Zerasca is an indigenous breed of sheep with endangered status, but it has a primary role in safeguarding Tuscan biodiversity, native livestock production improvement and protection of agricultural districts. Rough countryside with self-shown sloping natural pastures typifies the Zeri area, located in northwest Tuscany at an altitude of 600-1200 m. Over the years, the excellent production of the Zerasca, despite an adverse climate, underlines its strong overall links with the environment. Local shepherds habitually treat animals twice a year with antihelmintic drugs, without laboratory diagnosis, mainly due to a presumed loss of production. The aim of this work is to evaluate the possibility of carrying out a more effective antihelmintic control. The study was conducted in a single flock from January to November 2004 on 48 sheep, sampled monthly for coprological (modified McMaster method) and haematological (PCV) examinations. FECs were transformed [log(FEC+25)] to normalise the variance. ANOVA test was performed to evaluate environmental factors influencing gastrointestinal worm burden. Repeatability of monthly FECs and PCV were estimated by Pearson’s correlations, while the average repeatability between the monthly values was tested using the intra-correlation-class method. Results showed a significant seasonal and individual influence on FECs (mean 273±289.12). 65.0% of faeces samples showed an acceptable parasite burden (<300 eggs/g.). Data regarding monthly correlations of FECs appear significant in summer, when the helmintic burden does not reach high level. Higher monthly repeatability resulted for PCV (mean 29.7±3.65). Our results confirm the feasibility of reducing antihelmintics in Zerasca sheep by a careful investigation of seasonal and individual variability of FECs and PCV; this could have positive repercussions on residual drugs in the animal products and in the soil, and lesser problems connected with pharmacological resistance. In addition, very interesting are the increasing number of studies on genetic resistance: limiting treatment to the nonresistant animals may offer significant economical and ecological advantages for breeding management.
Observation on gastrointestinal strongylosis resistance in Zerasca breed
GIULIOTTI, LORELLA;BENVENUTI, MARIA NOVELLA;
2005-01-01
Abstract
Zerasca is an indigenous breed of sheep with endangered status, but it has a primary role in safeguarding Tuscan biodiversity, native livestock production improvement and protection of agricultural districts. Rough countryside with self-shown sloping natural pastures typifies the Zeri area, located in northwest Tuscany at an altitude of 600-1200 m. Over the years, the excellent production of the Zerasca, despite an adverse climate, underlines its strong overall links with the environment. Local shepherds habitually treat animals twice a year with antihelmintic drugs, without laboratory diagnosis, mainly due to a presumed loss of production. The aim of this work is to evaluate the possibility of carrying out a more effective antihelmintic control. The study was conducted in a single flock from January to November 2004 on 48 sheep, sampled monthly for coprological (modified McMaster method) and haematological (PCV) examinations. FECs were transformed [log(FEC+25)] to normalise the variance. ANOVA test was performed to evaluate environmental factors influencing gastrointestinal worm burden. Repeatability of monthly FECs and PCV were estimated by Pearson’s correlations, while the average repeatability between the monthly values was tested using the intra-correlation-class method. Results showed a significant seasonal and individual influence on FECs (mean 273±289.12). 65.0% of faeces samples showed an acceptable parasite burden (<300 eggs/g.). Data regarding monthly correlations of FECs appear significant in summer, when the helmintic burden does not reach high level. Higher monthly repeatability resulted for PCV (mean 29.7±3.65). Our results confirm the feasibility of reducing antihelmintics in Zerasca sheep by a careful investigation of seasonal and individual variability of FECs and PCV; this could have positive repercussions on residual drugs in the animal products and in the soil, and lesser problems connected with pharmacological resistance. In addition, very interesting are the increasing number of studies on genetic resistance: limiting treatment to the nonresistant animals may offer significant economical and ecological advantages for breeding management.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
