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An experiment was carried out over 2 years to examine the interactions between two planes of winter nutrition and summer gracing at 5.5 and 7.5 cm compressed sward height on the performance of Limousin X Friesian steers grazing grass/white clover swards. Diets were offered in winter to give liveweight gains of either 0.5 (low) or 0.8 (high) kg d?1. The experiment was repealed over 2 years. Liveweights gains (low 0.50 vs. high 0.84 kg d?1 s.e.d. ±0.044) were achieved in winter 1 and (low 0.55 vs. high 0.91 kg d?1, s.e.d. ±0.041) in winter 2. These differences resulted in animals from the high treatment being 44 and 60 kg head?1 heavier at turn-out than the low-treatment animals in years I and 2, respectively. There was evidence of compensatory growth with animals from the low treatment subsequently tending to grow faster than those from the high treatment, with liveweight gains during the period from turn-out to 84 d of 1.27 vs. 1.18 s.e.d. ±0.65 kg d?1; P= 0–213 and 1.11 vs. 0.95 s.e.d. ±0.062 kg d?1; P=0.015 in summers I and 2 respectively. In general, animals grazing the short sward tended to grow more slowly than those on the tail swards (1.18 vs. 1.27 s.e.d. ±0.065 kg d?1; P= 0.166 and 0.93 vs. 113 s.e.d. ±0.062 kg d?1, P = 0.002) for years 1 and 2 respectively. Growth rates in year 1 were significantly higher than those in year 2. However, increased summer growth rates did not compensate for the differences in live weight established during the winter, and more animals reached slaughter weight in a shorter time from the high than the low treatment. Mean stocking rate on treatments 5.5 and 7.5 over the 2 years were 5.2 and 4.3 animals ha?1: differences were significant in year 2 (P <0.01). The 5.5 cm sward treatment also gave a greater liveweight gain ha?1 than the 7.5-cm sward treatment in both years with a mean for the two years of 670 vs. 572 kg ha?1 but differences were not significant.  相似文献   
2.
Management treatments were applied to an established ryegrass/white clover sward with the aim of producing differences in clover content. The treatments were: mowing (M) with no fertilizer N (intended to give high clover), grazing by cattle (C) with no fertilizer N (medium clover) and grazing by sheep (S) with 300 kg N ha−1 applied (low clover). Following treatments significant differences ( P < 0.001) were observed, with M, C and S containing respectively. 237, 81 and 3 kg DM ha−1 of live clover. Treatment M swards had fewer ryegrass tillers but greater numbers of clover growing points than did treatment S, with values being intermediate on treatment C. Following overwintering most of the differences in the clover component between treatments C and M were lost, but those on treatment S still persisted. Management can be used to manipulate the botanical composition of ryegrass/white clover swards, but these changes may be only transient.  相似文献   
3.
YARROW  CHRIS 《Forestry》1966,39(1):59-67
The increasing recreational use of forests makes their appearanceof greater importance than ever. Varying, and often conflicting,opinions on forest amenity have been expressed by the forestryprofession and the public. In an attempt to quantify publicopinion, a postal questionnaire survey was conducted with regardto the desired appearance and permissible public access anduse of forest areas. The results were analysed statistically,and indicated a strong bias towards woodlands of natural appearance.There was a widespread demand for greater access into stateforests but for limited commercial developments. Afforestationwas generally acceptable, and it was considered that managementought to be a compromise between timber production and amenityconsiderations. In view of the Forestry Commission's commitmentto take account of amenity, it is urged that a definite policybased on the users' wishes be formulated and effected.  相似文献   
4.
The intake of maize silage by self-fed heifers was measured where access to the silage was limited either by reducing the width of the feed face or by restricting the time allowed for feeding. In the first experiment twenty heifers were allowed 0.4 or 0.2 m feed face per head for 7 h daily. In the second experiment fourteen heifers were allowed 0.5 m feed face per head for 5 or 3 h daily. Intake was measured either by estimating faecal output by the chromic oxide technique and then using the in vitro estimate of silage digestibility to calculate individual intakes, or by using the results of eight individually fed heifers to provide a direct relationship between the chromic oxide concentration of the faeces and total intake, and using this to predict the intake of the self-fed heifers from the concentration of chromic oxide in their faeces. The latter method was found to be the most satisfactory because it took into account the effect of level of feeding on the digestibility of maize silage. Restriction of access to the silage by limiting feed face width (Experiment 1) and time (Experiment 2) significantly reduced intakes by 4 and 7% respectively. In both experiments feeding time was significantly reduced by restriction, but this was partially compensated for by a significant increase in rate of eating.  相似文献   
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