The effect of feeding fodder beet or kale during winter on growth and behaviour of rising-one-year-old dairy heifers

Abstract

While fodder beet (FB) has been used by the dairy industry for winter grazing over the last 10 years, there is no published information on its effect on heifer performance. Farmers have recently expressed concern regarding the suitability of fodder beet for wintering growing dairy heifers due to the low crude protein (CP) content of the FB bulb. To compare liveweight gain and grazing behaviour, 191, 9- to 12-month-old heifers at the Southern Dairy Hub were offered either FB (n=93; HFR-FB) or kale (n=98; HFR-Kale), both with pasture baleage as a feed supplement, in winter 2019. Allocations were formulated to achieve similar energy intake, but HFR-Kale were offered a higher proportion of their diet as baleage. There were no differences in apparent DM intake, but HFR-FB consumed a diet with overall lower CP (11.4%) than did HFR-Kale (13.4%). Heifers in both treatments had a similar average daily liveweight gain (0.45 ± 0.083 kg/day) but neither group achieved the 0.6 kg/day average daily gain target for heifer growth. Differences were observed in eating and ruminating behaviour between the two groups, but more research is required to validate the measurement devices used in this study for animals grazing crop. The results indicate the challenges of achieving industry-recommended growth rates over winter in heifers grazing forage crops and highlight the importance of feed testing for nutritive value to ensure nutrient requirements are being met.