A simple factorial grazing experiment measured on 27 occasions

AbstractThe effect of the duration of grazing (experiment 1) and starvation time and placement in the rumen of inert bulk material before grazing (experiment 2), on the rumen content ferment ability, was investigated by means of measuring cumulative gas production. In experiment 1, a comparison was made of four durations of grazing (1, 1·75, 2·50 and 3·25 h) after overnight starvation. Rumen samples taken from the cows after 1 h of grazing had higher values of total accumulated gas with less (P < 0·05) time required to reach the maximum fermentation rate than cows grazed for 3·25 h. Following grazing, a 7·75·h starvation period was imposed on the four treatments. The extent of fermentation was significantly lower (P < 0·01) after starvation than immediately after grazing (49·7 v. 60·8% of incubated dry matter (DM), respectively). Experiment 2 consisted of a factorial combination of two durations of starvation before grazing (16·5 (LS) and 2·5 (SS) h) with the presence or absence in the rumen of 12·5 kg of a synthetic indigestible material. Before grazing the total accumulated gas production was less (P < 0·05) for the LS than for the SS cows. After the grazing session, the total gas of rumen samples from the LS cows was significantly higher (P < 0·05) than for the SS cows.This was in agreement with the observed higher DM intake during grazing and DM rumen pools after grazing in LS cows. For both starvation periods, the presence of inert rumen bulk led to a higher total gas, a shorter half-time and less DM left unfermented. The measurement of fermentation kinetics by cumulative gas production was suitable to detect changes in rumen content fermentation patterns due to the clearance of material from the rumen (effect of starvation) or DM intake during the grazing sessions.

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Root traits predict decomposition across a landscape-scale grazing experiment

New Phytologist ◽

10.1111/nph.12845 ◽

2014 ◽

Vol 203 (3) ◽

pp. 851-862 ◽

Cited By ~ 39

Author(s):

Stuart W. Smith ◽

Sarah J. Woodin ◽

Robin J. Pakeman ◽

David Johnson ◽

René van der Wal

Keyword(s):

Root Traits ◽

Landscape Scale ◽

Grazing Experiment

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Central Appalachian Hill Land Pasture Evaluation Using Cows and Calves. I. Ordinary and Generalized Least Squares Analysis for an Unbalanced Grazing Experiment 1

Agronomy Journal ◽

10.2134/agronj1983.00021962007500060005x ◽

1983 ◽

Vol 75 (6) ◽

pp. 865-871 ◽

Cited By ~ 5

Author(s):

J. C. Burns ◽

F. G. Giesbrecht ◽

R. W. Harvey ◽

A. C. Linnerud

Keyword(s):

Least Squares ◽

Generalized Least Squares ◽

Grazing Experiment

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Evaluating the adaptability of herbage species to environmental variation through a long-term grazing experiment

Grassland Science ◽

10.1111/j.1744-697x.2005.00038.x ◽

2005 ◽

Vol 51 (4) ◽

pp. 287-295 ◽

Cited By ~ 2

Author(s):

◽

Masae Shiyomi ◽

Shigeo Takahashi ◽

Tadakatsu Okubo ◽

Tsuyoshi Akiyama ◽

...

Keyword(s):

Environmental Variation ◽

Grazing Experiment

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Turnips and protein supplements for lactating dairy cows

Australian Journal of Experimental Agriculture ◽

10.1071/ea98176 ◽

1999 ◽

Vol 39 (4) ◽

pp. 389 ◽

Cited By ~ 11

Author(s):

P. J. Moate ◽

C. Grainger ◽

D. E. Dalley ◽

K. Martin ◽

J. R. Roche ◽

...

Keyword(s):

Dairy Cows ◽

Cottonseed Meal ◽

Dietary Treatment ◽

Control Group ◽

Financial Benefit ◽

Protein Supplements ◽

Grazing Experiment ◽

Lactating Dairy Cows ◽

Dietary Treatments ◽

Friesian Cows

Many farmers in southern Victoria grow fodder turnips as a summer feed for lactating dairy cows. This paper reports on 2 experiments that measured the milk yields and liveweight changes of cows offered a basal forage diet and combinations of turnips, barley and protein supplements (cottonseed meal or lupins). A stall feeding experiment was conducted over 26 days with 40 Friesian cows in mid lactation offered 1 of 5 dietary treatments. All cows were offered 10 kg DM/day of a basal diet comprising pasture, pasture hay and pasture silage which is similar to that available on many southern Victorian dairy farms during summer. Cows in a control group did not receive additional feed supplements. Cows in the other 4 groups were offered a supplement of 5 kg DM/cow.day of either turnips, barley or a mixture containing 3 kg DM/cow.day of turnips and 2.0 kg DM/cow.day of either crushed lupins or cottonseed meal. The marginal milk responses from barley, turnips, turnips + lupins and turnips + cottonseed meal were 0.80, 0.92, 1.15 and 1.00 L/kg DM of supplement eaten. There were no significant differences (P>0.05) in the liveweight changes of the supplemented groups. Samples of the feeds used in this experiment were placed in nylon bags and incubated in the rumen of non-lactating dairy cows. The ‘Ørskov’ protein degradation parameters for these feeds are compared with the published values for a range of Australian feeds. The rate and extent of degradation of protein from the turnip leaves, turnip bulbs and crushed barley were all similar. A grazing experiment was conducted over 65 days with 56 Friesian cows in mid lactation, offered 1 of 4 dietary treatments. All groups were allowed to graze pasture (5 kg DM/cow.day), were offered 3 kg DM/cow.day of pasture silage and were fed different combinations of barley, cottonseed meal and lupins. In addition, 3 of the groups separately strip-grazed turnips (about 5 kg DM/cow.day). The group fed a supplement of 8.0 kg/cow.day of barley yielded similar quantities (18.3 L/cow.day) of milk and milk constituents as another group fed 4.0 kg DM/cow.day of barley and 4.5 kg DM/cow.day of turnips. Furthermore, when either 1.5 kg DM of cottonseed meal or 2.0 kg of lupins were fed in place of barley, milk yield increased by 1.4 L/cow.day. Dietary treatment had no significant (P>0.05) effects on liveweight changes. From this grazing experiment it is concluded that turnips can be used as a cheaper alternative to barley in order to maintain high levels of milk production in summer–autumn. We estimate that if the above quantities of protein supplement were fed with turnips, at 1997–98 prices, lupins would increase profits by 12 cents/cow.day, but there would be no financial benefit from the cottonseed meal. The findings from both experiments show that supplements of rumen-degradable protein (lupins) can produce an economic milk response when fed to cows on typical summer diets (pasture/silage/barley and turnips) in southern Victoria.

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The herbage intake of cattle grazing lucerne and cocksfoot pastures

The Journal of Agricultural Science ◽

10.1017/s0021859600011953 ◽

1963 ◽

Vol 60 (3) ◽

pp. 359-369 ◽

Cited By ~ 9

Author(s):

F. E. Alder ◽

D. J. Minson

Keyword(s):

Organic Matter ◽

Sampling Methods ◽

Live Weight ◽

Ground Level ◽

Cattle Grazing ◽

Chromic Oxide ◽

Grazing Experiment ◽

Herbage Intake ◽

The Mean

1. From 1955 to 1957 a cattle grazing experiment was carried out on lucerne and cocksfoot pastures. Hereford-cross steers were used. Results obtained on the assessment of herbage intake either by the use of chromic oxide and faecal index methods or by herbage sampling are presented here.2. Except in 1955, when techniques were being developed, the digestibility of the herbage on offer to the bullocks was estimated by cold storing herbage, cut with an Allen Autoscythe and later feeding it to sheep in indoor digestion trials. The in vitro digestibility of herbage samples cut in 1955 and 1956 was also determined.3. In 1956 the mean intake of organic matter (lb.) per 100 lb. live weight by faecal methods was 2·38, 2·07, 2·20 and 2·29 on pastures of lucerne, cocksfoot, lucerne/cocksfoot (broadcast) and lucerne/cocksfoot (alternate 1 ft. drills), respectively, and 1·99, 1·76, 2·02 and 1·97, respectively, in 1957.4. In 1956 the mean intake of organic matter (lb.) per 100 lb. live weight by herbage sampling methods was 2·14, 1·70, 2·11 and 1·99 on the same pastures of lucerne, cocksfoot, lucerne/cocksfoot (broadcast) and lucerne/cocksfoot (drills), respectively, and 2·49, 1·32, 2·35 and 2·03, respectively, in 1957. The modified Tarpen trimmer, cutting to within 1 in. of the ground was used for sampling in 1956 and the Allen Autoscythe cutting to within 2 or 3 in. of ground level in 1957.5. Detailed botanical separation of herbage samples showed that the bullocks were selecting the more digestible parts of the plants; the top 4 in. of lucerne and the ends of leaves and stems of cocksfoot. This and other factors which could affect the estimates of digestibility of herbage eaten by the cattle are discussed together with possible sources of error in the herbage sampling methods.

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Caucasian clover/ryegrass produced more legume than white clover/ryegrass pastures in a grazed comparison

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2000.62.2394 ◽

2000 ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

A.D. Black ◽

K.M. Pollock ◽

R.J. Lucas ◽

J.M. Amyes ◽

D.B. Pownall ◽

...

Keyword(s):

Soil Fertility ◽

White Clover ◽

Early Years ◽

Pasture Production ◽

P Values ◽

Trifolium Ambiguum ◽

Olsen P ◽

Grazing Experiment ◽

Ewe Lambs ◽

Clover Pasture

The potential of caucasian clover to improve the legume content of lowland New Zealand pastures should result in enhanced animal performance. Liveweight gains from eight flocks of ewe lambs rotationally grazing irrigated ryegrass pasture with caucasian or white clover at two levels of soil fertility (Olsen P values 10 or 22) were compared during years 2 (1998/1999) and 3 (1999/2000) of an ongoing grazing experiment in a lowland environment. Clovers were sown in December 1996 and ryegrass in March 1997 into the pure clover swards. Lamb liveweight gains were similar in year 2 (1130 kg/ha/yr), but in year 3, gains were greater on pastures sown with caucasian than on those sown with white clover (1290 vs. 1110 kg/ ha/yr). Spring liveweight gains per head per day averaged 170 g/hd/d in year 2, and in year 3 were greater from caucasian than white clover pasture (180 vs. 160 g/hd/d). Caucasian clover pastures had more legume on offer than pastures sown with white clover in year 2 (26% vs. 17%) and year 3 (19% vs. 12%). In year 3, 39% of the total legume on offer in caucasian clover pastures was volunteer white clover. Soil fertility had little influence on results. Early years of this grazing experiment showed that caucasian clover can establish as well as white clover if sown alone, and that sowing caucasian clover can result in lowland pastures with an increased total legume content which may improve liveweight gains. Keywords: legume content, Lolium perenne, pasture production, sheep liveweight gain, Trifolium ambiguum, T. repens

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Infection of subterranean clover swards with bean yellow mosaic potyvirus: losses in herbage and seed yields and patterns of virus spread

Australian Journal of Agricultural Research ◽

10.1071/ar9941427 ◽

1994 ◽

Vol 45 (7) ◽

pp. 1427 ◽

Cited By ~ 15

Author(s):

RAC Jones

Keyword(s):

Field Experiments ◽

Subterranean Clover ◽

Trifolium Subterraneum ◽

Yield Losses ◽

Grazing Experiment ◽

Growing Seasons ◽

Heavy Grazing ◽

Herbage Yield ◽

Seed Yields ◽

Grazed Swards

During 1989-92, subterranean clover ( Trifolium subterraneum L.) was grown in field experiments in which swards of six cultivars were infected with bean yellow mosaic potyvirus (BYMV) by transplanting small BYMV-infected subterranean clover plants into them. The swards were then grazed by sheep or mown to simulate grazing. The infected transplants were the primary virus source for subsequent spread by aphids. Spread initially centred on infected transplants resulting in circular expanding infected patches. Later, secondary patches, isolated affected plants and more generalized infection sometimes developed. The extent of spread within swards from the transplants varied with cultivar, BYMV isolate, site and year. Final BYMV incidence ranged from 12% of plants symptom-affected by isolate MI in cv. Junee in 1991 to 100% by isolate SMB in cv. Leura in 1992. BYMV spread mostly occurred in spring and was increased around the edges of areas of bare ground in swards. In two experiments at one site in which 'mini swards' of cvv. Green Range, Karridale and Leura were mown repeatedly, BYMV-infection decreased herbage yields (dry weights) by 12-16% while seed yields were decreased significantly (by 37-40010) in one experiment. In a grazing experiment at a second site with swards of cvv. Esperance and Karridale, BYMV-infection decreased overall yields of herbage by 18-39% and seed by 11-12%; herbage yield losses within symptom-affected patches were 28-49%. In a further grazing experiment at this site with swards of cvv. Junee and Karridale, BYMV-induced losses determined from symptom-affected patches were 21-29% for herbage and 15-25% for seed. In a grazing experiment with swards of cvv. Denmark and ~ e u r a ' at a third site, BYMV-induced overall herbage yield decreases of 8-12% were still recorded despite extensive BYMV spread to control swards; yield losses within symptom-affected patches were 18-25% for herbage and 35-47% for seed. Seed yield losses were due to decreased seed size (mean seed weight), fewer seeds being produced, or both. Estimates of the effects of different levels of BYMV infection on herbage yields in partially infected grazed swards were obtained for cvv. Denmark, Karridale and Leura by plotting individual quadrat data for herbage dry weights against % symptom-affected plants. Losses increased in proportion to the level of infection, but their magnitude also varied with cultivar and experiment. It is concluded that BYMV infection of subterranean clover pastures is cause for concern, not only as regards herbage yield losses but also as regards depletion of the seed bank, which, when compounded year by year, results in pasture deterioration. Early and prolonged aphid activity, reseeding the pasture with susceptible cultivars, heavy grazing and extended growing seasons are all likely to magnify BYMV-induced losses.

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Sources of variation in the number of lambs born in a grazing experiment

Australian Journal of Agricultural Research ◽

10.1071/ar9720839 ◽

1972 ◽

Vol 23 (5) ◽

pp. 839 ◽

Cited By ~ 1

Author(s):

DA Hedges ◽

WT Williams ◽

JL Wheeler

Keyword(s):

Pattern Analysis ◽

First Year ◽

Reproduction Rate ◽

Pasture Management ◽

Standard Analysis ◽

Grazing Experiment ◽

Year Effect ◽

Before And After ◽

Sources Of Variation ◽

Stocking Rates

Considerable variation was observed in the number of lambs born to fine-woolled Merino ewes during a 4-year grazing experiment in which the factors were four pasture management systems x three stocking rates. Attempts at interpretation by standard analysis of variance were ineffectual and accordingly the data were subjected to further examination by using non-orthogonal and contingency models and pattern analysis. The strongest influence discerned was the tendency of particular ewes to consistently produce 0, 1, or 2 lambs. The majority of births (72%) were singles; twinning was relatively uncommon (<10 %) and was most prevalent in the third year; barrenness was relatively high (18 %) particularly in the first year. Significant associations were found between the number of lambs born and the ewe's liveweight and liveweight change before and after mating. Pattern analysis suggested that part of this variation was associated with differences in the initial pasture composition between plots. There was a highly significant year effect in all the relevant animal variables examined but it was not possible to separate the contributions of weight and age to this effect. It is suggested that some of the variation in reproduction rate between plots was due to non-uniform allocation of the inherently barren and twinning ewes.

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