Structural development in the prime sector has led to increasing herd sizes and new barn systems, followed by less summer grazing for dairy cows in Denmark. Effects of grazing on single welfare measures in dairy cows – for example, the presence of integument alterations or mortality – have been studied under different conditions. However, the effect of grazing on welfare, conceptualised as the multidimensional physical and mental state of the animal, has not yet been studied in contemporary cubicle loose-housing systems. The aim of our study was to investigate, based on a Welfare Quality® inspired multidimensional dairy cow welfare assessment protocol, the within-herd effect of summer grazing compared with winter barn housing in Danish dairy herds with cubicle free-stall systems for the lactating cows. Our hypothesis was that cow welfare in dairy herds was better during summer grazing than during full-time winter housing. Furthermore, we expected improved welfare with an increase in daily summer grazing hours. In total, 41 herds have been visited once in the winter and once in the summer of 2010 to assess their welfare status with 17 different animal- and resource-based welfare measures. A panel of 20 experts on cattle welfare and husbandry evaluated the relative weight of the 17 welfare measures in a multidimensional assessment scheme. They estimated exact weights for a priori constituted severe compared with moderate scores of welfare impairment concerning each measure, as well as relevance of the measures in relation to each other. A welfare index (WI; possible range 0 to 5400) was calculated for each herd and season with a higher index indicating poorer welfare. The within-herd comparison of summer grazing v. winter housing considered all the 17 measures. The mean WI in summer was significantly lower (better) than in winter (mean 2926 v. 3330; paired t-test P = 0.0001) based on a better state of the integument, claw conformation and better access to water and food. Body condition and faeces consistence were worse in summer. Many daily grazing hours (range average above 3 to 9 h) turned out to be more beneficial than few daily grazing hours (range average above 9 to 21 h) for the welfare of the dairy herds. In conclusion, this study reports a positive within-herd effect of summer grazing on dairy cow welfare, where many daily grazing hours were more beneficial than few daily grazing hours.

Structural changes lead to increasing sizes of dairy herds and a reduction in grazing use. Thus, cows spend more time in the barn and become more exposed to the barn environment. The cubicle surface can result in damages of the cows’ hock joint integument. Pasture is generally seen as a beneficial environment for cows. We hypothesized that a higher number of daily grazing hours reduce the probability of hock joint alterations in dairy cows from large herds. In total, 3148 lactating cows from 36 grazing and 20 zero-grazing dairy herds, with an average herd size of 173 cows, were assessed individually on one randomly selected body side for alterations in hock integument (score 0 for no alterations or hairless areas <2 cm, 1 for at least one hairless area of ⩾2 cm, 2 for lesion or swelling). The cows were further assessed for lameness and cleanliness. Information on breed, parity and days in milk per cow was extracted from a national database. Cubicle surface was evaluated for each herd. Daily grazing hours 30 days before herd visits were recorded by the stockmen and later categorized as follows: zero hours (zero-grazing), few hours (3 to 9) and many hours (>9 to 21). The effects of daily grazing hours and other potential cow and herd-level risk factors were evaluated for their impact on hock integument alterations using a logistic analysis with a multi-level model structure. The probability for hock integument alterations such as hair loss, lesions or swellings decreased with increasing amount of grazing hours (odds of 3 to 9 h 2.2 times and odds of >9 to 21 h 4.8 times lower than of zero-grazing). The probability for only lesions or swellings decreased with >9 to 21 grazing hours (odds 2.1 times) but not with 3 to 9 h (odds 1.0 times) compared with zero-grazing. Lameness, hard cubicle surface and Danish Holstein v. other breeds showed an increasing effect on the probability for integument alterations. Increase in days in milk only showed an increasing effect on the probability for lesions and swellings. We concluded that a long daily stay on pasture is most beneficial for the hock joint integument of a dairy cow.

Grazing cows could produce milk with a higher proportion of polyunsaturated fatty acids, which is beneficial to human health, compared with non-grazing cows, though grazing alone could compromise milk production. Under oceanic climate conditions, a study involving 15 dairy cows, fed total mixed ration (TMR) ad libitum in combination with different grazing times of 12 h (TMR12), 6 h (TMR06) and zero grazing time (TMR00) with the aim to evaluate different strategies on the fatty acids profile of milk and milk production. No differences were seen between the treatments with respect to milk yield (34·4±6·3 kg/d) or milk protein content (30·4±1·8 g/kg). The milk produced by the TMR12 cows had less total fat (36·2 vs. 38·2 g/kg) and saturated fatty acid (FA, 69·39 vs. 71·44 g/100 g FA) than that produced by the TMR00 cows. The concentration of vaccenic acid in the TMR06 and TMR12 milk was twice that of the TMR00 milk (4·22, 4·09 and 2·26 g/100 g FA respectively). Linear increases in conjugated linoleic (CLA) and linolenic acids were observed with increasing grazing time. Pasture was an important source of FA especially C18:3 for TMR06 and TMR12 cows. Under oceanic climatic conditions, the grazing of dairy cows as a complement to feeding with TMR can improve the FA profile of milk and increase its CLA content.

The study was carried out on a continuously stocked grass/white clover pasture, which was maintained at two sward heights: 3·5 cm (low; LSH) and 6·5 cm (high; HSH). Three oesophageal-cannulated and three other rumen-cannulated Merino sheep were allocated to each of the plots (LSH and HSH) in order to study the effects of sward height and advancing grazing season on rumen fermentation in grazing sheep. Three grazing periods (13 days) were considered: mid June, late July and early October. During each grazing period and after a preliminary period (7 days), samples of the grazed herbage and of grass hay were incubated in nylon bags in the rumen of each sheep for 0, 3, 6, 12, 24, 48, 72 and 96 h. On days 10 and 12 rumen fluid was sampled at the incubation time (11.00 h) and at 3, 6 and 12 h afterwards and pH, ammonia-nitrogen and volatile fatty acids (VFA) concentrations were determined. Sward height did not affect (P > 0·05) the degradation rate of dry matter (DM) and neutral-detergent fibre (NDF) from grazed herbage in any of the considered periods. Animals grazing LSH presented higher (P < 0·05) DM and NDF effective degradabilities (DMED and NDFED, respectively) during October but no differences were found during June and July. HSH grazing animals presented lower (P < 0·05) degradation rates of DM and NDF from grass hay during June and July than those found for LSH grazing sheep, with no differences (P > 0·05) observed during October. Sward height did not affect (P > 0·05) grass hay DMED and NDFED during July but during June and October HSH grazing sheep presented higher (P < 0·05) values. In general, DMED and NDFED from grazed herbage increased with advancing season, the lowest (P < 0·05) value being observed during June. Rumen ammonia-nitrogen concentrations were higher during October than during June and July for both sward heights but values were higher than 200 mg/l at any sampling time during all grazing seasons. Rumen pH values were within the range considered adequate for maintaining a normal cellulolytic activity at most of the sampling times, with the exception of sheep grazing LSH during October. Rumen VFA concentrations were within the range reported for other grazing studies and only a few differences between sward heights were found. Differences in rumen parameters are discussed in relation to both chemical composition of grazed herbage and pattern of intake.