Performance of sheep grazing in pastures of Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, and Andropogon gayanus with different protodioscin concentrations

Abstract

Brachiaria spp. are the most important grasses for ruminants in central-western Brazil. However, the use of these pastures is limited by their toxicity due to steroidal saponins. This experiment was conducted for 60 days to demonstrate the resistance of sheep raised on Brachiaria spp. pastures to steroidal saponin poisoning. The experiment was composed by 48 animals randomly divided into four groups (n = 12). Among them, 32 4- to 5-month-old castrated male crossbred Santa Inês sheep, originating from flocks that had been grazing on Brachiaria spp. for more than three consecutive years, and 16 were non-adapted (naïve) sheep from flocks that never had prior contact with pastures of Brachiaria spp. were randomly divided into four groups. Each of the four experimental groups was composed by eight adapted and four non-adapted animals. The four experimental groups were introduced into paddocks, each of which contained a single grass: either Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, or Andropogon gayanus. The addition of the naïve sheep to the groups was designed to detect pastures' toxicity to naïve sheep and to adjust the stocking rate to optimize the use of forage. The weight gains of sheep grazing on B. decumbens, B. brizantha, and P. maximum were similar; however, the A. gayanus group showed lower weight gains compared with the other groups (P < 0.05). The mean serum activities of γ-glutamyltransferase in the sheep grazing on B. decumbens were higher than those in the sheep from the other groups. No significant differences among the groups were found in aspartate aminotransferase, creatinine, albumin, or total protein serum concentrations. No clinical signs were observed in the adapted sheep in any of the pastures. Of the four non-adapted sheep introduced into the B. decumbens pasture, two showed clinical signs of steroidal saponin poisoning, and one died. No clinical signs were observed in the non-adapted sheep in the other pastures. The saponin (protodioscin) concentrations in the pastures varied from 3.3 to 12.2 g/kg DM in B. decumbens, from 2.8 to 9.1 g/kg DM in B. brizantha, and from 1 to 1.5 g/kg DM in A. gayanus. No saponins were found in P. maximum. It is concluded that sheep from flocks reared in pastures of B. decumbens and B. brizantha were resistant to steroidal saponin poisoning and showed similar weight gains to those of sheep grazing in other tropical pastures.

Clinical and histopathological study of the phototoxic dermatitis in Zebu calves in grazing of Brachiaria decumbens

“…The animals recovered 30 and 40 days after initiating the treatment strategy, which agrees with Gracindo et al (6) who reported that recovery time of the affected cattle was between 15 and 45 days after being removed from the areas with Brachiaria spp. ; however, it states that it is likely that the animals have cutaneous scars until slaughter.…”

“…located in canaliculi, bile ducts, and to a lesser extent in hepatocytes and is released when there these structures are damaged. Similarly, Gracindo et al (6) and Faccin et al (14) reported in their study that the mean serum catalytic activity of GGT in sheep that grazed on B. decumbens was higher than sheep that grazed in paddocks with other grass.…”

“…Ha sido reportada en diferentes especies; sin embargo, la mayor presentación de casuística se ha reportado en rumiantes, entre las cuales existen informes de presentación en ovinos (4)(5)(6), caprinos (7), bufalinos (8,9) y bovinos (2,10), de igual forma, se reporta mayor susceptibilidad en ovinos que en bovinos (7), así como la mayor presentación en animales jóvenes que en adultos (11).…”

“…It is known in Brazil as "requeima" (2) and in Colombia it is known on the Atlantic coast as "fiebre candela" and in the Andean region as "Brasa, lamparón or fiebrón" (3). It has been reported in different species; however, the largest presentation of casuistry has been reported in ruminants, including reports for sheep (4)(5)(6), goats (7), buffalo (8,9) and bovines (2.10). Also, greater susceptibility is reported in sheep than in cattle (7), and it mostly affects young animals rather than in adults (11).…”

“…Es importante la realización de pruebas sanguíneas, con el fin de evaluar la actividad catalítica de las enzimas hepáticas, en particular la GGT (Gamma Glutamil Transferasa) y la AST (Aspartato Amino Transaminasa), ya que un aumento considerable de las concentraciones séricas son indicadoras de alteración hepática, en especial la GGT que se ubica a nivel de los canalículos hepáticos (4)(5)(6).…”