New Zealand’s dairy industry is centred on a pasture-based system. Profitability of pasture-based dairy farms is dependent on high pasture utilisation. To facilitate this, the system is generally designed to match the profiles of feed supply and demand, through a compact spring-calving profile. To achieve this, pasture-based dairy production is centred on a seasonal calving system and the feed is harvested directly by the cow. However, during the late/autumn winter period due to low pasture growth rates the feed demand often exceeds the feed supply. Cows are dried off during this period to coincide with the low feed supply and to reduce feed demand however, for highly stocked farms the reduction is not sufficient to conserve feed on farm for the subsequent season. To remedy this farmers have used off farm grazing, supplementary feed and crops to feed cows during the dry period to maintain feed supply on the home farm prior to the calving period.
Grazing brassicas has been a popular wintering system in the South Island due to the ability to carry the crop grown in late spring/summer forward into the winter without loss of feed quantity and quality. Brassicas can allow high yields of high quality feeds to be grown at a relatively low cost. Kale has been a popular brassica for wintering dry cows however, other crops are becoming of interest. Fodder beet has recently gained momentum in New Zealand as a crop for the winter dry period. Fodder beet is high in metabolisable energy and low in protein in comparison to other commonly grazed brassica crops such as kale and swedes and therefore, can provide a good maintenance feed as well as providing additional energy for body condition gain. This high metabolisable energy content is due to the high water soluble carbohydrate concentrations in the roots. High water soluble carbohydrate concentrations in conjunction with low fibre contents can predispose cows to animal health risk when grazing fodder beet and requires strict management of the crop to prevent these risks. However, the information known about Fodder beet is limited and research is lagging behind the increasing popularity of using fodder beet for dry cow grazing. This is a limitation of fodder beet and further research in this area is required to provide more information regarding the crops nutrient composition, best practice management and potential animal health risks associated with grazing fodder beet. A large amount of the information currently available is anecdotal and based on the nutrient compositions, management strategies and animal health risks investigated for other brassica crops. There is an opportunity to expand our knowledge regarding the digestion of fodder beet in the dairy cow and the performance of cows grazing fodder beet as well as the metabolic risks associated with this crop. Additionally, there is an opportunity to create guidelines regarding the best practice management of fodder beet for farmers.
References:
Crosse, S., O'Farrell, K., and Dillion, P. (1994). Why calving date and compact calving are so important to profitable dairying. Irish Grassland and Animal Production Association 28, 3-8.
Dairy NZ Ltd. (September, 2006). Barkant turnips - Feeding the crop (1-67). Dairy NZ Farmfacts. Retrieved from http://www.dairynz.co.nz/media/253750/1-67_Barkant_turnips_feeding_the_crop.pdf
Dairy NZ Ltd. (May, 2013). Fodder beet - feeding to dairy cows (1-73). Dairy NZ Farmfacts. Retrived from http://www.dairynz.co.nz/media/253800/1-73_Fodder-beet_feeding_to_dairy_cows.pdf
Dillon, P., Crosse, S., and Stakelum, G. (1995). The effect of calving date and stocking rate on the performance of spring-calving dairy cows. Grass and Forage Science 50, 286-299.
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