Feeding Systems with Legumes to Intensify Dairy Farms - cgiar

Availability of grass forage at the beginning of grazing was greater in
Trial 2 as compared with Trial 1. This difference in forage on offer was
associated with changes in precipitation.
The quality of the grass varied considerably among treatments, the
IVDMD and CP levels being lower in the check treatment (B. decumbens
alone) in both experiments. The treatment and precipitation significantly
affected both amount and quality of the grass.
Milk production of cows on the associated Cratylia + Brachiaria pasture
under direct grazing was consistently higher than that of the check
treatment in both minimum (23% more milk) and maximum precipitation
(16% more milk), although this difference was not significant (Table 1). The
significant increase in milk production in Trial 1 can be partially explained
by the low amount and quality of the basal pasture, which was affected by
the lower precipitation. These results confirm once more the importance of
providing supplementation not only when the basal pasture is deficient but
also during the dry season, but not so in the rainy season (Avila, 1999).
Table 1. Milk production of crossbred Holstein x Zebu cows, supplemented
with Cratylia argentea in a cut-and-carry system as compared with
direct grazing (Quilichao, Cauca, Colombia).
Treatment
Trial 1 Trial 2
Milk yield
Milk yield
(kg/cow per day) (kg/cow per day)
Brachiaria decumbens 6.1 b* 6.3 a
B. decumbens + C. argentea
(cut-and-carry)
6.7 b 6.6 a
B. decumbens + C. argentea
(direct grazing)
7.5 a 7.3 a
* Values in the same column followed by the same letter do not differ significantly (P < 0.05),
according to Duncan’s test.
On the other hand, the levels of fat and non-fat solids (NFS) in milk were
similar for both trials. The milk urea nitrogen (MUN) levels differed
significantly (P < 0.05) among treatments for both trials. When C. argentea
was used as supplement, MUN levels were higher compared with the check
treatment. The levels of these indicators without C. argentea
supplementation were marginal (Table 2). MUN levels ranged from 9 to 10
mg/dL, suggesting a protein deficit (Hammond et al., 1994) and accounting
for the lower milk production of the group of cows that did not receive
legume supplementation.
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