Impact of winter fodder beet or kale allocation on body condition score gain and early lactation performance of dairy cows

Abstract

Forage crops such as fodder beet (FB) and kale are an important feature of dairy farming in Southland and Otago where winter pasture growth is negligible. However, farmers are concerned about poor performance of cows following winter FB feeding. In winter 2017, cows were offered FB or kale both with pasture baleage at two allocation rates: target (crop allocated to achieve a winter body condition score (BCS) gain of 0.7) or high (ad libitum crop). Diets with FB were lower in fibre, phosphorus, sulphur and calcium, but had a higher metabolizable energy, compared with kale diets. Body condition change and early lactation performance were monitored to compare effects of winter FB and kale diets. Average daily BCS gain before calving was similar for FB and kale cows. Crop type had a greater impact on cow performance than allocation rate. Cows wintered on FB had better reproductive performance (3-week pregnancy rate), and greater average milk solids, fat and protein yield (kg/d) than cows wintered on kale. Therefore, winter FB did not reduce cow performance compared with kale. However, the cumulative effects of a FB diet long term are yet to be determined and future research should monitor the impact on animal health.

The effect of winter fodder beet or kale allocation on behaviour and blood metabolite status of non-lactating dairy cows

“…The study was part of a winter-feeding trial conducted between 1 June and 16 October 2017 at the Southern Dairy Hub in Southland, New Zealand 46°18'37.8"S, 168°18'46.1"E, 11 m a.s.l. ; (Dalley et al 2020b). Crops compared were a fodder beet (FB; Beta vulgaris L.) and a brassica: kale (Brassica oleracea L.).…”

“…Cows were on their full crop allocations for an average of 55, 62, 74, and 73 days for FB-High, FB-Target, Kale-High, and Kale-Target, respectively, due to the different transition times for each treatment. This is described in further detail by Dalley et al (2020b).…”

“…There were 328 mixed-aged, multiparous, pregnant non-lactating Friesian × Jersey cross cows selected for the experiment and randomly allocated to feeding treatments balanced for body condition score (BCS; 10-point scale; Roche et al 2009), expected calving date, breeding worth ($BW), production worth ($PW), cow origin (the herd had recently been established) and age (Dalley et al 2020b). Calving dates ranged from 20 July 2017 to 16 October 2017.…”

“…Magnesium (MgO; 50 g/cow/d) and calcium (limeflour; 100 g/cow/d) were dusted onto the pasture breaks for the colostrum and milking groups. Crop and supplement measurements Crop establishment, cultivars of FB and kale and the method for determining the area of the feeding breaks required are described in detail by Dalley et al (2020b).…”

“…Kale was cut to ground level and fresh weight recorded. Subsamples of crop and baleage were collected for DM, feed quality and mineral analysis carried out by Hill Laboratories (Hamilton, NZ), results are published in Dalley et al (2020b).…”