Flexible feeding: Dairy cow personality affects changes in feeding behavior and milk production under feed competition conditions.

The objective of this study was to determine the effect of individual cow personality traits on feeding behavior and production under low levels of feeding competition, and to determine whether personality traits influence how feeding behavior changes in response to greater feeding competition. Forty-two Holstein cows were assigned to 1 automated feed bin per cow (low competition condition) from 15 to 28 d in milk (DIM; period 1, P1), and 2 feed bins per 3 cows (higher competition condition) from 63 to 76 DIM (period 2, P2). A total mixed ration (TMR) was fed into the automated feed bins which recorded each feed bin visit time, duration, and intake. Cow personality traits were assessed at 21 DIM during P1 and at 70 DIM during P2 using a combined arena test, measuring behavioral responses to a novel environment, novel object, and novel human. Principal components analysis of behaviors observed during the P1 combined arena test revealed 1 factor (interpreted as active-explorative) from the novel environment test explaining 51% of the variance, and 3 factors (interpreted as fearfulness, active-explorative, and sociability toward conspecifics) from each of the novel object (76% cumulative variance) and human (75% cumulative variance) tests. The principal components analysis of behaviors observed during the P2 combined arena test revealed 2 factors jointly from the environment, object, and human tests (interpreted as fearfulness and active-explorative) that together explained 68% of the variance. Fearfulness and active-explorative trait scores were correlated across P1 and P2, indicating stability of personality over a challenging period and advancing DIM. In P2 when competition for feed was increased at greater stage of lactation, the more active-explorative cows appeared to make few alterations to their feeding behavior, yet still maintained their milk yield, compared with lower competition in P1. In contrast, cows who were more fearful increased their feed bin visits from P1 to P2, and less fearful cows increased their eating rate, without increased milk production, despite advanced lactation. Overall, the results indicate that cows of different personalities adopt different feeding strategies in response to a change in their environment, and may benefit from tailored management during challenging periods.

Individuality of calves: Linking personality traits to feeding and activity daily patterns measured by precision livestock technology.

Animal personality has established connections with animal performance, resilience, and welfare which are related to stable behavioral patterns. Precision livestock technologies introduce the opportunity to measure these behavior patterns automatically and noninvasively. Thus, the primary aim of this study was to determine if personality traits in dairy calves measured via standardized personality assessments were associated with activity measured via a commercially available accelerometer. Secondary aims of this study were to investigate if personality traits were associated with feeding behaviors measured via an automatic feeding system (AFS) and with average daily gain (ADG). We characterized personality traits of Holstein calves (n = 49) utilizing standardized personality (novel environment, novel person, novel object, and startle) tests. Behaviors from these tests were summarized and 3 factors were extracted from a principal component analysis to represent calf personality traits: fearful, active, and explorative. Factor scores were regressed against behaviors from the accelerometer and AFS and with ADG. We found that calves that were more active were associated with taking more steps in the home environment, consuming more calf starter, and with reaching the benchmark of 1 kg of starter consumed in a day at a younger age. The trait active was also associated with greater ADG throughout the study. In addition, calves that were more explorative in the personality tests were associated with less starter consumed and lower ADG specifically during the weaning period. The findings of this research contribute to the existing literature by further establishing the links between personality traits and the daily behavioral patterns and performance of young calves. This study suggests the potential for using precision technology to assess and characterize personality traits, thereby enhancing their practical applicability on farms. Future research should focus on evaluating how personality traits, as measured through standardized assessments and precision technologies, correlate with deviations in behavior observed in dairy calves during stressors.

Effects of concentrate allowance and individual dairy cow personality traits on behavior and production of dairy cows milked in a free-traffic automated milking system.

The primary objective of this study was to determine whether the level of concentrate allowance in an automated milking system (AMS) affects the feed intake, eating behavior, milking activity, and performance of lactating dairy cows. The secondary objective of this study was to describe how the response to concentrate allocation, specifically in feeding and milking behavior, varies with cow personality traits. Fifteen Holstein cows were used in a crossover design with two 28-d periods, each including 14 d of adaptation and 14 d of data collection. The cows were housed in a freestall pen with free-traffic access to the AMS. Treatments consisted of a basal partial mixed ration (PMR) common to both treatment groups, with a concentrate allowance (on dry matter basis) of (1) 3.0 kg/d in the AMS (L-AMS) or (2) 6.0 kg/d in the AMS (H-AMS). Between the 2 treatment periods, each cow was assessed for personality traits using a combined arena test consisting of exposure to a novel environment, novel object, and novel human. Principal component analysis of behaviors observed during the novel environment and object tests revealed 3 factors (interpreted as active, social, and alert-curious) that together explained 76% of the variance, whereas principal component analysis of the novel human test revealed 2 factors (interpreted as active-vocal and fearful of novel humans) that together explained 77% of the variance. When on the H-AMS treatment, PMR dry matter intake (DMI) was less (24.5 vs. 26.0 kg/d) and AMS concentrate delivery was greater (5.9 vs. 3.1 kg/d), as per design. Consequently, total DMI was greater on the H-AMS treatment (30.4 vs. 29.1 kg/d). When on the H-AMS treatment, cows who were more alert-curious consumed more PMR, whereas cows who were more fearful of the novel human were less likely to receive the maximum amount of AMS concentrate available, limiting their total DMI and increasing the day-to-day variability of that intake. Although this was a preliminary study, these data suggest an association between dairy cow personality traits and how cows respond to increased AMS concentrate allowance.

Effects of intake-based weaning and forage type on feeding behavior and growth of dairy calves fed by automated feeders.

The objective of this study was to assess the effects of intake-based weaning methods and forage type on feeding behavior and growth of dairy calves. Holstein dairy calves (n = 108), housed in 12 groups of 9, were randomly assigned to 1 of 3 weaning treatments: milk reduction based on age (wean-by-age), individual dry matter intake (DMI; wean-by-intake), or a combination of individual DMI and age (wean-by-combination). Groups of calves were alternately assigned to 1 of 2 forage treatments: grass hay or a silage-based total mix ration (TMR; n = 6 groups per treatment). Until 30 d of age, all calves were offered 12 L/d of whole milk. Starting on d 31, milk was gradually reduced by 25% of the individual's average milk intake. For wean-by-age calves (n = 31), the milk allowance remained stable until d 62 when milk was again reduced gradually until weaning at d 70. For wean-by-intake calves (n = 35), milk allowance was reduced by a further 25% once calves consumed on average 200, 600, and (finally) 1,150 g of dry matter (DM) per day of calf starter and forage. For wean-by-combination calves (n = 35), milk intake remained stable until calves consumed on average 200 g of DM/d, at which point milk was reduced linearly until weaning at d 70. If calves failed to reach DMI targets by d 62 (n = 10), milk was then reduced gradually until weaning at d 70. Of the 35 wean-by-intake calves, 27 met all 3 DMI targets (successful-intake), and 33 of the 35 calves in the wean-by-combination treatment met the 200 g of DM/d target (successful-combination). Successful-intake and successful-combination calves had greater final body weight (BW) at 12 wk of age than wean-by-age calves (123.7 vs. 122.3 vs. 117.7 ± 3.1 kg, respectively). During weaning, successful-intake calves ate more starter and consumed less milk than successful-combination and wean-by-age calves (starter: 1.19 vs. 0.89 vs. 0.49 ± 0.07 kg of DM/d, respectively; milk: 2.7 vs. 4.2 vs. 5.9 ± 0.17 L/d, respectively). After weaning, successful-combination and successful-intake calves consumed similar amounts of starter; however, wean-by-age calves continued to consume less starter (2.85 vs. 2.78 vs. 2.44 ± 0.10 kg of DM/d, respectively). During weaning, hay and TMR calves ate similar amounts of forage, but hay calves consumed more starter (0.96 vs. 0.75 ± 0.07 kg of DM/d, respectively). After weaning, hay calves continued to consume more starter (2.88 vs. 2.50 ± 0.10 kg of DM/d, respectively), whereas TMR calves consumed more forage (0.33 vs. 0.15 ± 0.02 kg of DM/d, respectively). Hay calves had greater final BW at 84 d compared with TMR calves (124.0 vs. 119.0 ± 1.6 kg, respectively). These results show that the inclusion of a DMI target can improve starter intake and BW for calves that successfully wean, and that forage type can influence the transition onto solid feed. We also found that approximately 10% of calves failed to consume even 200 g of DM/d by 9 wk of age; more research is needed to better understand why some calves struggle to transition onto solid feed.

Automatic weaning based on individual solid feed intake: Effects on behavior and performance of dairy calves.

Calves are typically weaned from milk to solids once they reach a predetermined age or when they are consuming a predetermined intake of solids. The first aim of this study was to compare feeding behavior and performance of calves weaned based on age versus starter intake. The latter method can result in considerable variation in the age at which calves are weaned, so a secondary aim was to compare calves that weaned early or late when weaned based on starter intake. In experiment 1, dairy calves were randomly assigned to be either (1) weaned by age at d 70 (n = 16), or (2) weaned by intake, where calves were weaned based on starter intake (n = 16). All calves were fed using an automatic milk feeder and offered 12 L/d of milk until 30 d of age. On d 31, all calves had their milk rations reduced. Calves weaned by age were reduced to 6 L/d of milk over 5 d and received 6 L/d milk from d 35 until d 63, when milk was reduced over 7 d until complete weaning at d 70. For calves weaned by intake, the milk ration was reduced on d 31 to 75% of that calf's previous milk intake (3-d average) and further reduced by 25% when the calf met each of 3 targets for starter intake: 225, 675, and 1,300 g/d. Calves that failed to reach the final target by d 63 (failed-intake group; n = 6) were weaned over 7 d to complete weaning at d 70. Ten calves met all 3 starter intake targets (successful-intake group). In experiment 2, all calves were assigned to the weaned-by-intake treatment (n = 48). The weaning strategy was identical to that described for experiment 1, but calves were permitted up to d 84 to reach the final starter intake target. Forty-three calves met all 3 targets and were retrospectively divided into early-weaning (weaned before d 63; n = 31) and late-weaning (weaned on or after d 63; n = 12) categories. In both experiments, the weaning period was considered from the time of initial milk reduction at d 31 until complete weaning at d 70 (weaned by age) or when consuming 1,300 g/d (weaned by intake). Postweaning growth was monitored from weaning until final weight in the calf-rearing period at d 98 (experiment 1) and d 105 (experiment 2). Final weight in the grower period was measured at d 134 (experiment 1) and d 145 (experiment 2). In experiment 1, successful-intake calves (vs. calves weaned by age) consumed 125.3 ± 16.4 L less milk and 41.3 ± 9.3 kg more starter over the experimental period, engaged in more unrewarded visits to the milk feeder during weaning (11.1 ± 1.5 vs. 5.0 ± 1.3 visits/d), and achieved similar weights at the end of the grower period (188.2 ± 6.6 vs. 195.2 ± 5.7 kg). In experiment 2, calves that weaned by intake early (vs. late) consumed 93.3 ± 26.0 L less milk and 57.2 ± 12.2 kg more starter, engaged in a similar number of unrewarded visits during weaning (7.0 ± 0.6 vs. 7.6 ± 1.0 visits/d), had greater average daily gain during weaning (1.08 ± 0.02 vs. 0.94 ± 0.03 kg/d), and achieved greater final weights at the end of the grower period (203.2 ± 2.9 vs. 192.6 ± 4.2 kg). These results indicate that calves weaned based on starter intake can achieve similar weights to those weaned by age, despite consuming less milk. However, some calves will fail to meet starter intake targets unless given sufficient time to do so. Variation in preweaning feed intake provides an opportunity for individualized management of calves.

Behavioral changes before metritis diagnosis in dairy cows.

Metritis is common in the days after calving and can reduce milk production and reproductive performance. The aim of this study was to identify changes in feeding and social behavior at the feed bunk, as well as changes in lying behavior before metritis diagnosis. Initially healthy Holstein cows were followed from 3 wk before to 3 wk after calving. Behaviors at the feed bunk were recorded using an electronic feeding system. Lying behavior was recorded using data loggers. Metritis, based upon the characteristics of vaginal discharge at d 3, 6, 9, 12 and 15 after calving, was diagnosed in 74 otherwise healthy cows. Behavior of these cows, beginning 2 wk before calving until the day of diagnosis, was compared with 98 healthy cows (never diagnosed with any health disorder, including ketosis, mastitis, and lameness) during the transition period. During the 2 wk before calving, cows later diagnosed with metritis had reduced lying time and fewer lying bouts compared with healthy cows. In the 3 d before clinical diagnosis, cows that developed metritis ate less, consumed fewer meals, were replaced more often at the feed bunk, and had fewer lying bouts of longer duration compared with healthy cows. We concluded that changes in feeding as well as social and lying behavior could contribute to identification of cows at risk of metritis.

Changes in feeding, social, and lying behaviors in dairy cows with metritis following treatment with a nonsteroidal anti-inflammatory drug as adjunctive treatment to an antimicrobial.

Dairy cows with metritis display sickness behaviors, and nonsteroidal anti-inflammatory drugs (NSAID) have the potential to reduce these responses. The objective of this study was to investigate changes in feeding, social, and lying behaviors in dairy cows with metritis that had been treated with the NSAID meloxicam. After parturition, cows were housed in a dynamic, mixed-parity group of 20 animals with access to 12 electronic feed bins, 2 electronic water bins, and 24 lying stalls in a freestall pen. Every third day after parturition, vaginal discharge was evaluated to diagnose metritis based on the presence of foul smell and characteristic visual appearance. When diagnosed with metritis, animals (n = 87) were randomly allocated to receive either a single dose of meloxicam (0.5 mg/kg of body weight subcutaneously) or a placebo solution. All metritic animals received an antimicrobial (ceftiofur) for 5 d. We measured feeding and social behaviors at the feed bunk, as well as lying behaviors, and assessed within-cow changes from the day before to the day of (d 0) NSAID treatment, and from the day before to d 1 to 5 after treatment. Generally, behaviors changed around the day of diagnosis of metritis. Compared with the placebo group, cows that received meloxicam had a greater increase in the number of visits to the feeder, but tended to show less of an increase in dry matter intake and feeding time. These differences did not persist beyond 24 h after NSAID treatment. We observed no differences in changes in number of meals and feeding rate on d 0, but from d 1 to 5 cows treated with meloxicam had a lesser decrease in the number of meals and tended to have a greater decrease in feeding rate than did placebo-treated cows. In multiparous cows on d 0 and from d 1 to 5, meloxicam treatment was associated with decreased lying times. In primiparous cows, lying time changes were similar between treatments on d 0, but lying times increased more on d 1 to 5 for meloxicam than for placebo cows. Overall, cows changed the number of lying bouts on d 0, and this increase tended to be smaller for the meloxicam cows. There were no treatment differences in changes of social behavior. In summary, we observed inconsistent and generally small effects of a single dose of meloxicam in addition to antimicrobial therapy on the behavior of cows with metritis.

Parity differences in the behavior of transition dairy cows.

During the transition period, around the time of calving, cows experience a suite of stressful events, including regrouping, diet changes, parturition, and the onset of lactation. These changes may be more difficult for primiparous cows that have not had these experiences previously. The objective of this study was to compare feeding, social, exploratory, and lying behaviors of primiparous and multiparous cows during the transition period. Thirty-eight healthy primiparous and 62 healthy multiparous dairy cows were housed in mixed-parity groups of 20 with access to 12 electronic feed bins from 3wk before to 3wk after calving. Primiparous cows had lower dry matter intake, spent more time feeding, ate more slowly, visited the feeder more frequently, and explored their feeding environment more compared with multiparous cows. Primiparous cows also lay down more frequently, but for shorter periods, such that total lying time did not differ between these parity classes. Primiparous cows were also replaced at the feeder more often than multiparous cows. These results show how the behavior of primiparous and multiparous cows differs during the transition period, and support the idea that primiparous cows may benefit from different management during this period.

The effect of milk allowance on behavior and weight gains in dairy calves.

The objective of this study was to investigate how milk allowance affects body weight gains and behavior before, during, and after weaning in dairy calves. Fifty-six Holstein calves were randomly assigned at 1wk of age to 1 of 4 feeding treatments of whole pasteurized milk: 6, 8, 10, or 12 L/d. Milk allowance was reduced by 50% at d 42, and then reduced by 20% per day starting at d 50, so that calves were completely weaned at d 55. Calves were provided ad libitum access to calf starter and hay. Body weight was measured weekly from 2 to 10wk of age. Milk intake increased with milk allowance as intended, although actual intakes were lower than the treatment allowance (e.g., averaging 5.66±0.19 L on the 6-L treatment and 9.41±0.21 L on the 12-L treatment before weaning). Intake of calf starter was higher for calves that were fed less milk before weaning (averaging 0.25±0.03kg/d and 0.05±0.03kg/d on the 6-L and 12-L treatments, respectively) and also during the weaning period (averaging 1.15±0.13kg/d and 0.54±0.14kg/d on these same treatments), but we observed no effect after weaning. Time spent at the hay feeder did not differ with treatment. Average daily gain was higher for calves that were fed more milk, increasing from 0.77±0.04kg/d with the 6-L treatment to 0.90±0.03kg/d with the 12-L treatment. Before weaning, calves fed less milk engaged in more unrewarded visits to the milk feeder, averaging 11.1±0.73 visits/d with the 6-L treatment and 0.4±0.78 visits/d with the 12-L treatment. During weaning, calves fed less milk still had more unrewarded visits to the milk feeder than calves fed more milk (19.7±1.64 visits/d with the 6-L treatment versus 10.1±1.74 visits/d with the 12-L treatment), but treatments did not differ after weaning. We conclude that higher milk allowances result in weight gain advantages before weaning that can persist beyond weaning, and that the high number of unrewarded visits to the milk feeder by calves that were fed less milk are indicative of persistent hunger.

Review: Individual variability in feeding behaviour of domesticated ruminants.

Individual animals behave differently from one another, especially when confronting challenges such as changes in diet (e.g. weaning), environment (e.g. moving from pasture to feedlot) and social grouping (e.g. movement to lactating group after parturition). Each of these challenges involves some element of novelty, impacting the welfare and productivity of the animal. Indeed, the large individual variability in the development and expression of feeding behaviour cannot be fully explained by differences in genetics, management practices, body size or growth rate. In this review we outline evidence that individual variability in feeding behaviour is associated with the personality of the individual. We focus on three key personality traits: exploration, fear or reactivity and sociability. Individuals differ in how much they explore their feeding environment, with more exploratory individuals being less reactive to novel situations. Feeding behaviour can be impaired in individuals that are especially reactive to a change in their environment, change in diet or handling or restraint by humans. The social environment is also a major factor affecting how individuals express their behaviour. Sociability of the individual, including dominant-subordinate and affiliative relationships, affects how individuals make foraging decisions, gain access to feed and adopt particular social strategies to maintain or adjust feeding patterns when the social environment changes. Personality traits such as exploration, boldness and sociability also affect the use of social information when learning where, how or what to eat. Our review highlights the implications of feeding behaviour variability for the welfare and productivity of the individual, and how an understanding of personality can help tailor management to the needs of the individual.