scholarly journals The effect of deferred grazing in spring and early summer pastures on pasture growth rate and feed quality

2017 ◽  
Vol 79 ◽  
pp. 189-196 ◽  
Author(s):  
B.P. Devantier ◽  
D.R. Stevens ◽  
G.M. Rennie ◽  
K.N. Tozer

Abstract Maintaining pasture quality in late spring and early summer is a challenge in many hill country farming systems where pasture growth often exceeds animal demand. One possible management tool is to defer grazing on a portion of the farm to enable the desired grazing management and animal performance on the remainder. This study aimed to evaluate the effect of timing and duration of deferred grazing in mid-spring to early-summer on subsequent pasture accumulation rates, composition and quality, from mid-spring through to the following winter. A factorial design (3 durations x 3 closing times) in eight replicates compared withholding grazing (nil, 1 or 3 grazings), in three closing periods, mid spring, late spring, and early summer. Grazing pasture when covers reached 2500 - 3000 kg DM/ha to a residual of 1500 kg DM/ha was the standard grazing regimen used. Grazing after the exclusion period aimed to achieve the same residual as in the control treatment based on a feed budget. Short early closures resulted in little, or no change in pasture quality and quantity for the remainder of the season. Longer closure periods reduced pasture quality due to increases in the proportions of dead and reproductive stem. This effect was reduced with later closings. The control (nil deferred grazings) and mid-spring closings had a net loss of dead matter (-1000 and -420 kg DM/ ha, respectively), while the late -spring and earlysummer closings accumulated 60 and 180 kg DM/ha, respectively. These differences in dead matter were the major driver of the differences of net herbage accumulations (P=0.018), with net accumulations from 7990 kg DM/ha for the control (Nil) closings to 9660 kg DM/ha for the December (late) closings. Deferred grazing can be used to alter feed availability and utilisation while maintaining net pasture production over spring, summer and autumn. Keywords: grazing management, pasture quality, deferred grazing, net pasture accumulation, dead matter, reproductive tillers, metabolisable energy

2014 ◽  
Vol 76 ◽  
pp. 145-148
Author(s):  
G.M. Rennie ◽  
W.Mcg King ◽  
T.L. Knight ◽  
B. Devantier ◽  
C.J. Hoogendoorn

Abstract Management of late spring surpluses to restrict reproductive growth can increase the quality of hillcountry pastures during summer and autumn. This occurs through a reduction in accumulated stem and dead material and an increase in clover content. However, there is little information on the magnitude and longevity of these effects. This trial investigated the effects of four late spring defoliation intensities on herbage quality, measured at the end of spring and during summer. Treatments were applied through regular cutting of hill pastures in areas of medium fertility and slope on two aspects in each of four geo-climatically different hill-farming regions over two years. Pasture herbage quality at the end of spring followed expected trends: defoliation to low residual pasture height led to higher quality herbage. The maximum difference in quality between the lowest cutting height and nil cutting at this time was nearly 2 MJME/kg DM. With a change to uniform cutting height across all plots in early summer, these pasture quality differences reduced and disappeared. Keywords: Pasture quality, hill country, grazing management


Author(s):  
G.W. Sheath ◽  
R.W. Webby ◽  
W.J. Pengelly

Comparisons of controlling late spring to early summer pasture growth on either easy or steep contoured land with either a fast rotation or continuous grazing policy were made in self-contained farmlets for two years. Pasture control was maintained over more land by controlling steep land first and with continuous grazing. Animal performances (ewes, steers) were generally similar for the mid-November to early January treatment period, and subsequently until May shearing. In the first year better animal performances occurred in "steep control" farmlets during winter and early spring, but this was less evident in the second year. Priority control of steep land during late spring-early summer is recommended because of likely longer-term benefits in pasture composition,density and production. Quick rotation grazing through the period provides a better ability to recognise and manage pasture quantities and should be adopted if summer droughts are anticipated. For well fenced properties in summer-wet areas and with integrated stock grazing, continuous grazing during late spring-early summer may be equally suitable. Keywords: hill country, grazing management, pasture control


2018 ◽  
Vol 58 (12) ◽  
pp. 2269 ◽  
Author(s):  
D. Real ◽  
C. M. Oldham ◽  
A. van Burgel ◽  
E. Dobbe ◽  
J. Hardy

Tedera (Bituminaria bituminosa C.H Stirt. vars. albomarginata and crassiuscula) is a traditional forage species for goats in the Canary Islands, Spain. It has agronomic characteristics ideally suited to Mediterranean-like climates that allows it to provide high quality green forage for grazing animals during summer and autumn. It can be used to extend the growing season into late spring and early summer and/or to reduce or eliminate the need for expensive hand feeding of grain and hay to sheep to fill the ‘feed gap’ during the dry season in southern Australian farming systems. Three sheep grazing experiments were carried out with the objective to evaluate sheep production during summer and autumn with tedera as the sole diet. A 3-ha site at Dandaragan, Western Australia was grazed during the summer and autumn of 2014–2015 and 2016 and a 2.4-ha site was grazed at Kojonup, Western Australia during the same period in 2016. At each site, two grazing treatments were evaluated, continuous grazing and rotational grazing with six plots (14 days of grazing and 70 days of recovery). The first hypothesis tested was that tedera plants would not survive continuous grazing during summer and autumn. The second hypothesis tested was that without hand feeding, 10 dry sheep equivalents/ha would be able to at least maintain weight and condition score during summer and autumn. The third hypothesis tested was that rotational grazing would improve the production of the sheep (liveweight and condition score) compared with continuous grazing. The first hypothesis was rejected, the population of tedera plants did not significantly decline due to being continuously grazed during summer and autumn. The second hypothesis was confirmed, at the three experimental sites, 10 dry sheep equivalents/ha were able to at least maintain weight and condition score without any hand feeding. The third hypothesis was partially rejected; continuous grazing had a better performance of the sheep than rotational grazing. However, the rotational grazing plots had more tedera on offer in the remaining grazing plots in the rotation with the potential for a longer grazing time. These three experiments clearly demonstrate that tedera can be used to reduce or eliminate expensive hand feeding during summer and autumn using the simplest and least expensive grazing management; continuous grazing.


1993 ◽  
Vol 20 (6) ◽  
pp. 815 ◽  
Author(s):  
DL Robson

Rabbit-breeding stops were monitored over 35ha of improved farmland, with relatively stable rabbit numbers, in North Canterbury, New Zealand. The number of stops dug varied seasonally, with most in spring, fewest in autumn. Pasture quality appeared to have a marked influence on breeding activity and productivity of the rabbits. Of the 427 breeding stops located, litters were found in 33%. Most (97%) of these stops were lined with grass and belly fur from the doe. Most juvenile rabbit mortality occurred prior to weaning. Of the 126 litters monitored, 38% were preyed upon, 29% drowned and 20% were either preyed upon or drowned prior to emergence. Young drowned when sufficient rainfall for a particular soil type caused flooding of stops. In all, 13% of litters were weaned and left the breeding stop, with late spring-early summer being the most favourable period for survival. Predator numbers were lowest during this period. Ferrets were the most numerous predator; cats and harriers were also present. Disease was not significant. Of those rabbits that emerged, approximately 50% survived to 14 weeks of age. Less-frequent drowning during a sequence of dry years may explain an increase in rabbit number observed in previous years. This may make it possible to predict the need for control.


Author(s):  
D.J. Musgrave

Four years data from a steepland site near Omarama, North Otago (500 mm rainfall), shows that on average oversown lucerne produced 5.3 t/ha/annum, with 3.3 t/ha of this being produced between mid August and late November. The translation of this small-plot yield to expected production under normal grazing is discussed. In deriving the expected production, corrections are made for the long term production from nearby dryland lucerne stands, the effects of varying terrain within hill blocks and the effects of grazing management on utilisation. Recent research results and farmer practice both indicate that extensive areas of lucerne can be managed with simple systems that do not necessitate more intensive subdivision than for pasture. The expected production under grazing is used in a linear programme model of a semi-arid zone farm system, which includes a wide range of options. Examples investigated with the model included 'warm' and 'cold' properties, varying levels of development and allowing some irrigation. The likely costs of establishing lucerne are some 70% greater than for a clover-based pasture. However the model shows that the pattern and quantity of grazing provided by lucerne on low-sunny country makes it a profitable part of a development programme that balances year-round feed supplies, particularly on colder properties. Keywords: Medicago sativa, rangeland, semi-arid, oversowing, grazing management, profitability, model.


Author(s):  
K. Milligan

This collection of papers does four significant things: 1. It concentrates on hill country. 2. Precisely defines the research environment in pasture levels and animal production terms. One can clearly see the consequences in animal production at different times of the year when pre-grazing and residual herbage levels are defined and varied and to see the effects of different grazing systems at these pasture levels. Much better than high vs low stocking rates. 3. Attempts to set pature targets as well as animal production targets. 4. Defines critical pasture DM levels both below which pasture production is reduced, and above which control is lost. The proximity to these critical levels will, for a farmer, more precisely define the grazing management system he should adopt and the levels of animal production he should be able to achieve


Author(s):  
J.M. Mcgrath ◽  
J.W. Penno ◽  
K.L. Davis ◽  
R. Wrenn

The nutritional value of pasture silage made in New Zealand is often sub-optimal for lactating dairy cows. As farming systems require more pasture silage to be used in an attempt to increase lactation lengths and milksolids production per cow, the quality of this silage becomes more important. In spring 1995, pastures were closed for silage at weekly intervals from 11 September to 17 October, representing six distinct closure dates, to determine the effect that date and length of closure has on pasture quality. In spring 1997 pastures were grazed to different residuals (1.2- 1.4, 1.8-2.0, 2.1-2.4 and 2.5-2.9 t DM/ha) and then closed for silage to determine the effect that post grazing residual has on pasture quality. In both experiments pasture dry matter (DM) yield and chemical and botanical composition was monitored over the 63 day closure. Pasture closed on 11 or 17 September had higher metabolisable energy (ME) (P


2016 ◽  
Vol 16 ◽  
pp. 203-212 ◽  
Author(s):  
Mcg King ◽  
G.M. Rennie ◽  
B. Devantier ◽  
C.J. Hoogendoorn

Management of the balance of animal demand and feed supply is the result of a complex set of decisions. These decisions interact and are also variably affected by external drivers, including environmental. In particular, both pasture quantity and quality can be optimised by using appropriate grazing management, including stocking rate, livestock class, etc. In essence: apply sufficient grazing pressure at the appropriate time to maintain pasture covers at a level where the development of grass inflorescences is limited and pasture quality is maximised. The optimal grazing management strategy, however, may be different for each paddock and will change through the season. At a whole-farm scale, grazing management will be a set of trade-offs. Understanding the underlying ecological principles that drive the outcome of these grazing management decisions on pasture performance will have the greatest potential to drive the profitability and sustainability of hill country farms. Keywords: Grazing management, pasture performance, pasture quality, hill country


Author(s):  
M.G. Lambert ◽  
P.C. Luscombe ◽  
D.A. Clark

Soil, pasture and animal responses to 2 levels of superphosphate were measured within a farmlet trial, at Ballantrae hill country research area, near Woodville, during 1975-80. Soil and pasture measurements were also made for 3 years before the trial started. Pastures, which were dominated by low-fertility-tolerant grasses (LFTC;), moss and flatweeds, were oversown with 4 legumes before the trial started. Soil Olsen P level was 5 under untopdressed pasture in 1973, and 9 in 1975 after application of 500 kg/ ha superphosphate. Superphosphate rates were 120 (on low fertiliser areas q LF) and 640 (on high fertiliser areas = HF) kg/ ha/ yr average during 1975/80. Annual pasture production (adjusted for variable summer rainfall) was 7.1 t DM/ ha from untopdressed pasture and 8.1 t following 500 kg superphosphate/ ha in 1973-74. LF production rose to 8.5, and HF to 12.0, in 1980. Legume contribution rose from 5% in untopdressed pasture to 18% and 23% in LF and HF respectively in 1975/76. By 1979/80 legume contribution had steadily declined to 10% on both treatments, probably due to a measured increase in soil N availability and increased competitiveness of associated grasses. Ryegrass content rose at both fertiliser levels, while LFTG content fell; these trends were greatest under HF. Winter stocking rate was increased from 6 to 10.9 and 14.9 su/ha on LF and HF-respectively. Per animal performance did not decrease. A range of techniques which could increase efficiency of superphosphate use in hill country is discussed. These techniques include: selective application to responsive pastures; spring application; grazing management to encourage legume growth.


Author(s):  
C. Matthew ◽  
A.C.P. Chu ◽  
J. Hodgson ◽  
A.D. Mackay

Plugs of sheep-grazed, ryegrass-dominant pasture were transplanted to a glasshouse, in order to make detailed studies of tiller appearance from the base of flowering tillers in late spring-early summer. In 2 experiments, cutting treatments which reduced the opportunity for transport of assimilate from parent flowering tillers to daughter tillers markedly reduced both numbers of daughter tillers formed and their size. In one of the studies, proportion of radioactive carbon dioxide fed to flowering tillers, but recovered from daughter tillers, was 7.0%, and this transported radiocarbon appeared to be delivered preferentially to leaf elongation zones of young tillers. There appear to be fundamental differences in tillerbehaviour between 'Grasslands Ruanui' ryegrass and 'Ellett' ryegrass. The implications for farm practice are briefly discussed. Keywords ryegrass, tiller dynamics, radiocarbon, summer pasture production, pasture persistence


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