Yield and nutritive value of Urochloa hybrids at different regrowth ages

Resumen

Objective: To evaluate the productive behavior of Urochloa hybrids, depending on the regrowth age.

Design/Methodology/Approach: The study was carried out under rainfed conditions during 2018. The Cayman, Mulato II, Convert 330, Cobra, Camello I, and Camello II hybrids were evaluated based on the regrowth age (2, 4, 6, 8, and 10 weeks). The following variables were evaluated: plant height (PH), total dry matter (TDM) yield, dry matter per leaf (DMl) yield, dry matter per stem (DMs) yield, crude protein content (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF). The data obtained were evaluated by means of a randomized complete block design with three repetitions, divided into plots: a large plot for the cultivars and small plot for the regrowth ages.

Results: The Camello II cultivar obtained the highest TDM yields during the sixth and eighth weeks (4.15 and 6.35 t DM ha^-1, respectively); however, during the tenth week, the yield was equal to the yield obtained with the Mulato II and Cayman cultivars (p<0.05). The highest DMl yield was obtained by the Mulato II cultivar during the sixth, eighth, and tenth weeks (3.37, 4.56, and 3.86 t DM ha^-1, respectively). The Mulato II cultivar recorded the highest CP values during the second and fourth weeks (158 and 126 g kg^-1, respectively); however, the Camello II cultivar obtained the highest CP values during the sixth, eighth, and tenth weeks (99, 95, and 87 g kg^-1, respectively). The NDF and ADF values increased as the regrowth age increased: in the tenth week, the Camello II and Cobra cultivars obtained the highest NDF values, while the Camello II cultivar recorded the highest ADF value during the same period.

Study Limitations/Implications: Urochloa cultivars were developed for their establishment in humid tropical conditions, where their productive performance is greater. However, in dry tropical conditions, the Cayman, Mulato II, and Cobra cultivars have had a better performance than other grasses —such as buffel grass (Pennisetum ciliare), which is used to feed ruminants. In this sense, other Urochloa cultivars (e.g., Camello I and Camello II), which have greater tolerance to droughts, show desirable forage characteristics, such as yield and forage quality.

Findings/Conclusions: The cultivars with the best productive performance were Camello II, Mulato II, and Cayman.