Vagner Guasso da Costa

Avaliação de espécies forrageiras de inverno na Depressão Central do Rio Grande do Sul

The experiment was carried out to evaluate the herbage production of cool season forage species and cultivars from Instituto Nacional de Investigacion Agropecuaria- INIA/Uruguay breeding program. The following species and cultivars were evaluated: Italian ryegrass (Lolium multiflorum Lam.): Cetus, Estanzuela 284 and Titan; Oats (Avena byzantina): RLE 115a and 1095a; White clover (Trifolium repens L.): Estanzuela Zapican; Red clover (Trifolium pratense L.): Estanzuela 116 and Birdsfoot trefoil (Lotus corniculatus L.) Sao Gabriel. Dry matter production, structural components percentage and production, canopy height, neutral detergent fiber, and crude protein percentages were determined. It was used a split-plot arrangement in a randomized block design, where the subplots were the evaluation dates, with four replications. Among the grasses, Italian ryegrass Titan presented the greatest herbage production of DM, with 7.2 t/ha and higher leaf proportion. The production of Birdsfoot trefoil and Red clover were similar and had greater DM production than White clover. The tested species and cultivars were adapted to the local conditions, even with rainfall deficit occurrence during the experimental period.

Concentrate supplementation for beef heifers on cool-season cultivated pastures

Com o objetivo de avaliar as relacoes nao-aparentes em estudos individuais foram analisadas em conjunto variaveis provenientes de nove experimentos realizados com diversos niveis e tipos de suplementos para novilhas de corte em pastagens cultivadas de estacao fria. Os dados foram estratificados em dois grupos: com e sem suplemento concentrado. A massa de forragem e a oferta de lâminas foliares, assim como a estrutura do dossel (altura e relacao folha:colmo), foram semelhantes entre os grupos com e sem suplementacao. As novilhas que receberam suplemento consumiram pasto com menor teor de fibra em detergente neutro e apresentaram maior ganho medio diario. A suplementacao aumentou em 33,3% o consumo total de materia seca. Para cada kg consumido de MS do concentrado, o consumo de MS do pasto reduziu 0,7 kg. A eficiencia de transformacao da forragem foi semelhante entre os grupos com ou sem suplementacao, com valor medio de 9,5 kg de MS da forragem/kg de peso corporal ganho. As novilhas que receberam suplemento ingeriram 6,4 kg de MS do suplemento a cada kg de ganho adicional. O uso de suplemento concentrado permitiu o aumento da taxa de lotacao e do ganho de peso por area. Novilhas sob suplementacao com concentrado apresentam maiores pesos corporais, maiores alturas de cernelha e maiores escores de condicao corporal no final do periodo de utilizacao da pastagem.

Comportamento de pastejo e ingestão de forragem por novilhas de corte em pastagens de milheto e papuã

It was studied performance, behavior and forage ingestion by beef heifers on pearl millet (Pennisetum americanum (L.) Leeke) and Alexander grass (Urochloa plantaginea) pastures from January to April 2008. The continuous grazing method with a variable number of animals was used. Forage ingestion was estimated during vegetative and reproductive stage of forage plants using chromic oxide as fecal production marker. Evaluations of behavior were carried out by visual observation in four 24-hour continuous periods. Mean values of forage mass, forage offer and leaf blade offer were 3,927 kg/ha of DM, 14.6 kg of DM/100 kg BW and 3.36 kg of DM/100 kg BW, respectively. The variables of the pasture, animal performance, ingestive behavior and forage intake were similar for pearl millet and alexander grass. Variables of forage, animal performance and grazing times, idle and rumination and number of bites per day showed variation over days of pasture utilization. Forage ingestion was 2.49% of the body weight and it did not vary according to phenological stage. Use of sites infested with alexander grass as pastures provides performance similar to the one obtained with pearl millet.

Comportamento ingestivo diurno de novilhas de corte recebendo níveis de suplemento

The trial was conducted aiming to evaluate pasture botanical composition and diurnal ingestive behavior of beef heifers receiving different supplement levels. The animals were kept in black oats (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.) pasture, receiving 0; 0.3; 0.6 and 0.9% of live weight (LW) of supplement. The supplement utilized was a commercial ration. In four dates were registrated diurnal activities of grazing, ruminating, idle, number of visits and trough permanence time and bite rate. Increasing supplement levels reduced grazing time and increased idle time (P 0.05). Botanical and structural composition of pasture were influenced by supplement levels and related with herbage production cycle (P>0.05).

Ingestive behavior and displacement patterns of beef heifers on Italian ryegrass pasture

The effect of supplementation on ingestive behavior and displacement patterns of beef heifers grazing on Italian ryegrass (Lolium multiflorum Lam.) pasture was evaluated. The grazing method was continuous with variable stocking rate. The experimental design was completely randomized with repeated measures on time. The supplement utilized was a commercial ration (17% CP, 21.4% NDF), daily supplied at 2 pm, in the proportion of 1% of body weight. The evaluations were made through visual observations, in four continuous periods of 24 hours. There was no difference in the bite rate between heifers with and without supplement and bite rate was higher at the end of the period of pasture utilization. Supplemented animals increased bite mass. The number of stations/minute, bites/station and the displacement patterns was influenced by forage changes along the occupation period. The ingestive behavior and displacement patterns of heifers are modified by supplementation and structural variation of the grass along its biological cycle. In the reproductive stage of Italian ryegrass, grazing time, daily number of bites and, feeding stations and time for station are similar between not supplemented and supplemented heifers.

Grazing ecology of female lambs on Italian ryegrass plus red clover pasture under different defoliation intensities

The relationship between pasture dynamics and ingestive behavior of female lambs was studied on Italian ryegrass (Lolium multiflorum Lam.) plus red clover (Trifolium pratense L.) mixture under a range of defoliation intensities. Rotational grazing was used and the grazing interval was determined by the thermal sum of 313 degree days. The initial pre-grazing canopy height disappearance values were 65 (very high), 58 (high), 47 (medium) and 37% (low). The sward vertical structure was similar among defoliation intensities. The forage allowance decreased linearly as defoliation intensities increased, with 0.35 bite/minute reduction for each 1% increase in forage allowance. The bite rate and number of bites/feeding station decreased with reduced contribution of leaves in the sward structure. It was associated, respectively, with an increase and a decrease of NDF and CP levels in forage as grazed by female lambs. The pasture cycle proves to be more important than defoliation intensities as a source for changes in feeding stations and displacement patterns of female lambs.

Recria de bezerras de corte em pastagem de azevém sob frequências de suplementação

This research aimed to evaluate the performance of beef heifers submitted to Italian ryegrass (Lolium multiflorum Lam) pasture and under differents supplementation frequencies: exclusively on Italian ryegrass pasture; supplemented seven days/week and supplemented five days/week (Monday to Friday). The weekly amount of supplement (17% CP, 71% TDN) was similar for heifers daily supplemented and supplemented five days a week. The method used was of continuous grazing with variable stocking rate in a complet randomized design with three treatments and two area replication. The stocking rate is greater when animals are supplemented, regardless of supplementation frequency. The average daily weight gain, body condition score and live weight gain per area were similar among supplementation strategies. The reducion of supplementation frequency has no negative effects on animal performance and may be an option for feed management of herd.

Alternatives of utilization of Italian ryegrass pasture for rearing of beef heifers.

The beef heifers performance from eight to twelve months of age was evaluated in exclusive Italian ryegrass (Lolium multiflorum Lam.) pasture, ryegrass plus red clover (Trifolium pratense) LE 116 or in ryegrass pasture receiving supplement in proportion of 1% BW. The continuous grazing method with variable stocking rate was used. The supplement used was a commercial ration, with 17% of crude protein, 23.6% of neutral detergent fiber and 59.6% of total digestible nutrients. The means values of forage mass and offer and leaf blade offer were 1327.2 kg/ha of DM and 10.5 and 3.7 kg of DM/100 kg of BW, respectively. The daily body weight gain was similar for beef heifers receiving supplement or in Italian ryegrass plus red clover, with mean value of 1039 grams. The stocking rate and body gain per area were higher when animals were supplemented. The use of supplementation for grazing heifers caused additive effect on the total dry matter intake and replacement in the grass dry matter intake.