Page 308 - The Welfare of Cattle

heaLth, dIsease, and anIMaL WeLfare 285

DISeaSeS aFFeCteD BY CONFINeMeNt
COMPareD tO aCCeSS tO PaStUre

The following meta-analysis by Arnott, G., et al. (2017). addresses two of the freedoms that
relate to animal welfare, freedom from disease, and appropriate facilities, i.e., pasture vs. confine-
ment, and shows that there is reduction in diseases and mortality when dairy cattle have access to
pasture compared to animals in confinement facilities.
Arnott et al. conducted a review of the literature comparing pasture-based dairy cows to
continuously housed cows. The review showed significant benefits of pasture-based cattle over
continuously housed systems with respect to respect to health, behavior, and physiology. The
health benefits included less lameness, fewer hock lesions, less mastitis and metritis, and lower
mortality. Cattle which had access to pasture showed an overall preference for pasture when
given a choice between pasture and indoor housing. The 2010 National Animal Health Monitoring
System (USDA, NAHMS) study reported that 63.9% of North American dairies had some type of
housing system which accounted 82.2% of US dairy cows. However one third of US dairies use
some combination of grazing. But in 2007, 75% of dairy cows in the US were housed in free stall
or dry lots.

Lameness

The causes of lameness are multifactorial and the access to pasture is factor that can affect
the incidence of lameness. Two controlled studies have shown a significant improvement in loco-
motion scores and reduction in lameness when cows had access to pasture (Hernandez-Mendo et
al., 2007; Olmos et al., 2009) and two controlled studies showed difference (Baird et al., 2009;
Chapinal et al., 2010). For cows housed in confinement barns with free stalls, the odds of sole
ulcers and white-line disease were twice that of those housed on deep-bedded packs (Solano
et al., 2016). Other studies have shown that hard surfaces in confinement building contribute
to reduce cow comfort and increased incidence of lameness (Endres, 2017). Covering concrete
slatted floors with slatted rubber floors resulted in improved hoof health and animal hygiene
(Ahrens, 2011).

Mastitis

In this multiyear meta-analysis of seasonally calving cows, Holstein cows in confinement
had an increased prevalence of mastitis, a greater number (clinical cases of mastitis per cow) (1.1
vs. 0.6), and greater risk of being culled due to mastitis (9.7% vs. 1.6%) compared to cows on
pasture (Washburn, 2002). Many confinement dairies today have attained excellent udder health
as measured by bulk tank SCCs and a low incidence of clinical mastitis through implementa-
tion of a good mastitis control program, including a clean, dry environment, and good milking
procedures.

reproductive Disease

In a comparison of cows in confinement to cows in pasture-based system, cows in confinement
tended to have an increased incidence of dystocia, metritis, and endometritis on a small sample
size of cows and disease (Olmos, 2009). Cows in confinement tended to fared better nutritionally in
early lactation because dairies have greater control over the nutrient density of the ration than for
animals on pasture.