and social behaviors of cows were analyzed using video recordings and the changes in heart rate and heart rate variability were determined using heart rate monitors. Data were analyzed using mixed effect models by REML. When feeding space allowance was increased, we observed an increase in the time a cow spent feeding and a decrease in the number of feeding bouts in relation to the total time feed was available, particularly in subordinate cows. The number of aggressive behaviors and displacements decreased when space allowance increased. In addition, HR was reduced and the reduction was more pronounced in subordinate cows compared with dominant cows. Use of feed barriers increased cow feeding time and decreased the number of feeding bouts in relation to the total time feed was available, particularly in subordinate cows, and reduced the number of cow displacements during feeding. We conclude that increasing the feeding space from 0.6 to 0.75 to 1.0m reduces aggressive interactions and improves cow feeding behavior, with the effects being greatest for subordinate cows. The use of feed barriers further reduces competition at the feed trough in a partial mixed ration feeding system.

Ease of moving young calves at different ages.

BACKGROUND: Young ('bobby') calves transported to the abattoir in their first week of life have not yet developed natural herding behaviour. The calves are still in a 'hider' phase and naturally spend most of their time lying and sleeping. Anecdotally, calves are easier to handle as they get older, although it is unclear if they are inherently more responsive to a handler. METHODS: This study examined the ease of moving 3-, 5- and 9-11-day-old calves individually through an obstacle course involving a 12° incline, a 11° decline and two 90° turns. RESULTS: There was a significant effect of age on both the total time taken to move through the course (99 vs 86 vs 72s for 3-, 5- and 9-11-day-old calves, respectively; P < 0.05) and the number of interventions by the handler (8.4 vs 7.3 vs 4.8 interventions per calf for 3-, 5- and 9-11-day-old calves, respectively; P < 0.05). CONCLUSION: Ease of herding bobby calves improved with age, although individually handled calves were relatively easy to move regardless of age.

Behavioural responses of lambs to plastic clips as an alternative procedure to mulesing.

OBJECTIVE: Compare the effects on the behaviour of lambs of applying occlusive plastic clips, as an alternative procedure to surgical mulesing, with tail docking, surgical mulesing and a control treatment. PROCEDURE: We allocated 48 6-7-week-old Merino lambs to four treatment groups: plastic clips (Clip); surgical mulesing (Mules); tail docking with a rubber ring (Tail ring); no treatment (Control). For each posture and behaviour observed on each of the 4 days post-treatment, a Dunnett's multiple comparison test was used to simultaneously compare the Clip treatment with each of the comparator treatments (Control, Tail ring and Mules treatments). RESULTS: Most of the significant differences (P < 0.05) detected between the comparator treatments occurred on day 1. For four of these measurements, the Clip treatment differed (P < 0.01) from the Mules treatment, but from not the Control and Tail ring treatments: the Clip lambs spent less time standing immobile not interacting with ground, hay or feeder, less time standing immobile head down not interacting with ground, hay or feeder, more time walking and more time interacting with ground, hay or feeder. CONCLUSION: These behavioural results, together with previous behavioural and physiological research, indicate that the effect on lamb welfare of applying occlusive clips is less than that of surgical mulesing.

EEG changes in 4-week-old lambs in response to castration, tail docking and mulesing.

OBJECTIVE: To interpret changes in EEG in relation to perceived pain of castration, mulesing and docking in lambs. DESIGN: Analysis of covariance (randomised block design) to determine the effects of treatment on eight bandwidths of the EEG frequency spectrum. PROCEDURE: Ninety-eight, 3- to 4-week-old lambs were subjected to one of seven treatments: castration, tail docking, mulesing, ear tagging, sham shearing, formalin injection (to induce lameness) and handling. EEG was recorded for 15 min before treatment, during treatment, and for 15 min after treatment. RESULTS: Consistently lower mean power values across all bandwidths of the EEG were found at the time of mulesing and docking than at handling and shearing (P < 0.01). Formalin injection resulted in lower power values than handling and shearing (P < 0.01). Castration had lower power values than handling and shearing. Similarly, for 15 min after treatment, mulesing and formalin injection had significantly lower power values than handling, shearing, ear tagging and castration (P < 0.05). CONCLUSION: The consistent effects associated with mulesing, docking and castration compared to handling, shearing and ear tagging suggest that mulesing at both the time of treatment and during 15 min after treatment results in a response that is similar to that of induced lameness. Docking and castration result in a response at the time of treatment that is similar to induced lameness and mulesing, but during 15 min after treatment is similar to the non-noxious control treatments. However, the depressing effects on the mean power values are the reverse of that anticipated from a previously developed pain model, highlighting the need for further research to develop this technology to evaluate pain associated with husbandry procedures.

Pain-related cerebral potentials in response to acute painful electrical stimulation in sheep.

OBJECTIVE: To examine associations between late event-related cerebral potential amplitudes and behavioural responses to noxious electrical stimulation as an indicator of acute pain in sheep. DESIGN: Analysis of variance for the effects of stimulus intensity on the behaviour and event-related cerebral potential variables. PROCEDURE: Ninety-six brief constant current electrical pulse trains were presented to the front left leg of eight sheep at four intensities (2.5 to 10 mA) in a randomised order. An event-related cerebral potential and a graded flinch response were recorded for each stimulus and the 24 event-related cerebral potentials at each intensity were averaged to produce a mean waveform. Various components of this waveform were analysed and changes in these measures and the sheep's flinch response, as stimulus intensity increased, were determined. RESULTS: Both the flinch response and some event-related cerebral potential components, that is, peak amplitudes 114 [N1], 187 [P1], 318 [P2] and 230 [Pm] ms after stimulus onset, were significantly affected as stimulus intensity increased. CONCLUSION: These corresponding behavioural and event-related cerebral potential changes indicate the usefulness of using changes in the event-related cerebral potential to measure acute pain in sheep.