Discipline: animal welfare; Keywords: confinement housing, animal well-being, biological functioning.
Although limited in South Africa, many dairy cattle worldwide are still 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 the systematic review by Dr A Beaver and colleagues was to summarize the scientific literature pertaining to the welfare of tied dairy cattle through comparison with less-restrictive housing systems. To that effect they used the three-sphere concept of welfare that considers basic health and biological functioning, natural behaviour, and affective state. The Review was published in the Journal of Dairy Science, Volume 104 of 2021, page 9383 to 9417, the title being: The welfare of dairy cattle housed in tiestalls compared to less-restrictive housing types: A systematic review.
A total of 102 papers were included in the investigation. They addressed the measures of welfare related to affective state, natural behaviour, and health (with the latter 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 the papers); only 19% and 14% of studies addressed natural behaviour and affective state, respectively.
The review highlighted different health benefits for tethered and loose cattle. For example, tied cattle experienced reduced prevalence of white line disease and digital dermatitis, whereas loose cattle experienced fewer leg lesions and injuries. The prevalence of mastitis, transition diseases, and other conditions did not differ consistently across housing types. The expression of certain natural behaviours, particularly those associated with lying down (e.g., time spent kneeling, unfulfilled intentions to lie down), were impaired in tiestalls. Papers addressing affective state found benefits to loose housing, but these studies focused almost exclusively on physiological measurements and cow comfort, a concept that lacked a consistent operational definition across studies. Some measures of basic health and biological functioning were shown to be improved in loose housing and some in tiestall systems; providing outdoor access improved these measures for tied cows. The expression of natural behaviour, particularly lying behaviour, was inhibited in tiestalls. Most included studies showed benefits of loose housing on affective state, but this aspect of welfare has not been widely researched.
It was recommended that future research regarding the affective state of tied cattle should extend beyond the explorative and employs more sophisticated methodologies.