Felipe Jochims

Consumo de nutrientes e desempenho de cordeiros alimentados com dietas que contêm diferentes níveis de fibra em detergente neutro

Este estudo foi conduzido no Departamento de Zootecnia da Universidade Federal de Santa Maria, RS, no periodo de agosto a dezembro de 2003. O objetivo foi avaliar o consumo de nutrientes e o desempenho de cordeiros machos, nao castrados, cruzados Ile de France x Texel, submetidos a quatro niveis de fibra em detergente neutro (FDN): 25%, 31%, 37% e 43%. O volumoso utilizado foi a silagem de sorgo hibrido (AG 2005 E) e o concentrado foi composto de milho em grao triturado, farelo de soja, sal comum, calcario calcitico e fosfato bicalcico. As dietas dos quatro tratamentos eram isoproteicas, contendo 17% de proteina bruta. Foram utilizados 20 cordeiros desmamados em media aos 42 dias de idade e abatidos quando atingiram 30kg de peso vivo. O delineamento experimental foi o inteiramento casualizado, com quatro tratamentos e cinco repeticoes. Foram avaliados os consumos de nutrientes, o ganho de peso medio diario (GMD), a conversao alimentar (CA) e o numero de dias que os cordeiros levaram para atingir o peso vivo ao abate de 30kg. A adicao de niveis crescentes de FDN a dieta ocasionou um decrescimo linear nos consumos de materia seca, materia orgânica, proteina bruta, extrato etereo, carboidratos totais e carboidratos nao estruturais. Por outro lado, aumentou linearmente o consumo de fibra em detergente neutro e fibra em detergente acido. Verificou-se reducao linear do GMD e piora na CA com o aumento do teor de fibra na racao, o que proporcionou uma elevacao linear no numero de dias que os cordeiros levaram para atingir o peso de abate.

Comportamento ingestivo de ovelhas em lactação alimentadas com dietas contendo diferentes níveis de fibra em detergente neutro

The aim of this study was to evaluate the effects of different neutral detergent fiber (NDF) levels in the diet on ingestive behavior of lactating ewes. Eighteen 5/8 Ile de France 3/8 Texel ewes, housed in individual cage 24 hours postpartum, were used. Animals were assigned to one of three treatments: 34, 43 and 52% NDF in the diet, in dry matter (DM) basis. The total mixed rations, composed by corn silage (Zea mays L.), ground corn, soybean meal (Glycine max L.), limestone, salt and dicalcium phosphate, were given twice a day, at 0830 AM and 0430 PM. Ingestive behavior was determined by visual appreciation. The increase of the NDF level in the diet significantly influenced (P<.05) DM and NDF intakes, milk yield, and the feeding, rumination, idleness resting and total chewing times, that varied quadratically (P<.05). The NDF feeding and rumination efficiency increased, whereas DM feeding and rumination efficiency linearly decreased (P<.05) as effect of the NDF increased, being necessary more time to feed the same amount of total mixed ration. Highest NDF levels in the diet can cause depression in DM intake.

Long-Term Effects of Phosphorus on Dynamics of an Overseeded Natural Grassland in Brazil☆☆☆

ABSTRACT Fertilization can affect vegetation dynamics and natural grassland diversity. This study evaluated the vegetation dynamics of a natural grassland 16 years after the initial fertilization, discussing the long-term effects of addition of triple superphosphate (TP) or Gafsa rock phosphate (RP) sources, as well as the effect of exotic species introduction on the inter seasonal dynamic of floristic composition. Phosphate (P) was applied in 1997, 1998, 2002, 2010, and 2012 at the quantities of 78.6, 39.3, 43.7, 43.7 and 43.7 kg·ha-1, respectively, totaling 249 kg·ha-1 P. Total herbage mass production (THM) with RP (13 485 kg·ha-1) and TP applications (14 668 kg·ha-1) was higher than in the Control (11 291 kg·ha-1). There was a higher warm tussock perennial grasses C4 contribution on herbage mass (HM) during the summer season (1 106 kg·ha-1), whereas it was similar between treatments. In summer, the warm-season prostrate perennial grasses C4 group contribution for HM was on average 48% higher when RP was used (1 590 kg·ha-1) in relation to the other treatments. The HM contribution from the cool season annual grasses C3 group (CAG) in the total HM, over spring 2012, winter and spring 2013 in TP treatment, was 17% higher than the other treatments. The changes in the seasonal botanical composition dynamics mainly by inducing modifications in the proportion of Paspalum notatum A. H. Liogier ex Flüggé on RP treatment and Paspalum urvillei Steud. and Lolium multiflorum Lam. on TP treatment. However, no significant effects were observed in species richness, which ranged from 19–24 species among growth seasons. In the same way, the Shannon Diversity Index and Pielou Equitability Index were not modified by historical P sources. These results indicate that phosphorus fertilization has lower effects on natural grasslands diversity and could be used as a tool with important implications for livestock.