Beef heifers performance under continuous grazing on grassland structure

Introduction BEEF HEIFERS PERFORMANCE UNDER Salado river Basin is the main beef cattle CONTINUOUS GRAZING ON MODIFIED breeding region of Argentina. It is a flat flooding area with poor slopes (<3%). Their soils are FCAYF Natracuoles, Natraqualfes and Argiacuoles. GRASSLAND IN ARGENTINA FLOODING PAMPA In its grasslands predominates continuously grazed and set stocking rate cow - calf systems. Agnelli, María L., Refi, Roberto 0., Oyhamburu, Estrella M., Ursino, Mario C. Facultad de Ciencias Agrarias y Forestales · Universidad Nacional de La Plata (UNLP) - www.agro.unlp.edu.ar [email protected] Stocking rate and grazing pressure are two core variables that directly affect animal production. During 2010, 2011 and 2012 an experiment on the effect of stocking rate on animal growth | TRIAL DESIGN and its body condition with Anqus heifers MODIFIED MESOPHYTES LOCATION OMagdalena, Vieytes · Buenos Aires - Argentina 57° 07' W - 35* 01'S 5/ha glyphosate | 1/ha 2.4 - D continuously grazing winter grasses promotion GRASSLAND was carried out. Flooding Pompa wet grasslands "EL Amanecer" farm - UNLP 1.9 ha LSR 2EV /ha 1.4 ha HSR 3EV /ha Aim The aim of this study was to establish the stocking rate that optimizes beef rearing 1.9 ha LSR 2EV /ha heifer's performance for early mating. Experimental period Continuous grazing was performed from early June to late October in 2010 and 2011, and from MONTHLY RAINFALL mid-May to late October in 2012. HSR 3EV /ha 1.4 ha LSR 2EV /ha 1.9 ha HSR 3EV /ha 1.4 ha Methods Treatments expressed in cow equivalent (EV) (Cocimano et al. 1975): Aberdeen Angus Winter anual species Frame Score 3 High Stocking Rate (HSR), 4.4 animals/ha • Lolium multiflorum Low Stocking Rate (LSR), 3 animals/ha INITIAL BODY WEIGHT • Bromus catharticus 2010 2012 • Gaudinia fragilis Weather conditions during the three year operiment showed signicantvariations in autunn winter aintal wit positle Inpact on primary production and animal response. These oscilations are common in the mentioned neglon. 164.3 169.5 186.0 200 | RESULTS Effects of stocking rate, year and season on studied variables Treatments Years Seasons Treatments Years Seasons 2000 2011 -2012 Autumn - Water Spring 2010 201 2014 Autunn-Wter Spring 1317 4 45a 1827 45b 1717 556 1998 a SSc 1004 55a 1686 a 41b 1400 a 50a 215.6 + 1.0a 224.6 4 1.06 215.9 1.3a 230.4 + 1.36 215.5 1.1a 208 0.9a | 238 ま 1.1 と DT (om) 6.29 10.23a 8.70 t 0.23b 7.35 + 0.406 9.43 10.25c 5.93 10.24a 8.37 +0.21b 6.11 10.40a DWG 0.44 10.03a 0.55 t0.03b 0.65 0.04b 0.68 t 0.05b 0.24 t 0.04a 0.64 0.04b 0.38 t 0.03a Meanswith different letters doffer at0.0001 AMeans with drterent letters dffer-0.05 Comparison of variables at the end of the experiment, three - year average THB (kgOM) DT (cm)* LW (kg)* BCS • 1313 + 113a 4.34 10.30a 244.8 +4.2a 3.80 + 0.05a 1903 + 113b 6.19 +0.30b 262.2 + 4.4b 3.91 + 0.06a *Means with efferent letters differ at g0.01 Means with drterent letters dffer at p-0.05 Conclusions The outhors wish te edknowledge niversided Naclonal de le Plata, Buenos Aires, Argentina. The promotion of winter species using herbicides the possibilities of improving the efficient use of teferences AgrelL Unino RR GegerialR Eia, Rodriguet G.A, Aesla o (2011) Stocking ratni efects on performance and lagestive belaler of graeg beefeiters dfetaon. Proc, of te x Intavnational Rangland Congre, Roaria, Argeatina 2al02011 6s Evin RR Gegeriai R AgaeliL Uino Ansia 0(2011) Daly strie grazing er continos controled graing weh beef hefen onwiter spedes premotion galand. Proc. of the produces a suitable resource for the rearing heifers. spring forage production and high production of meat. LSR allowed reaching the threshold weight for early The productive planning was sensitive to high Intenational Rangland Conpress, Rearie, Argeatina 0a -02 4 Oante lde Aand Sestriel aooo) tete de la apicacdn de gifout ste la prodde veonoorids Rerica de un pestical n yeldn Latieaneriana de odudde Anima Congess Urvtun de Pducdde Aelal, Kontides. Uryty al--2000, Ardves mating in a high percentage of rearing animals. environmental variability expressed through the year HSR allowed sustaining high stocking rate in winter, effect. Latineamerlanes de Producdde Ainaa (1): . © 2013 DAIANA MARTINEZ. ALL RIGHTS RESERVED. Treatments - LSR- HSR -