This study aimed to develop calibrations for the measurement of pasture mass and pasture growth rate on sheep and beef pastures. Herbage within quadrats (0.12-0.2 m2) was measured with either an electronic rising plate meter (RPM) (n=2279), capacitance pasture meter (CPM) (n=693) or pasture ruler (n=2528) for the development of linear and curvilinear seasonal calibrations for pasture mass. Keywords: pasture mass, growth, rising plate meter, capacitance height, dead, dry matter, sheep, cattle

Pasture quality has a major effect on performance of grazing animals. Intake and nutritive value of pasture are major determinants of liveweight gain, milk production, health and reproductive performance of livestock. Digestibility and metabolisable energy concentration are the two most commonly used measures of nutritive value in New Zealand. In some situations protein, soluble carbohydrate, and mineral and trace element concentrations are also important. Fungal toxins, parasite larvae or other deleterious compounds lower pasture quality by compromising animal health. Potential intake of high nutritive value herbage is also greater because of rapid speed of passage through the animal. The major determinants of nutritive value are botanical and morphological composition, the environment in which the pasture is growing, and the regrowth period (i.e., herbage age). Legume leaf has higher nutritive value than grass leaf, leaf has higher quality than stem, and dead material has very low quality. Herbage grown at cooler times of the year has higher nutritive value than when grown in warmer conditions, and quality declines with age more slowly. Grass leaf declines in nutritive value as it ages, as does stem to an even greater extent. Soil moisture has only minor direct effects on nutritive value. Fertiliser application has direct effects such as increasing protein (by fertiliser nitrogen use) or trace element concentrations (if added to the fertiliser). It also has indirect effects through changing botanical and morphological composition. Keywords: digestibility, metabolisable energy, nutritive value, pasture quality

No abstract

A wide range of management techniques is available to enhance quantity and quality of forage supply to grazing animals throughout the annual production cycle. Within broad limits, dry matter (DM) production is relatively insensitive to management of defoliation frequency, severity and duration. However defoliation management has effects on feed quality which can be enhanced, in particular, by control of pasture growth in the spring through maintenance of relatively low average pasture masses. Treading damage can have significant immediate and ongoing effects on pasture production and farmers can use a range of management techniques to minimise these. Fertiliser application practices have a potent influence on pasture production and seasonality of that production. Available soil nitrogen is the primary nutrient deficiency limiting production in New Zealand's characteristically grass-dominant pastures. Nitrogen fertiliser usage has increased markedly in recent years, particularly to grow substantially greater amounts of forage during the cool season, and this trend looks set to continue. However, the use of nitrogen fertiliser has important environmental implications. Pasture renewal and forage crop use has also increased in recent years. Care needs to be taken in conducting cost-benefit analyses, selecting the options that best meet the needs, and in establishment and subsequent management practices. Ryegrass (perennial and hybrids) and white clover remain the primary choice for permanent pasture renewal, the availability of safe endophytes having largely alleviated effects of endophyte toxicosis. Special-purpose mixtures are used, especially in dry environments. Italian ryegrasses, brassicas and chicory are common choices for forage crops. A range of management techniques can be used to alleviate deleterious effects of some forages, including ryegrass endophyte toxicosis, facial eczema, and toxins associated with Fusarium fungi. Generally these techniques are not totally effective. More research is required to increase our understanding of these disorders, and in order to develop more effective and reliable management practices.

Sheep have a higher intake of nutrients when offered continuous free access to ryegrass and white clover growing separately than when offered the same species growing as a mixture. To determine if this greater nutrient intake would translate to higher animal performance, three experiments of 3-6 weeks duration measured liveweight gain by ewes+twin lambs in early spring, weaned lambs in mid-late spring and hoggets during late winter to identify the class of sheep most responsive to this form of forage presentation. Offering pasture comprised of ryegrass and clover growing separately resulted in higher average daily gains for weaned lambs (330 vs 185 g/ day, P