bluuebunny/crossref_metadata_2025 huggingface dataset:
THE USE OF LIVEWEIGHT‐GAIN TRIALS FOR PASTURE EVALUATION IN THE TROPICS
Authors: Stobbs T. H.
Published: April 2006

An experiment is described in which liveweight gains were measured from two grass/legume pastures using small East African Zebu animals and also progeny of small East African Zebu cows crossed with Bos taurus bulls. Significantly higher production was obtained from cross‐bred stock, which averaged 706 lb liveweight gain at per annum (791 kg/ha per annum), compared with 509 lb liveweight gain/ac per annum (571 kg/ha per annum) from Zebu stock, indicating that pasture management had advanced beyond the genetic potential of the local Zebu stock. The problems of designing, conducting and interpreting the results of such grazing trials are discussed.
EFFECTS OF TWO LEVELS OF APPLIED NITROGEN ON THE GROWTH OF S37 COCKSFOOT IN SMALL SIMULATED SWARDS IN A CONTROLLED ENVIRONMENT
Authors: Ryle G. J. A.
Published: April 2006

Two contrasting levels of N were applied in natrient solution to dense stands of cocksfoot plants grown in tins in controlled‐environment cabinets. During a 12‐week period of growth in a constant environment a full growth analysis was carried out. High N caused a three‐ or four‐fold increase in total dry weight per unit area by doubling shoot number and increasing shoot weight by approximately 60%. The increase in shoot weight arose mainly from a large Increase in leaf and sheath weight per shoot; root weight per shoot was for the most part negatively affected by high N. The large positive effect of N on leaf weight resulted from the development of slightly wider and much longer leaves, which had a similar or greater weight per unit area of leaf than equivalent leaves from the low‐N treatment.

The effect of high N on total dry weight was the consequence of a superior NAR and, in the first half of the experiment, a superior LAR. The physiological implications of the effects of high levels of applied N on DM production in the field are discussed. ice and analyses.
DETERMINING CUTTING SCHEDULES FOR MAXIMUM YIELD AND QUALITY OF BROME GRASS, TIMOTHY, LUCERNE AND LUCERNE/GRASS MIXTURES
Authors: Winch J. E. , Sheard R. W. , Mowat D. N.
Published: April 2006

Three grass‐ and two lucerne‐based harvest schedules were applied to pure sowings of timothy, smooth hrome grass, lucerne and the single grass/lucerne mixtures. Harvesting at the medium‐bud stage of development of lucerne was selected as the criterion which provided the highest DM yield in conjunction with high and consistent levels of rVD and CP from harvest to harvest, as well as persistence of the species in the pure sowings of lucerne/grass mixtures. On the same basis, the heads‐emerged stage of development proved most satisfactory for harvesting pure sowings of timothy and hrome grass.
SILAGE AND MILK PRODUCTION, A COMPARISON BETWEEN GRASS SILAGES MADE WITH AND WITHOUT FORMIC ACID
Authors: Castle M. E. , Watson J. N.
Published: April 2006

Two grass sUages made in June and two made in September, all from the same field, were compared in a 16‐week winter‐feeding experiment with 12 Ayrshire cows. The silages were fed ad lib. with a supplement of barley and groundnut eake. One of the sUages made in June and one made in September had been treated with 1/2 gallon of formie acid per ton of herbage when cut, whereas the other two silages were untreated. The contents of digestible organic matter in the silage DM made with and without the acid additive were 67.4 and 63.8%, respectively, in the June silage, and 66‐1 and 62.7% in the September silage. The intakes of silage and total DM were higher in the treatments containing the acid‐treated silages than in those containing the untreated silages. The mean daily milk yields from cows fed on the sUages made with and without the additive were 36.3 and 33.8 lb (16.5 and 15.3 kg), respectively, for silages made in June, and 35.4 and 34.1 lb (16.0 and 15.5 kg) for those made in September. The solids‐not‐fat (S.N.F.) contents of the milk averaged 8.60 and 8.50% respectively, from the silages with and without the additive. It is concluded that the silage with the formic‐acid additive was superior to the untreated silage as a feed for dairy cows.
THE EFFECT OF NITROGENOUS FERTILIZER ON THE RATE OF GROWTH OF ITALIAN RYEGRASS
Authors: Wilman D.
Published: April 2006

This paper describes the rate of growth of Italian ryegrass in the spring, measured by recording DM yield at weekly intervals up to 10 weeks. There were 3 levels of applied N: 25, 75 aud 125 lhJac (28, S4 and 140 kgJha). Rate of growth declined after the sixth week at all 3 levels of N. Grass receiving 25 Ib N produced 5000 Ib DMJac (5600 kgJha) in 10 weeks, that receiving 75 lb N 6800 Ib (7700 kgJha) and that receiving 125 lb N 7100 lb (8000 kgJha). The DM content of herbage fell after the first week and subsequently increased steadily up to 10 weeks; the fall was least marked and the rate of increase most rapid at tbe lowest level of N. In vitro digestibility (measured in one year only) was much affected by stage of growth and little affected by level of N.
DRIED FORAGES AND BEEF PRODUCTION*
Authors: Tayler J. C.
Published: April 2006

The vuluntary Intake of dried forage by young cattle rises with increasing D value and with increasing proportions of fine particles in the compressed package (wafer, coh, or pellet). Higher intakes are accompanied hy higher live–weight gains per day and per unit of food consumed.

When different amounts of pellets or cobs of dried forage of high D value or protein content are fed with silage of high digestibility, maximum liveweight gains at lowest food cost have been ohtained with 35–50% dried forage in the diet. The dried forage gave results comparable with alternative supplements of energy or protein fed with the same silage.

Hie application of the results of short‐term experiments in systems of heef production is discussed.
THE SIMULATION OF ANIMAL RETURNS IN GRASSLAND EXPERIMENTATION
Authors: Wolton K. Margaret , Brockman J. S. , Shaw P. G.
Published: April 2006

An experiment was carried out on a grass/white‐clover sward at North Wyke to evaluate the use of mixtures of inorganic and organic nutrient sources to simulate the nutrient effect of animal excreta, both with and without overall PK fertilizer. Grazing with sheep and the return of excreta from caged sheep both increased herbage yields, as did artificial return treatments. Artificial return treatments giving 75% of the nutrient level returned by excreta gave yields comparable with grazing. The effect of the simulated return treatments was not influenced by PK application. Grazing gave a very different botanical composition to that from the treatments in wbich natural or simulated excreta were returned to cut swards.

Mixtures simulating excreta may replace the nutrient effect of the grazing animal, but not its physical effect, in some forms of grassland experimentation. They are not recommended for fertilizer trials.
MINERALIZATION OF NITROGEN AND PHOSPHORUS FROM ORGANIC MATERIALS OF PLANT AND ANIMAL ORIGIN AND ITS SIGNIFICANCE IN THE NUTRIENT CYCLE IN GRAZED UPLAND AND HILL SOILS
Authors: Floate M. J. S.
Published: April 2006

Plant DM production from natural Nardus and Festuca–Agrostis pastures under two cutting regimes ranged from 1023 to 2265 kg/ha. The amounts of mineral N and P produced during the incubation of these plant materials, and from sheep faeces derived from them, were measured under a range of temperature and moisture conditions. These amounts, together with the N liberated in urine, and the increase in inorganic P concentration which resulted from the conversion of feed to faeces, were used to calculate the range in ‘potentially available’ plant nutrients derived from decomposition pathways in the presence and absence of sheep. Factors which infiuence the actual availability of nutrients for plant growth are considered and the results discussed in relation to the role of the grazing animal in the soil‐plant–aaimal nutrieut cycle.
PRODUCTIVITY AND CANOPY STRUCTURE OF TWO CONTRASTING VARIETIES OF PERENNIAL RYEGRASS (LOLIUM PERENNE L.) GROWN IN A CONTROLLED ENVIRONMENT
Authors: Rhodes I.
Published: April 2006

An experiment was conducted to measure the vertical distribution of LAI, sheath material and light in canopies of two contrasting perennial ryegrass varieties, S23 and Ba6280. In addition, the time course of DM production and LAI accumulation were measured over various periods of regrowth after defoliation. Considerable differences existed between these two varieties in canopy structure, light interception, LAI and crop growth‐rate over various periods of regrowth. The results offer explanations for intervarietal differences in productivity and differential responses to various cutting frequencies. A description is given of a technique for measuring the vertical distribution of herhage in a grass canopy.
THE VOLUNTARY INTAKE OF DIPLOID (S22) AND TETRAPLOID (TETILA TETRONE) ITALIAN RYEGRASS, AND WHITE CLOVER BY SHEEP
Authors: Thomson D. J.
Published: April 2006

Two experiments were conducted to measure the voluntary intake and digestibility of (a) primary growth and (b) regrowth of diploid (S22) and tetraploid (Tetila tetrone) varieties of Italian rye‐grass (Lolium muitifiorum): Sl00 white clover (Trifolium repens) was included as an additional treatment in the second experiment with the re‐growth herbage diets. Mature adult wether sheep, housed indoors in digesdhility crates, were fed individually on fresh herbage cut daily from late April to early June (primary growth) and in early Septemher (regrowth). The yield, digestihility, nitrogen and soluble–carhohydrate contents of the two ryegrass varieties were similar during the primary growth stage. Intake‐digestibility relationships for the graces were positive, linear and different (P=0.05). The voluntary intake of diploid ryegrass was approximately 14% higher than that of tetraploid ryegrass of the same digestibility. With regrowth herbage the digestibility and voluntary intake of white clover was higher than both the Italian ryegrasses. The digestihility of the regrowth tetraploid was 6% units higher than the diploid variety, but there was no difference in the voluntary intake of digestible organic matter between the varieties at the regrowth stage. The intake of regrowth herbage was higher thaa that of primary growth herhage of similar digestihility.
BURNING MOLINIA–DOMINANT VEGETATION FOR GRAZING BY RED DEER
Authors: Miles J.
Published: April 2006

Burnt Molinia caerulea–dominant range on the Isle of Rhum, N.W. Scotland, was grazed much more heavily by red deer than surrounding unhurnt Molinia stands. The effect was greatest in the first growing season after hurning. The practice of hurning Molinia in this region, where red–deer management is a major land use and Molinia is one of the main forage plants, is discussed.
SILAGE AND MILK PRODUCTION. A COMPARISON BETWEEN A DIPLOID AND A TETRAPLOID RYEGRASS
Authors: Castle M. E. , Watson J. N.
Published: April 2006

Two grass silages made in May and two made in August were compared in a 16‐week winter‐feediag experiment with 12 Ayrshire cows. The silages were fed ad lib. with a supplement of barley and groundnut cake. One of the silages made ia May and one made in August consisted of S24, a diploid variety of perennial ryegrass, and the other two of Reveille, a tetraploid variety of the same species. The silages made from Reveille had a higher content of lactic acid and a lower pH than those made from S24. The contents of digestihie organic matter in the silage DM made in May and August were 71.9 and 63.2%, respectively, for RevelUe and 68.7 and 60.9% for S24. Silage and total DM intakes were higher in the treatments where Reveille silages rather than S24 silages were fed. The mean daily milk yields from cows fed on the silages made in May and August were 39.6 and 34.5 lb (18.0 and 15.7 kg), respectively, for Reveille, and 38.0 and 34.1 lb (17.3 and 15.5 kg) for S24. The solids‐not‐fat (S.N.F.) and the crude protein contents of the milk averaged 8.64 and 3.29%, respectively, for Reveille, and 8.56 and 3.22% for S24. It is concluded (hat the silages made from Reveille were superior to those made from S24 as a feed for dairy cows.
PRODUCING GRASS FOR SUMMER MILK†
Authors: Wolton K. M.
Published: April 2006

Ways of using nitrogen fertilizer and long growth periods to produce grass for summer milk production are described. To exploit the extra production obtained from long growth periods it is suggested that the grazing system should be flexible, integrating cutting with grazing.
EFFECT OF DAY‐NIGHT TEMPERATURE REGIMES ON GROWTH AND MORPHOLOGICAL DEVELOPMENT OF TIMOTHY PLANTS DERIVED FROM WINTER AND SUMMER TILLERS
Authors: Smith Dale
Published: April 2006

Winter (vernalized) and summer (non‐vernalized) timothy tillers were grown to anthesis in day/night temperature regimes of 32/26°, 27/21°, 21/15°, and 15/10°C. Herbage and total plant yields, total leaf‐blade number and area, and total plant growth‐rate were highest, or very nearly so, in the 21/15°C regime for both the winter and summer plants. However, summer plants reached anthesis 13 to 14 days later than winter plants in each temperature regime. Even though virtually all primary shoots produced an infiorescence, summer plants had significantiy more leaves and leaf‐blade area, produced significantiy higher yields of leaf blade, stem plus sheath, stubble, and root tissues and had a significantly higher total plant growth rate than winter plants in each temperature regime.
STUDIES OF RESPONSE TO FERTILIZER NITROGEN
Authors: Hunt I. V.
Published: April 2006

Fifteen out of 36 possible combinations of 3 cutting dates for hay, 3 rates of N application and 4 intervals between N application and cutting date were compared to study the effects of pre‐harvest application of N on the N, P, K, Mg and Ca contents of the aftermath and the effectiveness of utilization of these elements.

According to the method of calculation given by ARC (1), the control haycrop harvested on 16 June was deficient in N, Ca, P and Mg, and the aftermath which was given no further N after harvest was of low bulk, but adequate in mineral content. Earlier harvesting improved the quality of the hay, and increased the bulk and reduced the mineral content of the aftermaths. Applying 125.6 kg N/ha after harvest resulted in a satisfactory increase in bulk, plus an improved mineral content in the aftermath. Applying N before harvest resulted in increased uptake of N, K, Ca, P and Mg in the hay and in the increased percentage of N, K, and Ca in the DM of the hay. Very early application of pre‐harvest N increased the percentage of Mg.

The general effect of pre‐harvest N on the aftermath was to reduce yield and uptake of N, K, Ca, P and Mg. Doubling the pre‐harvest N raised the mineral uptake. Very early pre‐harvest application resulted in low mineral uptake in the aftermath. The percentage of N, K and P in the aftermath was reduced by pre‐harvest N applied at both levels and on both dates.

Deferring the application of fertilizer N until 4 days after harvesting the hay crop produced the highest mineral contents in the aftermath, without reducing its bulk.

Mineral uptake in the regrowths was linearly related to N uptake at 1.43 kg K, 0.34 kg Ca, 0.157 kg P, 0.006 kg Mg/kg N uptake.
THE EFFECTS OF WHITE CLOVER AND APPLIED NITROGEN ON THE NITROGEN CONTENT OF VARIOUS GRASS/CLOVER MIXTURES
Authors: Chestnutt D. M. B.
Published: April 2006

Percentages and yields of N in various grasses and grass mixtures with clover and in associated clover grown at various levels of N application over 5 years are given. Grasses varied consistently in N content, percentages being highest in meadow fescue (cv. S53) and lowest in perennial ryegrass (cv. S24). N application did not significantly affect the N percentage in clover, but the associated grasses had a highly significant effect Percentages were highest in clover associated with meadow fescue and lowest in clover associated with ryegrass. The apparent transfer of N to grass per Ib N in associated clover was calculated for various treatments each year. Reasons for the changing levels of apparent transfer from year to year are considered.
THE EFFECTS OF HARVEST DATE ON THE YIELD AND QUALITY OF SEED OF TETRAPLOID HYBRID RYEGRASS
Authors: Williams S.
Published: April 2006

The ripening process in a tetraploid ryegrass is described in terms of seed moisture content changes. The heavier seeds of tetraploids appear to be shed at an earlier stage in the ripening process than those of diploid ryegrass. The seed moisture level at which a tetraploid ryegrass seed crop is harvested is shown to be a critical factor determining the yield and quality of from the crop harvested seed.
THE EFFECT OF A RYEGRASS COMPANION GRASS AND THE VARIETY OF RED CLOVER ON THE PRODUCTIVITY OF RED‐CLOVER SWARDS
Authors: Frame J. , Harkess R. D. , Hunt I. V.
Published: April 2006

An experiment was conducted to measure the effects of differrat ryegrass companion grasses and red‐clover varieties on the productivity of red‐clover swards. Three silage harvests per year were taken over a 2‐year period.

The addition of a companion grass increased total herbage yields; S24 perennial ryegrass gave the highest herbage yield over the two years, followed by Reveille perennial ryegrass. Because of lack of persistence, Tetila Italian ryegrass yielded poorly the second year. A companion grass had little effect on red‐clover yields in the mixed swards but improved percentage digestibility of the OM of the total herbage and lowered the CP percentage. Its presence also reduced the ingress of unsown species.

The variety of red clover used had little effect on total herbage yields or red‐clover yields in the first harvest year. In the second year, Hungaropoly and Tilo persisted better and so gave higher total herbage yields and red‐clover yields than Dorset Marl or Essex. The fall in total herbage yields from the first to the second year was entirely due to a fall in red‐clover yield since yields of the ‘non‐red clover’ fraction of the total herbage increased.

A red‐clover/grass sward may have advantages over a pure red‐clover sward nutritionally, for silage‐making and for its effect in diluting the oestrogenic activity of a pure clover sward. A major reappraisal of the role and potential of red‐clover swards in the UK is warranted because of their many valuable attributes, particularly their ability to give high herbage yields of high nutritive value without the addition of fertilizer N. The improved persistency of some of the tetraploid varieties of red clover enhances the value of the plant.
A COMPARISON BETWEEN A PADDOCK SYSTEM AND A ‘WYE COLLEGE’ SYSTEM OF GRAZING FOR MILK PRODUCTION
Authors: Castle M. E. , Watson J. N.
Published: April 2006

Two grazing systems, a paddock system and a ‘Wye College’ system, were compared in two 20‐week experiments nsing 16 and 20 spring‐calved Ayrshire cows in 1970 and 1971, respectively. A sward of S23 perennial ryegrass was used, and an average of 342 kg N/ha (305 lb N/ ac) was applied per annum. The paddock system had 28 separate paddocks; one paddock was grazed each day in rotation and occasionally topped in mid‐season. The Wye College system had 4 plots of equal size and the cows were offered 1/7 of one plot each day; no back fence was used and surplus herbage was neither cut nor topped. The stocking rate on hoth systems was 1 cow per 0.20 ha (0.49 ac) in 1970 and per 0.16 ha (0.40 ac) in 1971. The mean daily milk yields per cow on the paddock and the Wye College systems were 16.2 and 15.3 kg (35.7 and 33.7 lb), respectively, in 1970; and 18.1 and 18.4 kg (39.9 and 40.6 lb) in 1971. The average annual output of milk was 13,500 and 13,150 kg/ha (1200 and 1170 gal/ac) on the paddock and Wye College systems, respectively. The fat and solids‐not‐fat (S.N.F.) contents of the milk were not significantly affected by the grazing system. It is concluded that the Wye College system was as effective as the paddock system in producing a high output of mUk per ha, but at a lower cost and with far fewer management decisions.
THE NUTRITIVE VALUE OF WEEPING LOVEGRASS DURING THE SPRING SEASON
Authors: Vera R. R. , Irazoqui H. , Menvielle E. E.
Published: April 2006

A continuous digestibility trial, lasting 50 days with subperiods of 5 days each, was made with the spring regrowth of Eragrostis curvula grown in the semi‐arid region of Argentina. Five sheep were used to measure the digestibility of DM, organic‐matter, cell‐wall contents and N. DM yield was estimated simultaneously. The fall in digestibility of all fractions examined was described by quadratic equations. Cell‐wall digestibility explained 91% of the variation in organic‐matter digestibility. The rate of decrease in crude‐protein digestibility increased with time and was particularly noticeable after about 40 days of growth. Digestible DM yield increased at a decreasing rate as maturity advanced, but digestible crude‐protein content decreased linearly throughout the trial. It is concluded that the optimum stage of maturity for weeping lovegrass utilization depends upon the performance required from the animals that are to utilize it.
THE EFFECT OF CUTTING HEIGHT AND NITROGEN LEVEL ON THE YIELD, IN VITRO DIGESTIBILITY AND CHEMICAL COMPOSITION OF ITALIAN RYEGRASS SWARDS
Authors: Binnie R. C. , Harrington F. J. , Murdoch J. C.
Published: April 2006

Three cutting heights, 2±5, 7±6 and 12±7 cm (1, 2±5 and 5 in.) and three levels of fertilizer N, 168, 280 and 392 kg N/ha (150, 250 and 350 Ib N/ac) were imposed on a sward of Italian ryegrass (Lolium multiflorum) cv. Irish. Lowering the cutting height and increasing the level of applied N increased the yield of herhage DM. Increasing the level of applied N had a greater effect on the chemical composition of the herbage than altering the cutting height
STUDIES OF RESPONSE TO FERTILIZER NITROGEN
Authors: Hunt I. V.
Published: April 2006

The uptake of N was measured in 2 successive regrowths harvested on 12 June and 13 Aug. following harvests of primary growths 8, 12, 16, 23, 29, 45 and 57 (12 June) days after applying N at 59, 118 or 177 kg N/ha on 16 Apr.

Residual responses were obtained to both increments of N, leading to high apparent recoveries of fertilizer N, especially to the higher increment. This increased availability of soil N when high rates of N are applied is shown to vary with date of harvest of primary growth, reaching a maximum equivalent to 151% apparent fertilizer N recovery 23 days after N application.

In the second regrowth, percentage N in the herbage showed a negative response to N applied to the primary growth. This appears to reflect a reduction in available soil N brought about by its increased availability and uptake in primary growth and first regrowth.

The possibilities of improving the efficiency of fertilizer N by exploiting soil N are considered against the possible reduction in available N for future regrowths.
A COMPARISON OF SPRING‐ AND AUTUMN‐PRODUCED DRIED GRASS FOR MILK PRODUCTION
Authors: Gordon F. J.
Published: April 2006

An experiment designed to compare the nutritive values for milk production of dried grasses harvested in spring and autumn is described. The DM digestibility of the spring‐ and autumn‐dried grass was 67±7 and 66±0%, respectively. Both dried grasses were fed at two levels, 0±4 and 0±5 kg/ kg milk (4 and 5 Ib/10 Ib milk), to lactating cows in a randomized‐block design experiment using 24 animals. Each animal was also given 2±5 kg hay/day (5±5 Ib) and in addition sufficient of the dried grass under investigation to meet maintenance requirements.

Milk yield, milk energy output, live‐weight gain and the solids not fat (SNF) and protein contents of the milk increased with feeding level. Season of dried grass harvesting had no effect on milk yield, milk energy output or live‐weight change. The spring‐harvested dried grass resulted in a significantly higher milk SNF content than the autumn‐dried grass and also tended to reduce milk butterfat level.
A COMPARISON OF THE YIELDS OF FORAGE MAIZE GROWN FOR SILAGE IN 1972 AND 1973 AT THE NATIONAL INSTITUTE FOR RESEARCH IN DAIRYING
Authors: Phipps R. H. , Connell J.
Published: April 2006

The DM production from INRA 200, an early maturing hybrid maize grown for silage, was 10±6 and 14 5 t/ha in mid‐October 1972 and 1973 (4±2 and 5±8 tons/ac). The plant population in both years was approximately 112,000/ha (45,320/ac). Whole‐crop and cob DM percentages were 18±2 and 21±3 for 1972 and 39±9 and 53±0 for 1973, respectively. The cob yields were 49 and 10±4 t/ha (2±0 and 4±1 tons/ac) in 1972 and 1973 and cob in the two years accounted for 46 and 72% of total yield. At harvest the 1973 crop was 4–6 weeks more mature than the 1972 crop. These differences were attributed to the difference in accumulated temperature recorded from May till October, which was 567°C days in 1972 and 817 in 1973. Whole‐crop DM content, yield of cob and yield of cob as a percentage of total yield were studied against seasonal temperature accumulation. In the case of DM percentage there was a highly significant linear regression which showed that 627°C days were needed to mature maize to 24% DM content.
NEW OPPORTUNITIES IN THE ESTABLISHMENT OF GRASS AND FORAGE CROPS*
Authors: Elliott J. G. , Squires N. R. W.
Published: April 2006

In the management of British grassland lay there appears to be a marked divergence between the policies advocated by grassland science and general grassland practice. While science places emphasis on monocultures of sown species (mainly perennial ryegrass), heavily fertilized and intensively stocked, grassland farmers for the most part rely on lonstablished or indigenous swards composed of a variety of species and receiving modest applications of fertilizer. Since the gap between the two approaches is both substantial and of long duration the subject appears to be worth fresh attention. The purpose of this paper is to examine the current situation in relation to improvement in botanical composition and to suggest new approaches to that end.
THE EFFECTS OF CHANGES IN HEIGHTS OF CUTTING AND GROWTH ON THE DIGESTIBLE ORGANIC MATTER PRODUCTION AND BOTANICAL COMPOSITION OF PERENNIAL PASTURE
Authors: Clark Jennifer , Kat C. , Santhirasegaram K.
Published: April 2006

Irrigated plots of a mixed sward of Lolium perenne, Paspalum dilatatum, Bromus unioloides, Dactylis glomerata and Trifolium repens were used in 2 experiments during 4 years. In the first experiment, die treatments comprised factorial combinations of heights of cutting of 3, 6 and 10 cm (1.2, 2.4 and 3.9 in.) above ground level, and heights of growth of 5, 13 and 20 cm (20, 5.1 and 8.0 in.) above the height of cutting. In the second experiment, 8 combinations of dose (3 cm or 1.2 in.) or lax (10 cm or 3.9 in.) cutting were applied at various times during each year.

In the first experiment, DM production for cutting heights of 3, 6 and 10 cm was 50, 44 and 43 t/ha (198,17.5 and 171 ton/ac), respectively; the DOM production was 37, 32 and 32 t/ha (147, 12.7 and 12.7 ton/ac). DM production for growth heights of 5, 13 and 20 cm was 45, 46 and 48 t/ha (17.9, 183 and 191 ton/ac), respectively. DOM production, 34 t/ha (13.5 ton/ac), was not affected by height of growth.

Percentages of protein (26, 22 and 20) and DOM (76, 72 and 71) declined as the height of growth was increased; but cutting height produced no significant effects in them. As cutting height was increased the percentage of clover declined (40, 31 and 23) and that of grasses increased (52, 66 and 72); diere were smaller changes with changes in height of growth.

Hie second experiment showed that the difference between close and lax cutting became significant only when lax cutting was applied for at least half of the cuts each year. DM production was similar for treatments witii the same number of close or lax cuts, regardless of the time of year at which the two heights of cutting were applied.
THE INFLUENCE OF TYPE AND LEVEL OF SUPPLEMENTARY FEED ON INTAKE AND PERFORMANCE OF BEEF CATTLE ON PASTURE
Authors: Umoh J. E. , Holmes W.
Published: April 2006

Two experiments, each of 6 weeks dehydration, were conducted in 1972. In Expt 1, 24 cattle were grazed in individnal paddocks during July and August and received one of 4 treatments over a 6‐weeks period: no supplements; straw ad lib; 3.3 kgj. day sugar‐beet pulp; 4.0 kg/day molasses. Mean daily live weight gains were significantly increased by the sugar‐beet pulp and molasses supplements; which also increased OM and DOM intake significantly. The increase in total OM intake per kg OM in the supplement was 0.48 for sugar‐beet pulp and 0.67 for molasses.

In Expt 2, 18 cattle grazed in groups of 3 during November and December. Two groups each received 0.5, 3.5 or 6.5 kg/day sugar‐beet pulp over a 6–weeks period. There was no significant difference in live weight gain between treatments, and no significant difference in total intake. Intake from pasture declined with increasing level of supplement, so that the average increase in OM intake per kg OM in the supplement was 0.28.

Hie results are discussed in relation to availability of pasture and the effects of the supplements on intake.
FURTHER COMPARISONS BETWEEN A RIGID ROTATIONAL WYE COLLEGE' SYSTEM AND OTHER SYSTEMS OF GRAZING FOR MILK PRODUCTION
Authors: Castle M. E. , Watson J. N.
Published: April 2006

In two 20‐week grazing experiments, a rigid rotational system of grazing termed the ‘Wye College’ system was compared with a flexible paddock‐grazing system in 1972 and with strip grazing and set‐stocking in 1973. Eight spring calved Ayrshire cows were used on each treatment at a stocking rate of 5 cows/ha (2 cows/ac). The mean daily milk yields per cow were 17·7 and 17·0 kg(39·0 and 37·5 Ib) on the Wye College and the paddock systems, respectively, in 1972; and 17·9, 17·7 and 16·4 kg (39·4, 38·9 and 36·2 Ib) on the Wye College, strip, and set‐stocking systems in 1973. The average annual output of milk varied from 11,500 kg/ha (1030 gal/ac) on the set‐stocking system to 12,500 kg ha (1120 gal/ac) on the Wye College system, but none of the differences was significant. The most rapid decline in daily milk yield occurred on the set‐stocking system in August and September as the amount of available herbage declined. This system requires further investigation. It is concluded that the Wye College system, with its rigid and pre‐determined grazing cycle was as effective as either a one‐day paddock or a daily strip‐grazing system in producing high yields of milk.
EFFECT OF SOME GREEN‐CROP‐DRYING PROCESSES ON THE DIGESTIBILITY AND VOLUNTARY INTAKE OF HERBAGE BY SHEEP
Authors: Marsh R. , Murdoch J. C.
Published: April 2006

The effect of artificial drying under commercial conditions on the digestibility and voluntary intake of herbage by sheep was studied, using either van den Broek (900°C inlet temperature) or Swiss Combi (1100°C inlet temperature) triple‐pass drum‐type driers. Organic‐matter digestibility of chopped dried herbage was 8·3, 5·8 and 5·3% lower than that of fresh herbage in Experiments 1, 2 and 3, respectively. Packaging chopped dried grass into ‘cobs’ caused a further reduction in OM digestibility of up to 2·8%. Pre‐milling plus packaging (i.e. ‘pelleting’) depressed OM digesti bility of chopped dried grass by 5 to 6 percentage units. Digestibility of dried grass in its various physical forms was further reduced when offered ad lib.; the greatest fall (9·4%) occurred with pellets and the smallest fall (0·8−1·3%) with loose chopped material; cobs were intermediate at 4·3−7·0%.
THE EFFECTS ON DAIRY COWS OF GRAZING PASTURE CONTAINING HIGH LEVELS OF NITRATE‐NITROGEN
Authors: Phipps R. H.
Published: April 2006

Two paddocks each received a total of 412 kg N/ha (371 lb/ac) between April and July in four equal applications. The paddocks were grazed four times for four days by two groups of 5 Friesian cows starting 14 and 21 days after each N applica tion.

The nitrate‐N content of the herbage DM reached a peak of 0·76 % in the third grazing 14 days after N application. There was a significant (P < 0·001) correlation (r =0·67) between water soluble carbohydrates and nitrate‐N in the herbage DM.

No marked changes occurred in eitber the methaemoglobin or packed cell volume of the blood samples from either group.

No detrimental effects on animal health or production were recorded during the experiment.
THE EFFECT OF INCLUDING DRIED GRASS IN THE SUPPLEMENT GIVEN TO LACTATING COWS AT PASTURE
Authors: Gordon F. J.
Published: April 2006

An investigation into the effect of including dried grass in the supplement given to dairy cows at pasture is reported. Supplements containing 0, 50 and 100% dried grass were used in the investigation which was carried out in two parts. In the first part 12 high‐yielding cows with unrestricted access to pasture were used in an experiment with a change over design to assess the effects of feeding 5 kg/day of each supplement on milk yield and composition. In the second part 8 steers, housed in stalls and given cut herbage from the same sward as that grazed hy the cows, were used in a change over experiment to assess the effects of the three supplements on herhage and total DM intake. No significant differences in milk yield between supplements were ohtained, the mean yields being 23·9, 24·5 and 23·9 kg/day for the supplements containing 0, 50 and 100% dried grass, respectively. Milk composition was also not significantly affected by including dried grass in the supplement. In the indoor feeding trial using the steers, the addition of 3·5 kg DM from the supplement resulted in an increase in total DM intake of only 1·3 kg/day. There was no significant difference hetween supplements on herbage and total DM intake.
EFFECTS OF FOLIAR APPLICATION OF COPPER SULPHATE ON THE COPPER CONTENT AND YIELD OF HAY
Authors: MacPherson A. , Voss R. C. , Moon F. E.
Published: April 2006

Foliar application of CUSO4 to mature grass to increase the Cu content of the hay crop was markedly affected by rainfall within 24 h of the time of application. The mean Cu concentration of hay treated with 5·6 and 11·2 kg CuSO4/ha was 100 and 208 ppm, respectively, when no rainfall occurred during this period, but only 24 and 41 ppm when rain fell within 24 h. Rain 4 or 5 days after spray application had no effect on the ultimate Cu concentration of the hay. It is suggested that sheep could safely graze the aftermath as, with one exception, concentrations of Cu found were only from 11·4 to 20·6 ppm. l±l kg CuSO4/ha applied in dry conditions was sufficient to raise Cu concentrations in hay to levels which should preclude the occurrence of Cu deficiency when fed to cattle in winter. Reductions in hay yield following CUSO4 applications in dry weather suggest a need to examine the use of more dilute sprays, or other means for increasing the Cu content of hay.
NITROGEN AND ITALIAN RYEGRASS
Authors: Wilman D.
Published: April 2006

This paper describes the regrowth of Italian ryegrass, following a cut in late April, measured by recording DM yields at weekly intervals up to 14 weeks. There were 4 levels of applied N: 25, 75, 125 and 175 Ib/ac (28, 84, 140 and 196 kg/ha). Rate of growth up to 10 weeks was compared with that recorded in similar experiments in Cambridge in earlier years and was found to be generally similar. The highest yields of DM and digestible organic matter were recorded after 11 weeks; beyond this stage there was a fall in yield. There was a large response to 75 Ib N compared with 25, a moderate response to 125 Ib compared with 75 (greater during the last 7 weeks than during the first 7 weeks), and little response to 175 Ib compared with 125. The time‐saving value of N is noted. DM content was appreciably lower than in Cambridge, apparently because of both surface and internal moisture, but showed similar trends. In some of the early weeks, especially at high N, the crop appeared to be supplying water well in excess of livestock needs. In vitro digestibility was much affected by stage of growth and little affected by level of N.
THE EFFECT OF FEEDING RED CLOVER CONSERVED BY DRYING OR ENSILING ON REPRODUCTION IN THE EWE
Authors: Thomson D. J.
Published: April 2006

Forage diets were prepared from ryegrass (non oestrogenic control) and from red clover as pellets or as unwilted silage. Each diet was fed to separate groups of 20 Border Leicester × Cheviot ewes for three weeks prior to the introduction of the ram, and for two cycles after mating. Subsequently, all three groups of ewes were fed in a similar manner until lambing and the reproductive performance of the ewes was measured. The control diet was prepared by barn drying a primary growth crop of perennial ryegrass, Lolium perenne cv S23. Tetraploid red clover, Trifolium pratense cv. Hungarpoly, was harvested as a first regrowth crop and the pelleted diet prepared by high temperature drying, grinding (2 mm screen) and pelleting. The silage was prepared without wilting. The level of formononetin in the red‐clover silage was three times that in the dried red‐clover pellets.

Compared with the control grass diet, the feeding of red clover in either form significantly reduced (P<0·001) the number of lambs born. The incidence of barrenness was higher (P<0·001) for ewes fed red‐clover silage compared with red‐clover pellets and the control diet. The rate of twinning was significantly (P<0·001) higher for the ewes fed the control grass diet than for either of the red‐clover diets. The resultant lambing percentages were 190,165, and 100% for the control grass, red‐clover pellet and red‐clover silage treatments. In flock management, both the grazing of red clover and the feeding of red‐clover pellets or silage, prior to and during mating, should be avoided.
THE AUTOMATIC RECORDING OF THE GRAZING BEHAVIOUR OF DAIRY COWS
Authors: Castle M. E. , Macdaid Elizabeth , Watson J. N.
Published: April 2006

A technique for the automatic recording of the grazing behaviour of dairy cows was investigated, using ‘Vibracorders’ which transmit grazing movement via a pendulum and stylus to a 24 h recording chart. The total labour input was 2 h/day for 6 cows, which gave 144 h of results. In 2 months, 3312 h of recording were obtained. Total grazing time per cow in 24 h was 559 min. on a rigid rotational system of grazing and 638 min. on a system of set stocking. Grazing time was significantly and negatively related to the yield of available herbage DM. It is concluded that if the Vibracorders are sealed and fitted correctly, they are simple, reliable and accurate instruments for automatically measuring the grazing behaviour of dairy cows.
THE POTENTIAL VALUE OF BIRDSFOOT TREFOILS (LOTUS SPP.) FOR THE IMPROVEMENT OF NATURAL PASTURES IN SCOTLAND.
Authors: Charlton J. F. L.
Published: April 2006

A New Zealand selection of marsh birdsfoot trefoil proved more productive than white clover when oversown on wet upland pasture in the west of Scotland and exposed to close grazing during 1966–70. A number of introductions were assessed simultaneously at lowland and upland sites as spaced aggregate clumps in 1970–71 and showed variations in growth habit and time of flowering. These collections out‐yielded clover control varieties at the upland site during both harvest years, Chilean material being the most promising in terms of DM yield and recovery after defoliation.

Three New Zealand selections were compared with local material in two new experiments sown on the same day at the same sites and in a spaced‐clump experiment at the upland site. Establishment was adversely affected by prolonged dry weather after sowing, but at the lowland site, probably aided by the germination of hard seed, the plants developed sufficiently to allow DM yields to be determined. The induced tetraploid variety Grasslands Maku was high in seedling vigour and subsequently yielded well at both trial sites, whereas normal diploid varieties established less rapidly, yet produced similar DM yields in the second harvest year. The species clearly shows promise as an oversown legume for improving livestock feed in wet upland pastures.
The influence of date of sowing and seed rate on the production of pure‐sown red clover
Authors: FRAME J. , HARKESS R. D. , HUNT I. V.
Published: April 2006

Hungaropoly tetraploid broad red clover was sown at seed rates of 6, 12 or 18 kg ha‐1 on six dates from April to September 1971. Three crops were harvested in 1972 and one in June 1973.

In 1972, total herbage dry matter yields ranged from 5.22 to 12.22 t ha‐1 and red clover dry matter yields from 3.61 to 11.92 t ha‐1 when meaned over all seed rates. April to July sowing dates gave significantly higher yields than later sowings. In general, August and September sowings gave the lowest red clover contents in a range from 63.2 to 96.5%, the highest digestibilities within a range 61.9 to 65.0% and the lowest crude protein contents in a range 15.5 to 17.3%.

The influence of seed rate was less marked than sowing date. Mean annual yields of total herbage dry matter increased from 9.88 to 10.85 t ha−1 as seed rate was increased from 6 to 18 kg ha−1. Red clover dry matter yields and contents of red clover and crude protein in the total herbage also followed this trend.

The sowing date effects on total herbage yield and content of red clover did not persist into the second harvest year but the seed rate effects were still noticeable.

Plant numbers in spring the first harvest year and hence percentage survival from sowing were depressed by late sowing; plant numbers rose but percentage survival declined as seed rate was increased. The seed rate effects on plant population persisted until spring of the second harvest year but sowing date effects did not.

Better stands of red clover were obtained from sowings made between April and June, when a seed rate of 12 kg ha−1 was adequate. The adverse effects of late sowing cannot be fully compensated by raising seed rates of clover. There was a significant interaction between seed rate and date of sowing. For April‐May sowings, seed rate was not critical. Thereafter, a linear effect of seed rate on yield was discernible.
The assessment of persistence and its application to the evaluation of early perennial ryegrass cultivars
Authors: CAMLIN M. S. , STEWART R. H.
Published: April 2006

Botanical analyses were carried out on the herbage from plots of twelve early cultivars of perennial ryegrass (Lolium perenne) cut in their fourth year and the results related to visual persistence assessments carried out on the cultivars at the end of the second and third harvest years. Persistence assessments were found to be highly and positively correlated with the yields of sown cultivars (r=+0.96***,r=+0.99***) and to be highly and negatively correlated with the yields of unsown herbage species (r =+0.98***, r =−094***). The plots of the less persistent cultivars were invaded by unsown grass species and docks which contributed in varying degrees to total DM yield, reducing the correlation of total yield with persistence. Assessments of botanical composition of swards made at the end of the second year provided reliable predictions of the relative persistence of the cultivars. The results of the investigations indicated that assessment of persistence, as well as yield potential, is fundamentally important in cultivar evaluation.
The spatial distribution of excreta under intensive cattle grazing
Authors: RICHARDS I. R. , WOLTON KAREN M.
Published: April 2006

The spatial distribution of excreta from intensive cattle grazing was recorded and was described by a negative binomial function. This enabled the proportion of a pasture surface affected by excreta to be calculated for various grazing periods. Where the effect of excreta on the sward was short‐lived, as for urine N, or where the total area covered by excreta remained small, as for dung, then little overlapping of effective excreta patches could be expected. Appreciable overlapping of effective patches could, however, occur for the long‐lived urine K effect and this should be taken into account when estimating the proportion of a pasture surface affected.
Nitrogen fixation by white clover in hill pasture
Authors: HAYSTEAD A. , LOWE A. G.
Published: April 2006

An experiment is described in which the amount of nitrogen fixed by the white clover component of a surface‐sown hill sward was determined using small quantities of 15N‐labelled ammonium sulphate. Between 11 July and 22 August 1974 25 kg ha−1 N was fixed. No evidence of a transfer of N from clover to the associated perennial ryegrass was detectable over this period although the N content of the grass growing with the clover was higher. The relative advantages of the isotope technique and the acetylene reduction assay are discussed.
The drying pattern of grass swaths in the field
Authors: CLARK BRENDA J. , McDonald P.
Published: April 2006

The drying pattern of grass swaths was monitored using microclimate techniques during a 48 h summer wilting period of good drying conditions. Swath drying pattem, which is dependent upon the swath energy relations, water relations and resistances to evaporation, was explained in terms of changes in the balance of available energy, ambient vapour pressure deficit and swath internal resistance to water vapour transfer throughout the drying period. A typical drying pattern showed limited swath evaporation between sunrise and 09.00 hours, and rapid evaporation between 09.00 hours and 12.00 hours when available energy and vapour pressure deficit were high and swath resistance to water loss low. Between 12.00 and 18.00 hours, because of a decrease in available energy and increase in swath resistance, swath evaporation was reduced. Between 18.00 hours and sunset swath evaporation was near zero.
The effects of rates of nitrogen application on seven perennial ryegrass varieties
Authors: LEE G. R. , DAVIES L. H. , ARMITAGE E. R. , HOOD A. E. M.
Published: April 2006

The dry matter and crude protein production of the perennial ryegrass varieties S24, S23, Premo, Houba, Barlenna, Melle and Sceempter Pasture at annual nitrogen application rates of 212, 425, 637 and 1062 kg ha−1 were studied for the years 1972–74 inclusive. The DM and CP response curves for the variety Melle were steeper than those for other varieties tested and levelled off at a higher N application rate. The results suggest that Melle is a variety with a genotype capahle of utilizing N more efficiently at higher rates than the other varieties tested.
Grass growth in different parts of England in relation to invertebrate numbers and pesticide treatment
Authors: HENDERSON I. F. , CLEMENTS R. O.
Published: April 2006

Ryegrass swards at fourteeo widely separated sites in England were assessed for yield, botanical composition and invertebrate populations, with and without insecticide treatment during a 4‐year period. Treatment with insecticide reduced the numbers of almost all invertebrate groups sampled and increased grass growth at some time at all but one site. Annual DM output was increased by 0–32% depending upon the site concerned. Evidence is presented which suggests that the yield increases were due to the suppression of aphids, plant‐sucking bugs, stem‐boring fly larvae, and perhaps nematodes.