Cows: More freedom may mean less milk
'Free-stall', untied cattle in small herds produce less milk than cows tied to their stalls but have a higher reproductive performance and suffer less teat injuries and metabolic diseases. Researchers writing in BioMed Central's open access journal Acta Veterinaria Scandinavica compared performance and health within the two stall types in response to a ban on the construction of new tie-stalls.
Egil Simensen from the Norwegian School of Veterinary Science, Oslo, worked with a team of researchers to investigate data on 812 herds of Norwegian Red cattle, 192 of which were kept in tie-stalls.
He said, "Free-stall cows in smaller herds produced significantly less milk than those in tie-stalls, but more milk in larger herds. Cattle are social animals and readily form dominance hierarchies, especially at areas of access to feed, water and rest. It may be that cattle which are free to move around spend more time fighting and less time feeding in small free-stalls, particularly when the design of the stall is suboptimal."
Since 2004, all new cattle stalls built in Norway must be of the free-stall type. There has, however, been very little research on the impact of the interaction between housing system and herd size on animal welfare. Speaking about these results, Simensen said, "Performance and health is not universally better in small free-stalls than in tie-stalls. Herd size must be taken into consideration when preparing and evaluating regulations regarding housing system for dairy cows".