Nematode-Larvae Infestation in Goats Fed "Malojillo" (Pará Grass) and Merker Grasses in Puerto Rico

Abstract

1. The degree of nematode larvae infestation in goats fed malojillo (Pará grass) and Merker grass in Puerto Rico was investigated in an attempt to determine whether goats would become more significantly parasitized when eating either one of the two grasses. 2. The technique of raising and-maintaining parasite-free animals is described. 3. Blood samples for hemoglobin and packed-cell determinations and fecal samples for nematode ova counts were obtained every 15 days from the 10 experimental goats. 4. It was found that goats eating malojillo harbored a larger number of nematode parasites than those eating Merker grass. Ova of Strongyloides papillosus appeared in the feces of the goats even before the beginning of this work, but that infestation disappeared about a month before the end of the experiment. Haemonchus contortus ova were seen next, being followed chronologically by Trichostrongylus spp. and Oesophagostomum columbianum. The latter species was harbored only by the goats receiving malojillo. Goats eating Merker grass exhibited 8.9 ova per gram of fecal sample throughout the experiment, those receiving malojillo showed 48.2 eggs per sample, while those in the control group had only 0.57 eggs per sample. 5. All animals were sacrificed at the conclusion of this work and the digestive tracts thoroughly searched for helminths. More nematodes were secured from the goats eating malojillo than from the other two groups. A total of 1,028 nematodes was recovered from animals in the malojillo group, 191 from the Merker group, and only 3 from the control group receiving imported hay.