Compatibility of delayed cutting regime with bird breeding and hay nutritional quality

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• 作者：Nocera ; Joseph J. ; Parsons ; Glen J. ; Milton ; G. Randy ; Fredeen ; Alan H.
• 关键词：Bobolink ; Breeding phenology ; Crude protein ; Fledging rate ; Grassland birds ; Hay cutting ; Livestock nutrition
• 刊名：Agriculture, Ecosystems and Environment
• 出版年：2005
• 出版时间：May 20, 2005
• 年：2005
• 卷：107
• 期：2-3
• 页码：245-253
• 全文大小：142 K

文摘

The breeding phenology of three grassland bird species was studied in managed hayfields of Nova Scotia, Canada: bobolink (Dolichonyx oryzivorus), savannah sparrow (Passerculus sandwichensis), and Nelson's sharp-tailed sparrow (Ammodramus nelsoni subvirgatus), under delayed hay cutting regimes (post-1 July). Weekly changes were monitored in several measures of hay nutritional quality (percent crude protein (CP % ), acid detergent fibre (ADF), calcium (Ca) and phosphorus (P)). Timing of peak fledging was variable across years, but generally occurred in the first week of July. Delay of cutting by 1 week in late June or early July resulted in a small reduction in hay nutritional quality. However, that hay would still meet energy and CP % requirements for non-lactating beef cows. Regression models showed that a delay of 1.5 weeks (from 20 June to 1 July) in cutting translated to a mean decrease in CP % of 2.1. Conversely, this delay secured an increase in the rate of fledgling, from 0 to 20 % for bobolink, 56 % for savannah sparrow, and 44 % for Nelson's sharp-tailed sparrow. Postponing cut by 1 more week (to a minimum of 7 July) gave the benefit of allowing maximum fledging rates for all species, while CP % lost 3.5. While this level of CP % is unlikely to support high maintenance periparturient cows and feeder/finisher cattle, it could be made profitable through mineral supplementation. ADF levels were considerably elevated, while Ca and P improved in the same time period. These trends show delayed hay cutting can be a viable option for farmers opting to conserve breeding birds on hayfields. The feasibility of delaying cut varies with a farm's specialization, and to a degree, breed kept. Such practices can be incorporated into a holistic approach to agroecosystem management.