In many species, females display brightly coloured and elaborate traits similar to those that males use in intra- and inter-sexual selection processes. These female characters are sometimes related to fitness, and might function as secondary sexual characteristics that have evolved through sexual selection. Here, we used descriptive data from 674 females in 10 populations and an experimental re...

this investigation was performed on 1056 stool samples collected from isfahan area (with high intensity of infection) and dasht-mishan area of khuzestan. as indicated in tables 1, 2 and 3 the results of kato thick-smear technique is comparable to those conventional methods of formalin-ether and flotation methods, plus low cost, simplicity and practicability of kato's thick-smear. for ascaris eg...

For hundreds of years, the unmanaged Soay sheep population on St Kilda has survived despite enduring presumably deleterious co-infections of helminth, protozoan and arthropod parasites and intermittent periods of starvation. Important parasite taxa in young Soay sheep are strongyles (Trichostrongylus axei, Trichostrongylus vitrinus and Teladorsagia circumcincta), coccidia (11 Eimeria species) a...

Four groups of 6-7-month-old Merino lambs were each dosed with 40 000 infective larvae of Trichostrongylus axei on 2 November 1976 and subsequently exposed to challenge with Haemonchus contortus on natural grazing at the University of Pretoria's Experimental Farm in the eastern suburbs of Pretoria. One of these groups and one group of controls were killed every 8 weeks from the end of December ...

In 2004, a new concept was introduced for simplifying identification of larvae of the common nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L3) of each genus and/or species to that of Trichostrongylus spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean le...

When given to sheep as a single oral dose at 0.1 mg/kg, the B(1a) component of the avermectins caused a reduction of >95% in the numbers of Haemonchus contortus, Ostertagia circumcincta (including inhibited L(4) larvae), Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia oncophora, and Oesophagostomum columbianum. When given to cattle as a single oral dose at 0.1 mg/kg, avermectin ...

An observational study was performed to investigate the effects of yarding and ruminoreticulum bypass on the ef®cacy of oxfendazole against resistant Trichostrongylus spp. helminths. Ruminoreticulum bypass was observed in 9-month old Perendale lambs using video-taped ̄uoroscopy and the ef®cacy of oxfendazole was estimated using the faecal egg count reduction test. Yarding and withholding feed f...

Exsheathed infective larvae (L3) of 16 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen and stored in 0,09% NaCl solution in the gas phase of liquid nitrogen for periods of up to 59 months. A mean of greater than 90% of the L3 of Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Nematodirus ...

Relationships between egg production and infectivity were studied with infective larvae of Trichostrongylus colubriformis which had been stored for up to 22 weeks at 24 degrees C. After different storage times, larvae were administered to lambs and the number of parasites which reached the adult stage was counted five weeks after infection. Egg production was estimated for the same batches of a...