Management of Panicum maximum cv. Likoni for milk production. Effect of the dry matter offer

David Hernández Torrecillas
Estación Experimental de Pastos y Forrajes Indio Hatuey, Central España Republicana 44280, Matanzas, Cuba

ABSTRACT
A trial with four replications in time was conducted in order to study the management of Panicum maximum cv. Likoni evaluating the variations that occurred in its structure and quality as feedstuff, as well as in the performance of the pasture and the animals that consumed it when exploiting the grassland under three different levels of dry matter offer. The studied treatments were: A (15 kg DM/cow/day); B (35 kg DM/cow/day) and C (55 kg DM/cow/day) that were distributed in a 3 x 3 Latin square design in which 9 Holstein x Zebu crossbred cows were used. The studies on the pasture itself were made through random sampling following a completely randomized design. The structural fractions (leaf, stem and dead material) did not vary significantly among treatments in their average values. However, among strata the variations were highly significant (P < 0,001) in all the treatments with predominance of the leaves in the highest parts of the grassland and there was a very unfavorable structural balance in the lower stratum (leaf: 91, 64 and 21 %; stem: 4, 11 and 27 %; dead material: 5, 20 and 51 % in the higher, medium and lower strata, respectively) which determined a more favorable condition of density (DM/ha/cm) over 20 cm of height from the soil. The conformation of the availability of DM/ha and its quality as feedstuff behaved according to the variations observed in the structure. Thus, the leaf determined more than 40 % of the availability of DM/ha in all the treatments and the highest quantity contributed by this structural fraction was always in the strata measured above 20 cm, where it varied between 70 and 80 %, according to the offer increase. In addition, the leaf was the best balanced structural component in its bromatological composition, for which the pasture quality improved in the higher stratum and in the highest DM offer where it prevailed over the stem and dead material. When averaging the four replicas the DM intake increased, with significant differences (P < 0,001), as the offer increased (A: 9,8; B: 12,3 and C: 14,4 kg DM/cow/day) as well as milk production (A: 8,1; B: 9,2 and C: 10,2 kg/cow/day). The likoni percentage was not affected in the botanical composition when decreasing the DM offer and subsequently intensifying the exploitation; but the bunch diameter was significantly lower (A: 22,9; B: 26,6 and C: 29,5 cm). It is concluded that Guinea grass cv. Likoni was better balanced structurally and in its nutritional qualities in the strata higher than 20 cm and that 55 kg DM/cow/day was the ideal offer to manage and exploit this species with moderate to low potential fed pasture alone.