A practitioner's guide to pasture quality

Abstract

<jats:p>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</jats:p>

Controlling variegated thistle in East Coast North Island hill-country

“…The operator observed on several measurement dates that the sown species on the south aspect were defoliated by the livestock to a much greater extent than the unsown control and surrounding pasture, which is consistent with lower herbage production in the seven-species mix than the unsown control in March 2017. Productive pasture species such as perennial ryegrass, cocksfoot and legumes have a higher nutritive value and are more palatable than species such as browntop (Fulkerson et al 2007;Lambert & Litherland 2000) that were present at the field site where it formed a thick mat with a high proportion of dead material of low nutritive value. Based on these results and the problem of selective grazing, oversowing desirable pasture species into larger patches (>1 ha) of variegated thistle after herbicide application is unlikely to succeed.…”

Performance of indigenous and exotic×indigenous sheep breeds fed different diets in spring and the efficiency of feeding system in crop–livestock farming

“…High DMD of cereal forages at early vegetative stage exceeding 0·90 were also reported by Coblentz & Walgenbach (2010). The nutritive value of all fodder crops decreased with advancing maturity, especially after the switch from vegetative to reproductive growth, which typically occurs in temperate pasture and forage crops (Lambert & Litherland 2000; Waghorn & Clark 2004). Increased maturity in all forage groups resulted in decreased concentration of CP and digestibility but increased concentration of ADF and NDF.…”

The Relative Importance of Herbage Nutritive Value and Climate in Determining Daily Performance per Cow in a Pasture-Based Dairy Farm

“…Varying contents of ME and CP in herbage signify variation in the availability of these nutrients for metabolic processes per kilogram of dry matter consumed [3]. In addition, ME and CP also affect the total supply of nutrients by influencing DMI [37,38] and, thus, the performance of grazing cows [6]. More importantly, dietary protein content also alters the efficiency in which other nutrients are absorbed and partitioned toward mammary secretion [39,40].…”