Welfare parameters in dairy cows reared in tie-stall and open-stall housing systems

The increasing attention paid by both the legislature and consumers concerning animal welfare has raised criticism regarding the tie stall housing system of dairy cattle, since it restricts voluntary movement and limits the social behaviour of cows. The aim of this study was to compare the welfare of dairy cows kept in a tie-stall (TS)and an open-stall (OS) system by assessing metabolic, immunological and stress-related parameters. The study involved 155 cows in 18 farms located in Tuscany. Blood samples were collected in the morning in order to measure: aspartate-aminotransferase (AST), alanine-aminotransferase (ALT), betahydroxybutyrate (BHBA), blood urea nitrogen (BUN), nonesterified fatty acids (NEFA), total proteins (TP), creatinine (Creat), calcium (Ca), potassium (K), phosphorus (P), lysozyme (SL), haptoglobin (Hp), and oxygen free radicals (OFR). At the same time, hair samples were collected to measure cortisol levels and the body condition score was recorded. The results showed that the housing system affected AST, ALT, BHBA, BUN, SL and OFR levels. Most parameters showed values within the range of reference. However, the OFR level was higher in the OS system, probably due to the higher productivity than in TS. Cortisol did not raise particular concern related to chronic stress, since the values were lower than the data reported in literature. The study revealed that the evaluation of welfare based on physiological parameters showed no severe signs of impairment in cows reared in the TS system.