Effect of stocking rate, season and pasture characteristics on liveweight gain of beef steers grazing perennial pastures

1989 ◽  
Vol 40 (6) ◽  
pp. 1277 ◽  
Author(s):  
PR Bird ◽  
MJ Watson ◽  
JWD Cayley

In each of 4 years (1975-78) yearling steers at stocking rates (SR) of 1.1-3.6 steers/ha continuously grazed pastures sown in 1971 with Trifolium subterraneum cv. Mt. Barker, Phalaris aquatica cv. Australian and Lolium perenne cv. Victorian at Hamilton from Mar. to Jan. Data on liveweight gain (LWG), fat depth and pasture attributes were collected over the 4 years. Body composition was estimated periodically over the first 2 years, using tritiated water. Relationships between LWG and SR were established and the overall annual effect was LWG (kg)=237-39.7 SR. However, most or all of the gains made at intermediate or higher SR were achieved in the spring and summer. Compensatory gains in these 5 months were greatest at 3 steers/ha but varied from 6.5 kg (in 1976) to 34 kg (in 1978) more than achieved at the lowest SR. The heaviest steers had more subcutaneous fat and steers at higher SR were leanest, but in 1 year of prolonged spring growth (1978) there was no difference in fat depth at any SR despite a 68 kg difference in liveweight (W) between lowest and highest SR. Seasonal LWG was modelled from W and/or pasture mass (green and dead fractions). Use of green pasture mass rather than total mass substantially improved precision in all seasons. A smaller but significant further improvement was obtained using green mass, dead mass and the interaction in the regressions. Severe penalties to LWG occurred in grazed pastures with a large component of dead material.

1997 ◽  
Vol 77 (4) ◽  
pp. 669-676 ◽  
Author(s):  
J. D. Popp ◽  
W. P. McCaughey ◽  
R. D. H. Cohen

A 4-yr experiment was conducted (1991 to 1994) near Brandon, MB, to determine the effects of grazing system (continuous and rotational) and stocking rate [light (1.1 steers ha−1); heavy (2.2 steers ha−1)] on the productivity, botanical composition and soil surface characteristics of an alfalfa (Medicago sativa L.; approximately 70%), meadow bromegrass (Bromus biebersteinii Roem & Schult.; 25%) and Russian wild ryegrass [Psathyrostachys juncea (Fisch.) Nevski; 5%] pasture. Grazing season length was shorter (P < 0.05) for cattle in continuously compared with rotationally stocked pastures in 1991, while in 1993 and 1994 it was shortest (P < 0.05) in heavily stocked continuously grazed pastures. Carrying capacity (steer days ha–1) was greater (P < 0.05) in heavily stocked rotationally grazed pastures compared with other treatments in 1991, 1993 and 1994. In 1992, it was greater (P < 0.05) in heavy than light stocking rate treatments for both rotationally and continuously grazed pastures. Cattle usually gained more (P < 0.05) per day (kg d−1) and during the season (kg hd−1) at light than at heavy stocking rates, while total liveweight production (kg ha−1) was greater (P < 0.05) at heavy than at light stocking rates. Forage production and disappearance did not differ (P > 0.05) within grazing systems and stocking rates from 1991 to 1993, but in 1994, production and disappearance were greater (P < 0.05) at heavy than at light stocking rates. Mean seasonal herbage mass available and carry-over were greater (P < 0.05) in lightly stocked pastures than heavily stocked pastures from 1991 to 1994. After the first year of grazing, the proportion of alfalfa increased (P < 0.05), while grasses declined (P < 0.05) within all grazing treatments. In subsequent years, a trend was observed, where alfalfa declined and grasses increased in all pastures, except those stocked heavily and grazed continuously, which by 1994 had the greatest (P < 0.05) percentage of alfalfa. As years progressed, increases (P < 0.05) in basal cover concurrent with declines in bare ground were recorded on all grazing treatments, while litter cover often did not differ (P > 0.05) within either grazing system or stocking rate, except in 1992, when basal cover was lowest (P < 0.05), while litter cover was greatest (P < 0.05) on lightly stocked continuously grazed pastures compared with other treatments. Stocking rates were a key factor to optimizing individual animal performance and/or gain per hectare on alfalfa grass pastures, however differences in the effect of continuous and rotational stocking on pasture productivity were minimal. Key words: Alfalfa, grazing, stocker cattle, production


2001 ◽  
Vol 41 (8) ◽  
pp. 1099 ◽  
Author(s):  
R. A. Waller ◽  
P. W. G. Sale ◽  
G. R. Saul ◽  
G. A. Kearney

A 4-year field experiment was carried out in south-western Victoria to determine whether tactical stocking might improve perennial ryegrass (Lolium perenne L.) persistence and prime lamb production, compared with the more common practice of year-around continuous stocking. Tactical stocking consisted of variable length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a more typical naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. The effects of the grazing systems and pasture treatments on herbage production and stocking rate are presented in this paper. Herbage production was similar between the treatments, but tactical stocking significantly increased herbage mass during the growing season (P<0.05) compared with continuous stocking. In spring each year, the herbage mass generally exceeded 3000 kg dry matter/ha in tactically stocked paddocks and averaged 500–900 kg dry matter/ha higher than the mass on continuously stocked paddocks. This enabled the year-round stocking rate to be increased by an average of 9% over the 4 years of the experiment. We considered that the stocking rates could not be further increased, despite the higher herbage mass in spring, as stock reduced the dry herbage to a low residual mass by the opening rains in autumn. In contrast, stocking rates averaged 51% higher on the upgraded pasture compared with the typical pasture over the 4 years of the experiment. This indicates that pasture improvement and soil fertility status have a much greater impact on productivity than changes to grazing method. However, tactical stocking was able to increase the sustainability of prime lamb production on upgraded pastures in a dry summer climate, by maintaining herbage cover on the paddocks over the summer–autumn period.


1993 ◽  
Vol 73 (4) ◽  
pp. 715-724 ◽  
Author(s):  
Hélène V. Petit

Twenty percent of forage farmland was devoted to seeded and native pastures in 1991. Common white clover is widely found in native pastures but ladino clover is the main legume recommended. Timothy is the most popular grass for seeded pasture and its yield is increased by N fertilization. More than 30% ladino in pasture decreases the N fertilizer requirement. High fertilization of pasture where beef steers are kept at high stocking rates and moderately fertilized pasture where beef steers are kept at low stocking rates result in similar average daily gains. Excessive steer stocking rates can result in decreased herbage production at the end of the growing season which results in decreased weight gain. However, feeding concentrate can compensate for herbage shortage and maintain weight gain of steers with a high stocking rate similar to that of unsupplemented animals on pasture with a low stocking rate. The difference in total beef production per hectare between heavily and moderately fertilized pastures is only 10% higher for the former when herbage surpluses conserved as silage and hay are fed to steers during winter. When herbage allowance is not limiting, there appears to be no advantage in supplementing grazing cattle with concentrate or protein. Key words: Pasture, grazing, dairy cattle, beef cattle, sheep


Soil Research ◽  
1984 ◽  
Vol 22 (3) ◽  
pp. 343 ◽  
Author(s):  
ST Willatt ◽  
DM Pullar

Soil compaction caused by animal treading in grazing of pastures has not been considered a serious problem in Australian soils. However, recent circumstantial evidence suggests that in northern Victoria compaction does occur. In an experiment conducted at the Hamilton Pastoral Research Station (western Victoria) in 1973, grazed pastures with various stocking rates showed increases in bulk density and bearing capacity of the soil, and decreases in hydraulic conductivity occurred with increasing stocking rate. Some change in pasture composition was also noted.


1987 ◽  
Vol 27 (3) ◽  
pp. 389 ◽  
Author(s):  
PM Dowling ◽  
GG Robinson ◽  
RD Murison

Herbage mass on offer, botanical composition and livestock production of sheep grazing 3 types of pastures developed by 'aerial' methods at 3 stocking rates (5, 7.5 and 10 sheep/ha) were compared in a 3-year grazing trial at Glen Innes, N.S.W., during 1972-75. The pastures were: resident grass-white clover (F), resident pasture plus surface sown grass (SF), and as for SF but with herbicide application prior to surface sowing ofgrass (HSF). All pasture treatments had equivalent rates of superphosphate applied. The sowing effect and the herbicide effect were statistically analysed by contrasting the pasture treatments: SF-F, HSF-SF, respectively. The SF-F contrast showed that herbage on offer of the sown grasses on the SF pasture was greater, and this difference increased with time. Legume herbage on offer was greater on the SF pasture though it declined with time, and exhibited seasonal variation. The HSF-SF contrast indicated that herbage on offer: of sown grass was greater on the HSF pasture and increased with time; of the herbs component was greater on the HSF pasture during the initial and final stages of the experiment; oflegume was greater on the HSF pasture but the difference declined with time; of resident grass was greater on the SF pasture but the difference declined with time; and of dead material was consistently greater on the SF pasture. The contrasts for the resident grasses and dead material components varied seasonally. Herbage on offer of all pasture components declined as stocking rate was increased. Patterns of decline varied with pasture component and pasture treatment. Mean sheep liveweights were influenced by pasture treatment, with sheep on the HSF pasture being the heaviest, and those on the F pasture, the lightest. Increasing stocking rate decreased mean sheep liveweights on pastures F and SF but increased mean sheep liveweights on the HSF pasture. Liveweight declines were least for sheep grazing the F and SF pastures and liveweight increases were greatest on the HSF pasture during late summer-autumn. Greasy wool production per sheep was greatest on the HSF pasture during 1972-73 but thereafter there were no significant differences between treatments. We conclude that, although animal production was increased by the introduction of sown grasses in the short term, the level of superiority was not as great as expected. Changes in management strategies may be required if the greater production achieved is to be sustained.


2004 ◽  
Vol 55 (12) ◽  
pp. 1213 ◽  
Author(s):  
J. O. Hill ◽  
R. J. Simpson ◽  
A. D. Moore ◽  
P. Graham ◽  
D. F. Chapman

Botanical composition (basal cover) was measured in 4 replicated pasture treatments based on Phalaris aquatica and Trifolium subterraneum at Hall, ACT (unfertilised with low and high stocking rate; fertilised with low and high stocking rate) and in 2 unreplicated pasture treatments based on native perennial grasses (Austrodanthonia spp. and Microlaena stipoides) and T. subterraneum at Bookham, NSW (unfertilised and low stocking rate; fertilised and high stocking rate). Current economic pressures are encouraging graziers to increase their use of phosphorus (P) fertiliser and to adopt higher stocking rates. The objective of the research was to determine the changes in botanical composition that may result from these changes in grazing systems management. At Hall, annual species differed in their responses to P fertility. Notably, basal cover of Bromus spp. increased significantly with P application, whereas Vulpia spp. decreased significantly. Basal cover of T. subterraneum also increased significantly with P application when stocking rate was high, but was reduced by P application if stocking rate was low. Basal cover of perennial grasses (P. aquatica and Holcus lanatus) was significantly higher at low stocking rate when P was applied. The botanical composition of high stocking rate treatments was relatively stable over time, which contrasted with less stable composition at low stocking rate. At Bookham, fertilised pasture in unreplicated paddocks appeared to have a higher basal cover of productive annual species (i.e. Bromus spp. and T. subterraneum), but native perennial grasses appeared to have lower basal cover in comparison with the unfertilised area. These results indicated that in some cases, the influence of P fertiliser and high stocking rates on botanical composition was favourable (i.e. increased basal cover of P. aquatica and T. subterraneum) and in others it could be detrimental (i.e. lower basal cover of native perennial grasses).


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 90-90
Author(s):  
Stacey A Gunter

Abstract To evaluate the effects of stocking and supplementation rates on steers grazing mixed-grass prairie during winter, 16 pastures (10 to 21 ha each) were selected and treatments were arranged in a 3 x 2 factorial design; the first factor was an stocking rate of 39.4, 33.2, and 29.7 animal-unit-d/ha harvested over 88 d of grazing; the second factor was supplementation at 0.9 or 1.4 kg/d. Steers were fed a 43% CP cottonseed meal-based pellet. Pastures were stocked annually in late January (2009, 2010, and 2011) with British x Continental crossbred beef steers (body weight = 202 ± 6.7 kg; n = 137 steers/yr) at stocking densities described above. Data were analyzed by ANOVA with pasture as the experimental unit and year as a random variable; least-squares means were separated with linear and quadratic contrast. From late-January to mid-March, average daily gain (ADG, kg) did not differ (P = 0.13) among stocking rates, but ADG differed (P = 0.01) between 0.9 and 1.4 kg of supplement/d. From mid-March to late-April and over the entire grazing period, ADG responded to stocking rate and interacted (P &lt; 0.01) with supplementation rate; ADG tended to respond quadratically (P ≤ 0.09) to stocking rate at 0.9 kg/d of supplementation, but with 1.4 kg/d of supplement ADG was not affected (P ≥ 0.18). Body weight gain per hectare tended (P &lt; 0.08) to interact between stocking and supplementation rates. With 0.9 kg/d of supplement the BW gain per hectare increased quadratically (P &lt; 0.01) in response to increasing stocking rate, where supplementation at 1.4 kg/d resulted in BW gain per hectare increasing linearly (P &lt; 0.01). Optimal supplementation rates with high-protein feeds is related to stocking rate. At lower stocking rates, less supplement seems to be most beneficial. At higher stocking rates, more supplement is justified.


1975 ◽  
Vol 15 (72) ◽  
pp. 102 ◽  
Author(s):  
GD Kohn ◽  
EG Cuthbertson

The influence of pasture topdressing with superphosphate and of stocking rate on the Chondrilla uncea population in a clover-ryegrass (Trifolium subterraneum-Lolium rigidum) pasture was measured in a grazing experiment at Wagga Wagga, New South Wales, over the period 1962 to 1966. Superphosphate application reduced final weed populations at all stocking rates. Continuous grazing maintained skeleton weed populations at a low level, but increasing the stocking rate from 5 to 15 sheep ha-1 had little influence on weed numbers. A management comparison at a high stocking rate-high fertilizer rate showed that rotational grazing increased the weed population compared with continuous grazing systems.


1971 ◽  
Vol 11 (52) ◽  
pp. 498
Author(s):  
GW Arnold ◽  
A Axelsen ◽  
HR Gharaybeh ◽  
HW Chapman

In an experiment at Canberra, A.C.T., extending over four years, crossbred and Merino ewes were grazed at three stocking rates on pastures of either phalaris (Phalaris tuberosa), phalaris combined with separate paddocks of brome grass (Bromus inermis), and cocksfoot (Dactyllis glomerata), or separate paddocks of brome grass and cocksfoot. Subterranean clover (Trifolium subterraneum) was present in all pastures. One-, two-, and three-paddock systems and two times of lambing were also compared. Pasture availability and animal productivity were measured. Early lambing resulted in more prime lambs although the later lambs had slightly higher rates of gain. At the highest crossbred stocking rate studied (seven ewes per acre) wool production per acre was still increasing, but number of prime lambs and lamb liveweight gain did not increase above stocking rates of five ewes per acre. More feed was available to ewes during late pregnancy on treatments allowing feed rationing in autumn and early winter, but neither rationing nor including brome grass and cocksfoot in the system increased animal productivity beyond that achieved by grazing phalaris continuously. At stocking rates up to six ewes per acre, animal production was greatest from phalaris grazed continuously. Stocking rates were designed to provide similar weights of either Merino or crossbred ewes per acre at each stocking level. Because more lambs were born to crossbred ewes they had less feed than Merinos in spring and summer at all stocking rates. Lambs from crossbred ewes were heavier at birth and grew faster than lambs from Merino ewes. More prime crossbred lambs were produced per acre at all stocking levels. The reproductive rate and lamb production of Merino ewes dropped sharply with increased stocking rate. Fleeceweights were similar for both breeds, particularly at low stocking rates. Wool production per acre increased with stocking rate and was higher from Merinos at each level.


1992 ◽  
Vol 32 (5) ◽  
pp. 611 ◽  
Author(s):  
AD Craig

Two cultivars of subterranean clover, Trikkala and Mt Barker, were continuously grazed by Merino ewes and lambs at 3 stocking rates (8, 13, and 18 ewes/ha) from 1976 to 198 1. The pastures were assessed for clover seedling density, pasture availability and composition, seed reserves, and oestrogen content. Trikkala produced consistently higher seed yields than Mt Barker, with an average yield 3.36 times that of Mt Barker by January 1981 (1178 v. 350 kg/ka). The higher Trikkala seed yields resulted in improved clover seedling densities and increased amounts of clover in the pastures. At the last assessment (8 September 1980) there was an average of 3.15 times more clover in the Trikkala pastures than in the Mt Barker pastures (469 v. 149 kg/ha). Trikkala produced more total available pasture than Mt Barker, at several samplings, because the contribution of subterranean clover to total available pasture was greater after September 1978. The formononetin, genistein and biochanin A content of both cultivars decreased with increasing stocking rate. The most consistent effects were observed in genistein content, with reductions occurring in 7 of the 11 samplings.


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