R. A. Moss

Effect of herbage species on gastro-intestinal roundworm populations and their distribution

Abstract Sheep faeces containing strongylate eggs were applied to plots of perennial ryegrass, prairie grass, or chicory mixed with white clover, or lucerne without white clover. Plots were later harvested within four height zones and the herbage mass, numbers, and species of gastro-intestinal nematodes determined. Ryegrass, prairie grass, and lucerne plots produced similar yields of herbage dry matter (DM) (3580, 3180, and 3230 kg DM/ha respectively), whereas chicory produced 2250 kg DM/ha. Ryegrass–, prairie grass–, and chicory-based swards had similar proportions of herbage DM within each height zone, the quantities declining with increasing height. Lucerne swards had less DM in the central height zones than other swards but proportionally more above 125 mm from ground-level. Larvae from 0.73% of eggs were recovered, but the rate was influenced by herbage species. The grass-based swards had higher larval populations than had lucerne or chicory, and lucerne had more than chicory. Larval density tended t...

Lamb mortality, birthweight, and nutrition in late pregnancy

Abstract Mortality data on 5163 Romney × Suffolk lambs were collected at Winchmore Irrigation Research Station from 1976 to 1981. Mortality from birth to tailing (25 days) for single, twin, and triplet births was 14.1, 14.7, and 33.0% with mean birth weights of 5.2, 4.1, and 3.3 kg respectively. Ninety-four percent of all deaths occurred within 72 h of birth. Dystocia accounted for 50.4% of all single deaths and starvation/exposure for 45.0% of all multiple deaths. The proportion of ewes assisted at lambing increased with birthweight above 4.5 kg to reach almost 19 and 8% for single and twin births respectively. If lambs that were assisted at birth, but survived to weaning, are regarded as potential deaths, the overall potential mortality of single and twin lambs was 27.9 and 20.2% respectively. Ewe liveweight gain during the last 6 weeks of pregnancy was associated with increased birthweights of single and twin lambs (P < 0.05). A liveweight change of approximately 10 kg in ewes was required to alter bir...

Pasture production from a long-term fertiliser trial under irrigation

Abstract New Zealand pastoral farming has benefited greatly from the application of phosphorus (P) and sulphur (S) fertilisers supplied in the main by superphosphate (SSP). The long-term fertiliser trial at Winchmore, mid-Canterbury, New Zealand was set up in 1952 and has yielded a wealth of data on the effect of fertiliser, grazing by sheep and flood irrigation on pasture production. The trial was initially (1952–1958) designed to measure the effect of no fertiliser and SSP applied each year at 188, 376 and 564 kg ha−1. From 1958 to 1980, SSP applications were stopped to the 564 and one half of the 376 kg SSP y−1. The cessation of fertiliser decreased clover content and increased the proportion of weeds and low-fertility grasses. The decline in production once fertiliser application ceased followed a curvilinear pattern, but never reached the low production of the no fertiliser treatments even after 20 years. In 1980, the residual treatments were changed to compare a reactive phosphate rock (RPR)/S treatment as well as an intermediate (250 kg ha−1) rate of superphosphate. The 0, 188 and 376 kg SSP ha−1 have now been unchanged for 60 years, while the 250 kg SSP or equivalent in RPR/elemental S have remained unchanged for 30 years. The 188 and 250 kg SSP ha−1 y−1 treatments have shown that without any nitrogen fertiliser, ryegrass and clover will persist in irrigated pastures and result in high levels of pasture production (11–12 t ha−1) for up to 60 years.

Soil nutrient distribution in pastures flood‐irrigated by the border strip method

Abstract Two studies of the distribution of the levels of the nutrients phosphate, sulphate, potassium, magnesium, sodium, calcium, and of pH levels, were carried out in sheep pastures that were flood‐irrigated by the border strip method in mid Canterbury, New Zealand. The border strips had been formed by grading the land to a gently sloping plane surface, then creating c. 12 m‐wide, 200–300 m long strips by raising “borders” c. 1.8 m wide and c. 12 m apart, with strips aligned with the direction of maximum fall. The first study involved four 30‐year‐old border‐strip pastures at Winch‐more Research Station, whereas the second study involved 20 border‐strip pastures of varying age on nine commercial farms in Ashburton County. In both instances 75 nun‐deep soil samples were taken from the tops of the irrigation borders and from the border crutches and strips, at varying positions up and down the length of the border‐strip systems. In both studies nutrient levels were in general lowest in the strips, highest...

Winchmore and the long-term trials: the early history

Abstract Winchmore Irrigation Research Station was established in the late 1940s in the Ashburton–Lyndhurst irrigation scheme in Canterbury, New Zealand, to investigate problems associated with the introduction of border-strip irrigation to farming. Two large-scale field trials were established. The first, in 1949, aimed to investigate water requirements of permanent pasture and the second, in 1952, to examine fertiliser requirements of irrigated pasture. Initially designed to supply farmers with practical solutions, because of their longevity (61 and 58 years to date), consistent management, meticulous record keeping and archiving of regular soil and plant samples, both trials have yielded a rich source of material for many studies, some of which are reported in other papers in this issue of the journal.

Forward creep grazing of lambs to increase liveweight gain and post‐weaning resistance to endoparasites

Abstract An experiment was conducted in New Zealand to assess the effect of creep grazing of lambs on their liveweight and resistance to endoparasites. Comparisons included creep versus non‐creep grazing at two herbage allowances and regular an‐thelmintic drenching. Treatments commenced with 6‐week‐old twin reared lambs, and ceased when they were weaned at 13 weeks, with the exception of the drench treatment which continued post‐weaning. Pastures used contained sheep endoparasites. At 8 weeks post‐weaning one lamb from each twin set was slaughtered, remaining lambs were then drenched, and 8 and 9 days later were orally dosed with 180 Trichostrongylus colubriformis L3/kg liveweight each day (averaging 12 650/lamb). Three weeks later these lambs were also slaughtered. Measurements included liveweight, faecal worm egg count (FEC) and adult endoparasite numbers. Neither herbage allowance nor creep grazing affected FEC or adult endoparasite numbers. Fortnightly drenching of creep grazed lambs on the high allowance had no effect on weaning liveweight, but it improved live‐weights post‐weaning. Neither creep grazing, pre‐weaning herbage allowance, nor drenching, affected lamb resistance to endoparasites. Creep grazing and the higher allowance both increased weaning liveweights. The response to creep grazing was highest at the lower allowance, increasing weaning liveweights by 4 kg. Pre‐weaning treatment had no effect on post‐weaning growth rate.

Effect of cattle grazing strategies and pasture species on internal parasites of sheep

Abstract The results of a three‐year study in New Zealand undertaken to compare the effect of alternating sheep and cattle grazing and of different pasture species on internal parasitism in lambs is reported. Despite the commonly held belief that the use of cattle in sheep production systems improves sheep health by reducing nematode burdens, this did not occur. Cattle substantially reduced pasture larval numbers. However, this failed to reduce parasite burdens in lambs as those managed in the absence of cattle apparently developed increased immunity to parasites in response to the greater larval availability. Varying the number of successive grazings by sheep or cattle from 1 to 4 did not change this result. Lamb carcass weights were improved by the presence of cattle, primarily because of improvements in pasture quality. Substituting 30% of the ryegrass area with lucerne or replacing ryegrass with a multi‐species mix consisting predominantly of bromes, tall fescue, phalaris, timothy, and red and white c...

Prediction of ewe litter size using udder scores, liveweights, and condition scores

Abstract The usefulness of udder score, liveweight, and condition score measurements and their changes during pregnancy for predicting ewe litter size was tested using discriminant analysis on records of 7 058 ewes from 13 flocks covering a range of breeds. When each variable was used individually to discriminate between ewes bearing singles and those bearing twins, udder score was the best predictor variable with 65% being correctly classified Prelambing liveweight was the next best predictor with 62% correctly classified, and mating liveweight, liveweight change during gestation, and condition score were similar, averaging 58% correctly classified. When all variables were used together in a combined index, the accuracy of prediction was only slightly improved (68%) over that achieved by udder scoring alone. For on-farm use, udder scores or prelambing liveweights could potentially be used to correctly classify about two-thirds of ewes.

Winter grazing and dead material effects on early spring pasture production

ABSTRACT Improved performance of the national ewe flock along with the displacement of finishing farms into hill country has increased pressure on spring pasture production. Increasing spring pasture production to cope with this increased demand is considered one of the main areas of improvement needed in hill country farming. A trial was set up in the South Island of New Zealand to determine the response of spring pasture production to two winter grazing intensities across three levels of sward dead material. Total spring pasture production was unaffected by winter grazing intensity. Winter dead material levels significantly affected total spring pasture production. Plots with high dead material levels (>60%) grew 657 kg DM/ha less than plots with low dead material levels (<30%) over the spring period. Reducing the amount of dead material in the sward is recommended as the shading of grass tillers by dead material reduces growth of new pasture.

Effect of seed mix, sowing time, summer fallow, site location and aspect on the establishment of sown pasture species on uncultivable hill country

ABSTRACT This study aimed to determine which practices resulted in the greatest establishment (plant density) of a range of grasses, legumes and herbs at four geo-climatically different hill country sites in the North Island (three sites) and South Island (one site) of New Zealand. At each site, on a north and south aspect, a seed mix containing either grasses, legumes and herbs (GLH) or legumes only (LEG), was sown in spring 2011 and autumn 2012. The 2011–2012 summer rainfall was greater than the long-term average at all sites. Establishment of total sown species was greater in the GLH than LEG mix (14% vs 8% of germinable seed sown) although some species (white clover [Trifolium repens]) established more successfully when sown in the LEG mix. Establishment was greater from spring than autumn sowing at the two wetter sites, but greater from autumn than spring sowing at the two drier sites. Greater establishment occurred after a summer fallow or summer crop than after an autumn sowing for most species at most sites. Establishment of total sown species ranged from 5%–39%, depending on the site and treatment. Seedling establishment, as a percentage of germinable seed sown, was greatest for perennial ryegrass (Lolium perenne), white clover, red clover (T. pratense) and plantain (Plantago lanceolata) (up to 36%, 37%, 33% and 35%, respectively, averaged over sites), while cocksfoot (Dactylis glomerata), phalaris (Phalaris aquatica), grazing brome (Bromus stamineus), lotus (Lotus uliginosus), birdsfoot trefoil (Lotus corniculatus) and chicory (Cichorium intybus) were below 15%.