The impact of endophyte on the health and productivity of sheep grazing ryegrass-based pastures

Fletcher, L. R.; Sutherland, B. L.; Fletcher, C. G.

doi:10.33584/rps.7.1999.3403

Cited by 25 publications

(17 citation statements)

References 24 publications

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“…Although this trial utilised a diet containing both ergovaline and lolitrem B, it nevertheless highlights that sheep can exhibit heat stress symptoms even under thermoneutral conditions. Heat stress, measured as increased body temperature and respiration rate, at ambient temperatures in Canterbury, New zealand, during summer/autumn, has been reported in sheep grazing ryegrass with standard endophyte (Fletcher 1998;Fletcher et al 1999) (Table 4). Furthermore, although rectal temperature of lambs increased with increasing ambient temperature the rectal temperature of lambs grazing ryegrass infected with the 187BB endophyte which had higher concentrations of ergovaline (and no lolitrem B) were consistently higher compared to lambs grazing ryegrass infected with the standard endophyte, which had lower concentrations of ergovaline but did contain lolitrem B, as well as animals grazing endophyte-free ryegrass which contained no toxins (Figure 3).…”

Section: Sheepmentioning

confidence: 99%

“…Heat stress symptoms have been observed to be more severe in lambs forced to graze lower into the sward (Bluett et al 1999). Fletcher et al (1999) concluded from a review of results across New Zealand that heat stress in lambs and sheep due to ergovaline would be especially prevalent in the warm humid conditions of northern New Zealand. Fletcher et al (1991) in a trial in Canterbury demonstrated that after 14 days lambs grazing ryegrass infected with either standard endophyte or 187BB endophyte gained less weight than lambs grazing on endophyte-free ryegrass although only the lambs grazing the standard endophyte treatment lost weight after 28 days.…”

Section: Sheepmentioning

confidence: 99%

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Ergot alkaloids in New Zealand pastures and their impact

Caradus¹,

Card

Finch

et al. 2020

New Zealand Journal of Agricultural Research

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In identifying endophytes for use in pastures in New Zealand there have been two strategies used, either exclusion of ergopeptine and lolitrem alkaloids or, retaining some ergopeptine expression to enhance the stability of natural defences against invertebrate pests. Both have their strengths and weaknesses. It is a matter of balancing these to ensure the end-user has access to a product that satisfies their needsa persistent pasture with low to nil animal toxicity in terms of animal production and welfare. The range and intensity of ergot alkaloids in grazed pasture on both pasture and ruminants is reviewed, with emphasis on New Zealand. Ergot alkaloids associated with pasture are produced by associations between certain Epichloë endophyte strains and temperate grasses. Ergot alkaloids have been shown to improve persistence of pasture through providing resistance/deterrence to insect pests as well as deterring grazing animals. However, ergovaline is toxic to grazing animals. Some commercially available ryegrass-endophyte associations can produce ergovaline concentrations close to those found in associations between ryegrass and the standard endophyte. It is feasible to eliminate ergot alkaloids from pasture grasses in New Zealand as endophyte strains are commercially available that do not express ergovaline and yet still provide excellent pest resistance.

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Section: Sheepmentioning

confidence: 99%

Section: Sheepmentioning

confidence: 99%

Ergot alkaloids in New Zealand pastures and their impact

Caradus¹,

Card

Finch

et al. 2020

New Zealand Journal of Agricultural Research

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“…The use of a high-endophyte ryegrass was expected to further impede animal performance on the control treatment. Fletcher et al (1999) recorded suppressions in lamb summer/ autumn liveweight gains ranging from 20 to 185 g/d owing to the presence of endophyte in ryegrass.…”

Section: Animal Performancementioning

confidence: 99%

The effect of pasture species on pasture and animal performances in irrigated systems

Moss¹,

Fraser²,

Daly³

et al. 2000

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The effect of two contrasting forage supply options on forage and sheep production was evaluated on irrigated farmlet systems at Winchmore, mid Canterbury, over 3 years. One system was based on perennial ryegrass pastures (Control), and the other on hybrid ryegrass, tall fescue, and chicory pastures (Improved). Pasture growth rates were similar for all pasture types, however, pasture cover was on occasion, higher on the Control than Improved systems ensuring this system was self-sufficient in feed while the Improved system had a deficit averaging 714 kgDM/ha/yr. Swards on both systems contained similar proportions of legume but the Improved system contained less grass and more chicory before lamb grazing. Despite the apparent improvement in feed quality of the Improved system, its lamb performance was greater than that from the Control system for the first year only, when swards were newly established and contained greater proportions of chicory and legume. Although pasture production was similar between years there was considerable variation in lamb growth rates. This was most pronounced in the Improved system where pre-weaning rates averaged 266 and 216 g/d in years 1 and 3 respectively, and post-weaning rates 190 and 108 in years 1 and 2 respectively. The post-weaning variation appeared to coincide with fluctuations in clover and to an even greater extent, the chicory content of swards, the proportion of which declined as seasons progressed and pastures aged. The Improved system gave financial returns from lamb that were $49/ha higher than the Control in year 1 but offered no advantage in subsequent years. Compared to the Control, the Improved system had the added costs of more frequent pasture renewal and was further disadvantaged by a feed deficit necessitating buying-in supplies. Improvements anticipated to accrue from the inclusion of higher quality swards in an irrigated animal production system, were not supported by findings from this study. Keywords: irrigation, lamb production, pasture production, pasture quality, pasture species

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“…Lamb liveweight gain has been reported (Fletcher et al 1999) to have been reduced by up to 10 g/d in summer and autumn, for every 10% increase in endophyte infection, though there was variation between years and localities. The range in individual liveweight gains in the present study was large (-82 to 238 g/d), possibly precluding detection of any overall relationship between pasture mix (and thus endophyte) and liveweight gain.…”

Section: Figurementioning

confidence: 99%

“…This neurological disorder is characterised by uncoordinated movement and loss of appetite (Keogh 1973), and is often seen in stock grazing perennial ryegrass dominant pastures. Cattle, sheep, deer and horses are susceptible, with affected sheep having significantly reduced liveweight gains (Fletcher 1983;Fletcher & Borrell 1984;Fletcher et al 1999). Furthermore, these animals are difficult to move, and may become immobile and occasionally die of starvation, dehydration or misadventure.…”

Section: Introductionmentioning

confidence: 99%

Incidence and severity of ryegrass staggers and liveweight gain in lambs grazing different mixtures of ryegrass-cocksfoot pastures

Hyslop¹,

Fisher²,

Smith³

et al. 2003

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Livestock grazing ryegrass infected with endophytic fungi are susceptible to staggers, a neurological disorder characterised by uncoordinated movement and loss of appetite. A possible strategy to minimise staggers is to dilute the toxic effects of ryegrass by providing other non-toxic pasture species in the diet. Therefore, the incidence and severity of ryegrass staggers, and liveweight gain, was monitored in lambs grazing varying mixtures of ryegrass-cocksfoot pastures during four six-week periods throughout summer and autumn over two years. There was a significant effect of pasture type on staggers. On a scale of 0 (no staggers) to 5 (severe muscular tremors invariably resulting in collapse and tetanic spasm), pure ryegrass resulted in a mean of 3.1, S.E.M. + 1.6 compared with 0.3, S.E.M. + 0.9 with pure cocksfoot. Ryegrass/cocksfoot mixtures were slightly less toxic than pure ryegrass with means (+ S.E.M.) ranging from 2.2, S.E.M. + 1.6 to 2.9, S.E.M. + 1.8. Mean liveweight gains ranged from 62 g/d on both pure ryegrass and 80:20 ryegrass:cocksfoot mix, to 83 g/d on pure cocksfoot, with no significant effect of pasture type. In those periods when ryegrass staggers was significant, the percentage of ryegrass in the sward was positively related to the severity of staggers and negatively correlated with liveweight gain. The inclusion of cocksfoot in ryegrass-dominant pastures is thus able to reduce to some extent the adverse neurological effects of endophyte on lambs. Keywords: cocksfoot, endophyte, lambs, liveweight gain, ryegrass, ryegrass staggers

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The impact of endophyte on the health and productivity of sheep grazing ryegrass-based pastures

Cited by 25 publications

References 24 publications

Ergot alkaloids in New Zealand pastures and their impact

Ergot alkaloids in New Zealand pastures and their impact

The effect of pasture species on pasture and animal performances in irrigated systems

Incidence and severity of ryegrass staggers and liveweight gain in lambs grazing different mixtures of ryegrass-cocksfoot pastures

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