Calf performance in a cow-driven cow-calf contact system: Effect of 2 methods to gradually reduce cows' access to their calf

Knowledge is lacking on separation strategies that can best prepare calves to final separation from the dam in cow-calf contact (CCC) systems. This controlled trial compared the effects of 2 different methods to gradually reduce cows' access to their calf termed "debonding" on calf growth in a cow-driven CCC system. Initially, cows (Norwegian Red breed) had 24 h/d computer-controlled access to their calves. In the long debonding (LDB) treatment (n = 16), a gradual reduction of cows' access to their calves was initiated 28 d after calving over a total duration of 28 d; first to 12 h/d (14 d), and then to 6 h/d (14 d). In the short debonding (SDB) treatment (n = 14), reduction was initiated 45 d after calving over a total duration of 10 d; first to 12 h/d (5 d), and then to 6 h/d (5 d). From 6 h/d, access was finally reduced to 0 h/d for 4 d for both treatments, resulting in a study period of 60 d in total. Calves had ad libitum access to concentrate, hay and water throughout the study. Independent of treatment, ad libitum access to whole milk from an automatic feeder was granted once cow access was reduced. Cows and calves had the possibility for fence line contact at all times. The primary outcome variable calf weight gain was registered biweekly. Calf ADG was analyzed with a linear mixed model. The ADG was similar across treatments during 24 h/d access (1.04 ± 0.07 kg). Debonding treatment affected calf growth differently with each gradual reduction in cow access (12 h/d, 6 h/d and 0 h/d); however, no main effect of treatment was detected. The SDB calves had a pattern of increased ADG with the first reduction in access (+0.39 ± 0.18kg), followed by significant growth checks as access was reduced further to 6 h/d and 0 h/d (-0.41 ± 0.20 kg and -1.15 ± 0.31 kg, respectively). The LDB calves only showed significant weight checks at the final reduction in access (0 h/d access), yet at a lower degree (-0.46 ± 0.21 kg) than SDB calves. As expected, ADG was negatively associated with health events but positively associated with intake of concentrate and supplemental milk. Collectively, the results from the present study might point toward a long adaptation to separation which is initiated at a younger age being more favorable for calf performance.

Effects of simplified group housing on behavior, welfare, growth performance, and health of preweaned dairy calves on a California dairy

Most US dairy calves are raised in individual hutches for biocontainment purposes and to facilitate monitoring and handling of calves. However, individual hutches typically restrict calves' activity and social interactions. Previous studies showed that group housing (GH) is beneficial to calf welfare and is associated with social benefits. The adoption of GH on dairies is hindered by several concerns, with the primary concern being the potential for increased transmission of diseases due to heightened calf-to-calf contact. In light of this, our study aimed to compare the behavior, health, and growth outcomes of calves housed in groups of 3 to individually housed (IH) calves during the preweaning period. A total of 42 Holstein heifer calves on a commercial dairy in Northern California were enrolled in groups of 3 to different housing treatments; IH (n = 21) or GH (n = 21) between July and October 2020. Each treatment was composed of 7 groups of 3 calves each. Calves in the GH treatment were housed in groups of 3 from 6 to 10 d until 70 d of age. Individual pens consisted of one polyethylene hutch with a 1.5 m × 1.2 m outside exercise area. Group pens were constructed by assembling 3 polyethylene hutches with a 1.5 m × 3.6 m outside exercise area of wire panel fencing. Calves were weighed and measured for height at birth and weaning. Diarrhea and bovine respiratory disease (BRD) scores were recorded daily throughout the preweaning period. Cumulative incidence and hazard ratios were estimated for BRD and diarrhea for GH and IH. A mixed model with pen as a random effect was specified to evaluate the effect of treatment. Group-housed calves gained 0.64 ± 0.02 kg/d while IH calves gained 0.65 ± 0.02 kg/d. Similarly, there was no evidence for treatment differences in withers height gain in GH calves (0.22 ± 0.01 cm/d) compared with IH calves (0.21 ± 0.01 cm/d). The cumulative incidence of BRD based on the California scoring system in GH calves was 75 ± 9.68% compared with 66.66 ± 10.28% in IH calves. Group-housed calves had a BRD hazard of 1.14 times that of IH calves (95% CI: 1.21-2.40). The cumulative incidence of diarrhea (fecal score 3) in GH calves was 100% in comparison to 95.20% ± 4.66% in IH calves. The mean proportion of scan observations of calves feeding on concentrates was significantly higher in GH (0.145 ± 0.004/h) compared with IH calves (0.076 ± 0.003/h) during the preweaning period. The study results provide evidence that this simplified GH system provides benefits of GH without detrimental short-term effects on calf growth and health during the preweaning period.

Calf Management: Individual or Paired Housing Affects Dairy Calf Health and Welfare

Previous research has indicated that preweaned dairy calves reared in pairs compared with individually have improved performance and indicators of animal welfare. One hundred and thirty Holstein female calves completed the trial, with eighty-five being allocated to paired housing and forty-five calves being allocated to individual housing. Daily live weight gain (DLWG), treatments and mortality were recorded throughout the preweaning period. Salivary cortisol, latency to feed and latency to approach a novel object were assessed at batching. There were no significant differences in DLWG, mortality and disease treatments between the average of the pair and the individually housed calves, although the pair-reared calves were quicker to approach the milk feed after batching and interacted more quickly with a novel object. The heaviest born calves within the pair had the highest DLWG from birth to weaning, with a higher percentage of calves approaching the novel object, compared with the lightest born calf within the pair. This study shows that calves within a pair may have significantly different performance and welfare during the preweaning period, with the heavier calf outperforming and displaying less fear and more exploratory behaviour than the lighter calf within a pair.

Thermal comfort and ventilation preferences of dairy calves raised in paired outdoor hutches during summertime

Dairy calves are social creatures who are highly motivated for access to a companion. Additionally, heat stress negatively affects the welfare and productivity of calves housed in outdoor hutches. However, no studies have examined the potential tradeoffs pair-housed calves face between competing motivations for social contact and thermal comfort. We evaluated the effects of hutch ventilation on thermoregulatory and behavioral responses of pair-housed calves in outdoor hutches during a Wisconsin summer. Fifty Holstein-Friesian heifer calves were pair-housed (n = 25 pairs) in adjacent hutches with a shared outdoor area. In each pair of hutches, 1 was ventilated (V) with 2 windows at the rear base and the rear bedding door propped open; the other had no rear windows and a closed bedding door (nonventilated, NV). Calves were exposed to 4 conditions for 1 h each (1100-1200 h and 1230-1330 h on 2 consecutive days during wk 4, 6, and 9 of life) in a 2 × 2 factorial design in a balanced order: individually or in pairs in the NV or V hutch. Immediately before and after the 1 h hutch restriction period, respiration rate (RR) and rectal temperature (RT) were recorded while calves were outside. On the subsequent 3 d in those weeks, the locations of each calf (outdoors or inside a hutch) were recorded at 15-min intervals using time-lapse cameras. Linear mixed models were used to evaluate the fixed effects of ventilation, number of calves inside the hutch, week of life, and their interactions, on change in temperature-humidity index (THI), RR, and RT after 1 h; pair of calves was the subject of the repeated statement. Within weeks, the proportion of time calves spent in each hutch and together were averaged across the 3 d of observation. One-sample t-tests were used to evaluate preferences compared with 50% (chance, no preference): (1) for the V (vs. NV) hutch and (2) to be together (or separate) in either the V or NV hutch as well as overall. The THI gain inside the V hutch after 1 h with calves present was lower relative to the NV hutch (0.90 vs. 1.79 units, respectively, standard error of the mean [SEM] = 0.16). Calves in wk 9 of life increased the hutch THI more than in wk 6 of life (1.81 vs. 0.72 units respectively, SEM = 0.16). After 1 h, RR decreased versus was unchanged, respectively, when calves were in the V versus NV hutch (-14.4 vs. -0.9 breaths/min, respectively, SEM = 1.4 breaths/min). No differences were detected in RT. Calves chose to be together most of the time regardless of location (wk 4, 6, and 9, respectively: 83.1% ± 2.4%, 80.3% ± 2.1%, and 78.0% ± 3.1%). Calves had no hutch preference during wk 4 but developed a preference for the V hutch as they aged (wk 4, 6, and 9, respectively: 47.3% ± 4.5%, 61.2% ± 5.1%, and 72.8% ± 4.3%). This is the first study to demonstrate passive ventilation improves animal welfare by reducing heat stress in pair-housed dairy calves in outdoor hutches.

Comparison of behavior, thermoregulation, and growth of pair-housed versus individually housed calves in outdoor hutches during continental wintertime

Cold stress negatively affects the welfare of calves in outdoor hutches. No studies have examined the potential benefits of pair housing calves to buffer against cold stress. Our study evaluated the effects of pair versus individual housing on thermoregulatory, behavioral, and growth performance responses of calves in outdoor hutches during a Wisconsin continental winter. Forty-eight Holstein-Friesian heifer calves were enrolled into 1 of 2 housing treatments: individually (n = 16 calves) or pair housed (n = 16 pairs; 32 calves). Calves were fed milk twice daily, with ad libitum access to starter and water. Step-down weaning began on d 42 of life, and all milk was removed on d 54. Data collection continued through d 59. Calves were restricted inside a hutch (pair-housed calves in the same hutch) for 1 h during wk 4, 6, and 9 of life; internal hutch air temperature (T) was recorded with data loggers, and rectal temperature (RT) was recorded outside the hutch before and after restriction. On the subsequent 3 d in those weeks, calves' locations (outside or inside a hutch) were recorded at 15-min intervals using time-lapse cameras. Linear mixed models (change in T and RT after 1 h) and generalized linear mixed models with a β distribution (proportion of time spent inside hutches) were used to evaluate the fixed effects of housing treatment, week of life, and their interaction. For pair-housed calves, preference to be together was evaluated using one-sample t-tests comparing the proportion of time they were observed in the same location against 50% (chance, no preference), separately for each week of life. Predicted dry matter intake (DMI) of starter and body weight (BW) were standardized by day of life using regression models and used to calculate average daily gain (ADG) and feed conversion ratio (FCR; DMI of starter/ADG). Linear mixed models were constructed for each measure, separately for the preweaning, weaning, and postweaning periods, with a fixed effect of housing treatment; the models for BW included birth weight as a covariate. All mixed models included a random term for housing unit (individual or pair of calves) nested within treatment. Hutch T increased more after 1 h with pair-housed calves inside than with those housed individually (+2.3 vs. 1.4°C, respectively; standard error of the mean = 0.26°C). However, no treatment differences were detected in RT. Individually housed calves spent more time inside the hutches than pair-housed ones (93.9 vs. 90.7% of total time, respectively; standard error of the mean = 0.8%), and the latter chose to be together most of the time, regardless of location (90.0 ± 1.3%, 88.6 ± 1.2%, and 79.4 ± 4.2% in wk 4, 6, and 9 of life, respectively). After weaning, there was some evidence suggesting that pair-housed calves had greater starter DMI than those housed individually. No effects of housing type were found on FCR, BW, or ADG. Our study is the first to explicitly examine the potential benefits of pair housing for alleviating cold stress in outdoor-housed dairy calves, and we found limited evidence in support of our hypotheses.

Review: Opportunities and challenges for the genetic selection of dairy calf disease traits

Interest in dairy cow health continues to grow as we better understand health's relationship with production potential and animal welfare. Over the past decade, efforts have been made to incorporate health traits into national genetic evaluations. However, they have focused on the mature cow, with calf health largely being neglected. Diarrhoea and respiratory disease comprise the main illnesses with regard to calf health. Conventional methods to control calf disease involve early separation of calves from the dam and housing calves individually. However, public concern regarding these methods, and growing evidence that these methods may negatively impact calf development, mean the dairy industry may move away from these practices. Genetic selection may be a promising tool to address these major disease issues. In this review, we examined current literature for enhancing calf health through genetics and discussed alternative approaches to improve calf health via the use of epidemiological modelling approaches, and the potential of indirectly selecting for improved calf health through improving colostrum quality. Heritability estimates on the observed scale for diarrhoea ranged from 0.03 to 0.20, while for respiratory disease, estimates ranged from 0.02 to 0.24. The breadth in these ranges is due, at least in part, to differences in disease prevalence, population structure, data editing and models, as well as data collection practices, which should be all considered when comparing literature values. Incorporation of epidemiological theory into quantitative genetics provides an opportunity to better determine the level of genetic variation in disease traits, as it accounts for disease transmission among contemporaries. Colostrum intake is a major determinant of whether a calf develops either respiratory disease or diarrhoea. Colostrum traits have the advantage of being measured and reported on a continuous scale, which removes the issues classically associated with binary disease traits. Overall, genetic selection for improved calf health is feasible. However, to ensure the maximum response, first steps by any industry members should focus efforts on standardising recording practices and encouragement of uploading information to genetic evaluation centres through herd management software, as high-quality phenotypes are the backbone of any successful breeding programme.

Can a gradual weaning and separation process reduce weaning distress in dam-reared dairy calves? A comparison with the two-step method

The weaning and separation phase remains one of the biggest challenges for cow-calf-contact systems, but a gradual process that better mimics the naturally occurring reduction in milk intake has not yet been scientifically investigated. Therefore, the aim of our study was to compare behavioral and physiological indicators of distress in 3 mo-old dam-reared dairy calves (with previous full-time cow-calf contact) weaned and separated either via gradual reduction of contact time with the dam (GR, 1 week half day contact, 1 week morning contact, 1 week fence-line contact before complete separation, n = 18) or via 2-step weaning using a nose flap (NF, 2 weeks access to dam with a nose flap, 1 week fence-line contact before complete separation, n = 18). Behavior was recorded 1 week before (or for lying 3 weeks before) weaning start and during the 3 week weaning and separation period with direct observations on 4 d per week or via accelerometers (locomotor play, lying behavior). Blood and fecal samples were taken twice per week from weaning start until 3 weeks after weaning start. Calves were weighed weekly. Statistical analysis was conducted using (generalized) linear mixed models. Over the whole weaning and separation phase, NF calves showed a stronger decrease in the number of lying bouts, amount of locomotor play and average daily weight gains, as well as a higher increase in total mixed ration feeding time compared with GR calves, whereas GR calves vocalized more often and showed more searching behavior than NF calves. Also, the neutrophil:lymphocyte ratio of NF calves was elevated on d 3 after insertion of the nose flaps compared with baseline, but showed no change for GR calves on any sampling day. Overall, results point toward a favorable effect of a gradual weaning strategy on reduction of weaning and separation distress in dam-reared dairy calves, but the method requires further improvement from the protocol used in our study.

Invited review: The effect of weaning practices on dairy calf performance, behavior, and health - a systematic review

The aim of this systematic review was to summarize the literature assessing the effects of weaning practices on performance, behavior, and health of dairy calves. Only published, peer-reviewed articles written in English and specifically assessing the effects of weaning treatments on dairy calves were eligible for inclusion. Studies had to include 2 or more treatment groups that addressed at least one of 4 interventions: weaning age (i.e., when milk was fully removed), weaning duration (i.e., number of days from start of milk reduction to when milk was fully removed), weaning criteria (e.g., age vs. intake), or alternative weaning methods (e.g., water dilution). Outcome measures could include starter intake, growth (body weight or average daily gain), behaviors (5 specific sucking behaviors; play behavior; lying behavior; vocalizations; unrewarded visits to an automated milk feeder), and health (mortality rate, diarrhea, and respiratory illness). We conducted 3 targeted searches using Web of Science and PubMed. The articles underwent a 2-step screening process, resulting in a final sample of 44 studies. The majority of studies investigated weaning age (n = 22), followed by weaning duration (n = 13), weaning criteria (n = 9), and other weaning methods such as dilution, linear vs. step-down milk reduction, or meal-based approaches (n = 6). There was consensus for positive effects (or at least no negative effects) on overall growth of calves weaned at later ages, over longer durations, based on starter intake, or weaned using step-down or meal-based milk removal approaches. This is despite reduced starter intake in calves weaned at later ages; most studies found improved starter intake in calves weaned over longer durations. Weaning based on starter intake had superior growth and feed intakes compared with calves weaned at a fixed earlier age. Few studies assessed interactive effects of weaning method and milk allowance. However, weaning after 8 wk appears to support superior weight gain, provided pre-weaning milk allowances are adequate (above 6 L/d). Weaning can lead to hunger-related behaviors and reduced welfare, yet only half of the studies assessed the effects of weaning method on calf behavior. Weaning at later ages can reduce signs of hunger (based on unrewarded visits to the milk feeder), but it is unclear if weaning over longer durations or weaning by starter intake reduces or prolongs hunger. There was little consensus among the few studies that measured oral behaviors of calves. Positive welfare indicators, such as play behavior, were rarely measured, yet are crucial to understanding the emotional states of calves during this potentially stressful diet transition. Health was rarely the primary objective of the study, with low sample sizes to conduct statistical comparisons. Overall, there remains significant knowledge gaps in our understanding of how best to wean calves. A successful weaning program must minimize signs of hunger while promoting high growth and feed intakes, so we encourage future work to include behavioral indicators of hunger and positive welfare to evaluate how weaning methods are experienced by the calf.

Long-Term Effects of Pre-Weaning Individual or Pair Housing of Dairy Heifer Calves on Subsequent Growth and Feed Efficiency

Our objective in this exploratory study was to evaluate the long-term impacts of pre-weaning social isolation vs. contact on subsequent growth and feed efficiency of Holstein heifers. As pre-weaned calves, 41 heifers were housed individually (n = 15 heifers) or in pairs (n = 13 pairs; 26 heifers). At 18 months of age, heifers were blocked by body weight and randomly assigned to one of three pens within a block (six to eight heifers per pen; six pens total), with original pairs maintained. Body weight (BW), hip height and width, and chest girth were measured at the start and end of the study. Each pen was given 3 days of access to a GreenFeed greenhouse gas emissions monitor to assess potential physiological differences between treatments in enteric methane emissions or behavioral differences in propensity to approach a novel object. During the 9-week study, heifers were fed a common diet containing 62.3% male-sterile corn silage, 36.0% haylage, 0.7% urea, and 1.0% mineral (DM basis). To calculate daily feed intake, as-fed weights and refusals were recorded for individual heifers using Calan gates. Feed samples were collected daily, composited by week, and dried to calculate dry matter intake (DMI). Feed refusal and fecal samples were collected on 3 consecutive days at 3 timepoints, composited by heifer, dried, and analyzed to calculate neutral detergent fiber (NDF), organic matter (OM), and DM digestibility. Feed efficiency was calculated as feed conversion efficiency (FCE; DMI/average daily gain [ADG]) and residual feed intake (RFI; observed DMI-predicted DMI). Paired and individually housed heifers did not differ in DMI, ADG, FCE, or RFI. Although no differences were found in initial or final hip height, hip width, or chest girth, heifers which had been pair-housed maintained a greater BW than individually housed heifers during the trial. Methane production, intensity, and yield were similar between treatments. Pre-weaning paired or individual housing did not impact the number of visits or latency to approach the GreenFeed; approximately 50% of heifers in each treatment visited the GreenFeed within 8 h of exposure. Digestibility of OM, DM, and NDF were also similar between housing treatments. In conclusion, pre-weaning pair housing had no adverse effects on growth, feed efficiency, or methane emissions at 18 to 20 months of age.

Invited review: The effect of milk feeding practices on dairy calf behavior, health, and performance-A systematic review

The aim of this systematic review was to summarize the literature assessing the effects of milk feeding practices on behavior, health, and performance on dairy calves. Peer-reviewed, published articles, written in English, directly comparing the effects of milk allowance, milk feeding methods, or milk feeding frequency on dairy calves were eligible for inclusion. Outcome measures could include sucking behavior, sucking on a teat (nutritive sucking, non-nutritive sucking on a teat), abnormal sucking behavior (non-nutritive sucking on pen fixtures, other oral behaviors, or cross-sucking), signs of hunger (vocalizations or unrewarded visits at the milk feeder), activity (lying time or locomotor play), feeding behavior (milk intake, starter intake, milk meal duration, or starter meal duration), growth (body weight or average daily gain), and health (occurrence of diarrhea, respiratory disease, or mortality). We conducted 2 targeted searches using Web of Science and PubMed to identify key literature. The resulting articles underwent a 2-step screening process. This process resulted in a final sample of 94 studies. The majority of studies investigated milk allowance (n = 69). Feeding higher milk allowances had a positive or desirable effect on growth, reduced signs of hunger, and increased locomotor play behavior during the preweaning period, whereas starter intake was reduced. Studies addressing health pointed to no effect of milk allowance, with no consistent evidence indicating that higher milk allowances result in diarrhea. Studies addressing milk feeding methods (n = 14) found that feeding milk by teat reduced cross-sucking and other abnormal oral behaviors. However, results on the effect of access to a dry teat were few and mixed. Milk feeding frequency (n = 14 studies) appeared to have little effect on feed intakes and growth; however, there is some evidence that calves with lower feeding frequency experience hunger. Overall, findings strongly suggest feeding higher volumes of milk using a teat; however, further work is needed to determine the optimal feeding frequency for dairy calves.

Effects of Individual and Pair Housing of Calves on Short-Term Health and Behaviour on a UK Commercial Dairy Farm

Social pair housing of calves has previously demonstrated positive impacts for calves, so this study aimed to compare the health and behaviour of calves kept in individual compared to pair housing on a single commercial UK dairy farm. A total of 457 Holstein and Jersey heifer calves were recruited and systematically allocated to individual and pair housing. Weekly visits were conducted up to 8 weeks of age, with weight and presence of clinical disease measured using both a standardized scoring system and thoracic ultrasonography. A subset of calves (n = 90) had accelerometers attached to monitor activity, with CCTV placed above a further 16 pens to allow behavioural assessments to be made via continuous focal sampling at 1 and 5 weeks of age. During the study, there was a mortality rate of 2.8%, and an average daily liveweight gain (ADLG) of 0.72 kg/day, with no significant effect of housing group (p = 0.76). However, individually housed calves had increased odds of developing disease (OR = 1.88, p = 0.014). Accelerometer data showed that housing group had no effect on lying times, with a mean of 18 h 11 min per day (SD 39 min) spent lying down. The motion index was significantly higher in pair-housed calves (F_1,83 = 440.3, p < 0.01), potentially due to more social play behaviour. The total time engaged in non-nutritive oral behaviours (NNOBs) was not impacted by housing group (p = 0.72). Pair-housed calves split their time conducting NNOBs equally between inanimate objects and on their pen mates' body. Individually housed calves spent significantly more time with their head out of the front of the pen (p = 0.006), and also engaged in more self-grooming than pair-housed calves (p = 0.017), possibly due to a lack of socialization. The overall findings of this study indicate that within a UK commercial dairy management system, pair-housed calves were healthier and more active than individually housed calves, while housing group did not influence ADLG or the occurrence of NNOBs.

Welfare of calves

This Scientific Opinion addresses a European Commission request on the welfare of calves as part of the Farm to Fork strategy. EFSA was asked to provide a description of common husbandry systems and related welfare consequences, as well as measures to prevent or mitigate the hazards leading to them. In addition, recommendations on three specific issues were requested: welfare of calves reared for white veal (space, group housing, requirements of iron and fibre); risk of limited cow–calf contact; and animal‐based measures (ABMs) to monitor on‐farm welfare in slaughterhouses. The methodology developed by EFSA to address similar requests was followed. Fifteen highly relevant welfare consequences were identified, with respiratory disorders, inability to perform exploratory or foraging behaviour, gastroenteric disorders and group stress being the most frequent across husbandry systems. Recommendations to improve the welfare of calves include increasing space allowance, keeping calves in stable groups from an early age, ensuring good colostrum management and increasing the amounts of milk fed to dairy calves. In addition, calves should be provided with deformable lying surfaces, water via an open surface and long‐cut roughage in racks. Regarding specific recommendations for veal systems, calves should be kept in small groups (2–7 animals) within the first week of life, provided with ~ 20 m²/calf and fed on average 1 kg neutral detergent fibre (NDF) per day, preferably using long‐cut hay. Recommendations on cow–calf contact include keeping the calf with the dam for a minimum of 1 day post‐partum. Longer contact should progressively be implemented, but research is needed to guide this implementation in practice. The ABMs body condition, carcass condemnations, abomasal lesions, lung lesions, carcass colour and bursa swelling may be collected in slaughterhouses to monitor on‐farm welfare but should be complemented with behavioural ABMs collected on farm.

Welfare implications on management strategies for rearing dairy calves: A systematic review. Part 2 - Social management

Introduction

Raising a healthy calf up to puberty is essential for optimal farm performance. It is therefore, it is necessary to promote animal welfare from the three spheres during this short period. Social management has been postulated as essential in lowering stress and consequently improving calf welfare during this period. Only the health sphere has been studied for a long time, but more recent studies have recently promoted positive experiences and emotional states from affective states or cognitive judgment and natural living spheres. A systematic review of different management strategies in rearing dairy calves according to the three spheres of animal welfare has been conducted using an electronic search strategy.

Methods

The analysis and extraction of information from the studies were performed according to a protocol. From 1,783 publications screened, only 351 met the inclusion criteria.

Results

The publications identified in the search can be divided into two main groups, feeding and social management, based on the main topic of the publication. This review provides an overview of social management, understood as the calf's interaction with others around it.

Discussion

Primary social management issues that emerged were social housing with congeners, separation from the mother and human-animal interaction, distributed in the three broad spheres of animal welfare. The review highlights unresolved questions about how social management practices affect the three spheres of animal welfare at this life stage and the need to standardize good socialization practices for this stage. In conclusion, all the information shows that social housing has improved animal welfare from affective states, cognitive judgment, and natural living spheres. However, gaps in research were identified in relation to the optimal time to separate the calf from the mother, the optimal time to group with conspecifics after birth and group size. Further research on positive welfare through socialization are needed.

Welfare implications on management strategies for rearing dairy calves: A systematic review. Part 1-feeding management

Introduction

Calves are very susceptible to stress in the early stages of life, and it is necessary to ensure maximum welfare. Feeding management has been identified as a major risk factor for calf health and welfare at this stage. However, the management protocol for calf rearing and its impact on animal welfare is unclear. A systematic review of different management strategies for rearing dairy calves according to the three spheres of animal welfare was conducted using an electronic search strategy. In this review, management strategies were studied to identify scientific gaps, to know the welfare problems of these animals in order to prioritize actions and future research and to study the interpretive approach of this management from the three welfare spheres.

Methods

A protocol was used to analyze and extract information from the studies. Of the 1,783 publications screened, only 351 met the inclusion criteria for the management or welfare of calves' items.

Results

The publications identified in the search can be divided into two main groups feeding and socialization, based on the main topic of the publication. The main topics that emerged from the search in the feeding management group were milk replacer, colostrum, and weaning, divided into the three main areas of biological functioning and health, natural life and affective states or cognitive judgement.

Discussion

The main issues to be addressed were the different types of feed consumed by animals from birth to weaning and the weaning management. It has been found that the most researched issues are colostrum and solid starter feed management. Unresolved issues were highlighted, such as the lack of a clear protocol for the administration of milk replacers to reduce hunger and the best management of weaning to reduce stress.

Impact of early dam contact on veal calf welfare

Dairy calves, including surplus calves, are typically separated from their dam within hours of birth. The aim of this study was to assess the welfare impacts of raising surplus calves destined for veal with their dam for 2 or 4 weeks until transport. Surplus calves from one dairy farm were separated from their dam at birth (n = 39) or kept with the dam (n = 37) until transport to the veal farm at either 2 (n = 50) or 4 (n = 26) weeks of age, with abrupt separation for dam-reared calves. Calf measures of body weight, health, immunity, haematology and behaviour were recorded at the dairy and veal farms. Dam-reared calves had higher body weights in weeks 3, 4 and 5 at the DF, as well as at arrival at the veal farm, but by slaughter this advantage was lost. More dam-reared calves had fever in week 3 and showed signs of disease in week 5 at the dairy farm. Dam-reared calves did not differ in IgG, IgA or IgM levels but had higher counts of white blood cells, which could reflect a higher pathogen exposure rather than improved immunity. Dam-reared calves displayed more fear towards humans in a human approach test at 5 and 7 weeks after arrival at the veal farm, and more frequent social behaviours at the veal farm at 9 and 16 weeks of age. In conclusion, it seems that there may be both advantages and disadvantages to keeping veal calves with the dam in terms of welfare in the current system.

Investigating the effects of two weaning methods and two genetic hybrids on play behavior in weaner pigs (Sus scrofa)

In conventional pig production, suckling pigs are typically weaned between 3 and 5 weeks of age. This involves separation from the sow, dietary change, and regrouping in a novel environment, which challenge the welfare of pigs. We investigated the effects of two weaning methods [conventional weaning: two litters mixed in a weaner pen of different size and design (MOVE) vs. litter staying in the farrowing pen after removing the sow (STAY)] and two genetic hybrids [DanBred Yorkshire × Landrace (approximately 21 total pigs born/litter; DB) vs. Topigs Norsvin TN70 Yorkshire × Landrace (approximately 16 total pigs born/litter with higher individual birth weight and weaning weight than DB; TN)] on play behavior across weaning. Both genetic hybrids were inseminated with semen of DanBred Duroc boars. Litters were reduced to the number of functional teats at birth. The durations of locomotor-rotational play (LOC) and social play (SOC) of 24 indoor-housed litters [pigs/litter: (average ± SD) 13 ± 2; age at the weaning day: 26 ± 2 days] were video-recorded continuously between 14:00 h and 22:00 h on days −1, 1, and 2 relative to weaning and statistically analyzed with mixed-effects modeling at the individual level. Before weaning, TN pigs performed LOC longer than DB pigs. On day 2 post-weaning, STAY pigs engaged in more SOC than MOVE pigs. Moreover, TN pigs and STAY pigs displayed a steeper increase in LOC from days 1 to 2 than DB pigs and MOVE pigs, respectively. We demonstrated that pigs belonging to the genetic hybrid with higher weight at birth and weaning spent more time playing on the day before weaning. Additionally, weaning pigs in the farrowing pen and, hence, avoiding social mixing and relocation to an unfamiliar environment had a positive effect on social play after weaning. Our study illustrates that weaning stress in pigs may be reduced by using a genetic hybrid featuring higher birth and weaning weight and by keeping litters intact in a familiar environment after weaning. This study also supports the use of play behavior as an animal welfare indicator.

Graduate Student Literature Review: Role of pain mitigation on the welfare of dairy calves undergoing disbudding

This review synthesizes research findings on the pain and welfare of dairy calves undergoing disbudding procedures. We describe disbudding practices in North America as well as the use and perceptions of pain control for these procedures. Governing bodies across Canada and the United States, including each country's veterinary medical association and nationwide initiatives such as proAction and Farmers Assuring Responsible Management (FARM), recommend or require the use of a local anesthetic, a nonsteroidal anti-inflammatory drug (NSAID), and a sedative for disbudding procedures. Although the use of pain relief for disbudding has increased over the past decade or so, some in the dairy industry still do not believe that pain control for disbudding is necessary. As a painful procedure, disbudding has numerous welfare impacts on the calf both during and following the procedure that can be categorized under all 3 principles of animal welfare: natural living, biological functioning, and affective state. The use of pain control for disbudding; namely, a local anesthetic and NSAID, can improve welfare outcomes such as procedure-induced pain behavior, cortisol concentrations, mechanical nociceptive threshold, emotional states, and so on, compared with no pain control for the procedure. Although extensive research exists on pain control practices for disbudding, this review identified further gaps in knowledge and areas for future research. Mechanical nociceptive threshold can be evaluated around the disbudding wounds and is a reliable test in older calves; however, this outcome in very young calves after caustic paste disbudding has been reported to be inconclusive compared with that in older calves. As well, research evaluating xylazine sedation for disbudding has reported both potentially positive and negative results that are difficult to interpret or base suggestions on for the use of this drug. Finally, wounds caused by disbudding take a long time to heal (up to 13 wk) and have increased sensitivity for the entire healing process. Therefore, future research should aim to (1) determine accurate behavioral tests for calves under 1 wk of age undergoing disbudding to better understand their experience, (2) further attempt to understand the effects of xylazine sedation for disbudding and potential impacts of providing this medication, and (3) determine more ways to reduce the healing time and pain experienced by the calf after disbudding procedures.

Effects of Social Housing on Dairy Calf Social Bonding

Social housing for dairy calves has a range of benefits for social development, yet there is limited understanding of how social bonds form early in life. We characterized effects of early life social contact on the development of social preference for calves varying in familiarity. A total of 40 calves were tested in a social preference test at 4 weeks of age to assess the formation of social bonds and preference for their peers. Within an open-field social preference test, focal calves were presented with two stimulus calves, one ‘more familiar’ and one ‘less familiar’. We found that pair-housed calves spent more time in close proximity with either stimulus calf and had a greater preference for their pen-mate, compared to another calf reared within visual contact. Individually housed calves exhibited no preference for calves reared within visual but not physical contact compared to calves that were completely unfamiliar. Of the calves that approached both stimulus calves, individually housed calves that approached the ‘less familiar’ calf first spent less time near the ‘more familiar’ calf, whereas behavior of pair-housed calves was not affected by the first calf approached. These results suggest that physical contact is necessary for the development of social bonds in young dairy calves, and early life social housing may support the development of normal social behavior in dairy cattle.

Effects of group housing and incremental hay supplementation in calf starters at different ages on growth performance, behavior, and health

The present study examined the effects of age at group housing and age at incremental hay supplementation in calf starters from 7.5 to 15% (dry matter, DM) and their interaction on growth performance, behavior, health of dairy calves, and development of heifers through first breeding. A total of 64 calves (n = 16 calves/treatment, 8 male and 8 female) were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement, with age at group housing (early = d 28 ± 2, EG vs. late = d 70 ± 2, LG; 4 calves per group) and age at incremental hay supplementation of calf starters from 7.5 to 15% of DM (early = d 42 ± 2 d, EH vs. late = d 77 ± 2, LH) as the main factors. All calves (female and male) were weaned at 63 days of age and observed until 90 days of age. Heifer calves were managed uniformly from 90 days of age until first calving to evaluate the long-term effects of treatment. No interactions were observed between age at group housing and age at incremental hay to calves on starter feed intake, performance, calf health and behavior, and heifer development through first breeding, which was contrary to our hypothesis. The age at which incremental hay supplementation was administered had no effect on starter feed intake, growth performance, or heifer development until first calving. When EG calves were compared with LG calves, nutrient intake (starter, total dry matter, metabolizable energy, neutral detergent fiber, starch, and crude protein), average daily gain, and final body weight increased. In addition, frequency of standing decreased and time and frequency of eating increased in EG calves compared to LG calves. Overall, early group housing leads to improved growth performance in dairy calves with no negative effects on calf health compared to late group housing.

Views of Western Canadian dairy producers on calf rearing: An interview-based study

Calf rearing practices differ among farms, including feeding and weaning methods. These differences may relate to how dairy producers view these practices and evaluate their own success. The aim of this study was to investigate perspectives of dairy producers on calf rearing, focusing on calf weaning and how they characterized weaning success. We interviewed dairy producers from 16 farms in Western Canada in the following provinces: British Columbia (n = 12), Manitoba (n = 2), and Alberta (n = 2). Participants were asked to describe their heifer calf weaning and rearing practices, and what they viewed as successes and challenges in weaning and rearing calves. Interviews were recorded, transcribed, and subjected to qualitative analysis from which we identified the following 4 major themes: (1) reliance on calf-based measures (e.g., health, growth, and behavior), (2) management factors and personal experiences (e.g., ease, consistency, and habit), (3) environmental factors (e.g., facilities and equipment), and (4) external support (e.g., advice and educational opportunities). These results provided insight into how dairy producers view calf weaning and rearing, and may help inform the design of future research and knowledge transfer projects aimed at improving management practices on dairy farms.

Towards a Positive Welfare Protocol for Cattle: A Critical Review of Indicators and Suggestion of How We Might Proceed

Current animal welfare protocols focus on demonstrating the absence (or at least low levels) of indicators of poor welfare, potentially creating a mismatch between what is expected by society (an assurance of good animal welfare) and what is actually being delivered (an assurance of the absence of welfare problems). This paper explores how far we have come, and what work still needs to be done, if we are to develop a protocol for use on commercial dairy farms where the aim is to demonstrate the presence of positive welfare. Following conceptual considerations around a perceived “ideal” protocol, we propose that a future protocol should be constructed (i) of animal-based measures, (ii) of indicators of affective state, and (iii) be structured according to indicators of short-term emotion, medium-term moods and long-term cumulative assessment of negative and positive experiences of an animal's life until now (in contrast to the current focus on indicators that represent different domains/criteria of welfare). These three conditions imposed the overall structure within which we selected our indicators. The paper includes a critical review of the literature on potential indicators of positive affective states in cattle. Based on evidence about the validity and reliability of the different indicators, we select ear position, play, allogrooming, brush use and QBA as candidate indicators that we suggest could form a prototype positive welfare protocol. We emphasise that this prototype protocol has not been tested in practice and so it is perhaps not the protocol itself that is the main outcome of this paper, but the process of trying to develop it. In a final section of this paper, we reflect on some of the lessons learnt from this exercise and speculate on future perspectives. For example, while we consider we have moved towards a prototype positive welfare protocol for short-term affective states, future research energy should be directed towards valid indicators for the medium and long-term.

Feeding fennel (Foeniculum vulgare) seed as a potential appetite stimulant for Holstein dairy calves: Effects on growth performance and health

This experiment was conducted to determine the effect of increasing dietary doses of fennel seed powder (FSP) on growth performance and health status in calves. Holstein calves (n = 48; 3 d of age; 36.3 ± 1.06 kg BW; mean ± SE) were allocated randomly to diets containing 0 (FSP0), 1.5 (FSP1.5), or 3 g/d (FSP3) FSP in milk (morning feeding; during the first month) and then in the starter feed (top-dressed; from d 31 until weaning on d 71). The calves remained in the trial until d 81. Weight gain and final BW were greater in FSP-supplemented calves compared with control calves. Heart girth and hip width gained more in FSP-supplemented calves compared with control calves. Body weight gain and frame growth were not affected by calf sex. The calves receiving FSP had a lower chance of having elevated rectal temperature (≥39.4°C) and a lower probability of suffering from diarrhea or pneumonia. The chance of having diarrhea, but not pneumonia, was greater in female calves. The chance of medication occurrence for diarrhea and pneumonia was not affected by FSP and calf sex. The FSP3 calves had shorter days with elevated rectal temperature (≥39.4°C) compared with the FSP1.5 (1.2 d; SEM = 0.10) and FSP0 (2.9 d; SEM = 0.10) calves. Days with diarrhea but not its frequency and medication days was shorter (4 d; SEM = 0.10) in the FSP-supplemented calves. Control calves experienced more days with pneumonia compared with calves fed FSP1.5 (3.1 d; SEM = 0.08) and FSP3 (5.4 d; SEM = 0.08). Calves fed FSP3 experienced shorter days (2.3 d; SEM = 0.08) with pneumonia compared with calves fed FSP1.5. Feeding FSP tended to decrease (1.6 d; SEM = 0.10) medication days for pneumonia compared with control group. The duration (2.2 d; SEM = 0.10) and medication days (1.3 d; SEM = 0.15) for diarrhea were higher in female calves compared with the male calves. Compared with the control calves, feeding 3 g/d of FSP may be more beneficial in improving the weight gain and skeletal growth (heart girth and hip width) and in reducing the susceptibility to and duration of diarrhea and pneumonia in dairy calves.

Influence of milk feeding levels and calf housing on subsequent performance of Holstein heifers

The purpose of this study was to investigate the effects of increased milk feeding levels or social housing during the preweaning stage of Holstein dairy heifers on subsequent weight gain, health, and reproductive parameters over time. A total of 210 heifers were grouped by calving date in groups of 10 and randomly assigned to one of 3 treatments: low-milk individual housing (LMI; 4 L of milk/d), high-milk individual housing (HMI; 8 L of milk/d), or low-milk social housing (LMS; 4 L of milk/d). Data collected included passive transfer status, disease events, weight gain at different time periods, age at first calving, calving intervals, and milk yield over the first 3 lactations. Passive transfer was successful in 189 calves, and, overall, disease events were low in this herd. The average daily gain for heifers in the HMI group (0.79 ± 0.05 kg/d) was significantly higher (F _{2, 9} = 4.76) during the preweaning treatment period compared with the other groups (LMI: 0.59 ± 0.05 kg/d; LMS: 0.68 ± 0.04 kg/d). Although treatment groups did not differ with respect to age at first calving, the LMS and HMI heifers calved (22 and 15 d, respectively) earlier than the LMI heifers. Milk yield over 3 lactations was similar among the treatment groups. This suggests that both nutrition and social dynamics can influence performance of preweaned calves. Further investigation is needed to understand the mechanisms driving increased weight gain in socially housed calves.

Understanding Behavioural Development of Calves in Natural Settings to Inform Calf Management

Simple Summary

Animal welfare research is intended to address societal concerns regarding animal care, including natural living concerns. We reviewed the literature on calf behaviour when reared in more naturalistic outdoor systems with their mothers and herd. Understanding calf behaviour in more natural settings may help inform changes in calf management and housing that promote behaviours important to calf welfare.

Abstract

One important type of animal welfare concern is “natural living” (i.e., that animals are able to express natural behaviours that are important to them, and to engage with aspects of the natural world that they find important). The aims of this narrative review were to describe the behavioural development of calves (Bos taurus) in natural settings and use this to identify characteristics of natural systems that may be important to consider relative to this natural living conception of animal welfare. At birth, calves are licked by their mothers and soon stand to suckle for colostrum, and during the milk-feeding period, calves spend much of their time lying down. In natural systems, calves perform a variety of social behaviours with herd-mates, and slowly transition from their mother’s milk to eating solid food, by gradually increasing time spent grazing and ruminating. In contrast, on most commercial dairy systems, dairy calves are removed from their mothers at birth, housed individually, fed restricted amounts of milk and weaned abruptly at a young age. The results of this review suggest that accommodating key natural behaviours, for example through the use of teat feeding of milk, social housing, and gradual weaning, can help address welfare concerns.

Early weaning: new insights on an ever-persistent problem in the dairy industry

It is common practice in the dairy industry to separate the calf from the cow immediately after parturition, and in most parts of the world calves are housed individually during the milk-feeding period. Early and abrupt separation has major implications for the calf's physical and psychological development. In this Research Reflection short review we present and discuss the main housing systems and management practices regarding early weaning in today's dairy industry. Main benefits and disadvantages are critically addressed, and possible future research suggested. Furthermore, major policy issues related to consumers, scientific recommendations and economic performance of farms have been identified, as well as future drivers for more viable housing solutions for neonatal calves. This review serves as an introduction and preamble to the second section of this Special Issue, which is dedicated to cow-calf contact management systems.

Effects of early social contact on dairy calf response to initial social grouping and regrouping

Social contact affects social development and response to novelty in dairy calves, but the age of introduction to social housing varies on-farm and may have implications for behavioral development and response to social grouping. The objective of this experiment was to evaluate the effects of early social contact during approximately the first 2 wk of life on calf early life behavior and performance and responses following initial social regrouping, followed by subsequent regrouping. At birth, calves were randomly assigned to individual (IH; n = 16 calves) or pair-housing (PH; n = 8 pairs). Calves were mingled between treatments and initially grouped (4 calves/pen) at 13 ± 2 d of age (mean ± standard deviation) and then regrouped (8 calves/pen) at 20 ± 5 d of age. Calf ability to learn to feed independently from the teat bucket in early life, and from the autofeeder following grouping, was monitored. Calf health, feed intake, and weight gain were recorded throughout the first 3 wk of life. Activity and social interactions were continuously recorded from video for the first 24 h following grouping and regrouping (except for allogrooming, hay consumption, and social play, which were observed for 12 h due to nighttime visibility). During the period of exposure to different housing treatments, calf feed intake and weight gain did not differ, but calves housed in pairs tended to scour for fewer days [4.1 vs. 5.6 d; PH vs. IH; standard error (SE) = 0.58]. Previously pair-housed calves spent more time lying socially (within 1 body length of another calf) than previously individually housed calves following both initial grouping (9.8 vs. 5.7 h/d; PH vs. IH; SE = 0.83) and regrouping (11.3 vs. 9.1 h/d; PH vs. IH; SE = 1.1). We saw no effects of previous social contact on duration of brush use (31.5 min/d; SE = 4.2), hay feeding (5.1 min/12 h; SE = 1.6), allogrooming (4.1 min/12 h; SE = 0.16), or social play (0.52 min/12 h; SE = 0.19) following initial grouping or regrouping. However, previously pair-housed calves tended to have greater lying time after regrouping. These results suggest that early life social contact before social grouping in the first weeks of life may not greatly affect activity within the pen or active social interactions following the transition to group housing. However, persistent differences in duration of social lying suggests that early life social contact may influence overall comfort toward other calves following social grouping.

The effect of pair housing on dairy calf health, performance, and behavior

Individual housing of dairy calves prevails in Europe and North America despite its negative effects on calf development. One of the main reasons is that farmers find individual housing of calves more practical than group housing. A compromise between practice and welfare could be housing calves in pairs. Therefore, we aimed to compare health, feed intake, growth, and behavior in a novel arena of 22 individually (INDI) and 44 pair-housed calves that were randomly assigned a treatment. Diarrhea and respiratory problems were recorded every day for the period of 49 d. Intake of calf starter and milk were measured every day for the period 48 and 49 d, respectively. Calf body weight gains were calculated as average daily gain. Calves were individually tested in a novel arena at 11 to 18 d, and their behavior was recorded according to an ethogram including 8 behavioral categories. Behavioral categories were first diminished by principal component (PC) analysis. We found that 2 PC explained 66% of the total variation in calf behavior. Movement-related behaviors (activity, play, and crossing the stair) loaded positively on PC1, and PC2 had positive loading on self-grooming and negative loading on exploration. There were no effects of housing on calf health, feed intake, or average daily gain. The INDI calves had higher PC1 scores than pair-housed calves, indicating a rebound effect of movement. Our results are consistent with other studies that found no negative effect of pair housing of calves on their health, feed intake, or growth compared with individually-housed calves. The rebound effect of movement-related behaviors of INDI calves in a novel arena implies that individual housing of calves causes activity deprivation by the second week of age.

Calf health from birth to weaning - an update

Research on calf health and welfare has intensified in the past decades. This is an update on a review series on calf health from birth to weaning published ten years ago.

Good colostrum management is still recognised as the single most important factor to preventing calf morbidity and mortality, however, it is now known that immunoglobulins are only one of many components of colostrum that are vital for the calf’s development. Other non-nutrient factors like leucocytes, hormones and growth factors, oligosaccharides as well as microRNAs have significant effects on the development and maturation of the intestinal and systemic immune functions. They also promote the maturation and function of the intestine, thus enabling the calf to digest and absorb the nutrients provided with colostrum and milk. The improved energetic status of colostrum-fed neonates is reflected by an accelerated maturation of the somatotropic axis, which stimulates body growth and organ development. Colostrum oligosaccharides are presumed to play a major role in the development of a healthy intestinal flora.

A biologically normal (intensive) milk-feeding programme is subsequently necessary for optimal body growth, organ development and resistance to infectious diseases. Ad-libitum or close to ad-libitum feeding in the first three to four weeks of life also leaves calves less hungry thus improving calf welfare. Only calves fed intensively with colostrum and milk are able to reach their full potential for performance throughout their life.

Public interest in farm animal welfare is growing in past decades, which makes it necessary to have a closer look at contentious management practices in the dairy industry like early separation of the dairy calf from the dam with subsequent individual housing. Public objection to these practices cannot be mitigated through educational efforts. Contrary to common opinion there is no evidence that early cow-calf separation is beneficial for the health of calf or cow. There is evidence of behavioural and developmental harm associated with individual housing in dairy calves, social housing improves feed intake and weight gains, and health risks associated with grouping can be mitigated with appropriate management.

In conclusion, there are still many management practices commonly applied, especially in the dairy industry, which are detrimental to health and welfare of calves.

Milk- and starter-feeding strategies to reduce cross sucking in pair-housed calves in outdoor hutches

Social housing of preweaned calves can benefit their welfare, but housing and cross sucking are potential barriers to adoption for farmers. For farms using outdoor hutches, an option is to pair adjacent hutches with a shared fence. Our objective was to investigate milk- or starter-feeding strategies to mitigate cross sucking in this system. Holstein heifers were housed in pairs (n = 32 pairs) and divided into 4 treatments (n = 8 pairs each) in a 2 × 2 factorial design: milk in an open bucket with starter in only a bucket (OB-SB), milk in an open bucket and starter in both a bucket and a specialized teat bottle (Braden bottle; OB-BB), milk in a slow-flow teat bucket with starter in only a bucket (TB-SB), or milk in a slow-flow teat bucket and starter in both a bucket and a specialized teat bottle (TB-BB). When starter was first offered (d 6 ± 1 of life, mean ± SD), calf latency to approach was recorded, averaged within pairs, and compared between starter treatments using a linear mixed model with fixed effect of treatment and random effect of pair within treatment. Calves were initially bottle fed; milk treatments began on d 14 ± 1 of life and ended when calves were completely weaned (d 53 ± 1). Calves were observed for behaviors such as drinking milk and cross sucking twice weekly for 30 min during the afternoon milk meal using continuous video, with values averaged within pairs. Linear mixed models were run separately before (wk 3-6) and after (wk 7-8) weaning, with fixed effects of milk- and starter-feeding treatments, week, and the 2- and 3-way interactions, with week as repeated measure and pair as subject. Pairs with Braden bottles and buckets approached starter sooner than those with only buckets (Braden bottles vs. no Braden bottles: 13.1 ± 6.1 vs. 33.2 ± 6.1 min, LSM ± SEM). Before weaning, pairs with open buckets for both milk and starter cross sucked for at least twice as long (OB-SB: 2.9 ± 0.3 min) as all other treatments (OB-BB: 1.5 ± 0.3 min; TB-SB: 0.4 ± 0.3 min; TB-BB: 0.5 ± 0.3 min). This pattern held during weaning, when cross sucking increased overall (OB-SB: 3.9 ± 0.4 min; OB-BB: 1.8 ± 0.4 min; TB-SB: 0.9 ± 0.4 min; TB-BB: 1.6 ± 0.4 min). Regardless of starter treatment, calves spent less time cross sucking when fed milk in teat buckets, which extended the milk meal relative to open buckets (teat bucket vs. open bucket: preweaning = 7.0 ± 0.2 vs. 1.6 ± 0.2 min; weaning = 3.0 ± 0.1 vs. 0.6 ± 0.1 min). When calves are fed milk in open buckets, a novel option for reducing cross sucking is to provide starter through a specialized bottle. Nonetheless, providing milk in slow-flow teat buckets had the greatest effect on reducing cross sucking by directing suckling to the teat instead of another calf or pen objects.

The Health and Behavioural Effects of Individual versus Pair Housing of Calves at Different Ages on a UK Commercial Dairy Farm

Simple Summary

The way in which dairy calves are housed can have a significant impact on their health and productivity. This study compared three different housing groups from birth to weaning; individual housing, pair housing from birth, and pair housing from three weeks of age. Newborn Holstein heifer calves (n = 100) were recruited over a six-month summer period from a single commercial dairy farm in the UK. Each calf had a weekly visit by the researcher over a 10-week period, where they were weighed and assessed for the presence of disease, along with measuring solid feed intake and the time to approach a novel object. Other management aspects including milk allocation were the same across groups. There was no effect of the housing group on average daily liveweight gain (ADLG), the presence of disease or the time taken to approach a novel object. The housing group did impact solid feed intake, with calves pair housed at either time period ingesting significantly more than individually housed calves. This study demonstrated that there were no detrimental effects on the health or growth of calves housed in pairs, with the added benefit of increased solid feed intake for pair housed calves, which is important for a smooth transition over the weaning period.

Abstract

Housing management of dairy calves is one of the factors that contributes to a successful rearing outcome. Individual housing of pre-weaned calves is thought to provide enhanced biosecurity and easier monitoring of the individual, and so remains prevalent in the UK. Behavioural studies have, however, found that pair housing is important for social learning, with positive impacts on health and welfare. This study utilised a single UK commercial dairy farm to establish if individual housing, pair housing from birth, or pair housing from three weeks of age affected health and behavioural parameters. Calves were housed in these allocated groups from birth to eight weeks of age, when they were moved into group pens of five calves for weaning at 10 weeks of age. All management routines other than the housing group were the same for enrolled calves. One hundred Holstein calves were recruited over a six-month period, and systematically allocated to a housing group. Weekly visits were conducted up to 10 weeks of age (weaning) for each calf, with weight, solid feed intake, and presence of clinical disease measured. In addition, a novel object approach test was carried out at six weeks, and a thoracic ultrasound was performed at seven weeks. Housing group had no effect on the average daily liveweight gain (ADLG) (p = 0.74), with an average of 0.66 kg/day over the pre-weaning period. However, on group housing at 8–10 weeks of age, there was a numerical increase in ADLG in the pair housed calves compared to the individually housed calves over the weaning period. Housing group had no significant effect on disease prevalence (p = 0.98) or the time taken to approach the novel object (p = 0.29). However, pair housed calves had increased mean total solid feed intakes from weeks 2–8 (p = 0.011), with 6.2 ± 0.67 kg (standard error of the mean—SEM), 12.7 ± 0.73 kg and 13.6 ± 0.70 kg ingested by individually housed, pair housed from birth and pair housed from three weeks of age, respectively. The overall findings of this study indicate that within a UK commercial dairy management system, there is no detrimental effect of housing calves within pairs (either from birth or three weeks of age) compared to individual housing.

The effect of rearing conditions during the milk-fed period on milk yield, growth, and maze behaviour of dairy cows during their first lactation

The objective was to find whether cow growth, milk performance, and behaviour are affected by (1) rearing conditions until weaning after a milk-fed period of 84 d and (2) the sire lineage. Thirty-five Holstein heifers were assigned to one of three treatments: SM, n=13, pen with mother to 21st day, then group pen (they received a maximum of 6 kg of milk daily); SN, n=9, after 3 d with own mother in pen with nursing cow (they received a maximum of 6 kg of milk daily); H, n=13, in hutch from the 2nd to 56th day (6 kg of milk replacer daily), then loose housing pen to weaning (6 kg of milk replacer daily). After weaning at the 84th day, all heifers were kept in pens with the same ration as during calving. During lactation, live body weight (LBW) was measured each month and milk yield each day. Maze learning was evaluated in the fifth month of lactation. The data were analysed using a general linear model ANOVA. At the 30th day, the LBW tended to be the highest in SN (SM 528.2 ± 11.4 kg, SN 571.7 ± 15.3 kg, H 533.2 ± 12.3 kg). When lactation ended, the highest LBW was in SN and the lowest in H (SM 612.6 ± 12.2 kg, SN 623.1 ± 16.4 kg, H 569.8 ± 13.2 kg; P<0.05). The SN tended to have the highest production of milk (SM 7143.9 ± 241.5 kg, SN 7345.1 ± 319.0 kg, H 7146.7 ± 234 kg), and the H for FCM (SM 6290.3 ± 203.2 kg, SN 6307.6 ± 268.4 kg, H 6399.3 ± 197.1 kg) for 305 d lactation. Group SN crossed the maze fastest (SM 1141.4 ± 120.5 s, SN 810.3 ± 160.5 s, H 1120.8 ± 118.6 s). The vocalization number differed significantly (SM 32.3 ± 5.7, SN 20.8 ± 4.4, H 9.9 ± 2.6; P<0.01). The results indicated that the rearing method up to weaning may have an impact on dairy cows' performance and behaviour.

Negative play contagion in calves

Play is a strong outwardly directed, emotional behaviour and can contagiously spread between individuals. It has been suggested that high-playing animals could 'seed' play in others, spreading positive affective states. Despite the current interest in play contagion there has been no previous attempt to measure the strength of the play contagion effect. The calf (Bos taurus) is ideal for testing the strength of play contagion as play in calves is strongly related to energy intake from milk. We manipulated play in calves through their milk allowances and housed the calves in uniform groups all on the same milk allowance (high = UHigh or low = ULow) or in mixed groups with calves in the same group receiving either a high (= MHigh) or low (= MLow) milk allowance. We measured locomotor play using accelerometers on two consecutive days when calves were four and eight weeks old, in order to study play contagion over a protracted developmental window. We anticipated that differences in the level of play contagion between treatment groups would result in difference in the play levels observed in the MLow and ULow individuals. Contrary to our expectations we found that spontaneous play was suppressed in the high-milk calves housed in mixed groups (MHigh), in comparison to calves housed with group mates all receiving high-milk (UHigh). These results are the first to quantify a negative play contagion effect, particularly in a situation of long-term contact, and may suggest that negative contagion has a stronger effect on play behaviour than positive contagion.

The effect of age when group housed and other management factors on playing and non-nutritive sucking behaviour in dairy calves: a cross sectional observational study

BACKGROUND

The aim of this study was to investigate if calves' play behaviour and non-nutritive sucking behaviour, as indirect measures of welfare status, are associated with the age of the calf when group housed, age when observed, age difference within the group, pen size, milk feeding system, current or previous sicknesses, access to dry teat, indoor/outdoor rearing, sex, organic/conventional farm, group size and regrouping events. An observational study was conducted on 176 Danish dairy calves in the age range of 1-12 weeks, on both conventional (n = 17) and organic (n = 5) farms. All calves had been group housed before 8 weeks of age and had spent various periods of time with the dam and/or individually housed before being group housed. Behaviour was recorded continuously by filming each individual calf over a period of 30 min.

RESULTS

The calf's age when group housed for the first time was not found to be significantly associated with duration of either play behaviour (P = 0.55) or non-nutritive sucking behaviour (P = 0.44). It was found that calves had significantly reduced odds of playing for longer than the mean play duration (5.5 s) for each day of their lives (OR = 0.97, P = 0.003). Also, they had reduced odds of performing non-nutritive sucking behaviour for longer than the mean non-nutritive sucking duration (145.5 s) when milk was allocated by drinker buckets fitted with a teat compared to by bowl or trough (OR = 0.06, P = 0.02).

CONCLUSION

No significant associations were found between calves' age when group housed for the first time and play and non-nutritive sucking behaviour. It was found that calves' play behaviour decreased with increasing age, and that non-nutritive sucking behaviour decreased when milk was allocated with a teat compared to no teat.

Discriminating spontaneous locomotor play of dairy calves using accelerometers

Play behavior is a promising welfare indicator in dairy calves because it decreases in negative situations such as pain or hunger and increases in positive contexts such as in appropriate social environments. Directly measuring play is time consuming because it is performed in irregular bouts and can be inconsistent over days. To facilitate automatic recording of play, previous studies fitted triaxial accelerometers to the hind legs of calves and measured the velocity of movements in large arenas; high correlations were reported between vertical axis peak duration and the duration of locomotor play. The current study aimed to validate accelerometers for recording spontaneous locomotor play in calves' home pens over longer periods. Data were collected from 48 Holstein Friesian calves, housed in groups of 3 in pens of 10 m2, at either 4 or 8 wk of age. Acceleration at the vertical axis of the hind leg was recorded at a rate of 1 Hz. One active time period for each calf was randomly selected (mean duration ± standard deviation = 34 ± 9 min). From video of the corresponding time period, the frequency of locomotor play events, consisting of run, turn, and buck/buck-kick, was recorded using behavior sampling. Combined counts of play events were highly correlated (Pearson r = 0.91) with counts of acceleration peaks. However, for calves with higher levels of locomotor play, this method underestimated the extent of play. Alternatively, run, turn, and buck events obtained from video were transformed by creating intervals of 10 s and then classifying each 10-s interval as comprising events of play ("play") or not comprising events of play ("no play"). The corresponding accelerometer data for all 10-s periods, equaling 10 consecutive readings each, were classified into play or no play by using quadratic discriminant analysis; 79% of periods with locomotor play were correctly classified. Counts of observed play intervals correlated with the counts of play periods from accelerometers (r = 0.87), but the discriminant analysis consistently overestimated play. In conclusion, accelerometer measurements at 1 Hz (in 1-s intervals) and at the vertical axis cannot be used alone to exactly quantify absolute levels of locomotor play in the home pen. However, counts of peak accelerations can provide a rough estimate of inter-individual differences in play events, and discriminant analysis can be used as a proxy for one-zero sampling of inter-individual differences in locomotor play.

The effect of milk quantity and feeding frequency on calf growth and behaviour

Context Calves left with their dam to suckle will consume ~7–12 L/day; however, the amount of milk provided to dairy young calves removed from their dams may often be as low as 4 L/day, or 10% of their bodyweight. Aims This study compared once and twice daily feeding, as well as feeding levels of 10 and 20% of bodyweight and studied the effect on behaviour and metabolic indicators indicative of hunger. Methods Forty-six male dairy calves were allocated to one of three treatments from 3 to 8 days of age: (i) 10% of bodyweight offered daily as one meal (1 × 10%, n = 16); (ii) 10% of bodyweight offered daily over two meals (2 × 5%, n = 15); or (iii) 20% of bodyweight offered over two meals (2 × 10%, n = 15). Behaviour during and after feeding was observed by video, and blood samples taken on selected days were analysed for glucose, nonesterified fatty acids (NEFA), cortisol and packed-cell volume. Key results Milk intake on Days 3 and 4 was lower in those calves fed once daily compared with calves fed twice daily. Calves fed at 20% bodyweight had higher milk intake compared with calves fed at 10% bodyweight on all days other than Day 3 and growth was higher in those calves. Non-nutritive sucking was mainly associated with feeding times and it was highest in calves fed 10% bodyweight over two meals, with a suckling pattern that suggested that feeding at 10% bodyweight satisfied feeding motivation less than feeding at 20% bodyweight. Play behaviour was reduced in calves fed once daily, suggesting hunger and reduced welfare. There were significant effects on physiological indicators of metabolic state. NEFA concentrations were significantly higher in calves fed once daily and calves fed 10% of bodyweight at certain time points, indicating a lower energy balance. Conclusions Feeding twice daily offers benefits to calves up to Day 4 of life whereas feeding 20% of bodyweight was beneficial after Day 4 to increase satisfaction of feeding motivation and nutrition for growth. Although metabolic variables were within normal physiological range for all treatments, the effects on feed intake, growth and non-nutrient sucking suggest marked effects on hunger when calves are fed the lower milk allowance. Implications The fairly common practice of feeding dairy calves 10% of bodyweight, in one or two daily meals may leave calves hungry, and an increase in milk allowance should be considered.

Effects of Pair Versus Individual Housing on Performance, Health, and Behavior of Dairy Calves

Simple Summary

In modern dairy farming systems, calves are often housed in individual pens or hutches, which results in less social interaction with their peers during the milk-feeding period. The aim of this study was to evaluate the effects of pair versus individual housing on performance, health, and behavior of dairy calves from the milk-feeding period to the first week after mixing. Results showed that pair versus individual housing had no effects on body weight, starter intake or average daily gain during the milk-feeding period, while pair housing increased the growth performance of calves during weaning and postweaning periods, and the beneficial effects of pair housing on growth faded after calves were mixed and moved to group housing. Paired calves showed higher diarrhea frequency only in week three. The behavior of calves was altered at different periods, including increased time spent in feeding, chewing and ruminating, and decreased self-grooming time, and a drop of non-nutritive manipulation for all calves after they were mixed and moved to group housing. We also found less social contact may lead to more non-nutritive manipulation.

Abstract

The aim of this study was to evaluate the effects of pair versus individual housing on performance, health, and behavior of dairy calves. Thirty female Holstein dairy calves were assigned to individual (n = 10) or pair housing (n = 10 pairs). The results showed that both treatments had a similar starter intake and average daily gain (ADG) during the preweaning period. During weaning and postweaning periods, paired calves had a higher starter intake, and the ADG of paired calves continued to increase but calves housed individually experienced a growth check. Paired calves showed higher diarrhea frequency only in week three. The results on behavior showed that feeding, chewing and ruminating time increased, and self-grooming time decreased with age during weaning and postweaning periods, and paired calves spent less time feeding, standing and self-grooming but more time lying during this time. After mixing, feeding, and chewing and ruminating time continued to rise, and self-grooming time continued to decline for both treatments. All calves spent less time standing and non-nutritive manipulation after mixing, and previously individually housed calves tended to increase non-nutritive manipulation. These results showed that pair housing improved growth during weaning and postweaning periods and that calves altered their behavior at different phases. Less social contact may lead to more non-nutritive manipulation.

Key animal welfare issues in commercially raised dairy calves: social environment, nutrition, and painful procedures

Dairy calf welfare concerns are growing and new evidence suggests that the early life environment influences appropriate physical, behavioral, and cognitive development lasting into adulthood. This review highlights key evidence for the impacts of housing, diets, and painful procedures on calf welfare. We argue that these topics are currently critical welfare concerns, but are not the only points of concern. In addition to environmental requirements to maintain optimal health, dairy calves experience other challenges including social and nutritional restrictions. Individual housing is associated with impaired behavioral development and cognitive ability. Pair and group housing can mitigate some of these negative effects and should be encouraged. Restrictive milk allowances (<15% of body weight) lead to poor growth and hunger; these welfare concerns can be addressed with proper enhanced milk allowances and gradual weaning programs. Finally, dehorning is a critical animal welfare issue when pain control is withheld; calves show negative behavioral, physiological, and emotional responses during and after dehorning. The combined use of local anaesthetics and analgesics can mitigate these effects. An industry shift toward providing social companionship, enhanced milk allowances, and pain control during painful procedures would help to improve the welfare of dairy calves in intensive commercial rearing facilities.

Calf Barn Design to Optimize Health and Ease of Management

This article offers general calf barn design recommendations to optimize calf health gleaned from clinical and research experience in a Midwestern US climate. Barn components that are discussed include sizing the barn, ventilating the facility, and providing a clean, deeply bedded, dry area for the calf. In addition, considerations for maximizing labor efficiency and reducing the spread of disease by caregivers are discussed.

Current perspectives on the short- and long-term effects of conventional dairy calf raising systems: a comparison with the natural environment

Although the neonatal and infancy period is short, it is well documented that the early neonatal environment is critical for appropriate physical, behavioral, and cognitive development that lasts into adulthood. Dairy calves are commonly removed from the dam shortly after birth and raised in individual housing and fed limited milk allowances (4 to 6 L/d) in commercial farms around the world (conventional raising). Individual housing was developed to promote health status and facilitate individual animal monitoring. However, it is associated with high labor demand, and early life social isolation is associated with cognitive and behavioral abnormalities. Recently, group housing and enhanced milk-feeding programs are being increasingly adopted by farms; these practices more closely resemble the social and nutritional environments in natural or seminatural environments when the calf is raised with the dam. Conventional raising may lead to short- and long-term effects when compared to calves raised with the dam or peers. Short-term effects of conventional raising include impaired social skills when introduced to novel peers, reduced consumption of novel feeds, increased activity in a novel environment, and signs of hunger associated with limited milk intake and poor growth during the preweaning period. Evidence also suggests that the long-term effects of conventional artificial raising systems include behavioral differences, such as lower social submissiveness, increased heart rate and cortisol when presented with a novel environment, and production differences such as milk yield and reproductive performance. However, research on the long-term effects of maternal, social, physical, and nutritional restrictions in early life is still limited and should be encouraged. More research is needed to determine the long-term effects of artificial raising systems (individual, group housing, dam-raised) on future behavior, cognition, performance, and health parameters in dairy calves.

Producer perceptions of manual and automated milk feeding systems for dairy calves in Canada

As part of a cross-sectional survey, Canadian dairy producers were asked a set of questions to (1) determine factors that influenced them to continue using manual milk feeding (MMF) systems or to switch to automated milk feeding (AMF) and (2) investigate producers’ perceived advantages and disadvantages regarding both feeding systems. A total of 670 responses were received. Among respondents, 16% used AMF and 84% used MMF. The four most frequent factors that producers reported as important in motivating them to switch to AMF were to raise better calves, offer more milk to calves, reduce labor, and improve working conditions. For MMF farms, investment in equipment and group housing facilities, as well as farm size, were the primary reasons reported for their continued use of MMF systems. The principal perceived advantages of having an AMF were that calves are able to express natural behaviors and drink more milk without increased labor input. For MMF systems, the main perceived advantage was related to easier identification of sick calves. Results provide insights into factors affecting the choice of calf feeding methods by dairy producers, and improve understanding of producers’ needs and expectations regarding calf management and adoption of technology.