Henrique Mendonça Nunes Ribeiro-Filho

Pasture intake and milk production of dairy cows grazing annual ryegrass with or without corn silage supplementation

The use of corn silage to supplement grazing dairy cows can improve milk production and nutrient intake when the substitution rate is low. This enhancement occurs by increasing the total DM intake. The hypothesis tested in this study was that increasing corn silage supplementation level of dairy cows grazing annual ryegrass at medium pasture allowance could increase substitution rate and decrease milk production response. Three supplementation levels (0, 4 and 8 kg DM/day) were compared for dairy cows strip-grazing annual ryegrass (Lolium multiflorum cv. Common). The study was arranged as a 3 × 3 Latin square design, repeated three times using nine Holstein lactating cows. The supplement was a 7 : 1 mixture based on the DM of corn silage and soybean meal and was offered individually twice daily after the morning and afternoon milkings. Each treatment group of cows grazed separately at a common daily pasture allowance of 35 kg DM/cow to ground level. Each experimental period was 12 days, with an 8-day adaptation and a 4-day measurement period. The individual pasture intake was measured from Day 9 to Day 12 using the n-alkane technique. The daily pattern of grazing and ruminating times were measured by visual observations. The supplement DM intake was lower than expected, averaging 3.0 and 4.3 kg DM/day for cows receiving 4 and 8 kg DM/day, respectively. Pasture and supplement energy value were 7.0 and 6.3 MJ of NEL/kg DM, respectively. The substitution rate averaged 0.2 and was unaffected by the supplementation level. The pasture intake was similar for all treatments (14.0 kg of DM/day), and total DM intake and milk production (+0.5 kg of milk/kg DM of supplement) increased linearly with increasing supplementation level. The daily grazing time was shorter by 111 min/day for the supplemented cows than for the unsupplemented cows. Cows grazing the annual ryegrass at medium pasture allowance improved their total DM intake and individual performance when supplemented with corn silage.

Associative effects between Arachis pintoi and dwarf elephantgrass hays on nutritional value in sheep

The aim of the present study was to evaluate the effect of including different levels of peanut (Arachis pintoi cv. Amarillo) hay (167 and 572 g/kg dry matter (DM) of crude protein and neutral detergent fibre respectively) on the nutritional value of diets based on dwarf elephantgrass (Pennisetum purpureum Shum, cv. Kurumi) hay (98 and 668 g/kg DM of crude protein and neutral detergent fibre respectively). Peanut hay was included in the proportions of 0.0, 0.33, 0.66 and 1.00 of total diet DM. Eight Texel × Suffolk crossbred wethers provided with duodenal cannula were assigned to the treatments in a replicated 4 × 4 Latin-square experiment. The organic matter (OM) intake increased linearly (P < 0.05) and the total apparent OM digestibility decreased linearly (P < 0.001) with an increasing inclusion of legume. The nitrogen (N) intake and N urinary excretion increased linearly (P < 0.05), whereas linear and quadratic responses were significant for digestible OM intake, N retention, and for the efficiency of rumen microbial protein synthesis. Cubic positive responses were significant (P < 0.05) for duodenal flow of total N, non-ammonia-N and rumen microbial-N. The inclusion of A. pintoi in dwarf elephantgrass-based diets improved the nutrient supply to sheep, but no additive effect was observed as a result of increasing the peanut proportion in the mixed diet.

Intercropping black oat (Avena strigosa) and annual ryegrass (Lolium multiflorum) can increase pasture leaf production compared with their monocultures

Abstract. Multi-species pastures have been viewed as a means to increase forage production relative to monocultures through enhanced three-dimensional occupation of the canopy, which will intercept and use the incident radiation more efficiently. For this to occur, increased production of photosynthetically active tissues such as leaves is required. We tested the hypothesis that intercropping of black oats (Avena strigosa Schum.) and annual ryegrass (Lolium multiflorum Lam.) can increase total and leaf forage production compared with their monocultures. Monocultures and mixed pastures of black oat and annual ryegrass were established, and their tiller morphogenetic and structural traits, as well as components of herbage production, were measured throughout the usage period of the pastures. There was no difference between treatments for total growth rate (77.1 kg dry matter (DM) ha–1 day–1), but annual ryegrass pastures presented the greatest stem growth rate (38.1 kg DM ha–1 day–1). Taking into account only the vegetative phase, the intercropped pasture produced 20% more leaf than the monocultures. There were no differences between species, either in monoculture or intercropped, for phyllochron, final leaf length, leaf elongation duration and leaf elongation rate. The most important modification in morphogenetic variables due to the inter-specific competition was an increase in senescence rate of annual ryegrass leaves. The average specific green leaf weight in the intercropping pastures corresponded to 84.6% and 137.5% of those values observed for black oat and annual ryegrass pastures, respectively. On the other hand, the intercropping pastures presented 43.5% more tillers than the black oat pastures and 17.8% fewer tillers than the annual ryegrass pastures. It is suggested that intercropping black oat and annual ryegrass does not change tiller ontogenetic processes and that the association of their different size and shape in intercropped pastures could increase pasture leaf production over their monocultures.

Aspectos qualitativos e produção de biomassa em pastos de aveia e azevém cultivados puros ou consorciados e submetidos a pastejo leniente

ABSTRACTMixed pastures of oats + annual ryegrass have been considered a good alternative for animal feeding during the winter/spring period in subtropical regions. However, the impacts of lenient grazing under their qualitative and productive aspects, when compared to their monoculture, remain unclear. Thus, the aim of this study was to evaluate the morphological and chemical composition and biomass production of black oat (Avena strigosa cv. IAPAR 61) and annual ryegrass (Lolium multiflorum Lam cv. common) swards cultivated pure or intercropped, throughout the growing season and submitted to lenient grazing. Treatments (oats, annual ryegrass and intercropping oats + annual ryegrass) were arranged in a complete randomized block design with four replications. The pastures were defoliated in 40% of pre-grazing height by Holstein heifers, when the heights reached 17, 20 and 23cm for the ryegrass, intercrop and oat, respectively. The leaf blade:stem ratio decreased with the advance of the growing season for all treatments, but the proportion of stems in the grazed stratum remained lower than 20% of dry matter until the pastures begun reproductive development. Similarly, the crude protein (CP) and neutral detergent fiber (NDF) levels in grazed stratum were, respectively, above 16% and below 50% from the first to fourth grazing cycles. Mixed pastures of black oat + ryegrass and ryegrass alone had higher forage accumulation rate (average = 32.6kg DM ha-1 day-1), but mixed pastures were used for a longer period, resulting in a greatest total DM production (4809kg DM ha-1). Lenient grazing does not reduce the forage quality in potential grazing layer throughout the growing vegetative stage. Intercropping black oat and ryegrass increases total DM production when compared to their monocultures.