Effects of long-term indiscriminate use of macrocyclic lactones in cattle: Parasite resistance, clinical helminthosis, and production losses.

Our aims were to describe a case of clinical helminthosis caused by parasite resistance to macrocyclic lactones (MLs) after the long-term frequent use of these drugs in a cattle herd, and to evaluate the production losses prevented by the use of an effective anthelmintic treatment to control these resistant gastrointestinal nematodes (GINs). A case of clinical helminthosis culminating in the death of steers was investigated, the history of the antiparasitic treatments used during an 11-year period in the herd was assessed, and an efficacy test involving seven different drugs was performed. Thereafter, two groups of heifers naturally infected by ML-resistant GINs were formed and strategically treated with either a highly effective (levamisole) or less effective drug (doramectin) over a 9-month period.

Economic losses caused by the use of low-efficacy anthelmintic drugs in growing heifers.

The aim of this study was to compare the economic revenue related to the use of low- or high-efficacy anthelmintic drugs within suppressive or strategic schemes of treatment in growing heifers. Heifers raised in a semi-intensive grazing system in southern Brazil were used. Levamisole and ivermectin were selected as the high- and the low-efficacy drugs, respectively, based on a previous efficacy test.

Sarcocystis species identification in cattle hearts destined to human consumption in southern Brazil.

Sarcocystis spp. are ubiquitous protozoan parasites that can form cysts in striated muscle and CNS of cattle. Cattle hearts are commonly infected by microscopic sarcocysts.

Occurrence of Sarcocystis gigantea macrocysts and high frequency of S. tenella microcysts in sheep from southern Brazil.

The aim of this study was to investigate the occurrence of sarcocysts in sheep slaughtered in the Rio Grande do Sul state, Brazil. Heart and esophagus samples from 130 sheep were subjected to macroscopic and microscopic examination, followed by molecular analysis. Ten sheep (7.

Evaluation of Three Methods of Platelet-Rich Plasma for Treatment of Equine Distal Limb Skin Wounds.

Wounds localized on the distal limbs in horses are difficulty healing. No studies have been conducted to evaluate homologous platelet-rich plasma (PRP) in horses. The aim of this study was to evaluate the effect upon applying autologous PRP, homologous PRP, and autologous PRP gel on the wound healing process of wounds on the distal limb of horses.

Efficacy and economic analysis of two treatment regimens using toltrazuril in lambs naturally infected with Eimeria spp. on pasture.

This study evaluated the efficacy and the economic viability of two anticoccidial treatment regimens tested in lambs naturally exposed to Eimeria spp. re-infections in a grazing system during a 140-day period. Twenty-four suckling lambs were distributed into three groups based on the individual count of oocysts per gram of feces (OPG) and body weight.

Toxoplasma gondii infection in dairy ewes: Vertical transmission and influence on milk production and reproductive performance.

The present study aimed to evaluate the transmission of toxoplasmosis (vertical and venereal) and its influence on milk production and reproductive problems of Lacaune sheep seropositives for Toxoplasma gondii. Males and females were serologically selected using indirect immunofluorescence method in three steps of the study. Step 1: In order to evaluate the influence of toxoplasmosis on milk production, the volume of milk produced by 40 sheep (22 seronegatives and 18 seropositives for T.

DNA extraction methods and multiple sampling to improve molecular diagnosis of Sarcocystis spp. in cattle hearts.

Molecular detection of Sarcocystis spp. in tissue samples can be useful for experimental and diagnostic purposes. However, the parasite spreads unevenly through tissues, forming tissue cysts, and the cystic wall is an obstacle in DNA extraction protocols.

Effects of Adiponectin Including Reduction of Androstenedione Secretion and Ovarian Oxidative Stress Parameters In Vivo.

Adiponectin is the most abundantly produced human adipokine with anti-inflammatory, anti-oxidative, and insulin-sensitizing properties. Evidence from in vitro studies has indicated that adiponectin has a potential role in reproduction because it reduces the production of androstenedione in bovine theca cells in vitro. However, this effect on androgen production has not yet been observed in vivo.

Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil.

Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70-100 calves or more of both genders with ≥ 200 eggs per gram of feces (EPG) (sensitivity of 50 EPG).

Improving liveweight gain of lambs infected by multidrug-resistant nematodes using a FECRT-based schedule of treatments.

The aim of this study was to compare the liveweight gain of lambs, infected by multidrug-resistant nematodes, treated by conventional schemes of helminth control or using a schedule based on fecal egg count reduction test (FECRT). The flock was selected after a FECRT (experiment 1) which revealed a parasite population resistant to benzimidazoles, imidazothiazoles, macrocyclic lactones (ivermectin), salicylanilides, nitrophenols, and organophosphates. Despite the parasite resistance to ivermectin (an avermectin), the moxidectin (a milbemycin) was effective against the gastrointestinal nematodes (PR > 90%).

Multiple resistance of gastrointestinal nematodes to nine different drugs in a sheep flock in southern Brazil.

Based on clinical observation of a flock of approximately 5000 sheep (breed Merino) from southern Brazil, the failure of anthelmintic treatments was suspected. The sensitivity of the gastrointestinal nematodes that infected these sheep to nine drugs (Levamisole, Moxidectin, Albendazole, Ivermectin, Nitroxynil, Disophenol, Trichlorphon, Closantel, and a combination of Ivermectin, Levamisole and Albendazole) was evaluated. None of the drugs reduced the count of nematode eggs per gram of feces (EPG) in the sheep to an adequate extent (defined as a 95% reduction in EPG).