摘要:

AbstractThree silages were produced by harvesting grass using either a flail (F), double‐chop (DC) or a precision‐chop (PC) forage harvester. Each silage was ensiled unwilted and with formic acid additive applied at the mean rate of 2·2 1 t‐1of grass. All three silages were well preserved and had mean particle lengths of 54, 49 and 26 mm and digestible organic ma er in dry ma er (DOMD) values of 0·67,0·66 and 0·66 for the F, DC and PC silages, respectively.The three silages were offeredad libitumto three groups each of 21 British Friesian cows, with a mean calving date of 29 January, from day 8 of lactation until 9 April. Within each silage group all cows were offered 4·1 kg dry ma er (DM) d‐1of a control supplement divided equally in two feeds and given during milking. In addition, 24 kg DM d‐1of the control supplement (C), a high protein supplement (HP) or a supplement containing methionine hydroxy analogue (MHA) were given at midday. The mean crude protein contents of the total supplementary feeds given were 193 253.and 195gkg for the C, HP and MHA treatments, respectively.The treatment effects showed no significant interactions between silage harvesting system and type of supplement. Silage harvesting system influenced milk yield, with the mean yields over the final 21 days of the experiment being 26·1, 27·4 and 25·5 kg d‐1for the F, DC and PC silages, respectively, and the difference between DC and PC achieved significance (P<0·05). However, the milk from cows given DC had a significantly lower concentration of fat (P<0·01) and silage harvesting system had no effect on the yield of fat or protein. The type of supplement had no significant effect on milk yield, with the mean yields over the final 21 days of the experiment being 264, 267 and 259 kg d‐1for the C, HP and MHA su

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01785.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of management on dry matter yield and persistence of eight cultivars was assessed over a 3‐year period (1978–80) under integration of sheep grazing and simulated sheep grazing with cutting for conservation, and the two cutting frequencies used in the National List trials. A high correlation was obtained in the first and second harvest years between managements in respect of annual production, the ranking order of yield being similar for the range of cultivars. In the third harvest year yield correlation and persistence between sheep grazing and simulated sheep grazing was high and similar to previous years, but all other yield and persistence correlations were considerably reduced. A major effect of frequent cutting management used in the National List trials was the increase in the proportion of unsown grasses (mainlyPoaspp.) in the swa

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01786.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn experiment was carried out during 1982 in which the effects of three differing harvesting systems on the field losses occurring during the conservation of grass as silage were examined. The treatments were either (a) harvesting herbage directly by means of a flail harvester (unwilted flail, UF), or (b) pre‐cu ing of herbage with a rotary drum mower and lifting using a precision‐chop forage harvester with wilting (WP) and without wilting (UP). Herbage was harvested on 26 May, 21 July and 7 September 1982. The mean yields of herbage produced from plots harvested by the three systems were not significantly different, with dry ma er (DM) yields of 12470, 12300 and 12230 kg ha‐1for the UF, UP and WP treatments respectively. However, field losses with the UP and WP treatments were greater than with the UF treatment (P<0·01). As a result the yields of herbage ensiled with the UP and WP treatments, 11690 and 11320 kg DM ha‐1respectively, were significantly lower than with the UF treatment, 12710 kg DM ha‐1(P<0·05). Wilting of first cut herbage for a period of 72 h resulted in a significant reduction (P<0·05) in digestible organic ma er (DOM) concentration (determined in vitro), whereas small increases in DOM concentration were observed following wilting of second and third harvest material.It is concluded that, even under favourable weather conditions, both pre‐cutting and wilting of herbage prior to harvesting can result in considerable losses of nutrient

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01787.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractTo determine whether leatherjackets might be controlled by application of a pesticide in summer, before oviposition by crane flies, chlorpyrifos was applied to perennial ryegrass (Lolium perenne) swards on dates from July to September in anticipation of leatherjacket infestation. Subsequent winter population estimates showed that leatherjacket numbers had been reduced by at least 85% by 0·72 kg chlorpyrifos ha‐1applied on 13 July, and by 0·60 kg ha‐1applied on 3 August or later.The significance of leatherjacket control by pesticide application on these dates is discussed in relation to previously recorded effects of pesticide treatment on other known pests. It is concluded that control of all common arthropod pests of proven significance in established grassland may be achieved with one application of pest

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01788.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractTwo experiments are reported. In the first experiment the amino acid compositions of rumen bacteria and protozoa isolated from sheep given a diet of grass silage were compared with those taken from sheep given a diet of hay and barley; four sheep were assigned to each diet. There were no significant differences (P<0·05) between diets in the amino acid compositions of the microbial fractions and bacterial contents of α‐ɛ‐diaminopimelic acid were also similar for both diets.In the second experiment the digestion of a grass silage and barley diet (65:35; 135 g CP (kg DM)‐1) was studied using four non‐lactating Ayrshire cows fitted with cannulae in the rumen and in the proximal duodenum. The mean N intake was 154 g d‐1and the corresponding duodenal flow was 126 ± 10 g d‐1indicating that 0·21±0·07 of the N intake was absorbed between the mouth and the duodenum. The mean rumen NH3‐N concentration was high, 297 g litre‐1, and the mean rate of microbial protein synthesis in the rumen was low, 17 g microbial N (kg OM apparently digested in the rumen)‐1. There was a low content of bacterial N in the non‐ammonia N at the duodenum (mean proportion 0·52±005) and low concentrations of methionine and lysine in the duodenal digesta protein. The results are discussed in relation to previously published data on the digestion of silage diets in sheep and to the utilization of silage diets for milk production in the cow.It is concluded that with silage diets the supply of methionine and lysine to the duodenum is likely to be low because of the low rates of microbial protein synthesis in the rumen and that in cows those two amino acids may be

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01789.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractFour experiments were carried out to evaluate effluent from grass silage as a feed for beef cattle. Castrated male cattle (steers) with mean initial live weights of 380,460 and 400 kg in Experiments 1–3 were offered effluent, in addition to a diet of grass silage givenad libitumand supplemented with cereal‐based concentrates. The cattle readily consumed effluent in preference to fresh water, the mean intake over the three experiments being 12·71 per head daily containing 0·77 kg dry matter (DM). Supplementation with effluent did not affect silage DM intake and increased total DM intake by 10%. Digestible energy concentrations of 13·1 and 16·6 MJ kg‐‐1DM and organic matter, respectively, were determined for effluent in Experiment 4. There were no problems of ill health in any of the 69 cattle which were offered effluent. It is concluded that fresh or well‐preserved stored effluent from grass silage is readily consumed by beef cattle, is of high nutritive value and could enable savings to be made in tot

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01790.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA study is reported on the voluntary intake and digestibility by sheep of five lines ofCenchrus ciliariswhen grown as swards and cut at six different stages of growth. Previous studies withC. ciliarisgrown in small rows had shown large differences between these lines in grazing preference by cattle. The ranking order for preference wasline31>10 = 23>30 = 36.When offered singly to sheep in pens the five lines could be divided into three groups according to their voluntary intakes. Lines 10 and 30 had the highest mean daily intakes of 56·1 and 57·6 g (kg W)‐0·75compared with lines 23 and 36 with low mean intakes of 48·5 and 48·6 g (kg W)‐0·75. Line 31 was intermediate with a mean intake of 543 g (kg W)‐0·.Mean dry matter digestibility of the five lines ranged from 0·577 to 0·597%. Lines 10 and 30 had the lowest digestibility. The difference in intake between the five lines was positively correlated with their proportion of leaf (r= 0·97). Low‐intake lines (23 and 36) also had the highest proportion of seed head.It was concluded that selection ofC. ciliarison the basis of preference by cattle in a cafeteria study provided no useful guide to voluntary intake when the different lines were grown, cut, dried, chopped and fed se

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01791.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractVoluntary intake andin vivodigestibility of herbage harvested from five indigenous communities–Agrostis‐Festuca, NardusandMoliniagrasslands andEriophorum vaginatum‐andTrichophorum caespitosum‐dominated varieties of blanket bog–and also from sownLolium perenneandTrifolium repensswards were measured over two years. First growths of each sward were harvested at three stages of maturity and stored at — 20°C before feeding. Voluntary intake was measured while feedingad libitumto 15% excess of the intake on the previous day and digestibility when feeding at 80% of voluntary intake.There was a common positive relationship (r2= 0·86***) between intake (adjusted for year of feeding, range 72·8–16·7 g organic matter (kg LW)0·75d‐1) and organic matter digestibility (range 0·796–0·371), coveringLolium perenneand most of the indigenous communities. However, there were significant differences between the regressions of intake on the concentration of neutral detergent fibre for ryegrass and the indigenous communities, and also between the regressions for individual communities.The results demonstrated the general value of organic matter digestibility as a predictor of intake potential, and the high digestibility and intake potential of immature vegetation from the grass and

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01792.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractLucerne (DM 236 g kg‐1, WSC 49 g (kg DM)‐1) was ensiled in test‐tube silos with or without either glucose or fructose and with or without one of two commercial inoculants. The WSC content of the forage as ensiled was too low to obtain a well preserved untreated silage. By day 4 the pH values of the silages with added sugar or inoculant were significantly lower (P<0·001) than the control silage. A satisfactory fermentation was attained only in the silages to which sugar and an inoculant had been added. These silages had a lower pH, more protein‐N (P<0·001), less ammonia‐N (P<0·001), a faster increase in counts of lactic acid bacteria, and decrease in counts of coliforms than the other silages. Homo‐fermentative lactic acid bacteria dominated the fermentation in the inoculated silages while leuconostocs dominated the early stages of fermentation in the control silages. The results indicate that if there is insufficient sugar in the original crop, then the bacteria in an inoculant will not be able to produce enough lactic acid to lower the pH to an acceptable level. This has important implications for the ensilage of lucerne and other highly buffered l

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01793.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractOver a 24‐week period, three groups of dairy cows were continuously stocked at 8, 10 or 12 cows ha‐1between morning and afternoon milkings, and overnight were housed and offered grass silagead libitum.Due to a prolonged drought, sward heights only averaged 4·1 cm.The increase in daytime stocking rate led to a decline in herbage intake, and increases in silage intake. At the highest stocking rate (12 cows ha‐1), the silage intake failed to compensate for the reduced herbage intake. Consequently the total dry matter and estimated metabolizable energy intakes were lower than for the 8 and 10 cows ha‐1treatments. Milk yields and milk composition were not significantly affected by treatment but the 12 cows ha‐1stocking rate gave the lowest milk and milk solids yields.The utilized metabolizable energy (UME) on the grazed swards was greatest for the 10 cows ha‐1treatment. The sward cut to provide the silage had a UME level (GJ ha‐1) 32% greater on average than the grazed swards during the same growth period. The total areas utilized for grazing and silage production for 8, 10 and 12 cows ha‐1were 0·240, 0·224 and 0·215 ha respectively. Fat and protein yields per unit area were greatest for th

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1986.tb01794.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY