Lene Munksgaard

Dairy cows’ fear of people: social learning, milk yield and behaviour at milking

We examined the effects of the presence of an unfamiliar, a gentle or an aversive handler during milking on behaviour and milk yield, and whether cows can learn to approach or avoid a handler by observing the neighbouring cows responses. In Experiment 1, Danish Friesian cows (n=16) were treated gently (offering hay and concentrates) by one handler and aversively (hit every 15s on the head with the hand) by another handler for six periods of 2min each. The two handlers wore different coloured overalls, and each cow received either gentle or aversive treatment in the first week and the other treatment the following week. All cows kept a longer distance to the aversive than to the gentle handler in a 1min test after treatment. Milk yield and residual milk did not differ when the aversive or the gentle handler was standing in front of the cow during milking, although the cows moved their legs and tail less when the aversive handler was present. When an unfamiliar person was standing in front of the cows during milking, behaviour and milk yield did not differ from control milkings. Cows and heifers (n=10) that had observed their neighbours receiving gentle treatment by one handler and aversive treatment from another handler did not differ in the distance they kept from these two handlers. In Experiment 2, cows (n=15) that had observed the neighbours receiving a gentle treatment (eight times for 2min) kept a shorter distance to that handler after treatment of their neighbours, and the distance they kept was correlated with the distance kept by the neighbouring cows. This suggests that responses of observer cows may be affected by the responses of the cows being treated. The cows rapidly learned to avoid an aversive handler, but although the cows showed clear avoidance response to the aversive handler there was no effect on milk yield when the aversive handler was present at milking.

Effects of Sand and Straw Bedding on the Lying Behavior, Cleanliness, and Hoof and Hock Injuries of Dairy Cows

This experiment compared the effects of sand and straw bedding in free stalls on resting time, cleanliness, hock injuries, and hoof health of dairy cows and tested whether cow preferences for a bedding material depended on the familiarity with the material. A total of 52 dairy cows were kept either on straw bedded concrete stalls or sand stalls for at least 21 wk. The lying behavior was observed, and hock lesions, hoof health, and cleanliness of the cows and stalls were measured. A 5-d preference test between sand and straw stalls was conducted at the end of the experiment. The total daily duration of lying was longer for cows on straw bedding than on sand bedding (straw 749 +/- 16 vs. sand 678 +/- 19 min). During the preference test, cows that had been kept on straw bedding preferred lying in straw stalls [straw 218.7 (133.4 to 239.7) vs. sand 9.0 min (2.8 to 44.8)]; however, cows that had been kept on sand showed no preference [straw 101.3 (51.7 to 205.9) vs. sand 94.3 min (54.1 to 156.1, median and interquartile range)]. Although there were no differences in the dirtiness of stalls, the cows using straw stalls were dirtier than cows using sand stalls [straw 6.04 (5.39 to 6.28) vs. sand 4.19 (3.62 to 5.16)]. At the end of experiment the severity of hock lesions was lower for cows on sand than for cows on straw [sand 0.5 (0.0 to 1.0) vs. straw 1.0 (1.0 to 2.0)]. The improvement in overall hoof health over the observation period was greater for cows kept on sand compared with cows kept on straw [sand -2.00 (-3.75 to -0.25) vs. straw 0.00 (-2.00 to 2.00)]. Straw bedding increased the time that cows spend lying, and cows preferred straw stalls to sand stalls. However, previous experience with sand reduces avoidance of sand stalls. Sand stalls were advantageous for cow cleanliness and health; hock lesions and claw diseases healed more quickly for cows using sand stalls compared with straw.

Effect of single versus group housing and space allowance on responses of calves during open-field tests

Abstract 32 dairy heifer calves were housed in one of four pen types: (1) a small single pen (0.9 m × 1.5 m); (2) a large single pen (1.8 m × 3.0 m); (3) a small group-pen (1.8 m × 3.0 m for four calves); and (4) a large group-pen (3.0 m × 5.4 m for four calves) until three months of age. Thereafter, all calves were housed individually in tether stalls which were 0.9m wide. Each calf was subjected to two test-sessions: one before tethering at three months of age and one at six months of age. Each test session included two tests. The first test was an open-field test with an unfamiliar calf present and the second was an open-field test in an empty arena. Behaviour and heart rate were recorded. Based on the data for the open-field test with an unfamiliar calf present, two principal components reflecting exploratory motivation and fear of unfamiliar calves, respectively, were defined. At three months of age, individually reared calves had higher scores for the principal component reflecting fear of unfamiliar calves. Principal components reflecting exploratory motivation and fear, respectively, were also defined based on data for the open-field test in an empty arena. At three months of age, individually reared calves had higher scores for the principal component reflecting fear in this test. The results suggest that individually reared calves are more fearful when introduced to a novel social situation and when isolated in a novel arena. Differences in space allowance did not affect the measured responses during the tests at three months of age. At six months of age, no effects of either social rearing or space were found.

Effects of acute stressors on nociception, adrenocortical responses and behavior of dairy cows.

Effects of acute stressors on behavioral, adrenocortical and nociceptive responses were examined in 24 dairy cows kept in tie stalls, using 15 min of social isolation in novel surroundings (ISOL), fixation by the head in the home stall (FIX) and the provision of novel neighbors/stall (NEIGH) as acute stressors as well as a control treatment (CON). Each cow was exposed to one treatment daily in a balanced order. All stressors led to signs of hypoalgesia as indicated by slower (P=0.01) and reduced responses (P<0.10) toward nociceptive laser stimulation after exposure to the acute stressors. ISOL, however, had stronger effects than FIX or NEIGH. ISOL or FIX led to increased plasma concentration of cortisol (P<0.001), whereas NEIGH or CON did not. The behavioral responses were affected by treatments as well, as shown by decreased rumination for all stressors (P<0.001) and a gradual increase in active avoidance from CON to NEIGH to FIX (P<0.001). Furthermore, exposure to NEIGH led to increased exploration (P<0.001), aggression (P<0.10) and self-grooming behavior (P<0.10) compared with the CON treatment. The results suggest that nociceptive changes are part of responses toward acute stress in dairy cows. The nociceptive changes, however, were not direct reflections of the adrenocortical or behavioral responses toward the acute stressors. Therefore, quantification of nociceptive changes, in combination with behavioral and physiological registrations, can be one way to broaden the range of biological systems, considered for the study of animals under stress, and thereby extend the understanding of responses toward acute stress in dairy cows.

Behaviour of dairy cows kept in extensive (loose housing/pasture) or intensive (tie stall) environments I. Experimental procedure, facilities, time budgets - diurnal and seasonal conditions

Abstract Twelve dairy cows were placed in a stimuli-rich environment, a ‘dairy cow park’, for 2.5 years. The ‘park’ consisted of an extensive barn with deep bedding, a yard and a pasture. The cows were milked and fed twice a day in the barn, but had free access to the whole area at all times. During the experiment the cows were observed 2–6 days month−1, and their preference for being indoors or outdoors, for standing or lying, eating mixed rations or grass, their daily walking distance and synchronization of lying behaviour, were recorded. During summer the cows spent 17.2 h outdoors each day, mostly at pasture; in winter they only spent 4.8 h outdoors each day. With the exception of frosty days, the cows frequently spent 1–3 h outdoors on winter nights. On frosty days they remained indoors all day. The cows lay indoors on deep bedding only in winter, while in summer they mainly preferred to lie out on pasture. During winter the cows ate mixed rations for 2.2 h and grass for about 0.7 h day−1, and during summer, 1.3 h and 4 h, respectively. Time spent eating mixed rations was not correlated with rank order. The lying behaviour was more synchronized at pasture than in the tie stall. The synchronization on deep bedding was intermediate. During summer, the cows walked 2.5 km (SD 0.6 km) daily and spent most of the nights at pasture. The daily walking distance was 0.8 km (SD 0.6 km) during winter. Except for frosty days when cows remained indoors, the weather within a month had no significant effect on the walking distance.

Influence of milk yield, stage of lactation, and body condition on dairy cattle lying behaviour measured using an automated activity monitoring sensor

Time spent lying by lactating Holstein-Friesian cows of varying body condition scores (BCS) and milk yield was measured using an animal activity monitor. A 3-week average BCS was calculated for each cow; and in total, 84 cows were selected with 28 cows each among three BCS categories (Thin: BCS<2.75; Moderate: 2.75 > or = BCS<3.25; Heavy: BCS> or = 3.25) and two stage of lactation categories (<150 days in milk or >150 days in milk). Cows were kept in two management systems: parlour/freestall (n=60) or automated milking system/freestall (n=24). Behaviour was recorded for 5.3+/-0.1 d for each cow. Production levels were considered using a 28-d rolling average of daily milk production. Cows that exhibited clinical lameness before or during the observation period were excluded from analyses. For cows exhibiting oestrus, the day prior to, day of, and day following breeding were removed. The final analysis included 77 cows (408 d of observation). A mixed model was fitted to describe average daily hours spent lying. Results demonstrated that lying time increased as days in milk (DIM) increased (P=0.05). Variables that were tested but not significant (P>0.05) were BCS category, parity category (1 or 2) and 28-d rolling average daily milk production. Although a numerical trend for increasing hours spent lying with increasing BCS was observed, after accounting for other factors in the mixed model, BCS did not significantly impact lying time. Continued investigation of these management factors that impact lying time and bouts, using new technologies, more cows, and more herds will help dairy owners better manage facilities and cow movements to optimize this essential behaviour.

Measurement of acceleration while walking as an automated method for gait assessment in dairy cattle

The aims were to determine whether measures of acceleration of the legs and back of dairy cows while they walk could help detect changes in gait or locomotion associated with lameness and differences in the walking surface. In 2 experiments, 12 or 24 multiparous dairy cows were fitted with five 3-dimensional accelerometers, 1 attached to each leg and 1 to the back, and acceleration data were collected while cows walked in a straight line on concrete (experiment 1) or on both concrete and rubber (experiment 2). Cows were video-recorded while walking to assess overall gait, asymmetry of the steps, and walking speed. In experiment 1, cows were selected to maximize the range of gait scores, whereas no clinically lame cows were enrolled in experiment 2. For each accelerometer location, overall acceleration was calculated as the magnitude of the 3-dimensional acceleration vector and the variance of overall acceleration, as well as the asymmetry of variance of acceleration within the front and rear pair of legs. In experiment 1, the asymmetry of variance of acceleration in the front and rear legs was positively correlated with overall gait and the visually assessed asymmetry of the steps (r ≥ 0.6). Walking speed was negatively correlated with the asymmetry of variance of the rear legs (r=-0.8) and positively correlated with the acceleration and the variance of acceleration of each leg and back (r ≥ 0.7). In experiment 2, cows had lower gait scores [2.3 vs. 2.6; standard error of the difference (SED)=0.1, measured on a 5-point scale] and lower scores for asymmetry of the steps (18.0 vs. 23.1; SED=2.2, measured on a continuous 100-unit scale) when they walked on rubber compared with concrete, and their walking speed increased (1.28 vs. 1.22 m/s; SED=0.02). The acceleration of the front (1.67 vs. 1.72 g; SED=0.02) and rear (1.62 vs. 1.67 g; SED=0.02) legs and the variance of acceleration of the rear legs (0.88 vs. 0.94 g; SED=0.03) were lower when cows walked on rubber compared with concrete. Despite the improvements in gait score that occurred when cows walked on rubber, the asymmetry of variance of acceleration of the front leg was higher (15.2 vs. 10.4%; SED=2.0). The difference in walking speed between concrete and rubber correlated with the difference in the mean acceleration and the difference in the variance of acceleration of the legs and back (r ≥ 0.6). Three-dimensional accelerometers seem to be a promising tool for lameness detection on farm and to study walking surfaces, especially when attached to a leg.

EFFECTS OF HOUSING IN DIFFERENT SOCIAL ENVIRONMENTS ON OPEN-FIELD AND SOCIAL RESPONSES OF FEMALE DAIRY CALVES

To investigate the effect of social contact during early development on open-field responses and social responses, 80 female dairy calves were housed either in open single pens (SOpen), closed single pens (SClosed), calf-groups (GCalf), or groups of calves and cows (GCow) until 3 months of age. During the first 3 months, the calves were open-field tested at 2 and 10 weeks of age. Calves isolated in closed single pens (SClosed) performed more exploration during the open-field tests at 2 and 10 weeks of age than did calves housed in open single pens (SOpen). During the open-field test after the experimental period at 6 months of age, previously isolated calves (SClosed) had a longer latency to enter an open-field arena, and during a social test at this stage group-reared calves (GCalf and GCow) sniffed and mounted other calves more than calves housed in single pens (SOpen and SClosed). The results suggest that isolation increases the motivation to explore a novel environment, and that housing in groups faci...

Dairy cows' use of colour cues to discriminate between people

The role of the colour of overalls as a cue used by cows to discriminate between people was studied in four experiments using a total of 66 Danish Friesian cows kept in tie-stalls. In all experiments, the average distance cows kept from the person was calculated from 12 scores during 1 min with the person standing in front of the cow. Experiment A. The distance cows (n=24) kept, from two unfamiliar people wearing red or yellow overalls, was tested. There was no difference in the distance the cows kept from the two people and the two colours (P>0.10). Experiment B. The distance cows (n=18) kept from an unfamiliar person wearing familiar coloured overalls (blue) was compared to when the same unfamiliar person was wearing red or yellow overalls. There was no effect due to the colour of the overalls (P>0.10). Experiment C. Cows (n=12) were handled repeatedly, by two handlers wearing overalls of the same colour. Each person handled six cows gently and six cows aversively. There was no significant difference in distance kept from the gentle and the aversive handler, after 11 treatments (P>0.10). Experiment D. Cows (n=12) were handled repeatedly by one person wearing either red or yellow overalls. The person wore one colour when handling the cows gently and the other colour when the cows were handled aversively. The cows kept a longer distance when the handler wore the colour worn during the aversive treatment than when the handler wore the colour worn during the gentle treatment (P<0.01). The cows also responded according to the colour of the clothes when worn by an unfamiliar person, although they kept a shorter distance from the unfamiliar person than to the handler.

Milk yield affects time budget of dairy cows in tie-stalls

Effective selection in breeding programs and improved management has increased the milk production per cow. However, the effects of the increased yield on behavior have not yet been clarified. We investigated the effect of milk yield on the time budget of 29 Finnish Ayrshire cows in the same stage of lactation kept in tie-stalls. The time spent lying, eating, ruminating, lying inactive without ruminating, and lying with the neck muscles relaxed, as well as the milk yield of primiparous and multiparous cows were recorded for 2d. The effects of milk yield and parity on behavior were analyzed with mixed models. The mean milk yield was 38.3 kg (SD 7.8) per day. Higher-yielding cows spent more time ruminating while standing and less time lying than lower-yielding cows. The latency to lie inactive without ruminating after lying down decreased as milk yield increased and it was shorter in primiparous compared with multiparous cows. Multiparous cows ruminated more while lying than primiparous cows. High milk yield cows spent a shorter time lying and they fell asleep (lay with neck relaxed) sooner. The degree of daily milk yield was associated with modifications in behavior and cows with high milk production had less lying time even with free access to lie down in the tie-stall.