The welfare of dairy cattle housed in tiestalls compared to less-restrictive housing types: a systematic review

Many dairy cattle worldwide are housed in tiestalls, meaning that they are tethered by the neck to individual stalls. On some farms, tied cattle are permitted seasonal access to pasture, but otherwise their movements are restricted compared with cows housed in freestall barns or other loose housing systems. The aim of this systematic review is to summarize the scientific literature pertaining the welfare of tied dairy cattle through comparison with less-restrictive housing systems. Articles identified by PubMed and Web of Science underwent a 5-phase screening process, resulting in the inclusion of 102 papers. These papers addressed measures of welfare related to affective state, natural behavior, and health (with the lattermost category subdivided into hoof and leg disorders, lameness, mastitis, transition disease, and other diseases or conditions). Health was the most researched topic (discussed in 86% of articles); only 19% and 14% of studies addressed natural behavior and affective state, respectively. Our review highlights different health benefits for tethered and loose cattle. For example, tied cattle experience reduced prevalence of white line disease and digital dermatitis, whereas loose cattle experience fewer leg lesions and injuries. The prevalence of mastitis, transition diseases, and other conditions did not differ consistently across housing types. We found that the expression of certain natural behaviors, particularly those associated with lying down (e.g., time spent kneeling, unfulfilled intentions to lie down), were impaired in tiestalls. Articles addressing affective state found benefits to loose housing, but these studies focused almost exclusively on (1) physiological measurements and (2) cow comfort, a concept that lacks a consistent operational definition across studies. We call for future research into the affective state of tied cattle that extends beyond these explorations and employs more sophisticated methodologies

Calf- and herd-level factors associated with dairy-calf reactivity

A positive relationship between handlers and animals in farm systems is essential because the human–animal relationship has implications for welfare and productivity. For this reason, on-farm animal welfare assessment protocols often include the behavioral response of animals to humans to measure the quality of the human–animal relationship. The existing literature has described this relationship as having a multifactorial nature. In the current study, we aimed to investigate the potential influence of farm management and infrastructure characteristics, calf manager traits, and intrinsic features of dairy calves on the human–animal relationship. To this end, an escape test was conducted with 698 calves on 30 dairy farms in Chile. This test measured the calf's response to the active approach of an unfamiliar human (and was scored from 0 [fearful] to 4 [friendly]). The explanatory variables used to predict calves' response in the escape test were grouped according to the following categories: (1) farm management and infrastructure (e.g., calf-dam separation age, space allowance); (2) calf manager (e.g., attitudes, behavior, and background); and (3) calf (e.g., breed, sex, age). We concluded that calf managers with additional jobs on the farm, no training, low job satisfaction, a greater proportion of negative contacts, and more negative attitudes were predictive of fearfulness in the escape test. Holstein breed (compared with Holstein and Jersey crossbreeds) was associated with greater odds of fearful calves. Our study confirms the association between animals' fear and handlers' features, which can potentially be used to select employees on a farm. Understanding the factors that influence fear responses in calves may highlight ways to improve the relationship between animals and humans

Measuring lameness prevalence: effects of case definition and assessment frequency

Lameness assessments are commonly conducted at a single point in time, but such assessments are subject to multiple sources of error. We conducted a longitudinal study, assessing the gait of 282 lactating dairy cows weekly during the first 12 wk of lactation, with the aim of assessing how lameness prevalence changed in relation to case definition and assessment frequency. Gait was scored using a 5-point scale where scores of 1 and 2 were considered sound, 3 was clinically lame, and 4 and 5 were severely lame. We created 5 lameness definitions using increasingly stringent thresholds based upon the number of consecutive events of locomotion score ≥3. In LAME1, a cow was considered lame when locomotion score was ≥3 at any scoring event, in LAME2, LAME3, LAME4, and LAME5, a cow was considered lame when locomotion score was 3 or higher during 2, 3, 4, and 5 consecutive scoring events, respectively. We also assessed the effect of assessment frequency on measures of prevalence and incidence using weekly assessment (ASSM1), 1 assessment every 2 wk (ASSM2), 1 assessment every 3 wk (ASSM3), and 1 assessment every 4 wk (ASSM4). Using LAME1, 69.2% of cows were considered lame at some point during the trial, with an average point prevalence of 31.8% (SD: 2.8) and average incidence rate of 10.9 cases/100 cow weeks (SD: 3.7). Lameness prevalence decreased to 28.0% when using LAME5. Survival analysis was used to assess the effects of parity, using these different case definitions. Parity is a known risk for lameness, such that case definitions and prevalence estimates should be stratified by parity to inform management decisions. Using the LAME3 criterion, primiparous cows had the highest chance of reaching 12 wk without a lameness event, and fourth and higher parities had the lowest. Weighted linear and quadratic kappa values were used to assess agreement between different assessment frequencies and lameness definitions; we found substantial to excellent agreement between ASSM1 and ASSM2 using LAME1, LAME2, and LAME3 definitions. Agreement was fair to substantial between ASSM1 and ASSM3 and low to fair between ASSM1 and ASSM4. Likewise, the agreement between LAME1 and LAME2 was fair in primiparous cows, substantial in second and third parity cows, and poor to fair in fourth and greater parity cows. We conclude that lameness prevalence estimates are dependent upon case definition and that the use of more stringent case definitions results in fewer cows classified as lame. These results suggest that routine locomotion assessments be conducted at least every 2 wk, and that cows should be defined as lame on the basis of 2 consecutive assessments

Differences in the fecal microbiota of dairy calves reared with differing sources of milk and levels of maternal contact

The practice of rearing cows and calves together is gaining popularity on dairy farms, with different systems currently under assessment in mainland Europe, the United Kingdom, and Oceania. Research into the effects of cow–calf rearing has primarily focused on direct health and welfare implications, and little work has examined the role of different rearing paradigms on calf microbiota. We trialed a cow–calf rearing system on a Canadian dairy farm and compared fecal microbiota of these calves with the microbiota of calves reared according to the conventional practice of the same farm (separated from the dam and fed waste milk). At 4 wk, the conventionally reared calves had reduced relative abundance of Lactobacillus and higher relative abundance of other taxa, including Sutterella, Prevotella, and Bacteroides. We also detected predicted functional differences, such as reduced l-tryptophan biosynthesis in conventionally reared calves. These results suggest that maternal contact may influence the calf microbiota, but the observed differences are also likely related to other aspects of the rearing environment independent of maternal contact (e.g., potential exposure to antibiotic residues in waste milk). These findings provide preliminary evidence of the effects of early rearing environments on the establishment of the dairy calf fecal microbiota. This research is needed, given the critical role of the bovine gut microbiome in behavioral, metabolic, and immune development

Early pair housing increases solid feed intake and weight gains in dairy calves

Dairy calves have traditionally been kept in individual pens throughout the milk-feeding period. Social rearing is associated with increased solid feed intake and hence higher weight gains before and after weaning. Little is known about the effect of the age at which social housing begins. The aim of this study was to assess the effects of early versus late pairing on feeding behavior and weight gain before and after weaning. Holstein bull calves were reared individually (n=8 calves), or paired with another calf at 6 ± 3 d (n=8 pairs) or 43 ± 3 d of age (n=8 pairs). All calves were fed 8 L of milk/d for 4 wk, 6 L/d from 4 to 7 wk and then milk was reduced by 20%/d until calves were completely weaned at 8 wk of age. Calves were provided ad libitum access to calf starter and a total mixed ration (TMR). Body weight and feed intake were measured weekly from 3 to 10 wk of age. Intake of calf starter was significantly higher for the early-paired calves than for individually-reared and late-paired calves throughout the experimental period. At 10 wk of age, starter dry matter intake (DMI) averaged 2.20 ± 0.22 kg/d, 1.09 ± 0.25 kg/d and 1.26 ± 0.33 kg/d for early pair, late pair and individually housed calves, respectively. Intake of TMR did not differ among treatments, TMR dry matter intake (averaged 3.27 ± 0.72 kg/d, 3.08 ± 0.46 kg/d, and 2.89 ± 0.54 kg/d for the same three treatments). Calves in the early pair treatment also showed significantly higher average daily gain (ADG) over the experimental period (0.89 ± 0.04 kg/d versus 0.76 ± 0.04 kg/d and 0.73 ± 0.04 kg/d for the early paired, individual and late-paired calves, respectively). These results indicate that social housing soon after birth can increase weight gains and intake of solid feed

Invited review: Sustainability of the US dairy industry

The US dairy industry has realized tremendous improvements in efficiencies and milk production since the 1940s. During this time, farm and total cow numbers have decreased and average herd size has increased. This intensification, combined with the shift to a largely urban public, has resulted in increased scrutiny of the dairy industry by social and environmental movements and increased concern regarding the dairy industry's sustainability. In response to these concerns, a group of scientists specializing in animal welfare, nutrient management, greenhouse gas emissions, animal science, agronomy, agricultural engineering, microbiology, and economics undertook a critical review of the US dairy industry. Although the US dairy system was identified as having significant strengths, the consensus was that the current structure of the industry lacks the resilience to adapt to changing social and environmental landscapes. We identified several factors affecting the sustainability of the US dairy industry, including climate change, rapid scientific and technological innovation, globalization, integration of societal values, and multidisciplinary research initiatives. Specific challenges include the westward migration of milk production in the United States (which is at odds with projected reductions in precipitation and associated limitations in water availability for cattle and crops), and the growing divide between industry practices and public perceptions, resulting in less public trust. Addressing these issues will require improved alignment between industry practices and societal values, based upon leadership from within the industry and sustained engagement with other interested participants, including researchers, consumers, and the general public

Pessimism and fearfulness in dairy calves

Abstract Animals that experience situations likely to induce negative emotions show changes in judgment associated with pessimism. Few studies have focused on whether animals express stable differences in pessimism and whether these differences are related to personality traits. The first aim of this study was to explore if dairy calves are consistent over time in making judgments under ambiguous situations. Our second aim was to determine whether individual differences in judgment bias are related to conventional personality traits assessed using four standardized tests (Open field, Novel object, Human reactivity and Social motivation test). We subjected animals to two sessions of judgment bias and personality trait tests at 25 and 50 d of age. Individual differences in judgment bias were consistent over time with some animals persistently making more pessimistic choices compared to others. Two main dimensions of personality (Fearfulness and Sociability), obtained through principal component analysis, were also highly consistent over time. Pessimism was related to fearfulness, with more fearful calves making more pessimistic judgments. We conclude that dairy calves differ in the way they perceive and react to ambiguity and that this relates to individual differences in fearfulness