Conference Papers
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7616
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Item Persistency and lactation curves modelled using nonlinear random regression in dairy cows milked once a day(2020) Jiang, H; Hickson, R; Woods, O; Morandeau, M; Burke, J; Correa-Luna, M; Donaghy, D; Lopez-Villalobos, NItem Implications of using an extended lactation to change from a spring-calving to an autumn-calving farm system in South Taranaki(2020) Jarman, J; Kay, J; Neal, M; Donaghy, D; Tozer, PRecent changes to pasture-supply curves in South Taranaki, and the availability of winter milk premiums have increased farmer interest in changing from a spring-calving to an autumn-calving farm system. One approach to changing the season of calving from spring to autumn is to extend the calving interval (CI) by delaying the mating period by ~8 months, so that they next calve in autumn and undertake an extended lactation [>305 days in milk (DIM)]. A large-scale farmlet experiment was established in South Taranaki to investigate the production and reproduction responses of cows using this approach. In June 2017, 602 springcalving cows were allocated to two farmlets. In one farmlet (SPR) 301 cows were mated in October to maintain a 12-month CI spring-calving pattern. In the other farmlet (AUT, n=301 cows), mating was delayed for eight months, and cows underwent an extended lactation (mean DIM, 488; max DIM, 577) to calve next in autumn 2019. The experiment analysed two lactations for the AUT farmlet and two and a half lactations for the SPR farmlet. Across the total experimental period, milksolids (MS) production was similar between farmlets (1,194 vs. 1,174 kg MS/cow), however, cows in the AUT farmlet were fed more supplementary feed [2,371 vs. 1,951 kg dry matter (DM)/cow]. The extended lactation changed the relationship between feed supply and herd demand, which led to excessive BCS gain and ryegrass staggers for AUT farmlet cows. Further research is required to examine grazing management during extended lactations and to assess the economic implications of this approach.Item Opportunities to improve grazing management(New Zealand Grasslands Association, 5/11/2014) McCarthy, S; Hirst, C; Donaghy, D; Gray, D; Wood, BA; New Zealand Grasslands AssociationImproved efficiency in growing and converting pasture into product is required to maintain New Zealand’s competitive advantage in dairying. This study focused on two areas of grazing management, the first an assessment of the indicators leaf stage, pre-grazing yield and grazing residual. In summary, 49% of measured paddocks were grazed too soon based on leaf stage, 62% were grazed outside the recommended pre-grazing yield, and 48% of measured paddocks were not grazed to a desirable height. The second part of the study provided an insight into farmer decision making at an operational level of grazing management with three key components identified. These were: 1) The recruitment of paddocks into a grazing plan; 2) The shuffling of the paddock grazing sequence within the grazing plan; and 3) The management of individual grazing events before, during and after the event. An improved understanding by rural professionals of grazing management decision making would result in extension strategies which generate increased farmer engagement, adoption of grazing management technologies and improved on-farm productivity.Item Technical note: A comparison of editing criteria for lying-behaviour data derived from three-dimensional accelerometer devices on grazing dairy cows(2020) Hendriks, S; Phyn, CVC; Turner, S-A; Mueller, KR; Kuhn-Sherlock, B; Donaghy, D; Huzzey, J; Roche, JRItem Milk composition and productive and reproductive performance of cows from A1 and A2 β-casein variants, milked once or twice a day(2020) Lu, Y; Hickson, R; Gedye, K; Correa-Luna, M; Donaghy, D; Lopez-Villalobos, N
