| Journal: | Scientia Agricola |
| Database: | PERIÓDICA |
| System number: | 000455482 |
| ISSN: | 0103-9016 |
| Authors: | Batalha, Camila Delveaux Araujo1 Congio, Guilhermo Francklin de Souza1 Santos, Flávio Augusto Portela1 Silva, Sila Carneiro da1 |
| Institutions: | 1Universidade de Sao Paulo, Departamento de Zootecnia, Piracicaba, Sao Paulo. Brasil |
| Year: | 2022 |
| Volumen: | 79 |
| Number: | 2 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, analítico |
| English abstract | There is limited information regarding both nitrogen (N) and energy partitioning of dairy cows grazing well–managed tropical pastures. The objective of this study was to investigate the N and energy partitioning of mid–lactation dairy cows on rotationally grazed elephant grass using two pre–grazing targets: 95 % or maximum canopy light interception (LI95% or LIMax) during regrowth. The study used 26 Holstein × Jersey dairy cows arranged in a randomized complete block design with three 40–day periods of sampling. Grazing at LI95% increased organic matter and crude protein intake by 20 % (p ≤ 0.05) which resulted in a 9 % increase in fat corrected milk yield (p ≤ 0.05) relative to LIMax. Cows grazing at LI95% had greater concentration of total volatile fatty acids, butyrate and valerate (p ≤ 0.05), and smaller acetate (p ≤ 0.05) than those grazing at LIMax. Intake of net energy for lactation (NEL) and NEL secreted in milk were greater (p ≤ 0.05), while partitioning of NEL towards maintenance tended to be greater (p = 0.07) for cows grazing at LI95% than those grazing at LIMax. Milk urea nitrogen and both urine and fecal N excretion were greater for cows grazing at LI95% (p ≤ 0.05), but N excretion intensity was lower than in cows grazing at LIMax (p ≤ 0.05). Strategic grazing management using the LI95% pre–grazing target increases N losses through both urine and feces; however, it reduces N excretion intensity of dairy cows by 9 % |
| Disciplines: | Medicina veterinaria y zootecnia |
| Keyword: | Bovinos, Zootecnia, Pastoreo, Ganado lechero, Excreción, Nitrógeno |
| Keyword: | Bovines, Animal husbandry, Grazing, Dairy cattle, Excretion, Nitrogen |
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