Herbage intake and liveweight gain of bulls and steers continuously stocked at fixed sward heights during autumn and spring

Two experiments were conducted to examine the relationship between sward surface height, herbage intake and liveweight gain in beef cattle grazed on pasture. In Experiment 1, two 'animal types' (18 Charolais × Angus steers and 18 Friesian bulls) were continuously grazed for 22 days during the late autumn on replicated swards maintained at sward surface heights of 6, 10 and 15 cm. Herbage intakes, assessed from the faecal concentration of chromium delivered from an intraruminal controlled release capsule and the in vitro digestibility of hand-plucked herbage samples, were curvilinearly related to sward height (r = 0·76, p <0·0·01). Average liveweight gains were 0·02, 0·61 and 1·31 kg d^-1 ( P <0·05) and increased linearly ( r = 0·84, P <0·001) with sward height. The maintenance organic matter intakes of the steers and bulls, with initial mean (± s.e.) live weights of 225 ± 15 kg and 172 ± 15 kg respectively, were estimated to be 3·6 and 3·5 kg d^-1 respectively. In Experiment 2 (spring) 36 cattle, including 35 of those used in Experiment 1, were reallocated to sward heights of 5, 10 and 15 cm using the same design as for Experiment 1. Average liveweight gains were 0·94, 1·57 and 1·68kg d^-1 ( p 0·05) and were curvilinearly related to sward height ( r = 0·093, p <0·05). Maintenance intakes could not be reliably extimated for the cattle in Experiment 2 because few animals had liveweight gains close to zero. These trials confirm that liveweight gain in continuously grazed finishing steers and bulls increases with sward surface height to maximum of 8–10cm with spring ryegrass/white clover pastures while, in autumn, swards of 12–15cm height are required to achieve maximum performance.     

Effect of stocking rate in early season on dairy cow performance and sward characteristics

A comparison was made of stocking rates of 4·7, 5·6 and 6·4 cows ha^-1 during the first 7 weeks (period 1) of the grazing season. Each group of British Friesian cows was continuously stocked on a day and a night field. In the subsequent periods 2 and 3 (each lasting 7 weeks) the three groups were maintained at the same stocking rate within periods (4·2 and 31 cows ha^-1, respectively). The differential stocking rates were achieved by the addition and removal of cows.
The stocking rates applied in period I had no significant effects on milk yield, milk composition, liveweight change or condition score, in any period. Milk production ha^-1 over the three periods totalled 12390,13 978 and 14986 kg, and the estimated utilized metabolizable energy totalled 773, 81·5 and 86·6 GJ ha^-1 for low, medium and high stocking rates, respectively.
Increased stocking rate in period I was associated with a decrease in sward height in periods 1 and 2. This led to an increase in herbage metabolizable energy, and crude protein contents, and to an increase in tiller population density. The lowest stocking rate gave greater live individual tiller weights throughout the experiment and a longer interval between defoliation of individual tillers in period 1.
The results indicate that high stocking rates in the spring are not necessarily detrimental to overall summer performance of spring calving dairy cows. However, high stocking rates in the early season ensure a high level of herbage utilization and milk output ha^-1 in that period. Although this practice leads to a reduced sward height in mid season, the sward has less rejected area, a higher tiller population density and a higher digestibility than swards stocked at a lower level.     

The effect of sward height on the liveweight gain of farmed yearling red deer (Cervus elaphus) stags

The effect of sward height on the liveweight gain of yearling farmed red deer stags grazing permanent upland pastures in the UK in two successive years is described. The swards received nitrogen fertilizer at a rate of 218 kg ha⁻¹. Red deer stag calves, which had been weaned in September and housed over winter on a hay and concentrate diet to gain on average 57 g d⁻¹ in year 1 and 75 gd⁻¹ in year 2, grazed at one of fourmean sward heights of 4, 6, 8 and 10cm from the beginning of June until September. Liveweight gains were recorded over a period of 15 weeks. All animals were slaughtered and carcass weights were recorded after the end of the grazing period. Liveweight gains and final live weights and carcass weights were significantly ( P <0·05) lower on the 4-cm sward than on the other swards, but there were no differences between the performance of animals on the 6-, 8- and 10-cm swards.     

Effect of breed and sward height on sheep performance and production per hectare during the spring and autumn in Northern Spain

Abstract Effects of breed and sward surface height on ewe liveweight and body condition changes and on lamb liveweight gains during grazing in the spring and autumn were studied. The output per hectare in each season was also calculated. A total of 112 Gallega ewes (35·6 kg live weight) and 204 Latxa ewes (47·5 kg live weight) with their lambs were used during the spring (March–June) to study the effect of five target sward heights (3·0, 4·5, 5·5, 6·5 and 8·0 cm) and the interaction with breed. In autumn (October–December) 155 Gallega and 126 Latxa ewes were used to study the effect of three target sward heights (4·0, 5·5 and 7·0 cm) and the interaction with breed. Each study was replicated twice. A quadratic relationship was found between sward height and ewe liveweight and body condition changes and lamb liveweight gain during the spring grazing season, with the maximum individual performance being achieved at around a sward height of 6·0 cm. There were significant breed × sward height treatment interactions for ewe liveweight and body condition changes, and lamb liveweight gains. Higher liveweight gains were achieved by Latxa ewes and lambs in swards taller than 6·5 cm but they also sustained higher liveweight losses in swards shorter than 4·5 cm. Nevertheless, a higher output (liveweight gains of ewes + lambs) per hectare for a given weaning date or age was achieved by the Gallega ewes. In autumn, the relationship between liveweight change and sward height was linear, with a breed–sward height interaction similar to that observed in the spring. Sward surface heights of 4·0–4·5 cm and 4·5–5·0 cm were required to maintain live weight and body condition in spring and autumn respectively. Lamb and ewe liveweight gains per hectare decreased considerably in swards taller than 6·5 cm.     

Post‐grazing cutting management in tall fescue affects the sward structure,forage and liveweight production

Tall fescue is the main perennial grass of the pastures of the temperate region of Argentina. However, after flowering in spring, tall fescue loses productivity and quality. Based on this, the objective of this work was to evaluate the effects of different post‐grazing mechanical cutting managements on the forage mass, leaf proportion, stocking rate, liveweight gain and liveweight production of tall fescue pastures. The treatments were post‐grazing mechanical cutting at anthesis (FC), post‐grazing mechanical cutting throughout spring and summer (SSC), and no post‐grazing mechanical cutting (NC). The experiment was performed from 2011 to 2014 in Argentina. The greatest and lowest forage mass were determined in September–November and May–September respectively. The leaf proportion of the SSC treatment was greater than that of the NC treatment, except in September–November. NC had higher stocking rate and lower liveweight gain than SSC, and neither NC nor SSC differed from FC. The liveweight production of the treatments was characterized by a trade‐off between stocking rate and liveweight gain. We conclude that FC is an attractive management because, with a single post‐grazing cutting, swards remain productive and leafy.     

Effect of sward height and vertical distribution of clover on performance of cashmere goats in autumn

To investigate the effect of sward height on liveweight change in goats grazing grass/white clover swards, an experiment was conducted from mid-August to mid-November with groups of non-lactating female cashmere goats that continuously grazed perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) swards. Three replicated different sward height treatments — 10–8 cm (high), 7–5 cm (medium) and 5–3 cm (low) — were used to examine the effects on the competitive ability of grass and clover components within the sward canopy and their effect on liveweight. The pasture after grazing by goats had relatively higher ryegrass leaf (+0·26, high; +0·32, medium; and +0·18, low) and lower dead ryegrass proportions (?0·28, high; ?0·23, medium; and ?0·18, low) than at the beginning of the experiment, whereas the white clover fraction in the sward remained constant (+0·04, high; ?0·02, medium; and +0·03, low). Higher proportions of the white clover leaf lamina and petiole were found near the top of the sward canopy and were negatively correlated with the rate of liveweight gain by goats (P < 0·05). Goats gained 50·2 g Live weight (LW) d^?1 on the tallest treatment (high) but lost 0·01 and 42·3 g LW d^?1 on the medium and low sward height treatments respectively (s.e.d. 13·21, P < 0·001). Liveweight changes that occurred between sampling periods were also correlated (_R2= 0·858, P < 0·001) with changes in the mean sward height and proportion of white clover lamina-petiole at the sward surface in relation to the proportion found within the whole sward. These results suggest that goat liveweight gains would be increased if another species was introduced to reduce the white clover proportion in the surface horizon.     

The effects of autumn closing date on sward leaf area index and herbage mass during the winter period

The provision of grass for early spring grazing in Ireland is critical for spring calving grass‐based milk production systems. This experiment investigated the effect of a range of autumn closing dates (CD), on herbage mass (kg DM ha^?1), leaf area index (LAI) and tiller density (m^?2) during winter and early spring. Thirty‐six grazing paddocks, closed from 23 September to 1 December 2007, were grouped to create five mean CD treatments – 29 September, 13 October, 27 October, 10 November, 24 November. Herbage mass, tiller density and LAI were measured every 3 weeks from 28 November 2007 to 20 February 2008; additionally, herbage mass was measured prior to initial spring grazing and tiller density was measured intermittently until September 2008. Delaying CD until November significantly (P < 0·05) reduced herbage mass (by approximately 500 kg DM ha^?1) and LAI (by approximately 0·86 units) in mid‐February. On average, 35% of herbage mass present on swards on 20 February was grown between 28 November and 30 January. LAI was positively correlated with herbage mass (R² = 0·78). Herbage mass increased by approximately 1000 kg DM ha^?1 as spring grazing was delayed from February to April. Tiller density increased from November to February, although it did fluctuate, and it was greatest in April (9930 m^?2). This experiment concludes that in the south of Ireland adequate herbage mass for grazing in early spring can be achieved by delaying closing to early mid‐October; swards required for grazing after mid‐March can be closed during November.     

收获期籽粒田间霉变对大豆产量和品质的影响

为明确收获期籽粒田间霉变对大豆产量和品质的影响,采用人工降雨室内模拟连阴雨天气,对18个大豆材料进行高湿诱导霉变处理,通过籽粒霉变程度分级,比较不同材料间的霉变敏感性差异,同时考察霉变对大豆产量和品质的影响。结果表明,不同大豆材料对籽粒田间霉变的敏感性存在显著差异,黑色和棕色种皮大豆较黄色种皮大豆的霉变抗性更强。霉变使各大豆材料产量显著下降,产量损失在23.14%~96.55%之间,产量损失率与霉变指数呈极显著正相关(P0.01),产量损失率(Y)与霉变指数(X)的回归拟合方程为Y=1.34X+24.51,R=0.98。霉变还影响大豆品质,籽粒蛋白质、脂肪的相对含量随霉变程度的增加先降低后升高,可溶性糖的相对含量随霉变程度的增加而降低,而蛋白质、脂肪和可溶性糖的绝对含量均随霉变程度的增加而降低。此外,霉变使籽粒百粒重降低,并随霉变程度的增加而逐步降低。大豆收获期籽粒田间霉变会对大豆产量和品质产生不利影响,不同抗性的大豆种质资源为抗霉变大豆品种的选育提供了物质基础。     

优质再生稻新组合对比试验效应分析

汕优６３作再生稻栽培,在我省已种植多年,农艺性状有所下降,加上生育期偏长,影响了再生稻向中高海拔地区发展;汕优６６９又因米质偏差而不被接受。为适应粮食结构调整的要求,进一步提高再生稻的产量和米质,２０００年我们在永泰、武夷山、尤溪等地进行优质再生稻新组合筛选试验,比较了米质较好的福两优２１６３、Ｄ７０２优多系１号、Ｄ优６８等新组合作再生稻栽培的产量、再生力等表现,结果如下： 一、试验设计与管理 １．参试组合 参试组合有：Ｄ７０２优多系１号、Ｄ７０２优５２７、Ｄ宝优６号、Ⅱ优６号、Ｄ优６８、Ｄ优５２…     

Effects of grazing by lambs in autumn on a red clover-perennial ryegrass sward

In 1976, 1977 and 1978 a red clover-perennial ryegrass sward was cut twice for silage, and in the autumn of 1976 and 1977 it was either grazed at low and high stocking rates, i.e. seventeen and thirty-four lambs per ha respectively, or was cut with a forage harvester. The effects of grazing on yield in the following year were examined. Herbage growth in the grazing period was slow and did not differ significantly between the treatments. The yield of silage dry matter taken in May and July was highest in ungrazed plots (9·8 and 8·1 t ha^-1 in 1977 and 1978 respectively) and lowest in plots stocked at the high rate (5·9 and 5·7 t ha^-1 in 1977 and 1978 respectively). The aftermath yield for grazing in 1977 was slightly but significantly greater on treatments grazed in the previous year compared with ungrazed treatments. Red clover content decreased markedly during grazing, the high stocking rate treatment containing 2·4% clover and the ungrazed treatment 57·3% clover. The high stocking rate treatment also had the lowest red clover content in the first silage cut. Red clover content in grazed plots increased to a level similar to that in ungrazed plots by the start of the grazing period in the subsequent harvest year. Animal performance was higher at the low than at the high stocking rate but herbage consumption per head did not differ significantly between the two grazing treatments. Possible reasons for the adverse effect of grazing on the red clover are defoliation and treading. It is concluded that such experiments can form the basis of an economic assessment of red clover and help the farmer decide whether or not he should integrate the crop into his system.     

The liveweight gain of Limousin × Friesian heifers grazing perennial ryegrass/white clover swards of different clover content and the effects of their grazing on sward botanical composition

An experiment was carried out in 1992 and 1993 to examine the effect of white clover content of perennial ryegrass/white clover swards on the performance of Limousin × Friesian heifers. Swards with low (L), medium (M) and high (H) white clover contents were established and managed by continuous variable stocking. A compressed sward height of 5·5 cm was maintained using a buffer fence to vary plot areas, with herbage surplus to grazing requirements cut, removed and yields measured. The mean white clover proportions for treatments L, M and H were 0·02, 0·19 and 0·18 in 1992 and 0·13, 0·16 and 0·31 in 1993 respectively. White clover contents of the swards reached a maximum in August and September, and differences between treatments diminished. There was no significant difference between treatments in the content of white clover in the swards in autumn 1993.
Liveweight gains of heifers increased asymptotically with increasing white clover content of the sward. Below a white clover herbage mass of 300 kg DM ha^–1, there was little effect on liveweight gain, which was 0·70 kg day^–1 over the grazing season. Between 400 and 450 kg DM ha^–1 white clover, liveweight gains were 0·85–0·90 kg day^–1. While clover content of the sward did not significantly affect utilized metabolizable energy output; the mean output over the grazing season in the two years from liveweight gain and herbage yield was 78 GJ ha^–1. It is suggested that, using this grazing system, white clover reached an equilibrium with a mean herbage mass of about 400 kg DM ha^–1 over the grazing season.     

Effect of grazing severity on perennial ryegrass herbage production and sward structural characteristics throughout an entire grazing season

The objective of this study, which was part of a larger grazing‐systems experiment, was to investigate the cumulative impact of three levels of grazing intensity on sward production, utilization and structural characteristics. Pastures were grazed by rotational stocking with Holstein–Friesian dairy cows from 10 February to 18 November 2009. Target post‐grazing heights were 4·5 to 5 cm (high; H), 4 to 4·5 cm (intermediate; I) and 3·5 to 4 cm (low; L). Detailed sward measurement were undertaken on 0·08 of each farmlet area. There were no significant treatment differences in herbage accumulated or in herbage harvested [mean 11·3 and 11·2 t dry matter (DM) ha^?1 respectively]. Above the 3·5 cm horizon, H, I and L swards had 0·56, 0·62 and 0·67 of DM as leaf and 0·30, 0·23 and 0·21 of DM as stem respectively. As grazing severity increased, tiller density of grass species other than perennial ryegrass (PRG) decreased (from 3,350 to 2,780 and to 1771 tillers m^?2 for H, I and L paddocks respectively) and the rejected area decreased (from 0·27 to 0·20 and to 0·10 for H, I and L paddocks respectively). These results indicate the importance of grazing management practice on sward structure and quality and endorse the concept of increased grazing severity as a strategy to maintain high‐quality grass throughout the grazing season. The findings are presented in the context of the need for intensive dairy production systems to provide greater quantities of high‐quality pasture over an extended grazing season, in response to policy changes with the abolition of EU milk quotas.     

Effect of concentrate, dried grass and dried white clover ratios on intake, digestibility and liveweight gain by early-weaned lambs

Early-weaned lambs were offered rations of conventional concentrate, dried grass and dried white clover pellets ad libitum for 52 days. In vivo OM digestibility coefficients of concentrate, grass and clover were 80.0, 53.4 and 66.6% respectively. Dry matter intake of dried grass was similar to that of concentrates but supported significantly lower (P < 0.001) daily gains (0.18 kg). Supplementation of dried grass with an equal proportion of dried clover significantly increased (P <0.05) DM and DOM intake and daily gains. Daily gains by lambs offered the 1:1 grass:clover diet (0.29 kg) were similar to gains by lambs offered either dried clover (0.30 kg) or concentrates (0.30 kg).     

Effect of stage of maturity of whole-crop barley on intake and liveweight gain by dairy steers differing in initial live weight

The effect of maturity at harvest of whole-crop barley for ensiling on intake and liveweight gain of dairy steers differing in initial live weight (LW) was evaluated in an experiment over two years. Light (104–120 kg) and heavy (402–419 kg) dairy steers were fed diets containing predominantly whole-crop barley silage harvested at the milk stage [dry matter (DM) content of 284 g kg⁻¹ and neutral-detergent fibre (NDF) concentration of 526 g kg⁻¹ DM] or the dough stage of maturity (DM content of 328 g kg⁻¹ and NDF concentration of 445 g kg⁻¹ DM) and supplemented with up to 1 kg of concentrate. Dry matter intake (g kg⁻¹ LW) was higher for whole-crop barley harvested at the dough stage than at the milk stage of maturity and the difference was greater in heavy than in light steers ( P <  0·001). Liveweight gain was higher and feed conversion ratio was lower for dough-stage compared with milk-stage silage ( P  <   0·05) but there was no interaction with size of steer. Whole-crop barley harvested at the dough stage of maturity promoted higher liveweight gains in dairy steers compared with whole-crop barley harvested at the milk stage due to a higher DM intake.     

How do severity and frequency of grazing affect sward characteristics and the choices of sheep during the grazing season?

The effect of grazing frequency and severity on sward characteristics and preferences by sheep was investigated from April to September. Two levels of grazing severity were imposed by varying the numbers of ewes grazing 200 m² plots for 24 h: four (S, severe) or two (L, lax) ewes. Grazing frequency was either 1 d week^?1 (F, frequent) or 1 d every 2 weeks (I, infrequent). By combining frequency and severity, four treatments were obtained: SF, LF, SI and LI. The six binary combinations (SF/LF, SF/SI, SF/LI, LF/SI, LF/LI and SI/LI) were studied in preference tests. Treatments LF, SI and LI were characterized by a high sward surface height, biomass and amount of reproductive green tissues relative to treatment SF. Herbage quality was not different between the grazing treatments between April and July. In September, after a 6‐week period of regrowth, herbage quality was significantly higher for the SF treatment than the other treatments. The sheep preferred the swards grazed at a low frequency between April and July, and then changed their preference in favour of the sward with higher quality herbage (treatment SF). The relative abundance of green laminae and the relative digestibility of the swards helped to explain the preferences observed. For a low grazing pressure at the spatio‐temporal scale studied, sheep should graze swards at a relatively low frequency but at a high severity of grazing rather than the reverse.     

Effects of field drainage on the growth of herbage and the liveweight gain of grazing beef cattle

A long-term field grazing experiment was begun in 1982 to examine the impact of efficient field drainage on herbage and animal production from swards on an impermeable clay loam in the south-west of England. Drained and undrained lysimeter plots (each of 1 ha) were established on the existing permanent sward and received annual applications of fertilizer N of 200 or 400 kg ha⁻¹. Similar plots were initially ploughed and reseeded with Lolium perenne (cv. Melle), and received fertilizer N at an annual rate of 400 kg ha⁻¹. All plots were continuously stocked by beef cattle and stock numbers were adjusted to maintain a constant sward height and to avoid poaching damage. Results for the first 5 years show that the benefits from drainage were modest and, for beef production, unlikely to pay for its costs over the shorter term. The main benefit was in spring when herbage dry matter yield was 11% greater on the drained plots, but with no significant interaction with fertilizer N level or sward type. This benefit was reduced to 3% on an annual basis, due to the effect of the larger soil water deficits sustained by the drained swards in mid-season. Drainage increased the annual liveweight gain per ha by the grazing cattle by 11%. Possible mechanisms accounting for these effects are discussed in relation to the influences of seasonal patterns of weather.     

The effect of stocking rate and calving date on grass production,utilization and nutritive value of the sward during the grazing season

A 2‐year whole‐farm system study compared the accumulation, utilization and nutritive value of grass in spring‐calving grass‐based systems differing in stocking rate (SR) and calving date (CD). Six treatments (systems) were compared over two complete grazing seasons. Stocking rates used in the study were low (2·5 cows ha^?1), medium (2·9 cows ha^?1) and high (3·3 cows ha^?1), respectively, and mean CDs were 12 February (early) and 25 February (late). Each system had its own farmlet of eighteen paddocks and one herd that remained on the same farmlet area for the duration of the study. Stocking rate had a small effect on total herbage accumulation (11 860 kg DM ha^?1 year^?1), but had no effect on total herbage utilization (11 700 kg DM ha^?1 year^?1). Milk and milk solids (MS; fat + protein) production per ha increased by 2580 and 196 kg ha^?1 as SR increased from 2·5 to 3·3 cows ha^?1. Milk production per ha and net herbage accumulation and utilization were unaffected by CD. Winter feed production was reduced as SR increased. Increased SR, associated with increased grazing severity, resulted in swards of increased leaf content and nutritive value. The results indicate that, although associated with increased milk production per ha, grazed grass utilization and improved sward nutritive value, the potential benefits of increased SR on Irish dairy farms can only be realized if the average level of herbage production and utilization is increased.     

Effects of an autumn defoliation on overwintering, spring growth and yield of a white clover/grass sward

An established sward of binary mixtures of meadow fescue (Festuca pratensis) and white clover (Trifolium repens) (either AberHerald, Grasslands Huia or Sandra) was subjected to (A) no further defoliation, (B) a defoliation in late September or (C) a defoliation in late October after four harvests had been taken during the grazing season. About a tonne of dry matter (DM) was removed by the autumn defoliations. There were two levels of nitrogen application in spring, either 0 or 90 kg ha^?1. The development of grass and clover morphology and population sizes from early autumn until the first harvest the following year was followed by regular sampling of the above-ground material. Stolons were analysed for total non-structural carbohydrates (TNCs), and the temperature at stolon level was continuously recorded. There were no interactions between autumn defoliation, clover cultivar or nitrogen treatments on any of the parameters studied. White clover growing-point numbers and stolon morphological characteristics were reduced in size during the winter and did not recover during the spring. A defoliation in late September resulted in the greatest reduction, whereas there were no differences between the other two treatments. The grass tiller population increased from early autumn until the last sampling occasion in May, but both autumn defoliations resulted in a smaller increase. Defoliation in late September had the greatest impact. The TNC content of white clover stolons fell from about 350 g kg^?1 to 150 g kg^?1 DM from late autumn until late April. There were small differences between the treatments, but a defoliation in late September resulted in a significantly lower level in late autumn. The temperature amplitude at stolon level was consistently greater in plots defoliated in late September. Total DM harvested in spring was 4367, 2564 and 3536 kg ha^?1, of which 388, 352 and 460 kg ha^?1 was white clover, from treatments A, B and C respectively. It is concluded that an autumn defoliation may affect the overwintering of white clover negatively, but that the effect on the grass may be even more detrimental.     

华南籼稻新品种（组合）早季品质性状的综合分析和讨论

采用国家优质稻谷标准GB／T17891－1999对广东省早季不同稻作区种植的同一套不同质量档次新品种（组合）进行品质测定，品质性状方差分析结果表明：出糙率、整精米率、不完善粒的地点效应达极显著水平；垩白粒度、垩白度、直链淀粉含量、食味品质、胶稠度、粒型的地点效应不显著。综合分析了广东省新品种（组合）品质性状的现状，讨论了加权法定级的合理性，初步提出了广东省优质稻质量标准意见。     

The effect of summer management of perennial ryegrass-dominant swards on plant and animal responses in the autumn when grazed by sheep. 1. Tissue turnover and sward structure

An experiment was conducted lo compare the effects of the grazing by ewes and weaned lambs on aftermath and previously continuously grazed perennial ryegrass-dominant swards, at two sward heights (4 and 8 cm) in (he autumn, on changes in structure and growth of the swards. The experiment had a factorial design, was replicated twice and was conducted from mid-August to early November with measurements being made on three occasions in the autumn. Aftermath swards had lower tiller population densities and lower herbage masses than those that had been previously continuously grazed, the differences being greatest in August. On an area basis net growth rates of herbage on aftermaths were lower than those on previously continuously grazed swards in August and September but not in October. Growth rates of herbage were higher on the taller sward, but the senescence rates were similar at the two sward heights. It was concluded that autumn swards may be managed at taller sward heights than summer swards without increasing senescence of the sward and a consequent reduction in efficiency of utilization. The effects of previous sward management on tissue turnover in the autumn were not long lasting.