Italian ryegrass

Bijeenkomst: EGF2015
Auteur: Müller J. and Jänicke H.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
High merit cows (>10.000 l cow‑1 year‑1) are usually fed rations high in carbohydrates and low in fibre. In these diets the percentage of silage made from permanent grasslands is low, due to their limited energy contents. As a consequence, adding straw to high carbohydrate mixed rations is a common practice to ensure effective fibre for proper rumen function. However, low digestibility fibres negatively affect feed intake, especially when ruminal distention dominates control of feed intake around peak lactation. Therefore, an alternative diet, high in digestible fibre, seems an option to break the cycle of structural and energetic demands on the roughage. We examined a range of Italian ryegrass cultivars to obtain information about quality characteristics and variations which may be helpful for advisers asking for forages appropriate for high output systems. Samples from three cuts of a field trial with 22 Lolium multiflorum cultivars and candivars were analysed by near infrared reflectance spectroscopy for quality traits including acid detergent fibre (ADF), neutral detergent fibre (NDF), enzyme insolubility and water soluble carbohydrates. We considered NDF-ADF differences as most suited for assessing applicability in high carbohydrate rations. Based on these criteria we find significant varietal differences exist in Lolium multiflorum.

Bijeenkomst: EGF2015
Auteur: Dachraoui M., Jiménez-Calderón J.D., Martínez-Fernández A. and Vicente F.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
The dairy sector plays an important role in the emission of greenhouse gases (GHG). Dairy cows are a significant contributor to total livestock GHG emissions, being the main sources carbon loss from land use change, methane emissions from enteric fermentation, soil nitrous oxide emissions and manure management. For this reason, the objective of this study was to estimate methane emissions using the IPCC model in lactating Holstein cows with feeding rations based on Italian ryegrass silage grown conventionally or fava bean-rapeseed silage fertilized with manure and slurry in two grazing seasons, and to compare the results obtained with other models tested. Two trials were carried out in spring and autumn 2013, each with ten lactating Holstein cows. Both trials were performed using a crossover design. Considering the IPCC Tier 2 as an international reference to estimate enteric methane emissions, the estimations were similar considering both seasons and diets. When the IPCC predictions were compared to other models, the results showed the same variation of methane production, but with higher values for Mills and Yates models and lower estimations based on Ellis equations.