Haldis Kismul

Forsker

(+47) 454 12 776
haldis.kismul@nibio.no

Sted
Steinkjer

Besøksadresse
Innocamp Steinkjer, Skolegata 22, Bygg P1, 7713 Steinkjer

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Sammendrag

With increasing intensification of the dairy sector in many countries and with the introduction of automatic milking, exercise paddocks combined with full indoor feeding, as an alternative to production pasture, are being used as a compromise between farm economics and cow welfare. This study examined whether there are production benefits for high-producing dairy cows in an alternative system that uses pasture at a level of approximately 50% of the total roughage intake in the diet. In an automatic milking system with 12-h night access to the outdoor environment, we compared milk production and behavior of cows in 2 systems: an exercise paddock combined with ad libitum grass silage indoor feeding and a production pasture combined with a restricted daytime grass silage ration. There were 20 cows in the former and 21 cows in the latter system, with the treatments running in parallel. The experiment started in late June with no complete darkness during the night, and lasted for 12 wk, with 5.6 h of darkness at the end. We therefore also explored the effect of night length on milk production and behavior parameters. All cows showed strong motivation for going outdoors and grazing when pasture access was given in early evening, but after a few hours both groups went to the barn and did not return to the pasture area during the remaining night. As the season progressed and nights became longer, cows on the exercise paddock treatment reduced time spent outdoors and grazing time, whereas they increased time spent resting outdoors. The group on exercise paddock had a greater milk yield (kg of milk) over the experimental period than the production pasture group. The latter group also showed a greater drop in milk yield over the duration of the trial. Thus, for cows milked in an automatic milking system and offered nighttime outdoor access, no milk production benefits were observed in offering production pasture with restricted indoor silage allowance instead of an exercise paddock with ad libitum silage. We therefore suggest that automatic milking farmers with similar production levels and automatic milking-management systems as in the present experiment, who wish to in-clude grazed grass as part of the dairy cow diet, should ensure that cows have pasture access in the afternoon and evening.

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Sammendrag

Although pasture is low-cost feed, many farmers find it difficult to maintain high milk yield when using pasturefor high-yielding dairy cows in automatically milked herds. Therefore, a seven-week experiment with 40 cows inearly to mid-lactation was performed to evaluate a management model for including pasture in the diet withoutjeopardizing milk production. Within a part-time grazing system with morning and evening outdoor access, wecompared a group with ad libitum grass silage indoors combined with access to a small grass-covered permanentpaddock for exercise and recreation (group EX) with a group offered production pasture at a high allowance percow and day combined with restricted grass silage allowance at night (group PROD). Both groups had the sameoutdoor access times and the same concentrate allowance based on pre-experimental milk yield. Milk yield andmilking frequency were recorded daily in the automatic milking unit. Milk recordings and samplings for de-termination of milk composition took place weekly and outdoor behaviour of cows was recorded during pastureaccess hours on six observation days, evenly distributed over the experimental period. During the experiment,average metabolisable energy concentration was higher in the grass silage offered both groups than in pastureherbage. However, our results showed no significant difference in daily milk yield between treatments.Furthermore, no signifi cant differences between treatments were found in energy-corrected milk, milk fatproduction, or body weight change. Milk protein production was, however, significantly higher in group PROD.In early lactation, no difference in milking frequency was observed between treatments while for cows in mid- tolate lactation, milking frequency was significantly higher in group EX than group PROD. Over the entire ex-periment, group EX cows spent significantly less time outdoors than group PROD. In conclusion, offering highyielding dairy cows in automatic milking systems high-quality pasture at a high allowance for a few hours inmorning and afternoon appears to be an interesting alternative to exercise paddock with full indoor feeding, as itcan reduce costs for supplementary silage, facilitate natural behaviour, and encourage cows to spend more timeoutdoors, while maintaining milk production at a level comparable to that of full indoor feeding.

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Sammendrag

In Scandinavia, pasture for dairy herds with automatic milking (AM) is frequently offered purely for exercise and recreation, rather than as a feed-source. In the present study, cows in an AM-system with 12 h nightly outdoor-access from summer solstice until mid-September were offered either fresh production pasture (treatment P; ≥15 kg dry matter (DM) cow‑1 nightly, combined with 6 kg DM grass silage daytime) or exercise pasture (treatment E; <1 kg DM cow‑1 combined with ad libitum silage allowance day and night). Treatment showed a significant effect on milk yield (P:31.3, E:33.0 kg, P=0.05), and a tendency for milking frequency (P:2.25, E: 2.37 milkings × day‑1, P=0.06). Group P spent more time outdoors than E, 4.0 and 3.2 h, respectively (P<0.001). Cows in P grazed approximately 2.5 h throughout the season, while E grazed less overall, 0.6 h (P<0.001) and decreased their time spent grazing over the season (1.0 to 0.3 h). In conclusion, night-time pasture is poorly exploited by cows, irrespective of the quantity of both of pasture and silage that are available.

Sammendrag

LEgislation in Sweden and Norway requires that Dairy cattle have outdoor acess in summertime. PAsture utilization can be challenging with high-yielding cattle abd karge herd-sizes. Tehrefore, many farmers choose to offer their cows Access to an exercise- and recreation area only, rather than a full Production pasture. However, is an exercise paddoc as attractive as Production pasture for the cow? We compared part-time production and exercise grazing in an automated milking system, with outdoor acess in the morning (4.5 h) and the evening (4 h). The Production pasture group (P)was offered fresh Production pasture daily and given a Limited silage ration night-time. The exercise pasture group (E) was given Access to a small exercise paddoc and were fed silage ad libitum 24 hours. Milk yield dit not differ significantly: 36.1 kg for P and 36.0 kg for E. However, behaviour differed, with 5.5 (P) and 2.6 h(E) spent outdoors, and 3.7 h (P) and 0.6 h (E) grazing time. In conclusion, while milk-yields were similar between the Groups, lower ammounts of supplementary feed were needed for cows on treatment P, who also spent longer hours putdoors and grazing.

Sammendrag

Legislation in Sweden and Norway requires that Dairy cattle have outdoor acess in summertime. Pasture utilization can be challenging with high-yielding cattle abd karge herd-sizes. Tehrefore, many farmers choose to offer their cows Access to an exercise- and recreation area only, rather than a full Production pasture. However, is an exercise paddoc as attractive as Production pasture for the cow? We compared part-time production and exercise grazing in an automated milking system, with outdoor acess in the morning (4.5 h) and the evening (4 h). The Production pasture group (P)was offered fresh Production pasture daily and given a Limited silage ration night-time. The exercise pasture group (E) was given Access to a small exercise paddoc and were fed silage ad libitum 24 hours. Milk yield dit not differ significantly: 36.1 kg for P and 36.0 kg for E. However, behaviour differed, with 5.5 (P) and 2.6 h(E) spent outdoors, and 3.7 h (P) and 0.6 h (E) grazing time. In conclusion, while milk-yields were similar between the Groups, lower ammounts of supplementary feed were needed for cows on treatment P, who also spent longer hours putdoors and grazing.