Abstract Four trials are described in which the liveweight gains of hoggets grazing different types of pasture over the autumn period were compared. In the first trial, hoggets grazed on white clover (Trifolium repens L.) had a greater liveweight gain (2.9 lb per week) from 26 February to 4 June 1963, compared with a 2.01b gain of those on mature perennial ryegrass (Lolium perenne L.) plus white clover, 1.1 lb on short (1–2 in.) perennial ryegrass plus white clover, and 0.61b on short perennial ryegrass. In the second trial, hoggets grazed on white clover-dominant pasture from 11 March to 20 May 1964 had a liveweight gain of 3.01b per week, those fed on lucerne (Medicago sativa L.) hay and short perennial ryegrass 1.51b per week, and those on short perennial ryegrass 0.91b per week. In the third trial, hoggets grazed on short (1–2 in.) pasture gained 1.1 lb per week in liveweight, compared with a 1.61b per week gain of those on longer (2–5 in.) pasture from, 13 March to 7 June 1963. In the fourth trial, t...

A trial involving the body and carcass analysis of 7885 lambs sired by 15 different breeds of ram and run at two New Zealand locations (Ruakura and Manutuke) over a 10 year period was analysed to determine the significance and size of the year effect on lamb composition. Animal size (growth rate) differed between sites with the Manutuke lambs being approximately 10% larger. Year had a very significant effect on the muscle, fat, and bone measurements investigated, with this effect remaining after adjusting measurements to the same carcass weight. Carcass fatness was strongly influenced by carcass weight which differed between years. At the same carcass weight, lambs differed by around 5% fat as a proportion of carcass weight or around 20% fat as a proportion of total fat, between the most extreme years at each location. Year differences were as large as those associated with identifiable management factors (breed, strains, sex, etc). Unfortunately, the underlying factors contributing to the year effect are at this stage unknown, but may provide a fruitful field for additional research.

The proportions of cuts from 7885 lamb carcasses sired by 15 different ram breeds, reared on pasture at two locations over 10 years, were measured and examined for breed differences. Although highly significant breed differences were found, their magnitude was small reaching a largest difference between crosses of 1.22% for the leg and 1.26% for the loin compared at the same carcass weight. Compared at the same time of slaughter (age), the maximum differences between the progeny of different ram breeds were 1.02% for the leg and 1.06% for the loin. Wether lambs had a slightly higher proportion of forequarter cuts. Sire breed had a major effect on the proportion of lambs reaching the fatter P grade (class) with the meat breeds Southdown, Dorset Down, South Dorset Down, Hampshire, and South Suffolk sires producing 68-76% P carcasses and the wool breeds such as the English Leicester, Merino, Romney, and Lincoln producing 18-23% of P carcasses. Lambs sired by the Poll Dorset, Dorset Horn, Suffolk, Ryeland, Border Leicester, and Cheviot produced 49-62% P carcasses.

Results on the body and carcass composition of 7885 lambs sired by 371 rams of 15 different breeds mated to Romney cast-for-age ewes are given. Trials were run at the Ruakura Agricultural Centre and the Manutuke Research Station from 1963 to 1972. Lambs of the different breeds were slaughtered at the same average age so that differences between breeds/crosses in liveweight and carcass weight reflected differences in growth rate. Ranked from heaviest to lightest mean age-adjusted carcass weights, lambs sired by the Dorset Horn, Poll Dorset, Hampshire, Border Leicester, Suffolk, Dorset Down, South Suffolk, and South Dorset Down produced the heaviest carcasses, and those sired by the Cheviot, Southdown, English Leicester, and Ryeland were intermediate. The Lincoln, Merino, and Romney sired carcasses were lighter. The longer-woolled Romney, Merino, and Lincoln had lowest dressing out percentages based on full liveweights and the short finer-wooled breeds such as the Southdown, Dorset Down, and Poll Dorset/Dorset Horn dressed 2-3% higher. When compared at the same carcass weight, lambs sired by the Southdown followed by the Ryeland had the fattest carcasses and those sired by the Suffolk, Cheviot, and Dorset Horn produced the least fat, leanest carcasses. The Southdown, Dorset Horn, South Dorset Down, and Poll Dorset crosses had the largest eye muscle areas for carcasses of similar weight.

The effect on grain yield of changing the plant population in 76 cm rows was studied over 3 years. Grain yields for the full season hybrid p×610 were maximised around 14 t/ha in the range of 80–90 000 plants/ha but the response curves gave no indication of any marked changes over the range of 70–100 000 plants/ha. These plant populations are above those recommended for full season hybrids overseas. The optImal plant population in these trials was similar to the optima in lower yielding New Zealand trials.In contrast, overseas results suggest that the optimal population would be higher in higher yielding trials.Plant lodging was severe only in the crop following pasture and here it rose as plant population increased.It is recommended that crops be established to give harvest populations of 80–90 000 plants/ha except for crops immediately following pasture when populations of 70–80 000 plants/ha should be established.

Two trials were undertaken, each with 72 grazing lambs. In trial 1, the lambs were Romney wethers and ewes with an average live weight of 27 kg and a mean initial age of 91 days. In trial 2, lambs were Southdown × Romney wethers and ewes that weighed 32 kg and had a mean initial age of 118 days. The animals were given either ad libitum or restricted postweaning access to pasture over a 6-week period, which was aimed at producing weight gain, weight maintenance or weight loss. In trials 1 and 2, respectively, the live weight changes in the gain groups were 5.6 and 6.6 kg; in the maintenance groups, the changes were 1.7 and 2.4 kg, and in the loss groups, they were —.5 and —1.5 kilograms. The gain groups lost more weight (P<.01) during transport and holding before slaughter than did the loss groups. The nutritional treatments resulted in differences in carcass composition; the carcasses from the gain group were heaviest and fattest (P<.01). However, the nutritional treatments apparently had no additional effect on carcass composition other than that normally associated with carcass weight. In the first trial, shear force values were higher (P<.01) for the loss group than for the gain group, and in both trials, the loss group had a lower (P<.01, P<.05, respectively) flavor score than the other groups. However, differences in palatability due to the fairly severe 6-week grazing treatments were small and considered to be of minor significance compared with the more important differences in carcass weight and composition.

N fixation rates were low at all times, with very low rates in some months probably because of low rainfall and dry soils. As soil moisture decreased, relatively more fixation occurred below 75 mm. Estimates of annual total N fixed were 92 and 122 kg/ha for 1974–75 and 1975–76 respectively. High levels of available N must be present to support the high levels of pasture production (14.1 t DM/ha and 15.2 t DM/ha for the two trial years).

Pasture growth rates are presented for a site at Manutuke on the Gisborne Plains. Growth rates were obtained over 27 years from a grazing trial cut by a standard method using a movable cage technique. The mean yield and standard error of individual samples over all years of measurement are given for standard dates at 14-day intervals. The seasonal pattern of growth had a spring peak, fluctuated over summer and autumn, and declined over the winter. On average 17% of the annual growth was produced in winter (June, July, and August), 35% in spring, 25% in summer, and 23% in autumn. Lolium perenne dominated the pasture, and its growth pattern closely resembled that of the total sward. Trifolium repens was a minor component throughout the year and produced on average 44% of its annual growth during summer. General climatological data, and rainfall and temperature during the period of pasture measurements are given.

An experiment is described in which the nutritive value and chemical composition of oven-dried herbage from shaded perennial ryegrass pasture (SR) were compared with those of unshaded ryegrass (R), shaded + nitrogen-fertilised (SR + N), and unshaded + nitrogen-fertilised (R+N) ryegrass herbage, and with those of white clover (C). Higher food intakes and live weight gains were found with C herbage than with the ryegrass herbage (SR, R, SR + N, R + N = P), and with unshaded than with shaded herbage. Application of nitrogen fertiliser prior to harvesting did not affect live weight or food intake. A higher D.M. digestibility was found for C than for P herbage, and in the second trial only, a higher digestibility was evident for unshaded than for shaded, and for nitrogen than for no nitrogen treatments. A higher proportion of soluble carbohydrate and lignin, but lower hemiccllulose and cellulose content, were found in dried C than in P herbage. Shading perennial ryegrass pastures reduced the proportion of soluble carbohydrate and increased the proportion of cellulose and lignin. Nitrogen fertiliser reduced the proportion of cellulose and lignin in dried herbage. Freeze-dried herbage had a higher soluble carbohydrate, but lower insoluble carbohydrate, content than oven-dried herbage.

Spraying trials have been carried out using thiabendazole as a fungicide in an attempt to control the growth of Pithomyces chartarum (Berk. & Curt.) M. B. Ellis in the field. One application of thiabendazole in January was compared with repeated sprayings at times when it was predicted that heavy sporulation of Pithomyces would occur. Both treatments controlled sporulation throughout the facial eczema season and prevented liver damage in animals grazed on the treated pasture.

A trial is described in which the liveweight growth of hoggets grazing six different pastures was compared. The six pastures comprised short perennial ryegrass (SP), long perennial ryegrass (LP), short perennial ryegrass plus white clover (SP + C), long perennial ryegrass plus white clover (LP + C), short white clover (SC), and long white clover (LC). Mean liveweight gains were 6.4, 16.9, 18.1, 24.6, 34.0, and 34.7 lb respectively from 4 April to 28 June 1966.

Thornton and Sinclair's method of counting spores from washed herbage samples and Brook's volumetric spore trap were used to measure the seasonal fluctuation in numbers of spores from Pithomyces chartarum on pasture, and the results obtained from the two methods were found to agree closely. A strong positive correlation was obtained between estimated numbers of spores on pastures and the degree of facial eczema in lambs grazing thereon. Strong negative correlations were obtained between spore numbers and liveweight gains of the lambs, and between degree of liver damage and liveweight gains.

Summary The incidence in pastures of the spores of Sporidesmium bakeri, observed to grow saprophytically on dead pasture-plant material, has been studied with a simple spore-counting method. High spore counts were favoured by large amounts of dead and damaged plant materials and warm, moist conditions. A relationship has been established between relatively high counts of spores and facial eczema disease in lambs. A correlation has been shown between spore counts and “beaker test” values. The incidence of spores was higher in pasture samples from Gisborne and Palmerston North than in samples from Hutt Valley, Lincoln and Gore.