A database containing 140 articles published in journals (731 treatment means evaluated) was used to examine the effect of different lactic acid bacteria (LAB) on fermentation, chemical composition and aerobic stability of maize (corn) silage. Compared with the control, dry matter (DM) loss increased by 8% and 50% (p < .01) due to inoculation of maize silage with either homolactic LAB ( ho LAB) or heterolactic LAB ( he LAB). In vitro DM digestibility of maize silage increased only with ho LAB inoculation (+2.22%; p < .01). The he LAB inoculation increased (p < .01) the aerobic stability of maize silage by 71.3 hr. To investigate the effect of silage inoculation on livestock production, a second database comprising 35 articles [99 treatment means evaluated based on results from 648 cattle (429 beef cattle and 219 dairy cows) and 298sheep] was used. Inoculation of maize silage with either ho LAB or he LAB did not affect milk yield (p > .05), but their combination ( mix LAB) depressed milk yield (-2.5 kg/ day; p < .01). Inoculation with ho LAB increased DM intake in sheep (+0.15 kg/day; p = .02), but decreased it in beef cattle (-0.26 kg/day; p = .01) without affecting average daily gain for both sheep and beef cattle (p ≥ .06). In conclusion, fermentative loss increased regardless of the bacterial inoculant used, while aerobic stability increased mainly by using he LAB. Benefits from ho LAB inoculation on animal performance were noted only for feed intake in sheep, while productive performances of dairy cows and beef cattle were not improved. K E Y W O R D Saerobic deterioration, animal performance, fermentation, Lactobacillus spp., silage inoculant | 597

RESUMO O presente trabalho visou empregar um estudo metanalítico para sumarizar e analisar dados sobre adubação nitrogenada em pastagens formadas por gramíneas dos gêneros Brachiaria, Cynodon e Panicum. Foram selecionados 36 trabalhos de pesquisa realizados no Brasil nos últimos 10 anos, incluindo artigos científicos, teses e dissertações. Com base nos dados contidos nesses trabalhos, foi calculado o incremento relativo de matéria seca e de proteína bruta em relação ao tratamento controle (ausência de adubação nitrogenada) e a eficiência da utilização do nitrogênio na produção de matéria seca e proteína bruta. Os dados obtidos foram submetidos à análise de variância para efeito linear e quadrático em cada uma das variáveis dentro de cada gênero e, no caso de significância, foi realizada análise de regressão. A produção de matéria seca e de proteína bruta de forrageiras tropicais responde de forma expressiva à adubação nitrogenada, principalmente a segunda, porém o acréscimo nas doses de nitrogênio reduz a eficiência da adubação. Verificou-se uma frequente omissão de informações relevantes em trabalhos com adubação nitrogenada em pastagens.

The use of larger seeds may improve the initial development, plant stand, and mass productivity in forage crops. The present study aimed to evaluate the effect of the size of seeds of Sudan grass (Sorghum sudanense L.), standardized on density, on parameters of physiological quality and crop productivity. Seeds were processed in a gravitational table in order to become uniform in terms of density and then submitted to sieves with apertures of 1.75 or 2.00 mm. Three different treatments (seeds without size classification, seeds with diameter between 1.75 mm and 1.99 mm, and seeds with diameter above 2.00 mm) were compared. This study consisted of a laboratory stage for the analysis of physiological variables of seed, and a stage in field plots under a randomized block design and 3 replicates. Larger seeds presented better physiological and productive performance and had a higher germination rate, seedling growth, and forage yield at the first cut. Both the sieve with opening of 1.75 mm and that of 2 mm were suitable for processing of seeds of this species.

This study compared the effects of unchopped and chopped hay on milk production and composition, feed digestibility, and physiology of Lacaune sheep. Eighteen ewes were stratified by parity (two or three), days of lactation (60 ± 3.7 days), and milk production (1.04 L/ewe/day), and were randomly assigned to 1 of 2 treatments: 1) Unchopped or 2) Chopped Tifton 85 hay. Corn silage and concentrate were also provided. Chopped hay ewes gave lower (P≤0.01) dry matter intake and greater (P=0.02) crude protein digestibility. No effects of treatment were detected (P≥0.38) for the digestibility of dry matter, or of neutral and acid detergent fibers. Chopped hay ewes had greater (P≤0.01) milk production (d 7 and d 12), lactation persistence, and feed efficiency. Ewes eating chopped hay had greater (P=0.03) protein concentration in their milk. However, there were no effects of treatment × day and treatments (P≥0.16) for concentrations of fat, lactose, minerals, deffated dry extract, or density. Ewes eating chopped hay presented lower (P<0.01) serum concentrations of urea and tended to have lower (P=0.10) serum concentrations of glucose only on d 12. However, there were no effects of treatment × day and treatments (P≥0.16) for serum concentrations of total protein, albumin, globulin, triglycerides, or cholesterol. These data suggest that chopped hay promotes lower dry matter intake and serum concentrations of glucose and urea, but improves milk production, lactation persistence, feed efficiency, and protein concentration.

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