Epsilon Archive for Student Projects

Abstract

The dry period is usually 6-8 weeks and in this period the basis of the performance in the following lactation is settled. In an average herd about 15% of the cows are dry (Marcussen & Krog Laursen, 2008). In many herd the dry cows are set aside, that means setting aside 15% of your herd, at the time when they are preparing for their next lactation. The recommendation for number of groups differs depending on country traditions or reasons for grouping. If you look at recommendation for feeding, some companies selling feeding equipment advocates one group throughout the dry period, but the number differs from one to three. The recommendation from USA is for two groups, where the time to planned calving decides. From 8-3 weeks precalving the cows are in a Far-off group, where the feed is low in energy density and high in fiber. 3 weeks precalving the cows move into a Close-up group where they stay until calving. There they are fed with a feed containing more energy, to meet the needs of the cow near calving. It is also beneficial to mix in some of the lactation feed in this groups feed, to allow the rumen to adjust to the different feeds in the lactation feed. In Sweden the recommendations are for three groups; Drying off, Far-off and Close-up. If the grouping is based on health in the herd you get a more complex grouping. You then divide the dry cows in proven sound, proven sick and heifers. The optimal number of groups is six, because you also should move the cows and heifers near calving into a service unit, and keep the three groups previously stated (Landin et al, 2007). Another strategy for grouping is after udder health class (Herlin et al, 2007). If you get S.aureus into your herd these cows should be considered as disease carriers and be separated from the rest of the herd, even those with bad udder health class. Heifers should be separated from the rest of the cows if you don’t know the health status of your cows. The work has been done as a documentary research and we have also visited three large dairy farms to get a practical view on grouping. The knowledge has then been used when we have drawn up designs for Fröstorp Mjölk AB, where a building for dry cows and heifers is planned at Djupatorp, a farm nearby. We have also given suggestions for some changes in the dairy stall at Fröstorp. In the changes we have focused on improving the work environment and efficiency improvement in drying off and treatment of cows. We have also given two suggestions on designs for Djupatorp, where the focus has been on a good environment for the animals together with a good and rational work environment together with a good service unit. We think that Fröstorp mjölk AB has a god feeding strategy, but it is time for them to start focusing on improving the grouping on basis of health, and foremost udder health. We want the cows infected with S. aureus separated from the rest of the cows throughout the whole lactation cycle. With this strategy we hope to minimize the transmission of infection to uninfected animals and in time we think that the number of infected animals will decrease.
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We also would like to see a grouping based on udder health class, to prevent cows with poor udder health class infecting cows with good udder health class. Our conclusions are that in large herd you should group based on health, because you already have the sufficient size so that you can divide the dry cows into different groups depending on time in the dry period and thus different feeds. If you have only one feed in the dry period then you could add groups based on health. If you have different feeds in the dry period groups easily can be created by having gates set up to separate the feeding group into subgroups and still have a rational system. S. aureus cows should be separated from the rest of the herd throughout both lactation and dry period. It is also important that you keep a good balance of vitamins and minerals to sustain your cow’s health.