bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME OBSERVATIONS ON THE BEHAVIOUR AND HILL‐PASTURE UTILIZATION OF IRISH CATTLE
Authors: O'Donnell T. G. , Walton G. A.
Published: April 2006

During June to September 1966 grazing activities of four randomly selected individuals in a herd of 17 non‐lactating, free‐ranging cattle were observed on an Irish hill‐farm of approximately 15 hectares which provided a choice of four distinct vegetative associations. A marked preference for Holcus‐Poa‐Anthoxanthum‐Agrostis sward was noted. Grazing did not take place at night. During daylight it occupied three distinct periods, ceasing shortly after sunset and beginning at dawn.
THE EFFECT OF METHOD OF DETERMINATION OF ACID‐DETERGENT FIBRE ON ITS RELATIONSHIP WITH THE DIGESTIBILITY OF GRASSES
Authors: McLeod M. N. , Minson D. J.
Published: April 2006

The acid‐detergent fibre (ADF) contents of 50 grass samples of known in vivo and in vitro digestibility were determined by hydrolysing with acid for 1, 2, 3,4, 5, and 6 h. The 50 samples used consisted of 6 Lolium perenne, 9 Cenchrus ciliaris, 15 Chloris gayana, 10 Digitaria spp., and 10 Setaria spp. Regression and residual standard deviations (RSD) were calculated for each hydrolysis time for each grass and for all 50 samples.

Increasing the hydrolysis time decreased the RSD for Lolium perenne and Setaria, had no effect on Chloris gayana and Digitaria and increased the RSD for Cenchrus ciliaris regressions. For regressions based on all 50 samples die RSD varied between ±4.8 and 5.0 digestibility units with only minor differences between hydrolysis times. Correcting the ADF for contaminating ash generally increased the RSD.

Changing the acid strength from the 10 N recommended by van Soest (8) did not lead to any major improvement in the RSD for regressions based on Cenchrus ciliaris, but with Setaria the RSD was reduced from ±2.8 to 1.7 digestibility units when 2N acid was used and hydrolysis was extended to 2 h.

It was concluded that unless the optimum conditions for determining ADF for each grass are known then the in vitro technique provides digestibility estimates with a lower error.
STUDIES OF RESPONSE TO FERTILIZER NITROGEN
Authors: Hunt I. V.
Published: April 2006

The effects of 59, 118 or 177 kg N/ha were measured on 7 occasions from 8 to 57 days after application to a perennial ryegrass sward in terms of changes in composition.

The first increase Dt of N significantly raised percentages of CP, non‐protein N, K, P, Ca, Na and Mg and significantly depressed percentages of DM, OM and OM digestihility. The second increment of N resulted in a further rise in the percentages of CP, true protein, non‐protein N, K, P, Ca, Na and Mg; the percentages of DM and OM were further depressed but OM digestihility was not significantly depressed. Percentages of P and Na showed increased responses for the more mature herbage; while percentage non‐protein N showed a more marked response in younger herbage. As herbage matured percentages of OM and Na rose, the latter only from days 16 to 45. All other attributes showed falling percentages to levels which could be inadequate for a 500 kg dairy cow yielding 15 kg milk. CP percentage reached this critical level (1.4% N) at days 37, 45 or 56 given 59, 118 or 177 kg N/ha; P percentage became critically low (< 0.36%) at days 27, 35 or 38, respectively; Mg percentage fell to the critical level (0.12%) at days 23, 35 and 46. Na percentage showed the reverse trend, being deficient (< 0.13%) in the earliest samples and becoming satisfactory from days 23 or 27 at 118 and 177 kg N/ha but it remained inadequate at 59 kg N/ba.
PREDICTING ORGANIC‐MATTER DIGESTIBILITY FROM IN VIVO AND IN VITRO DETERMINATIONS OF DRY‐MATTER DIGESTIBILITY
Authors: Mcleod M. N. , Minson D. J.
Published: April 2006

The DM digestibility (DMD) and organic matter digestibility (OMD) of 36 tropical grass samples were determined both in vivo and in vitro. Regressions relating OMD to DMD were calculated. In vivo OMD=1·02 in vivo DMD+ 0·1, r=0·99. In vitro OMD=1·05 in vitro DMD—4·7, r=0.99. At the same DMD, the in vitro method predicted OMD 2·8 to 3·4 percentage units lower than the in vivo method. This difference was caused by the difference in mean apparent digestibility of the ash, in vitro 71%, in vivo 47%.

In vivo DMD was correlated (r=0·92, P<0·01) with in vitro DMD and the regression relating these two factors had a residual standard deviation of ±1·42 digestibility units. This deviation was reduced to ±1·9 digestibility units when OMD was determined. For both DMD and OMD significant differences were found between grass species in the relation between in vivo and in vitro digestibility.

To overcome biased estimates of OMD it was suggested that conversion equations should be avoided, and that the in vitro method be standardized with samples of known in vivo OMD as similar as possible to those being tested.
Relationship between digestibility and faecal nitrogen in sheep and cows offered herbage ad libitum
Authors: THOMAS S. , CAMPLING R. C.
Published: April 2006

A comparison was made of the digestibility, voluntary intake and concentration of N in faecal organic matter in castrated male sheep and non‐lactating cows offered herbage ad libitum. The sheep ate 22% more herbage DM per kg liveweight than the cows. In general, the sheep and cows digested the organic matter of the herbage to the same extent, although on two occasions significantly higher digestibilities were observed in cows than in sheep. Similar concentrations of N in faecal organic matter in sheep and cows were matched by similar digestibilities of herbage organic matter. Regression equations relating herbage organic matter digestibility to faecal N concentration were not significantly different between sheep and cattle.
The physiology of tiller death in grasses.
Authors: ONG C. K.
Published: April 2006

A reproducible method of causing tiller death on individual ryegrass (Lolium perenne L., cv. S23) plants is described. This was achieved by subjecting whole plants grown previously for 7 weeks in full light (100%) and full nutrient (100%) to either light stress (17.5% or 2.5%) or nutrient stress (10% or 0%) or various combinations of light and nutrient stress. Detailed records were made of tiller appearance, position and weight, and the probability of tiller death was calculated. Analysis of each plant indicated that the smallest tiller, which was often, but not always the youngest, was the most vulnerable when the whole plant was stressed. Tiller position was relatively unimportant in determining survival. The results are discussed in relation to tiller mortality in natural populations and crop communities.
The effect of herbage allowance upon the herbage intake and performance of suckler cows and calves
Authors: BAKER R. D. , ALVAREZ F. , LEDU Y. L. P.
Published: April 2006

Twenty‐four Hereford × Friesian cows and their South Devon cross calves were allocated to three herbage allowances allotted daily for three periods of 8 weeks in a Latin square design. The daily allowances were 17, 34 and 51 g dry matter per kg cow plus calf live weight. Milk production was depressed by 0·2 and 1·2 kg d‐1 at the medium and low allowances. The corresponding falls in liveweight gain were for cows 0·26 and 0·25, and for calves 0·27 and 0·24 kg d‐1. Residual sward height after grazing gave a better indication of the animals' reaction to sward conditions and the management imposed than actual herbage allowance. The quantity per unit area and the composition of material present were important factors influencing intake. Calves were unable to compete with their dams to maintain herbage intake at the lower allowances and therefore are likely to benefit from additional feeding or creep grazing when residual sward height falls below 6cm for periods in excess of 1–2 weeks.
Silage and milk production: a comparison between barley and dried sugar‐beet pulp as silage supplements
Authors: CASTLE M. E. , GILL M. S. , WATSON J. N.
Published: April 2006

Two grass silages made from perennial ryegrass, and with D‐values of 0·216 and 0·255, were offered ad libitum to 18 Ayrshire cows in two feeding experiments. On the control treatment the silages were supplemented with soybean meal only, and on the other two treatments with equal weights of DM from either barley or dried molassed sugar‐beet pulp plus the same weight of soya as on the control treatment. The daily intakes of silage DM were not significantly different on the barley and beet‐pulp treatments, and, on average, the intake of silage DM was reduced by 0·24 and 0·20 kg by feeding 1 kg barley and beet pulp DM respectively.

The daily milk yields were not significantly different on the barley and beet‐pulp treatments with mean values of 19·2 and 19·2 kg per cow respectively compared with 17·2 kg on the control treatment. On the barley and beet‐pulp treatments the fat, SNF, CP and lactose concentrations in the milk and the live weights of the cows were not significantly different. It is concluded that the barley and beet pulp had similar feeding values and replacement rates when used as supplements with grass silage, and that the two feeds were interchangeable on an equal DM basis.
Pest damage to white clover and perennial ryegrass seedlings after reseeding with a slot‐seeder
Authors: CLEMENTS R. O. , BENTLEY B. R. , SQUIRES N.R.W.
Published: April 2006

A high risk of pest damage to seedlings of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) was shown to exist after reseeding with a slot‐seeder. Damage varied between years and sites; white clover appeared to be more affected than perennial ryegrass. Insecticides of feasible commercial use (chlorpyrifos granules and γ‐HCH seed treatment) were found to prevent damage. There was no evidence of phytotoxicity from any of the pesticides studied at the dose rates used in the field.
Value of a rising‐plate meter for estimating herbage mass of grazed perennial ryegrass‐white clover swards
Authors: MICHELL P.
Published: April 2006

A rising‐plate meter was used in a double sampling technique to measure the herbage mass of rotationally grazed perennial ryegrass‐white clover swards over a period of 2 years. The meter was calibrated by developing a linear regression between meter reading and herbage dry matter mass as measured by cutting 0·2‐m2 quadrats to ground level.

There was a strong relationship between meter reading and herbage mass, and correlation coefficients were consistently 0·2 or above. The calibration regression was normally constant for extended periods, especially over the winter and spring. The relationship was more variable over the summer but appeared to follow a pattern that was to some extent repeatable between years. The slope of the regression (kg DM ha‐1 cm‐1) was 312 and 267 in the two winters and reached values of 800 and 452 in the two summers. The calibration relationship was adequately described by a linear model over the winter and spring but there was a tendency for a curved relationship in mid‐to late summer.

The standard pooled regression found with winter ryegrass‐clover swards was not applicable to the more erect prairie grass, and the standard regression overestimated slightly the yield of heavily grazed swards. There was no evidence of a difference in relationship between irrigated and non‐irrigated swards over the summer.

The individual meter readings could be used to develop a useful diagrammatic picture of the changes that occurred in sward structure as the pastures were subjected to different managements and this could be used to illustrate problem areas in pasture management.

The meter was useful in overcoming the problem of variability of herbage mass within paddocks and could give precise estimates of herbage mass, especially when it was possible to use a pooled regression encompassing a large number of calibration cuts. In these cases the meter could be used to detect differences of about 8%.
The effects of temperature and fertilizer nitrogen on the spring growth of tall fescue and cocksfoot
Authors: LEMAIRE G. , SALETTE J.
Published: April 2006

A detailed study of the spring growth curves of two forage grasses, tall fescue and cocksfoot, over three successive years showed a large variability of growth over the vegetative phase. This variability was evident at levels of fertilizer N which were considered to be non‐limiting (60 kg N ha‐1 in autumn plus 120 kg N ha‐1 in February).

At this level of N there was a relationship between yield in the vegetative phase and accumulated temperatures from the last cut in the autumn which was described by a regression common to the three years. The slope of this regression represents the potential growth of a variety. At a lower level of N a separate regression was needed in each year to relate growth to accumulated temperature.

Variation in spring growth was not related to accumulated net radiation. Growth in the reproductive phase was related to accumulated temperature and accumulated net radiation from the 10‐cm ear stage.
Slot‐seeding investigations
Authors: Haggar R. J. , Koch D. W.
Published: April 2006

Red clover cv. Hungaropoly was slot‐seeded into a perennial ryegrass‐dominant sward in April 1979. Glyphosate and paraquat were applied separately as bandsprays each at two doses and at two band widths. Control plots were either slot‐seeded without a herbicide bandspray or received ±150 kg N ha−1 a−1. Red clover establishment was assessed and amounts of dry matter (DM) and total N accumulated were measured at two harvests in 1979 and three harvests in 1980. Bandspraying increased seedling vigour and development and resulted in the eventual replacement of 1 t grass DM ha−1 by an equivalent amount of red clover. Of the treatment variables investigated, bandspray width had the greatest influence on red clover establishment and productivity. The slot‐seeded area, meaned for all treatments, produced a total of 6.40 and 13.16 t DM ha−1 in 1979 and 1980. This was estimated to be equivalent to the all‐grass sward receiving 112 kg N ha−1 a−1 during the second year of the experiment or 238 kg N ha−1 over the 2 years when measured in terms of N yield. Slot‐seeding overcomes several of the problems associated with conventional establishment of red clover.
The production and persistency of different grass species cut at different heights
Authors: JONES E. L.
Published: April 2006

The effect of two heights of cutting (5 and 8 cm) on the dry matter harvested and persistency of a range of different grass species and varieties were monitored over a 3‐year period (1976 to 1978). Dry matter harvested was measured in the second and third harvest year and persistence of sown grass was assessed at the end of the first and third harvest year. The grasses were managed under a frequent cutting system, i.e. simulated grazing. Results showed that at the low cutting height tetraploid hybrid ryegrasses and diploid Italian ryegrasses in the third harvest year gave lower annual dry matter harvests of sown grass and were less persistent than at the high cutting height, whilst, in contrast, perennial ryegrasses gave higher annual harvests of sown grass but persistency was unaffected. In general at the low cutting height varieties of cocksfoot, meadow fescue and tall fescue gave comparatively higher annual harvests of sown grass in the second harvest year but lower yields of sown grass in the third harvest year. A notable exception was Cambria cocksfoot which in the second harvest year gave higher yields of sown grass and was more persistent at the low cutting height.

However, at 5 cm cutting height, the proportions of weed grasses (mainly Poa spp.) in swards sown to tetraploid hybrid ryegrasses and diploid Italian ryegrasses were generally greater, particularly in mid‐season.
A technique to record automatically some aspects of grazing and ruminating behaviour in sheep
Authors: PENNING P. D.
Published: April 2006

The construction of a transducer and the use of a recording system to measure jaw movements of grazing sheep is described, The time spent grazing, ruminating and idling may be measured by this equipment and the data produced automatically processed using a microprocessor which determines each minute whether the animal is grazing, ruminating or idling and also summarizes these data to give total times. The accuracy of this technique in relation to manual observation is discussed.
Defoliation and productivity of a phalaris‐subterranean clover sward, and the influence of grazing experience on sheep intake
Authors: CURLL M. L. , DAVIDSON J. L.
Published: April 2006

Swards of Phalaris aquatica‐Trifolium subterraneum were subjected to four defoliation treatments—zero, low (11 sheep ha−1) and high (22 sheep ha−1) stocking rates, and weekly cutting. At high stocking rate the annual grass Hordeum leporinum dominated while clover was dominant at low and zero stocking rates. Weekly cutting suppressed species other than clover and so failed to simulate grazing.

There were similarities in net herbage production between zero and lightly grazed swards and between heavily grazed and repeatedly cut swards. Net herbage production decreased in the order undisturbed sward < lightly grazed sward < heavily grazed sward < repeatedly cut sward.

When sheep grazed swards where herbage mass was low their daily consumption of herbage, and therefore liveweight change, depended on their recent grazing experience. Sheep accustomed to swards where herbage mass was low ate more because they grazed for much longer each day than unaccustomed sheep, although they selected a diet of similar digestibility.
The estimation of herbage mass of perennial ryegrass swards: a comparative evaluation of a rising‐plate meter and a single‐probe capacitance meter calibrated at and above ground level
Authors: MICHELL P. , LARGE R. V.
Published: April 2006

A rising‐plate meter and a single‐probe capacitance meter were calibrated on perennial ryegrass swards (cultivars S23, Endura, Melle) over the spring and summer (13 March to 14 September 1981). The swards were rotationally grazed by cattle and from mid‐June onwards they were irrigated and cut at 5 cm after grazing to remove rejected herbage. Linear regressions were calculated relating meter readings to herbage dry matter mass as measured by cutting 0–2 m2 quadrats to either 18 mm above ground or to ground level.

The regression for the rising‐plate meter was constant over the spring (slope 275 kg DM ha−1 cm−1) and again over the summer (slope 385 kg DM ha−1 cm−1). The regression for the capacitance meter changed slightly over the spring (slope 11.2 to 14.0 kg DM ha−1 unit reading−1) and was also constant over the summer (slope 20.3 kg DM ha−1 unit reading −1). Correlation coefficients were always above 09 and residual standard deviations ranged from 258–525 in Spring up to 636–918 kg DM ha−1 in summer. Residual standard deviations were lower with the plate meter than with the capacitance meter and were lower with the above‐ground cutting height. Neither meter was able to give accurate results with tall rejected herbage containing a build‐up of senescent material.

Herbage mass below 18 mm was greater on summer than spring swards. When compared with a ground level cut. cutting above ground underestimated herbage mass on summer relative to spring swards; there was also a tendency to underestimate herbage mass on tall pastures relative to short pastures.

There was no evidence of a curved relationship between herbage mass and meter reading with either meter and both meters gave readings related to herbage dry matter mass rather than mass of green herbage or water.
Changes in the structure and physiology of a perennial ryegrass sward when released from a continuous stocking management: implications for the use of exclusion cages in continuously stocked swards
Authors: PARSONS A. J. , COLLETT B. , LEWIS JANINE
Published: April 2006

A perennial ryegrass sward was managed by continuous stocking with sheep (April–September) for 4 successive years after sowing. The sward was grazed to maintain a leaf (lamina) area index (LAI) close to 1.0. Areas of the sward were released from grazing on three occasions: once during summer in the third year after sowing, and twice during spring and summer in the fourth year after sowing. There were marked changes in the structure and physiology of the continuously stocked sward following release from grazing. After several successive years of continuous stocking, the sward comprised a large population of small tillers and the small LAI resulted in consistently low rates of photosynthesis. Following release from grazing, photosynthesis increased markedly as the LAI increased but this change was associated with the loss of a large proportion of the population of tillers. There were seasonal differences in the pattern of changes in photosynthesis and tiller numbers following release from grazing which were not apparent under continuous stocking. The changes in the structure and physiology of the sward following release from grazing suggest that the net accumulation of herbage in areas of sward from which the animals are excluded, for instance using cages, may be an unreliable estimate of production under continuous stocking.
Effect of pH and added ammonium hydroxide on in vitro digestibility of roughages of different origin treated with sodium hydroxide and ammonia*
Authors: LESHEM Y. , GOLDMAN A. , YULZARI A.
Published: April 2006

Ammonia and sodium hydroxide (NaOH) have been used to improve the dry matter (DM) digestibility of roughages or to conserve them. These treatments have had incidental effects on pH alone or both the pH and nitrogen contents of the roughages. in the present study, the effects of pH and NH4OH on the in vitro dry‐matter digestibility (IVDMD) of eight roughages—four legumes and four grasses—were investigated. The pH levels of approximately 5, 7, 9 and 12 were achieved by adding appropriate amounts of NH4OH or NaOH and H2SO4. Nitrogen levels of approximately 20, 30, 40 and 50 g kg−1 on a DM basis were obtained by adding NH4OH. Results of a multiple regression showed that increasing the pH caused a linear increment in IVDMD and that the added NH4OH reduced the increment of IVDMD. The effects of both pH and N on IVDMD were found to be specific to the individual roughage; the response of grasses to both pH and NH3 was greater than that of legumes
The influence of the epidermis on the drying rates of red clover leaf petioles and stems and of Italian ryegrass stems at low water contents
Authors: HARRIS C. E. , DHANOA M. S.
Published: April 2006

Previous results with red clover (Trifolium pratense) leaflets, leaf petioles and stems indicated that the epidermis continued to impose a barrier to water loss at low water contents. Further experiments with red clover leaf petioles and stems suggest that cuticular wax is the epidermal component concerned and that treatments which remove or merely modify this will also increase drying rate. However, when treatments to reduce epidermal resistance were applied to pseudostems and flowering stems of Italian ryegrass (Lolium multiflorum) the initial increase in drying rate produced was not sustained at low water contents. The pseudostems consisted of three layers of leaf material rolled one within the other and the true flowering stems were surrounded by one leaf sheath. Their pattern of response to treatments suggested that these affected only the outer sheath, which produced an initial acceleration in drying rate, but that this was not sustained after the outer sheath was dry because the lower untreated layers dried in a similar way to untreated controls.

The results suggest the possibility of devising practical treatments to increase drying rate at low water contents with crops containing a high proportion of leaf or stem not surrounded by leaf sheath. Devising such treatments for crops with a high proportion of grass pseudostem or flowering stem surrounded by leaf sheath will be considerably more difficult.
Potential pasture production in the uplands of Wales
Authors: DAVIES D. A. , MUNRO J. M. M. , MORGAN T. E. H.
Published: April 2006

Only a very limited number of species, including red fescue (Festuca rubra), perennial ryegrass (Lolium perenne), timothy (Phleum protense) and white clover (Trifolium repens) are considered as suitable for wet hill land. Detailed comparison of red fescue, perennial ryegrass and timothy on contrasting acid brown earth and stagnogley soils from 1966 to 1969 at Pant‐y‐dŵr Hill Centre (305 m OD) highlighted the advantages of red fescue in annual DM production and its more even distribution over a longer growing season but also indicated drawbacks of slow initial establishment and lower feed quality. In vitro DOMD of red fescue averaged 645 g kg−1 over the year compared with 690 g kg−1 for perennial ryegrass and timothy. Assessment of a narrow range of species under surface seeding conditions on a stagnogley soil from 1971 to 1975 confirmed the value of red fescue in DM production and persistence. The results are discussed in relation to the characteristics required in herbage species for hill land improvement.
Grazing cycle length and silage supplementation: effects on the performance of lactating ewes with twin lambs
Authors: ORR R. J. , NEWTON J. E.
Published: April 2006

Masham ewes, stocked at 20 ewes ha−1, reared twins at pasture in 1979 and 1980 and were rotationally grazed around six paddocks. There were three lengths of grazing cycle (18, 30 or 42 d) and the ewes at pasture were either offered silage ad libitum (S) for 8 weeks of lactation or they were not supplemented with silage (N). By feeding silage, S ewes and lambs moved into greater herbage masses (3735 u. 3390 kg organic matter (OM) ha−1), but there was little effect on net herbage accumulation (10.5 v. 10.0 t OM ha−1) and herbage intakes per ewe were similar (2.31 v. 2.27 kg OM d−1) over the 7‐month grazing season. During the period of silage supplementation, total intake was 19% higher for S than N ewes, lamb growth rates were slightly higher (280 v. 273 g d−1) and the ewes lost less weight (−78 v−96 g d−1).

For 18‐, 30‐ and 42‐d grazing cycles respectively the herbage masses before grazing were 2825, 3620 and 4240 kg OM ha−1; net herbage accumulations were 9.8, 10.4 and 10.6 t OM ha−1; mean daily herbage intakes by each unit (ewe+lambs) were 2.22, 2.35 and 2.30 kg OM and lamb growth rates from birth to weaning at 20 weeks were 205, 204 and 204 g d−1.

Frequent grazing of relatively light herbage masses or infrequent defoliation of heavier herbage masses made little difference to sward or animal performance. It is concluded that, at this stocking rate, different grazing cycles of 18, 30 or 42 d do not affect the performance of lactating ewes.
Some changes associated with the field drying of lucerne and timothy
Authors: ALLI I. , ROBIDAS E. , NOROOZI E. , BAKER B. E.
Published: April 2006

Lucerne (approximately 10% flowering, 270 g dry matter kg−1) and timothy (boot stage, 310 g dry matter kg−1) were harvested and allowed to wilt for a period of 52·5 h. During the early stages of wilting of lucerne there were increases in the proportion of leaf material (dry weight basis), as well as increases in total available carbohydrate and water soluble carbohydrate concentrations. Approximately 50% of the leaf material in lucerne and in timothy was lost after a drying period of 52·5 h and after tedding and raking operations prior to baling of the hay. This resulted in considerable reduction in the protein content of both lucerne and timothy.
Growth responses to lime and fertilizers and critical concentrations in herbage of white clover in Scottish hill soils
Authors: RANGELEY ANNE , NEWBOULD P.
Published: April 2006

The responses in dry matter (DM) production and changes in nutrient concentration in the shoots of white clover (cv. New Zealand Grasslands Huia) to additions of lime, N, P, K and Mg were investigated in pot and field experiments in a deep peat soil and to additions of N, P, K in two other hill soils in pot experiments. DM production and nutrient concentrations were assessed also for perennial ryegrass in the field experiment. There was no response by white clover to N, but in all soils, and in particular a deep peat, production of shoot DM was increased greatly by lime, P and K, and slightly by Mg. Interactions between lime and P and between P and K were observed. Critical concentrations of nutrients (g kg−1) for white clover appeared to be about 2.0 for P, 10·15 for K and 20 for Ca. Herbage production and nutrient contents of ryegrass and white clover grown on a deep peat in the field suggests that critical concentrations may possibly help to diagnose the need fur maintenance fertilizer dressings.
Effect of silage additives and wilting on silage fermentation, digestibility and intake, and on liveweight change of young cattle
Authors: HAIGH P. M. , PARKER J. W. G.
Published: April 2006

Data from thirty‐three experiments conducted at three ADAS Experimental Husbandry Farms were used to compare unwilted non‐additive‐treated silage with silage treated with formic acid, a formalin and formic‐acid mixture, a calcium‐formate and sodium‐nitrite mixture, a formalin and sulphuric‐acid mixture and wilted silage made without or with formic acid or a formalin and formic‐acid mixture.

Formic acid significantly reduced pH and wilting significantly increased silage pH compared with other treatments. Formalin‐acid mixtures significantly reduced pH compared with untreated silage. Formic acid in conjunction with formalin or wilting significantly increased water‐soluble carbohydrate in silage compared with other treatments except wilting. Formic acid either alone or combined with either formalin or wilting significantly reduced silage butyric acid content compared with other treatments. Formic acid treatment either alone or combined with formalin significantly increased lactic acid as a proportion of total silage acids compared with other treatments except sulphuric acid‐formalin.

All treatments significantly increased silage dry matter (DM) intake compared with untreated silage and intakes of wilted silage were significantly greater than of unwilted silage. Daily liveweight gains on all treatments were significantly higher than on untreated silage.

Herbage water‐soluble carbohydrate necessary for successful preservation as silage without additive use was approximately 30 g (kg DM)−1 and with additives containing formic acid it was approximately 25 g (kg DM)−1.

It is suggested that formic acid application to unwilted silage either alone or in conjuction with formalin was the best treatment for improving subsequent preservation as silage, and that animal performance was enhanced by addition of acid‐formalin additives to unwilted herbage or formic‐acid application to unwilted or wilted herbage.
Alfalfa establishment without tillage as influenced by insecticide and vegetation suppression
Authors: ROTH G. W. , WOLF D. D. , HAGOOD E. S.
Published: April 2006

Conventional alfalfa (Medicago sativa L.) establishment methods may create considerable potential for erosion. Conservation tillage practices that result in stand establishment without disturbing the soil greatly would be beneficial in reducing soil losses. Thus, field experiments were conducted to evaluate the success of alfalfa establishment without tillage in a perennial grass sod. Variables included rate of carbofuran (2, 3‐dihydro‐2, 2‐dimethyl‐7 benzofuranyi methylcarbamate) insecticide and control of existing vegetation with chemicals. Establishment without tillage was compared with a conventional method of establishment. Carbofuran at 1.1 kg ha−1 applied in the row with the seed, when compared with a control, increased yields during the year of planting but no response was observed in the year after seeding. Yields of alfalfa established without tillage using either glyphosate (N‐(phosphonomethyl)glycine) or paraquat (1,1‐dimethyl‐4, 4‐bipyridinium chloride) for sod suppression were equivalent to or better than yields obtained from conventional sowings except for the 2 April sowing. Paraquat was more effective for tall fescue (Festuca arundinacea Schreb.) suppression when applications were made on 26 April after spring tiller emergence was complete than on 2 April when some of the tillers may have been protected from the spray by basal sheath tissue.

Broadcast application of paraquat resulted in higher alfalfa yields and decreased non‐alfalfa components due to more complete sod suppression than application in bands over the row.
The effect of temperature on the spring growth of perennial ryegrass at three contrasting sites
Authors: BAKER ANNE‐MARIE , YOUNGER A.
Published: April 2006

The effect of temperature on the spring growth of perennial ryegrass swards was studied at three contrasting sites. Two of these were situated on land restored after opencast coal mining, one of which had been drained. The third was on undisturbed land of the same soil type. Rates of leaf extension were measured in an attempt to give an early indication of differences in plant growth in the spring of 1982.

Spring growth started earliest on undisturbed land. On the restored land drainage proved beneficial, for although the onset of growth was delayed compared to the undisturbed site the subsequent rates of growth were similar. Both the onset and the rate of growth were slower on the undrained site. Highly significant relationships existed between leaf extension rate and soil temperature at each site. However, when sites were compared, differences in soil temperature could only partly explain observed differences in growth rate between sites.

It was concluded that some factor other than soil temperature was responsible for the difference in spring growth between the undisturbed site and the undrained opencast site in this experiment.
Concentrate supplementation of grazing dairy cows. 2. Effect of concentrate composition on herbage intake and milk production
Authors: MEIJS J. A. C.
Published: April 2006

The effect of feeding either traditional concentrates containing starch or high quality fibrous concentrates on the performance of grazing dairy cows was examined in a trial in which cows were given concentrates with either 350 g starch and sugars (kg dry matter (DM))‐1 (high‐starch) or 100 g starch and sugars (kg DM)‐1 (high‐fibre). The swards used consisted predominantly of perennial ryegrass and were usually aftermaths following cutting. Each area was grazed for 3 or 4 d at each grazing and a two‐machine sward‐cutting technique was used for estimating herbage intake.

The effect of concentrate composition on the herbage intake of grazing cows at a high daily herbage allowance of 28 kg OM above 4 cm cutting height was investigated in 1983 and 1984. With 54 kg OM d‐1 of high‐starch concentrates the mean herbage intake was 11·5 kg OM d‐1 per cow while cows fed 5.3 kg d‐1 of high‐fibre concentrates consumed on average 12–6 kg OM d‐1. The mean substitution rate of herbage by concentrates was reduced from 0·45 kg herbage OM (kg concentrate OM)‐1 with the high‐starch concentrate to 0·21 with the high‐fibre concentrates.

The effect of the treatments on milk production was studied in 1984. The cows consumed 5·5 kg OM d‐1 as concentrates and grazed at a lower herbage allowance of 19 kg OM above 4 cm cutting height. With high‐fibre concentrates milk production and 4% fat‐corrected milk production were 13 and 1·8 kg d‐1, respectively, higher than with the high‐starch treatment. The daily live weight gain with the high‐starch concentrates was 0·17 kg per cow more than with the high‐fibre concentrates.
Effect of grazing severity on grass utilization and milk production of rotationally grazed dairy cows
Authors: MAYNE C. S. , NEWBERRY R. D. , WOODCOCK S. C. F. , WILKINS R. J.
Published: April 2006

Two experiments were carried out to examine the effects of grazing severity on the performance of January/February calved British Friesian dairy cows. In Experiment 1, three groups of cows were rotationally grazed across twenty‐four one‐day paddocks with high (H), medium (M) or low (L) herbage allowances. Cows on treatment M were offered a daily herbage allowance designed to achieve a residual sward height of 50 mm, assessed by a rising‐plate sward stick. The daily herbage allowance (g organic matter (kg live‐weight)‐1 on treatments L and H were 0.30 below and above that for M, respectively, to give residual sward heights of 42 and 59 mm. In Experiment 2, three groups of cows were grazed across twenty‐four one‐day paddocks to obtain residual sward heights of 50 mm (severe), 60 mm (moderate) and 80 mm (lax).

Average milk yields on the L, M and H treatments in Experiment 1 were 11.8, 14.6 and 14.5 kg d,‐1 and in Experiment 2 they were 13.7, 16.0 and 17.0 kg d‐1 on the severe, moderate and lax treatments, respectively. The results indicate that the critical herbage height below which milk production per cow declines may vary with the production potential of the animal. There were no significant treatment effects on milk composition.

Milk output ha‐1 and utilized metabolizable energy ha‐1 were greatest with the low herbage allowance in Experiment I and the moderate treatment in Experiment 2. Net herbage accumulation on the severe treatment in Experiment 2 was 30% lower than that on the lax treatment, as a result of treading damage in early season.

It is concluded that, in a rotational grazing system, a reasonable compromise between sward utilization and animal performance can be achieved by grazing January/February calved cows to a residual sward height of 60 mm as assessed by a rising‐plate sward stick. This is equivalent to a sward surface height of about 80 mm.
Slot‐seeding investigations. 6. A comparison of the spread and productivity of different white clover varieties introduced into permanent pasture
Authors: WILLIAMS E. D. , HAYES M. J.
Published: April 2006

Seeds of six cultivars of white clover were sown in 1983 in slots in tares of permanent pasture in soil‐filled tanks in spring and in small plots in the field during midsummer. The clover cultivars investigated were the large‐leaved Olwin and Milk nova, the medium‐leaved Grasslands Huia and Aberystwyth S100, and the small‐leaved Kent Wild White and Aberystwyth S184. Seeds from an indigenous clover population were also sown in the tanks. All herbage was defoliated at three‐ to six‐week intervals to simulate rotational grazing and assessments were made until autumn 1984.

Leaf and stolon production and spread of stolons from the slots were more rapid in Milkanova, S184, Huia and Kent than in Olwen and S100 In the tanks, harvested yields of clover leaf and petiole were largest for Milkanova and Olwen and least for the indigenous population; both Olwen and S100 had a smaller percentage of their total weight outside the slot area than had the other varieties. In the field, Milkanova greatly out yielded all other varieties and S100 yielded the least, contributing 48 and 27%, resf actively, to total herbage yield. The yield of grass differed little between varieties in tanks but in the field it tended to be higher with the smaller than with the larger‐leaved varieties. Total herbage yield was largest for Olwen and Milkanova in tanks and for Milkanova in the field. The greatest weight of stolons in tanks was produced by Olwen and in the field by Olwen and Kent, but the greatest length of stolons and number of nodes in both environments occurred in the smalt‐leaved varieties, especially Kent. Least length of stolons and fewest nodes in the tanks were produced by Olwen and in the field by Milkanova.

It was concluded that all the varieties investigated could be successfully slot‐seeded into permanent pastures but that the choice of variety will depend on subsequent use and management of the resulting swards.
The practical and economic consequences of integrating maize with grass production on dairy farms in southern England: a computer simulation
Authors: DOYLE C. J. , PHIPPS R. H.
Published: April 2006

A mathematical model of the production, harvesting and utilization of maize and grass silage on a dairy farm with an autumn‐calving herd is described. Using the model the comparative costs and benefits of growing and feeding maize in place of grass silage are examined for three sites in southern England. It is concluded that a winter milk production system based on maize rather than grass should improve profits by at least £30, and possibly by as much as £80 cow‐1. This financial improvement is attributable to higher feed intakes and lower harvesting and fertilizer costs with maize silage. Simulating the results over a 10‐year period also revealed that the switch from grass to maize should lower the risks in terms of the annual variability of silage yields and herd profits. Furthermore, it would appear unnecessary to completely turn over from grass to maize production to realize a significant financial benefit. Setting aside just 25% of the conservation area to maize and feeding a mixture of maize and grass silage is projected to increase profits from winter milk production by £30 to £45 cow‐1.
Ingestive behaviour of beef cattle grazing alfalfa (Medicago sativa L.)†
Authors: DOUGHERTY C. T. , SMITH E. M. , BRADLEY N. W. , FORBES T. D. A. , CORNELIUS P. L. , LAURIAULT L. M. , ARNOLD C. D.
Published: April 2006

Development of simulation models of grazing beef cattle requires measurement of the components of the ingestive process and the establishment of relationships between these components and the structure of the sward. The ingestive behaviour of eight half‐sib Angus steers (live weight (LW), x̄= 270 kg) grazing alfalfa (Medicago sativa L.) was studied at three stages of maturity (26, 40 and 47 days of regrowth) and at four allowances of herbage dry matter (DM) (1·0, 1·5, 20 and 2·5 kg per 100 kg LW) at each of two daily grazing sessions. A tethering system of grazing was used in which the experimental unit was a tethered steer and its plot for one grazing session. Grazing sessions commenced at 08.00 and 14.00 h EDT. Intake (DM) increased linearly from 1·98 kg per steer session at a DM allowance of 1 kg (100 kg LW)−1 to 2 89 kg steer session at an allowance of 2·5 kg (100 kg LW) −1 as utilization of herbage declined linearly from 0·69 to 0·43. Herbage DM in take per bite increased from 1 0 g at 1 kg (100 kg LW) −1 allowance to 1·5 g at 2·5 kg (100 kg LW) −1 allowance. Rates of biting were not affected by herbage allowance and averaged 21 bites min−1. Dry matter intake increased from 1·77 to 3 41 kg per steer session as the alfalfa matured and herbage mass changed from 1500 to 4656 kg ha−1. Mean rates of biting were 24 bites min−1 for steers grazing the youngest alfalfa and 16 bites min−1 for steers on the oldest forage. Herbage DM intakes per bite were 1·1 g and 1·7 g at the same stages. Rates of DM intake approached 2 kg h−1 and maximum daily DM intake was estimated at 2 75 kg (100 kg LW) −1. Intake of alfalfa was limited by allowance and mass of herbage above a canopy horizon of 20 cm and, to a lesser extent, by the length of fast.
Forage quality and animal selection of Arachis pintoi in association with tropical grasses in the eastern plains of Colombia
Authors: LASCANO C. E. , THOMAS D.
Published: April 2006

A small plot grazing trial was conducted in the Eastern Plains of Colombia to assess seasonal forage quality and selection by oesophageal‐fistulated steers of Arachis pintoi associated with four Brachiaria species. Quality of the legume was high in terms of leaf crude protein (CP) (17%) and in vitro dry matter digestibility (IVDMD) (62%) but varied with season of the year. Associated grasses bad high average leaf CP levels in the dry (7.8%) and wet (98%) seasons. The legume content in the forage on offer was high and varied, from 28% in the dry season to 58% in the wet season. Corresponding values m the diet selected were 37%. and 60%, indicating that animals selected legume in a slightly higher proportion than was present in the total forage on offer. This was further confirmed by selection indices greater than 0–5 in three of the four associations and by a selection index of 0–56 when pooling the data for the four pastures. Increased grass quality and high legume selection resulted in a high quality diet in the dry (CP 9 7%; IVDMD 61 %) and wet (CP 156%; IVDMD 62%) seasons. The results indicated that A. pintoi is a high quality legume, well accepted by grazing cattle throughout the year in the savannas.
Leaf age structure and canopy photosynthesis in rotationally and continuously grazed swards
Authors: PARSONS A. J. , JOHNSON I. R. , WILLIAMS J. H. H.
Published: April 2006

The leafage structure of ryegrass canopies and its role in canopy photosynthesis were compared under continuous and rotational grazing by sheep. Under continuous grazing, an increase in the intensity of grazing increased the proportion (by leaf area) of young leaves in the sward. A mechanistic mathematical model was used to demonstrate how this may have arisen, even though it would largely have been the young leaves that were eaten.

However, the observations do not confirm the hypothesis that continuously grazed swards have a characteristically greater proportion of young leaves, and so a greater photosynthetic potential, than rotationally grazed ones. The proportion of young leaves increased during regrowth following severe rotational grazing (residual LAI < 05) and the photosynthetic potential of the canopy became greater than under continuous grazing.

A model of canopy photosynthesis was used to demonstrate that the observed difference in the proportion of young leaves alone was unlikely to account for all the differences in canopy photosynthesis between managements, and further differences in canopy structure were evaluated. Despite the delay in the restoration of leaf area following severe grazing in a rotation, the total photosynthetic uptake of a system involving some 12–13 days regrowth and 3 days grazing exceeded that of a well‐utilized continuously grazed sward. Re growths of longer duration led to progressively greater total photosynthetic uptake, though this was not considered synonymous with greater yield.
The chemical composition and nutritive value of grass silages prepared with no additive or with the application of additives containing either Lactobacillus plantarum or formic acid
Authors: ROOKE J. A. , MAYA F. M. , ARNOLD J. A. , ARMSTRONG D. G.
Published: April 2006

A mixture of perennial and hybrid ryegrasses(234 g DM kg‐1) was forage harvested and ensiled after a 24‐h wilt in good ensiling conditions in 2‐t capacity silos with no additive application (control) or with the application of either Lactobacillus plantarum, 4 × 106 (g fresh weight of grass)‐1, or of 31 formic acid t‐1. Sufficient 2‐kg capacity laboratory silos were also filled with grass to monitor the changes in chemical composition of the ensiled grass with time. In laboratory silos, inoculation with L. plantarum resulted in a more rapid fall in silage pH (p < 0.001) and a more rapid production of lactic acid (P < 0.001) than in the control silage. At the end of the storage period (laboratory silos, 80 d; 2‐t silos, 200‐300 d), the inoculated silos had lower pH (p ammonia‐N (g kg N1) and acetic acid contents (p < 0.01) and higher water soluble carbohydrate (WSC), lactic acid (P<00.1) and ethanol (p < 0.05) contents than the control silage. The formic acid‐treated silage had significantly lower contents of ammonia‐N (g kg N‐1, p < 0.05), acetic and tactic acids (p<0.01) and higher contents of WSC and ethanol (p < 0.01) than the control silage. When fed to wether sheep, the digestibilities of DM, organic matter and gross energy were not altered by additive treatment. The digestibility of modified acid‐detergent fibre was lower for both the inoculated (P < 0.01) and formic acid‐treated silages (p < 0.05). However, N retention was improved (p < 0.05) by both additive treatments. Silage intake was improved (p < 0.01) by additive treatment from 53.4 (control) to 58.0 (inoculated) and 60.4 (formic acid) g DM (kg live weight0.75)‐1d‐1.