Pasture characteristics of Italian ryegrass and milk production under different management strategies
The objective of this work was to assess the effects of the sward structure of Italian ryegrass (Lolium multiflorum), during the first grazing cycle, on its morphological and bromatological characteristics throughout the growing season, and on the performance of dairy cows. The treatments consisted...
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| Published in: | Pesquisa agropecuaria brasileira Vol. 47; no. 6; pp. 863 - 868 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Embrapa Secretaria de Pesquisa e Desenvolvimento; Pesquisa Agropecuária Brasileira
01-06-2012
Embrapa Informação Tecnológica |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The objective of this work was to assess the effects of the sward structure of Italian ryegrass (Lolium multiflorum), during the first grazing cycle, on its morphological and bromatological characteristics throughout the growing season, and on the performance of dairy cows. The treatments consisted of two structures obtained as a function of canopy-light interception: high-light interception (HLI) and low-light interception (LLI), with different pre-grazing heights in the first grazing cycle. Pasture was managed under rotational grazing with a herbage allowance not below 30 kg dry matter (DM) per cow per day. Three grazing cycles, with a grazing interval of 30 days, were evaluated. Pre-grazing herbage mass was greater (2,240 vs. 1,656 kg ha-1 DM), but the proportion of leaf blades was smaller (0.35 vs. 0.43) for HLI swards. Neutral detergent fiber (NDF) content and organic matter digestibility (OMD) were similar between treatments in the first grazing cycle, but in the second and third ones NDF was greater, and OMD lower, for the HLI swards. Milk yields were greater for cows grazing LLI swards (19.4 vs. 21.1 kg per day). Initial grazing with 90% of light interception promotes greater nutritional value in the subsequent cycles.
O objetivo deste trabalho foi avaliar os efeitos da estrutura do pasto de azevém anual (Lolium multiflorum), no primeiro ciclo de pastejo, sobre suas características morfológicas e bromatológicas, ao longo da estação de crescimento, e sobre o desempenho de vacas leiteiras. Os tratamentos consistiram de duas estruturas, obtidas em função da intensidade de interceptação luminosa do dossel: alta interceptação luminosa (AIL) e baixa interceptação luminosa (BIL), com diferentes alturas de pasto na entrada para o primeiro ciclo de pastejo. A pastagem foi manejada sob lotação intermitente com oferta não inferior a 30 kg de matéria seca (MS) por vaca por dia. Três ciclos de pastejo, com intervalos de 30 dias entre eles, foram avaliados. A massa de forragem pré-pastejo foi superior (2.240 vs. 1.656 kg ha-1 de MS), mas a proporção de lâminas foliares foi inferior (0,35 vs. 0,43) nos pastos AIL. Os teores de fibra em detergente neutro (FDN) e a digestibilidade da matéria orgânica (DMO) foram semelhantes, no primeiro ciclo de pastejo, mas, no segundo e no terceiro, o FDN foi superior e a DMO inferior nos pastos AIL. A produção de leite foi superior nas vacas dos pastos BIL (19,4 vs. 21,1 kg por dia). O início do pastejo com 90% de interceptação luminosa promove maior valor nutricional nos ciclos subsequentes. |
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| ISSN: | 0100-204X 1678-3921 0100-204X |
| DOI: | 10.1590/S0100-204X2012000600018 |