Alfalfa Pasture Research Articles

Rumensin helps to reduce the incidence and severity of legume bloat in cattle (1985)

Monensin at 300 mg and 450 mg per 1000 lbs body weight reduced the severity of alfalfa pasture bloat by 41.2 and 73.1 %, respectively. Lasalocid at the same levels reduced the bloat score by 25.5 and 12.4%. The difference between the two antibiotics appears to be in their ability to inhibit rumen protozoa. Monensin reduced protozoal population in the rumen, whereas lasalocid had no effect. A smaller protozoal population decreases compounds that contribute to frothiness and also increases substances such as plant chloroplasts, which have antifrothing properties.; Dairy Day, 1985, Kansas State University, Manhattan, KS, 1985;

Effects of pasture type on the growth and wool production of weaner sheep during summer and autumn

The productivity of weaner sheep grazing lucerne, white clover, red clover or Persian clover and pastures sown with subterranean clover and perennial ryegrass, cocksfoot or tall fescue, was measured in summer-autumn trials incorporating four soil types in each of three years. During summer and autumn, the mean growth rate of sheep grazing lucerne, white clover or Persian clover pastures was 50 g/d compared with 1 g/d for sheep grazing perennial grass-subterranean clover pastures. Sheep grazing strawberry clover on reclaimed swampland, and sheep in a feedlot (fed hay and lupin grain) averaged 100 and 75 g/d, respectively. Sheep grazing red clover averaged 45 g/d over years 1 and 2. In year 2, a subterranean clover-dominant pasture was included in the study. Its feeding value was similar to that of the perennial grass-subterranean clover pastures. Sheep grazing legume pastures, and sheep in the feedlot, consistently produced more wool (up to 700 g/head) than sheep grazing the perennial grass-subterranean clover pastures. The concentration of neutral detergent fibre in herbage from legume pastures was frequently lower (P< 0.05) and the concentration of crude protein was frequently higher (P< 0.05) than in herbage from grass pastures. The dry matter digestibility of legume herbage was higher (P<0. 05) than that of grass herbage on only one occasion. Measurements of crude protein and neutral detergent fibre of pasture in December accounted for 67% of the variation in liveweight gain (P<0.01). Ewe weaners grazing red clover pasture exhibited an increase (P< 0.05) in teat length of 3.9 mm in 21d of grazing. Oestrous activity of ewe weaners was related to liveweight gain (r = 0.77). The implications of the results for agricultural systems are discussed.

Effects of grazing management on the botanical composition of a lucerne pasture in south-eastern Queensland

The influence of six grazing and three mowing treatments on the botanical composition of lucerne (Medicago sativa cv. Hunter River) pastures was studied at the end of a six-year experiment on black earth in southern Queensland. Rest intervals of 32-60 d were combined with grazing durations of 4, 8 or 16 d, or with mowing. Sheep were used for grazing at a year round rate equivalent to 20/ha. Frequency of occurrence of all species and their relative herbage yield contribution were estimated in autumn and spring of the last two years. Seventy-four species were recorded, but only 17 occurred in more than 5% of grazed quadrats. Survival of lucerne, the only sown species, was good (Leach 1979a); it occurred in about 70% of quadrats but its relative yield ranged from 8 to 75%. Chloris gayana was the principal volunteer perennial grass, especially in treatments grazed for short periods (4 d) where its frequency ranged from 26 to 49% and the corresponding relative yield totals from 26 to 33% in the final spring. The volunteer species most characteristic of particular treatments were Dichanthium spp. and Chloris virgata in autumn, and Malvastrum coromandelianum, annual Medicago spp. and Trifolium repens in spring. Grazing duration or mowing influenced botanical composition more than changes in resting interval. This mainly reflected the intensity of utilization rather than grazing duration per se. Opportunities for controlling volunteer species through grazing management will be limited by compensatory responses between species. However, management should aim to ensure adequate grazing of both the lucerne and the volunteer species.

Influence of rest interval, grazing duration and mowing on the growth, mineral content and utilization of a lucerne pasture in a subtropical environment

SUMMARYThe influence of rest interval and grazing duration on herbage production of dryland lucerne (Medicago sativa L., cv. Hunter River) pastures was studied in a 6-year experiment on a black earth in subtropical southern Queensland. Rest intervals (R) of from 32 to 60 days were combined with grazing durations (G) of 4, 8 or 16 days, or with mowing (M), in the following treatments: (1) R32-4, (2) R32-G16, (3) R44-G4, (4) R44-G16, (5) R56-4, (6) R40-G8, (7) R36-M, (8) R48-M and (9) R60-M. Grazing was with sheep at a rate equivalent to 20/ha on a year-round basis. Amounts of dry matter of lucerne and of volunteer species on offer were measured prior to grazing or mowing, and some measurements of the residue remaining after grazing were made. Chemical composition of representative lucerne samples was also determined.Mean total amount of lucerne on offer declined from 10·8 to 7·2 t/ha/year between the first 2 years and the last 2 years, whereas total amount of volunteer species, principally grasses, increased from 3·0 to 18·2 t/ha/year over the same period. This difference was partly due to lower utilization of volunteer species. The decrease in amount of lucerne was due to loss of plants, and treatment effects arose through differences in the degree to which amounts from individual surviving plants increased to compensate for stand thinning. Concentrations of mineral elements in lucerne were always above critical levels for plant and animal growth.Treatment R40-G8 maintained the largest amounts of lucerne on offer to the end of the experiment, with treatments R32-G4 and R32-G16 then having least. Large amounts of grass were associated with 4-day grazing, and to a lesser extent with short rest periods. The results confirm the need for a minimum rest period between grazings in a subtropical environment and also show the need for grazing to control excessive grass growth as well as lucerne if lucerne productivity is to be ensured. Some requirements which would lead to more successful management of lucerne in the subtropics are discussed.

Factors influencing the accuracy of herbage mass determinations with a capacitance meter

Abstract Pasture herbage mass was determined before and after grazing of grass-clover and lucerne pastures with a capacitance meter using the ‘paddock mean method’. This proved to be an accurate and efficient technique for estimating herbage mass for both types of pasture either before or after grazing. Capacitance meter reading was most significantly correlated with the fresh weight of pasture (r>0.900) and least with dead pasture (r>0.140). The proportion of dead herbage and DM % of pasture were significantly correlated (r=0.811), and both affected the regression of meter reading on herbage mass, making selection of sites at the ‘paddock mean’ critical as the variability of these components in pasture increased. The accuracy of herbage mass estimation can be improved by making a visual assessment of the mean dead matter content and selecting cutting sites at the mean meter reading which also correspond to mean dead matter content.

Productivity of grazed Makarikari grass-lucerne, Rhodes grass-lucerne and lucerne pastures in the northern wheat belt of Australia

Three Makarikari grasses (Panicum coloratum var. makarikariense) viz. 0.4634, cv. Pollock and cv. Bambatsi and Rhodes grass (Chloris gayana) cv. Pioneer, each grown with lucerne (Medicago sativa) cv. Hunter River, and sward lucerne were compared for productivity and stability in a rotational grazing system at three stocking rates (22.2, 14.8 and 7 . 4 Merino wethers/ha for grasslucerne pastures; 14.8, 11.1 and 7.4/ha for lucerne swards) on a cracking clay soil on the Darling Downs, Queensland over four years. There were no differences between the Makarikari grass cvv. Pollock and Bambatsi pastures. However, each produced more dry matter and animal liveweight, and persisted better, than Rhodes grass pasture during dry conditions that occurred during the first two years. Rhodes grass nevertheless recovered during two subsequent wet summers. During those two dry years, wool production from sward lucerne was equal to that of the grass-lucerne pastures at both 14.8 and 7.4 animals/ha. Animal liveweight from lucerne was greater than from grass-lucerne pastures at 7.4 animals/ha only. Wide variation, both between and within seasons, was measured in the quantity of feed produced by pastures in this study. This is discussed in relation to the concept of stocking rate of pasture grown on limited areas of grain farms in the northern wheat belt, and to the provision of a continuing feed supply in integrated crop-pasture systems.

The productivity of breeding ewes grazing on lucerne or grass and clover pastures on the tablelands of southern Australia. II. Wool production and ewe weight.

Spring-lambing Merino and crossbred ewes grazing on dryland lucerne pastures were generally heavier throughout the year than ewes grazing on phalaris and subterranean clover pastures, even though they experienced greater weight losses during winter. These losses were mostly eliminated by compensatory gains in spring. Annual fleece weights of the Merino ewes grazing on lucerne or phalaris and subterranean clover pastures declined linearly by 146 and 64 g respectively for each additional ewe carried over a range of stocking rates from 9 to 18 ha-1. Corresponding figures for crossbred ewes were 114 and 46 g. In each case the difference between pasture species was significant (P < 0.02). Only at the lowest stocking rates were fleeces from ewes on lucerne heavier (by c. 500 g) than those from ewes on phalaris. At the highest stocking rates, there were no advantages in terms of wool production from grazing breeding ewes on lucerne. Not only was there a greater need for supplementary feed during late pregnancy to avoid losses from pregnancy toxaemia, but the lucerne pastures at all stocking rates proved more sensitive to unfavourable physical and chemical characteristics of soils than did phalaris and subterranean clover pastures. The fleece weights of Merino and crossbred ewes declined, on average, by 70 and 50 g per year for ewes aged between 1+ and 6+ years. Pregnancy reduced fleece weights by 5-10% in Merinos and 5-21% in crossbred ewes, depending on seasonal conditions which varied from year to year. For Merinos only, dry ewes grew about 4% more wool than lactating ewes. No other effects of reproduction on fleece weights were observed.

Some Advances in Application of TLC to Diagnostic Toxicology

Abstract During this last year we have progressed in our abilities to make diagnostic toxicological analyses by TLC. Two which I will present are the analysis for Lincomycin and Slaframine.(1) The former, a drug which is very bad for horses, and the latter, a naturally occurring mycotoxin which has had a very large effect on animals this last year.(2) In addition to cases involving closer pastures, this last year alfalfa pasture and hay and grasses have been involved.

Ruminal and Intestinal Digestion in Brahman Crossbred and Hereford Cattle Fed Alfalfa or Tropical Pasture Hay

Ruminal and Intestinal Digestion in Brahman Crossbred and Hereford Cattle Fed Alfalfa or Tropical Pasture Hay

7.1 Protein Digestion in Grazing Sheep

In 23 experiments, measurements were made over 4 or 5 day periods of the digestion of herbage by lambs (Expts 1-10 and 14-18, Table 7.1.1) and adult sheep (Expts 11-13 and 19-23) grazing phalaris (P. aquatica), lucerne and unfertilized native pastures. All 38 animals used (Corriedales) had rumen and simple abomasal cannulae; seven adult sheep also had a simple ileal cannula. Corbett, Furnival, Inskip, Perez and Pickering (1976) and Corbett (1981) have described the techniques used for estimating intakes of organic and digestible organic matter and nitrogen (OMI, DOMI, NI) and the fractional outflow rates (FOR/h) of liquid from the rumen, the rate and composition of digesta flows and microbial protein production by reference to intra-ruminally infused 103Ru-phenanthroline, 51CrEDTA and Na235S04.

Reseeding by Eight Alfalfa Populations in a Semiarid Pasture

Eight nlfnlfa populations were seeded in a dryland pasture in northern Utah. Densities of mature plants, seeds, seedlings, and l-year-old plants were measured in each of 3 years. The populations did not differ for mature plant stands or seed production. There was a higher rate of seedling survival for populations that primarily originated from Medicago sativu rather than M.falcata. All populations had some one-year-old plants persisting to replace mature plants killed by disease or rodents. Alfalfa (Medicago satin and A4. falcata) is a valued component of pastures in subhumid environments. Its contribution to livestock production in dryland pastures and modified rangelands of semiarid areas is less well documented, although Townsend et al. (1975) regarded alfalfa as one of the most promising forage legumes for dryland seedings in the Great Plains. Hervey (1960) reported that lamb gains increased after alfalfa and crested wheatgrass (Agropyron desertorum) were interseeded into native sod in Wyoming. The introduction of the dryland alfalfa cultivar ‘Nomad’was one of the most successful techniques used to improve antelope (Antilocapra americana) ranges in southeastern Oregon (Yoakum 1979). After 36 separate aerial seedings on more than 26,000 ha, alfalfa constituted 10% of the vegetation present for 6 years or longer. Lee and Rothwell (1966) and Norman (1968) successfully used alfalfa pasture to supplement native pasture for sheep and cattle in Australia. Vallentine et al. (1963) recommended the use of alfalfa in sagebrush zone range sites in Utah where annual precipitation averaged 30 cm or more. The merit of using alfalfa for supplementing native pasture or for interseeding will depend on the longevity of plants and the ability of the species to reseed in a droughty environment while subjected to grazing. Kilcher and Heinrichs (1965), Pearse (1965), and Rumbaugh and Pedersen (1979) presented evidence that alfalfa lived up to 23 years in environments that received 20 to 30 cm average annual precipitation. Gomm (1974) reviewed results from more than 50 seeding experiments on 1 I vegetation types in dryland areas of Montana. Annual precipitation at the study locations ranged from an average of 20 to more than 50 cm. Alfalfa either failed to become established or the stands declined rapidly in more than half of these plantings. The causes of the declining stands were not stated. Author is research geneticist, U.S. Dep. Agr., Agr. Res. Serv., Crops Research Laboratory, Utah State University, UMC 63, Logan, Utah 84322. This study is a contribution from the U.S. Dep. Agr., Agr. Res. Serv., in coopcration with the Utah Agricultural Experimental Station, Logan, Utah. Journal Paper No. 2525. Manuscript received May 2, 1980. 84 Gomm (1964) did find that ‘Ladak’ alfalfa and ‘Madrid’ sweetclover (Melilotus officinalis) established equally well in a dryland experiment where the seedbed was prepared with a moldboard plow. Nichols and Johnson (1969)concluded that biennial sweetclover was well adapted as a legume for rangelands with heavy clay soils in western South Dakota whereannual precipitationaveraged 39 cm. Natural reseeding was successful every 2 years and sufficient hard seed remained in the soil to safeguard against elimination of the species in a season when drought killed the seedlings. They believed that periodic seedset would provide sweetclover stands whenever growing conditions were suitable. Similar data and observations with alfalfa have not been reported. A mature stand of alfalfa in northern Utah was available as a study site to provide such information.

Effect of Rumensin on legume bloat in cattle (1982)

Rumensin with or without Bloatguard was fed to rumen-fistulated cattle grazing lush alfalfa pasture. Although Rumensin alone or in combination with low doses of Bloatguard reduced bloat, it was not completely effective. Hence, Bloatguard at the recommended dose is still necessary for full bloat control.

Grass seed contamination of the wool and carcases of sheep grazing natural pasture on the north-western slopes of New South Wales

A group of six-month-old Merino wether weaners was grazed from January to July 1977 on a natural pasture containing seeds of wiregrass (Aristida ramosa), corkscrew grass (Stipa variabilis), barley grass (Hordeum leporinum) and burrs of Medicago minima. The sheep were then removed from the natural pasture, shorn and grazed for a further 23 months on lucerne and oats pastures that were free of grass seed. The number and species of grass seeds and burrs in the wool, hide and carcases were measured to determine the levels of seed and burr contamination and the long-term fate of seeds entering the carcase. The highest number of seeds in the wool, hide and carcase of sheep grazing natural pasture were those of wiregrass. Numbers of seeds of this species per 100 cm2 ranged from 85 to 651 in the wool, 43 to 159 in the hide, and 1 to 8 in the carcase. Most of the grass seeds in the wool were located on the stomach and shoulders, while most of the burrs were on the hind legs and stomach. Percentages of grass seed were highest about the stomach area and shoulders for the hide and carcase, respectively. After the sheep were removed from the natural pasture, and grazed on lucerne and oats pastures for 23 months, the mean grass seed contents decreased by 81% in the hide and 83% in the carcase. Wiregrass seeds were the only seeds that penetrated the hide and remained in the carcase. Numbers of contaminating seeds decreased most rapidly within 6 months of the sheep being removed from the natural pasture. Over the experimental period no seed-free hides or carcases were observed.

Persistence of creeping-rooted lucerne under grazing in subtropical Queensland

The persistence of four synthetic lines of creeping-rooted lucerne was compared with that of Hunter River over three years on a fertile brigalow clay soil in south-eastern Queensland. The lucerne was sown either as pure stands that were grazed by cattle continuously or intermittently, or as lucerne and grass pastures that were grazed, according to two different intermittent systems. The persistence of the creeping-rooted lines was worse than that of Hunter River, and the stands had virtually disappeared after two years. The creeping-rooted lines seem more vulnerable to drought and show poorer recovery from drought. A grazing lucerne for the semi-arid tropics will probably need to, at least, incorporate the vigour and tap-root characteristics of Hunter River to ensure survival.

RELATIONSHIPS BETWEEN RUMINANT BLOAT AND THE COMPOSITION OF ALFALFA HERBAGE. II. SAPONINS

Although herbage proteins are generally recognized as foaming agents in pasture bloat, a possible secondary role for saponins has not been ruled out. The role of saponins in pasture bloat was re-examined by feeding rumen-fistulated cattle fresh herbage from high saponin (HS) and low saponin (LS) near-isogenic strains of alfalfa. Each alfalfa strain was fed to six animals for 100 days. Feeds from the two alfalfa strains differed significantly in saponin concentration but were equal in protein concentration. At 1.5–2 h after feeding, the cattle were examined for the occurrence of frothy rumen ingesta and for bloat. The HS alfalfa produced 86 instances of frothy rumen ingesta and 50 cases of bloat. The LS alfalfa produced 103 instances of frothy rumen ingesta and 61 bloat cases. There were no significant differences (P > 0.1) between HS and LS alfalfa in the occurrence of bloat or of frothy rumen contents. Generally, saponin concentrations in rumen fluid were below detectable levels and below the estimated level of toxicity to the animals. In view of these results and other strong evidence opposing the saponin theory of pasture bloat, we conclude that saponins do not contribute to the occurrence of alfalfa pasture bloat by either the toxic or the foaming modes of action.

Beef production from lucerne and subterranean clover pastures. 1. The effects of pasture, stocking rate and supplementary feeding

The production and management of weaner steers on two pasture types were studied over 3 years at Wagga Wagga in southern New South Wales. One pasture (LC) was sown with a mixture of lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) and the other (C) was sown only with subterranean clover. On each pasture the management treatments were 1.3 and 2.0 steers ha-' in 1975, and 2.1 and 3.0 steers ha-1 in 1976 and 1977, with a grain supplement at the heavier stocking rate in all years. Each year, steers gained more liveweight in February-March or April-May on LC than on C, and this advantage was maintained or increased until slaughter in the following January. The faster growth of steers on lucerne-clover was always associated with an increased supply of green herbage. Annual liveweight gain on LC exceeded that on C by 20-30 kg/head in 1975 and 1977, and by up to 90 kg/head in 1976, when the rainfall pattern was unsuitable for clover growth. Carcases from steers on LC were heavier (all years), covered with a greater depth of fat (1 975 and 1976) and showed better eye muscle development (1 76 and 1977) than those on C. In 1975, neither stocking rate nor supplementary feeding affected liveweight or carcase development. In the following 2 years, increasing the stocking rate from 2 to 3 steers ha-1 reduced annual liveweight gains by 35-40 kg/head. Oat grain supplements (2-3 kg/head day-1 in February-March, June-July and December-January) improved weight gains and carcase quality on both pasture types in 1977, but only on C in 1976

Beef production from lucerne and subterranean clover pastures. 2. Bloat occurrence and effect of anti-bloat capsules

Over 3 years (1975-77), the occurrence of bloat was recorded in steers grazing two legumedominant pastures, one (LC) containing lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) and the other (C) subterranean clover. The effect of intraruminal capsules on both the occurrence of sub-lethal bloat and liveweight gain was assessed in spring 1976 (anti-bloat capsules), and in spring 1977 (anti-bloat and monensin capsules, singly and together). In unprotected steers, bloat occurred only during winter or early spring on both pastures. Over the 3 years, seven steers died from bloat on LC, and three on C. Sub-lethal bloat (rumen distention) was more frequent and severe on LC than on C in 1975 and 1976. However, in 1977 it was more frequent on LC in June-July, but more frequent on C in August-September; there was no difference in severity between pastures. The anti-bloat capsules halved the rumen distention index and improved liveweight gain by an average of 0.2-0.3 kg/head day-1 for short periods in October 1976 and August 1977. The results with monensin capsules were inconclusive. Bloat occurrence is discussed in relation to pasture and environmental conditions, and to beef production on lucerne-clover and clover pastures.

The growth rates of weaned lambs grazing three legume-based pastures during summer

An experiment was conducted on the Central Western Slopes of New South Wales with Dorset Horn x Merino lambs to assess their liveweight gains during summer when weaned on to a lucernebased pasture under dryland conditions, and when weaned on to irrigated lucerne and red clover pastures. Lambs grazing irrigated lucerne, irrigated red clover and dryland lucerne had average growth rates of 155, 178 and 124 g day-1/head, respectively, throughout the 106 day experimental period. The poor growth rates of lambs on the dryland lucerne were apparently due mainly to the low digestibility of the dry feed on offer as a result of low rainfall, which also caused feed supply to be limiting during part of the experimental period. Lamb growth and intake data suggest that the diets selected from the red clover were of higher digestibility than those selected from the irrigated lucerne. It was concluded that irrigated red clover and irrigated lucerne provided useful diets for young lambs in this environment, although the growth rates achieved were less than reported elsewhere for these species in cooler climates. Growth rates achieved by lambs grazing dryland lucerne were less satisfactory for prime lamb production.

Beef production from lucerne and subterranean clover pastures. 3. Composition and quality of the diet selected

During 1976 and 1977 in southern New South Wales, diet samples were obtained at approximately 3-week intervals from oesophageally fistulated steers grazing a lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) pasture (LC) and a subterranean clover (C) pasture. On LC, green lucerne was the predominant diet component for much of the 2 years. On C, the diet consisted mainly of dry material during a drought in autumn-winter 1976, green wireweed (Polygonurn aviculare) until late autumn 1977, green clover and grass in winter and spring 1977, and finally dry material again. During 1976 and early 1977, diets on LC had a higher digestibility (61.7% vs 49.4%) and nitrogen content (2.55% vs 2.04%) than those on C. This difference was due to the contribution of lucerne on LC, and also because the wireweed on C was of very low quality, even when green. During the latter part of 1977, LC and C had equivalent digestibility and nitrogen levels. The information on the diets helped explain changes in liveweight and the incidence of bloat of cattle grazing the plots.

Growth of cattle on phalaris and lucerne pastures II. Helminth parasite populations and effects of anthelmintic treatment

In young beef cattle, the effects on helminth parasite populations of anthelmintic treatment, pasture type and stocking rate are reported from a four-year experiment at Canberra. The animal production results are given by Morley et al. (1978). Anthelmintic treatment was at three levels — none, at weaning in autumn, and frequent treatment intended to be suppressive. In the last two years of the experiment when helminth populations were moderately high, treatment in early autumn recouped roughly half the production loss from uncontrolled helminth infection. Most of this effect occurred in spring and not soon after treatment. Monthly anthelmintic treatment failed to suppress Ostertagia ostertagi infection and delayed the natural development of host resistance. Treatment at intervals of two weeks or less largely prevented O. ostertagi egg output and eventually reduced pasture infectivity and worm burdens to low levels. In three of the four years, worm burdens in untreated cattle were lower on lucerne than on phalaris pastures.