Eduardo Londero Moojen

POTENCIAL PRODUTIVO DE UMA PASTAGEM NATIVA DO RIO GRANDE DO SUL SUBMETIDA A NÍVEIS DE OFERTA DE FORRAGEM

A grazing experiment on rangeland was conducted at the Estacao Experimental Agronomica, UFRGS, Eldorado do Sul, RS, Brazil, to evaluate the average daily gain per animal and liveweight gain per hectare of beef cattle, pasture accumulation rate, dry-matter production , crude protein content, in vitro organic matter digestibility and litter percentage in dry matter, under levels of 4.0, 8.0, 12.0 and 16.0% liveweight as forage on offer. Forage on offer conditionated different residual dry matter/area. By reducing the grazing pressue there was an increase in residual dry matter/ha. Different amounts of forage on offer affected animal performance. The best accumulation rate of the pasture, average daily gain and liveweigh gain/ha were obtained under the range of 11.5 and 13.4% of forage on offer. The quality of dry matter available was reduced by increasing the amount of forage on offer.

Potencial produtivo, alterações da estrutura e qualidade da pastagem de milheto submetida a diferentes níveis de nitrogênio

It was conducted an experiment with pearl millet under grazing with different levels of N (0, 250, 300, 450 and 600 kg/ha). The objective was to study the dry matter (DM) production, the utilization efficiency, the recuperation rate, forage density and quality. The experiment was completely randomized design with two replications. Total density and per layer, the distribution and quality of leaf blade, stem and dead material components in distinct pasture layers (0-10, 10-20, 20-30, 30-40 and >40 cm above soil level) were evaluated. It was used beef heifers in continuous grazing systems, with an offer of 10 kg day of DM to 100 kg of LW. To maintain the intended offer was used the put-and-take technique. The DM production showed a quadratic relation with nitrogen levels. The recuperation rate and utilization efficiency of N showed negative linear relation with nitrogen levels. Occur increase in contribution of leaf blade and decrease in stem and dead material percentage and forage density of lower layer in direction to top of pasture in all treatment. The nitrogen fertilization no change leaf/stem relation and density of pearl millet pasture. The crude protein of stem and dead material showed positive linear relation with nitrogen levels from top to base of pasture and for leaf blade until 30 cm height. The in vitro organic matter digestibility was indifferent to nitrogen levels, except leaf blade above 10 cm, that showed a quadratic relation with nitrogen levels.

PRODUÇÃO ANIMAL EM VÁRZEA SISTEMATIZADA CULTIVADA COM FORRAGEIRAS DE ESTAÇÃO FRIA SUBMETIDAS A DIFERENTES NÍVEIS DE ADUBAÇÃO

The use of lowland areas in the Central Depression of Rio Grande do Sul State, Brazil is basically limited to irrigated rice. Those areas stay on fallow during the winter due to lack of a good natural drainage. Improvement in drainage can be obtained througth area leveling and microrelief correction associated to the establishment of superficial drains. Therefore, an experiment was conducted in order to evaluate cattle production on a leveled lowland area with several grazing winter plant species under different fertilizer rates. The experiment was conducted at the Federal University of Santa Maria in a soil of the Vacacai mapping unit. The area was leveled with a 0.06% slope gradient and the plant species were ryegrass (Lolium multiflorum), white clover (Trifolium repens) and birdsfoot trefoil (Lotus corniculatus). The fertilizer levels were 50%, 100% and 150% of the official recomended rate and the soil had its pH corrected to 5.5 using limestone. The experiment design was a randomized block with two replications and each experimental unit measured 0.5ha. The beef calves had 8-10 months of age and placed under continuous grazing, with 480 kg ha-1 of live weight for treatment. The parameters evaluated were: individual daily weight gain, animal load, weight gain per area, average dry matter accumulation by the pastures, in vitro digestibility, protein and botanical composition. The dry matter of the pastures was around 1000kg ha-1 and average accumulation for dry matter of the pastures was 19.9kg ha-1 day-1. The average weight gain per animal was 1016g animal-1 day--1, with an average load 738.6kg per hectare and the average weight gain was 469.7 kg ha-1. The total number of grazing days were 98, 121 and 128 for the 50, 100 and 150% recommended fertilizer rates. The NPK fertilizer levels, keeping constant the nitrogen fertilization, didn´t affect the average daily weight gain, animal load and weight gain per area.

PRODUÇÃO ANIMAL EM PASTAGEM DE MILHETO SOB DIFERENTES NÍVEIS DE NITROGÊNIO

An experiment was conducted at the Universidade Federal de Santa Maria, in Santa Maria, RS, Brazil, with the objective of evaluating the effects of three N levels (0, 150 and 300 kg/ha), in pearl millet (Pennisetum americanum (L.) Leeke) cv. Comum, on animal production. Beef steers were assayed through daily liveweigh gain, gain per hectare and animals.day/hectare. A continuous grazing system was used, with stocking rate adjustments to maintain a 10% grazing pressure that characterized a medium residue of 3,168 kg of DM/ha. The dependent variables showed a positive linear relationship with the N levels, denoting the high animal production potential of pearl millet.

Desempenho de pastagem nativa e pastagem sobre-semeada com forrageiras hibernais com e sem glifosato

The experiment was developed in Bage-RS, Brazil, to evaluate the dry matter production (DM), stocking rate (kg LW ha-1), live weight gain per animal (ADG, kg head-1 day-1) and gain per area (GPA, kg LW ha-1) in: T1-native pasture (control); T2-native pasture sodseeded with Italian ryegrass (Lolium multiflorum), white clover (Trifolium repens) and birdsfoot trefoil (Lotus corniculatus); T3-similar to anterior, plus glyphosate spraying; T4-similar to anterior, but with double fertilization. It were utilized Braford steers. The grazing method was the continuous stocking, with stocking adjustments to maintain a level of forage on offer of 10% (10kg of DM 100kg LW-1 day-1). To determine the DM of pasture, it was utilized the double sample method with a disc meter and the cage method for the pasture accumulation rate. The experimental design was a complete randomized blocks, with two blocks and four treatments. The introduction of cool season species in native pasture, with or without glyphosate spraying, contributes to increase native pasture productivity. Over-seeding cool season species allowed a higher stocking rate and animal production per animal and per area as compared to natural pasture.

EFEITO DA ÉPOCA DA DESMAMA E DA PASTAGEM NO DESEMPENHO DE VACAS E TERNEIROS DE CORTE. 1 - DESEMPENHO DAS VACAS

RESUMO Foi avaliado o desempenho de vacas de corte desterneiradas antecipadamente, aos 101 dias apos o parto, e que no periodo anterior ao desterneiramento haviam permanecido em campo nativo (CN) ou pastagem cultivada (PC) e apos o desterneiramento, em CN. Foi mantido ainda um grupo de vacas em CN desterneiradas aos 213 dias, seguindo o metodo de criacao normalmente empregado na regiao. Considerando todo o periodo experimental, foi verificado um maior ganho de peso (P < 0,01) e melhor estado corporal (P < 0,05) nas vacas cujo desterneiramento precoce foi precedido pela alimentacao em PC. A taxa de aparecimento de cio pos-parto, foi de 100% nas vacas desterneiradas aos 101 dias e mantidas previamente em PC, 41,7% para as vacas desterneiradas antecipadamente e que permaneceram em CN, e de 14,3% naquelas desterneiradas aos 213 dias.

Produção animal em gramíneas de estação fria com fertilização nitrogenada ou associadas com leguminosa, com ou sem fertilização nitrogenada

The experiment was conducted in Santiago, RS, Brazil, during the period from April 24, 1996 to May 11, 1996. Animal production systems in pastures were evaluated in which the treatments were comparisons between oats + annual ryegrass + arrowleaf clover (O + R + A); oats + annual ryegrass + arrowleaf clover + 150kg/ha of nitrogen (O + R + A + N) and oats + annual ryegrass + 300kg/ha of nitrogen (O + R + N), in a complete randomized design, with three replications. The grazing method was the continuous, with stock adjustements to maintain the dry matter on offer (grazing pressure) in 10%. It was used weaned calves. The parameters evaluated were stocking rate, average daily gain per animal (ADG) and liveweigth gain per hectare (LWG). The stocking rates were higher in the treatments with nitrogen. They were 1140, 1490 and 1652kg LW/ha, respectively to O + R + A; O + R + A + N and O + R + N. The ADG were 0.928 1.091 and 0.839kg/an/day, determining liveweight gains per hectare of 515; 720 and 650kg LW/ha, to the treatments O + R + A; O + R + A + N and O + R + N. The obtained results suggest the utilization of nitrogen fertilization in pastures of oats + annual ryegrass + arrowleaf clover, raising a new alternative to increase the efficiency of pastures production, reduce costs, and achieve hight liveweight gains per area.

Produção de cordeiros em pastagem de azevém e trevo-branco sob diferentes níveis de resíduos de forragem

The objective of this research was to analyse the effects of different forage mass levels on lamb production. The experiment was conducted in Tupancireta, Planalto Medio region at the State of Rio Grande do Sul, Brazil, in a mixture of italian ryegrass cv. Estanzuela 284 (Lolium multiflorum Lam.) + white clover cv. Yi (Trifolium repens L.), under different forage mass (FM) levels. The experimental design used was completely randommized, and the FM levels studied were: 1,119, 1,320, 1,477, 1,695, 2,146, 2,166, 2,410 and 2,483 kg/ha of dry matter (DM - kg/ha). The experimental period was from September 30 to December 8, 1992 and the animals used were cross lamb Ile de France x Corriedale early weaned (mean ± 80 days). Were evaluated the daily liveweight gain (DLG), gain per hectare (G/ha), stocking rate carryed, animals.day/ha and the DM of conversion efficience in kg of lamb liveweight. The results showed a positive linear relationship between DLG and G/ha with increased of FM levels. The FM levels higher to 2,400 kg of DM/ha reached 497 kg of total lamb liveweight gain/ha, and DLG/lamb of 0.12 kg/day. There was no FM levels effect at the stocking rate and animals.day/ha; there was a negative linear relationship between DM of conversion efficience with FM levels studied. The results show the effect of FM levels on animal response.

Precisão da estimativa da massa de forragem com discos medidores em pastagem nativa

O objetivo do trabalho foi avaliar a precisao da estimativa da massa de forragem (MF) em pastagem natural (PN) com emprego de discos medidores. Os tratamentos foram tres diferentes areas de disco, respectivamente 0,1, 0,2 e 0,3 m2 e cada uma combinada com tres pesos de disco 5, 10 e 15 kg/m2. O delineamento experimental foi inteiramente casualizado com 50 repeticoes, em um arranjo fatorial 3 x 3 (3 areas de discos x 3 pesos de discos). Os resultados obtidos foram submetidos a analise de regressao entre altura do disco e MF determinada em cada data de avaliacao, area e peso de disco. Dos modelos matematicos obteve-se os coeficientes de variacao residual (CV). Posteriormente, adotou-se o metodo de analise de variância em delineamento de blocos ao acaso com sete repeticoes de um experimento fatorial 3 x 3 (3 areas de discos x 3 pesos de discos) para epocas avaliadas. As relacoes entre as combinacoes das tres areas dos discos associadas com os tres pesos e o CV das medidas obtidas com disco foram quadraticas e positivas. A area de disco de 0,1 m2 e peso 5 kg/m2 apresentou o menor CV das leituras obtidas com disco nos periodos avaliados. A medida que aumentou a area de disco, aumentou o CV para os pesos de 5 e 10 kg/m2. As relacoes entre as combinacoes dos tres pesos e areas dos discos e o CV foram lineares e positivas. O menor peso de disco, de 5 kg/m2, associado a area de 0,1 m2 apresentou o menor CV. A relacao entre epocas de avaliacao e o CV foi linear e positiva. O disco de menor area 0,1 m2 e peso 5 kg/m2 apresentou o menor CV para a estimativa da MF da PN, sendo portanto o mais indicado para avaliar a MF da pastagem natural. O avanco da epoca de avaliacao aumentou o CV na estimativa da MF da PN com discos.

EFEITO DE ÉPOCA DA DESMAMA E DA PASTAGEM NO DESEMPENHO DE VACAS E TERNEIROS DE CORTE: DESEMPENHO DE TERNEIROS

SUMMARY The experiment evaluated the weight gain of beef calves weaned 101 days after calving, kept before weaning on cultivated winter pasture or native pasture. After early weaning, the calves were kept on a drylot and fed during 41 days, afterward they were kept on cultivated summer pasture. One control group of calves was kept on native pasture and weaned 213 days after calving. Prior to early weaning, calves kept on cultivated winter pasture had a higher weight gain (P 0.05) for calves previously kept on cultivated winter pasture to those kept on native pasture. Calves from the control group showed a higher weight gain (P<0.05) from 101 to 213 days, than those early weaned. At the end of the experiment, when the calves of the control group were weaned (213 days after calving), the calves early weaned and previously kept on cultivated winter pasture had the highest weight (P < 0.05).