Pasture quality and nutrition

Se resumen las actividades de la seccion de Calidad de Pasturas y Nutricion del Programa de Patos Tropicales del CIAT durante 1981, cuyos objetivos incluyen: (1) identificar y caracterizar los factore de calidad en el germoplasma que ayuden en el proceso de seleccion; (2) estudiar los factores de calidad en el germoplasma en sistemas de pasturas y su relacion con el comportamiento de los animales en pastoreo; y (3) identificar los usos alternativos de germoplasma en sistemas de pasturas con base en factores de calidad. Especificamente se presentan los resultados de (a) la caracterizacion de factores de calidad in vitro e in vivo de gramineas (9) y leguminosas forrajeras (12); (b) el efecto del manejo, tipo de asociacion graminea-leguminosa, epoca del ano y fertilizacion en los factores de calidad del germoplasma en sistemas de pasturas medidos en animales fistulados y (c) los usos alternativos del germoplasma en sistemas de pasturas. (CIAT

Management of Pasture Quality for Sheep on New Zealand Hill Country

The control of pasture quality over spring is central to the achievement of high levels of sheep performance on hill country. Despite this, with the exception of the work of Lambert et al. (2000), little is known about how farmers actually manage pasture quality. The purpose of this research was to describe how a high performing hill country farmer manages pasture quality on their sheep area over spring and from this develop a framework that will assist other farmers improve their pasture management

Remote Sensing of Pasture Quality

Worldwide, farming systems are undergoing significant changes due to economic, environmental and social drivers. Agribusinesses must increasingly deliver products specified in terms of safety, health and quality. Increasing constraints are being placed on them by the market, the community and by government to achieve a financial benefit within social and environmental limits (Dynes et al. 2003). In order to meet these goals, producers must know the quantity and quality of the inputs into their feeding systems, be able to reliably predict the products and by-products being generated, and have the skills to be able to manage their business accordingly. Easy access to accurate and objective evaluation of forage is the first key component to meeting these objectives in livestock systems (Dynes et al. 2003) and remote sensing has considerable potential to be informative and cost-effective (Pullanagari et al. 2012b)

Improving Summer/Autumn Feed Quality in New Zealand Hill Country

Pasture management in spring has a strong influence on pasture quality in summer and autumn in New Zealand hill country pastures. Manipulation of defoliation frequency and intensity during mid-late spring can impact summer and autumn pasture quality and quantity (Orr et al. 1988). Summer/autumn management is mainly concerned with maintaining herbage quality in summer wet areas and controlling animal pressure in summer dry areas for drought management and winter feed stocks (Clark 1994). Deferred grazing to transfer pasture growth from late spring into summer and autumn deficits is difficult due to detrimental effects on pasture quality, plant density and species composition (Sheath et al. 1987). Various grazing management models have been published to inform hill farmers of pasture management considerations during this period (Smith and Dawson 1977; Sheath and Bircham 1983; Sheath et al. 1987). It has previously been shown that management of late spring surpluses to restrict reproductive growth will increase summer pasture quality through a reduction in accumulated stem and dead material and an increase in clover content (Sheath et al. 1987). However, there is no information on the longevity of these effects. This trial aimed to determine the effect of different defoliation intensities during spring on herbage quality and composition throughout the subsequent summer-autumn period

Calf Performance Related to Pasture Quality and Supplements

WVU-Extension fact shee

A study of patchiness in mid-season dairy pastures : consequences and control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science at Massey University

There is interest among some dairy farmers in increasing herbage intake of cows during spring by increasing pasture cover but without compromising pasture quality into the summer. "Late control" is a grazing management strategy developed in Massey University that meets those requirements (Matthews et al., 1996). In addition, it has been demonstrated in previous trials that Late control increases pasture production in the summer-autumn period by increasing ryegrass tillering vigour. Late control requires a period of lax grazing during spring to allow some reproductive growth development on ryegrass pastures, which is then controlled by hard grazing in late spring before anthesis. However, patchiness may develop in Late control during the lax grazing period when the herbage allowance is high. The objectives for the present experiment were to compare the pasture characteristics under Late control and conventional "Early control" spring management strategies in December-January, with particular reference to the consequences of vegetation heterogeneity to pasture production and utilisation over this period, and to discuss the implications to spring grazing management. The experiment involved detailed studies on three paddocks chosen from each of two farmlets of 22 paddocks used for a system trial comparing Early and Late control spring management on herds of 120 cows. Herbage mass distributions were estimated by taking 200 capacitance meter readings at random on each paddock. Relationships between herbage mass and utilisation and accumulation were estimated by using two 30 m permanent transects in each paddock. To determine botanical composition and tiller population variability within a sward, five tall patches and five short patches were sampled in each paddock. Paddocks in Late control before the control phase in December had more herbage mass than paddocks in Early control (3600 vs. 5000 kg DM/ha), but the variability of herbage mass was similar (1000 vs. 1000, standard deviation in kg DM/ha). The skewness of the herbage mass distribution was positive but greater in Early control than in Late control (0.57 vs. 0.32). Botanical composition was similar between treatments and within paddocks. Pasture morphology showed tiller size-density compensation in both treatments. Pasture characteristics in late control were not an impediment for efficient pasture removal in late control and more herbage was harvested than in Early control (1900 vs. 1000 kg DM/ha), although herbage allowance was greater in Early control. Short patches in both treatments were defoliated in less proportion than tall patches, but in Late control the proportion of short patches was less than in Early control. Therefore, low herbage mass and greater proportion of short patches in Early control had a negative effect on total herbage utilisation. Harvesting efficiency was controlled on Late control paddocks to avoid limitations to herbage intake, and the skewness of the distribution of herbage mass after grazing increased compared to Early control, as well as the proportion of tall poorly utilised patches. Topping of pastures after grazing was effective in removing poorly utilised material and in decreasing patchiness in January. In January, Late control paddocks had more herbage mass, but less patchiness than Early control paddocks (6300 vs. 4700 kg DM/ha). Sward characteristics were affected by treatment, and in general Late control increased ryegrass content and its leafiness during January compared to Early control. In January, herbage utilisation was greater in Late control than in Early control (3000 vs. 1700 kg DM/ha). It was concluded that because Late control had greater responses in tall patches, the objective should be to modify management to a longer rotation length before controlling reproductive growth in late spring, to allow a greater proportion of the sward to achieve high herbage mass. The combination of grazing and topping of pastures gave high herbage intakes and effective pasture control. More pasture was produced in Late control than in Early control and the rotation length can also be increased during the summer in Late control, which may benefit further ryegrass tillering

Performance and parasitosis in heifers grazing mixed with sows

The aim of the study was to investigate the effect of mixed grazing with first season heifers and pregnant sows on animal performance, gastro-intestinal helminths, pasture quality and sward structure during three grazing seasons. This presentation will focus on results from 1999, primarily regarding performance and parasitosis in heifers. There have been no earlier reports on such mixed grazing systems. Three grazing systems were studied in replicate: 1) Heifers grazing alone; 2) sows grazing alone; 3) heifers grazing together with sows. The heifers were inoculated with low doses of infective O.ostertagi larvae at turn-out. Continuous grazing was practised in paddocks regulated in size according to herbage allowance. Individual weight gain, faecal egg output and serum pepsinogen concentrations - as indicator of O.ostertagi infection - were measured fortnightly. The sward structure and quality were greatly influenced by the applied grazing system. The average daily gain of the heifers was significantly higher (P=0.0006) when grazing together with sows (1,121±45 g/day, n=16) than when grazing alone (869±48 g/day, n=14). The mean pepsinogen concentrations were elevated in the heifers grazing alone. It is concluded, that weight gains were significantly better and infection levels with O.ostertagi were significantly reduced in heifers grazing together with sows

Use of LANDSAT data to monitor pasture project in Amazonia

The author has identified the following significant results. No differences were found between acreage evaluation by visual and automatic interpretation of LANDSAT images. It was necessary to interpret both channels 5 and 7 to exactly outline the deforested areas. Channel 7 was necessary for the identification of deforested areas in the presence of recently grown natural vegetation, and channel 5 was necessary to identify the deforested areas in the cerrado regions. Automatic interpretation permitted the discrimination between areas with predominant grass coverage and recently grown natural vegetation

A study on the effect of sward conditions on herbage accumulation during winter and spring : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University

Recently there has been an increased trend for farmers to adopt farm systems that operate at a reduced stocking rate, with the aim to improve per hectare production through achieving higher production per cow. The emphasis of these farming systems is on improving cow intakes and production and increasing herbage accumulation through the maintenance of pasture conditions with emphasis on pasture quality and higher post grazing residuals. A key issue at the centre of such a grazing system is whether the increase in pasture accumulation will outweigh the decrease in pasture utilisation at the time of grazing, thus increasing overall efficiency. The objectives of this study were to measure the effect of herbage mass present after grazing on subsequent net herbage accumulation rate, and to explain these differences through monitoring changes in sward components, as well as discussing the practical implications of these within a dairy farming system. Two experiments were conducted on a commercial dairy farm near Dannevirke in 1998, Experiment I over winter (June 19 – August 28) and Experiment II in spring (September 18 – October 28). The farm was situated approximately 300m A.S.L. with the soil type being a combination of an Ashhurst stony silt loam and a Dannevirke silt loam, with high soil fertility levels. Treatments involved a range of post-grazing residuals representing cow intake levels from under fed to ad-lib (900, 1200, 1500, 1800, 2100 kg DM/ha in winter and 1200, 1500 1800 2100 kg DM/ha in spring, Treatments 1-5 and 1-4 respectively). The spring experiment also involved nitrogen treatments at rates of 0, 25 and 50 kg N/ha. Heifers and dry cows were used to graze plots with grazing intensities calculated for stock to reach the targeted residuals in 24 hours (Experiment I) and 8 hours (Experiment II). Experiment I was designed as a randomised complete block design, and Experiment II as a randomised split plot design. Both experiments were replicated three times. In both experiments a range of post-grazing residuals was achieved (870, 1140, 1394, 1635, 1917 in Experiment I, and 1098 1424, 1704, 1913 in Experiment II). Post-grazing residuals in both experiments were significantly different (P<0.05). A post-grazing residual of 1394 and 1704 kg DM/ha in winter and spring respectively resulted in the greatest net herbage accumulation rates (16.3 and 81.7 kg DM/ha/day) from grazing until a pre-grazing target level of 2600-2700 kg DM/ha was achieved. Net herbage accumulation rates measured in both experiments were higher than those used in practice on the case farm. No statistical differences existed in Experiment I. In Experiment II Treatment 3 (1704 kg DM/ha residual) was significantly (P<0.05) higher than the other treatments. The relationship between herbage mass and net herbage accumulation rate showed a positive trend in both experiments. The herbage mass at which pasture accumulation was optimised was greater in spring (2900 kg DM/ha) than winter (2500 kg DM/ha). In both Experiments tiller density was greater in more intensely grazed swards, and showed a compensation effect with tiller weight. In Experiment I all treatments increased in tiller density with Treatment 1 having a significantly greater (P<0.05) increase than the other treatments. In Experiment II tiller density in all swards declined over the entire experiment, being greatest (P<0.01) in Treatment 3. Leaf extension rates had a similar trend to tiller weight in Experiment I with the laxer treatments (Treatments 3-5) having a significantly higher (P<0.01) extension rate than Treatments 1 and 2. Treatment 3 also had the fastest leaf appearance rate (17.1 days/leaf), although this was only statistically different to Treatment 5. Leaf appearance rates in Experiment II showed no trend, with Treatments 2 and 4 having the fastest appearance rates, and Treatment 3 the slowest. Tiller appearance rates showed some evidence of a trend (although not significant) with more intensely grazed swards tending to have a slightly faster appearance rate compared to more laxly grazed swards. Tiller weight and leaf extension rate were significantly correlated (P<0.05) to net herbage accumulation in winter. In spring all sward components measured were correlated (P<0.01) to net herbage accumulation with leaf appearance rate being the most significant (P<0.001). Botanical composition in Experiment I showed that more intensely grazed plots had a greater (P<0.05) proportion of leaf, lower proportion of dead material and higher clover content. In Experiment II the trend between variables and grazing level was similar but not significant. The proportion of clover and dead material in spring swards was low (averaging 9.8 and 14.9% respectively) given the herbage mass levels reached. NIR results in general reflected the changes in botanical composition. It was concluded that there is benefit in the use of sward conditions (targets) in the planning and management of grazing systems in enhancing both pasture and animal performance. Compensatory effects between sward components resulted in non-significant differences in herbage accumulation rates, and in practice, differences in pasture growth are likely to occur at extreme grazing residuals. Grazing management decisions are therefore more likely to be based on residual dry matter to achieve desired intakes for high per cow production, high pasture utilisation and high pasture quality, rather than to optimise pasture accumulation. It is recommended that residual herbage mass after grazing should be 1200-1300 kg DM/ha and 1500-1600 kg DM/ha in winter and spring respectively. The practical implications of these are discussed