In small ruminants gastrointestinal parasitosis represent a severe limit to the quality of productions and animal welfare. The difference between the dissimilar levels of sheep’s infection in the flock is a relevant marker of the high variability about the gastrointestinal parasite resistance. In fact, there is considerable interest in the assessment of the resistance of a parasitised host, especially for nutrition and breeding studies. The aim of this work is the evaluation, in a farm of ovine Massese’s breed, of heritability and repeatability coefficients about the main phaenotipic traits connected with resistance to gastrointestinal strongylosis: faecal egg count and packed cell volume. Animals were tested eight times, during periods of moderate and high elmints infestations. One faecal sample per animal was collected and processed in order to determine the faecal egg count, using the modified McMaster tecnique by Permin and Hansen, transforming the values obtained into natural logarithm log (FEC+25). At the time of faecal collection, the animal also underwent blood analyses for determination of haematocrit. This preliminary results show that heritability coefficient of faecal egg count was quite low, with a value of 0.10; repeatability coefficient was little higher, with a value of 0.16. Packed cell volume genetic values were clearly more favourable, presenting respectively 0.22 (heritability) and 0.58 (repeatability). These results, derivate from first Italian studies on Massese’s breed, can give an interesting direction on the possibility to adopt suitable genetic improvement plans for gastrointestinal parasite resistance and, in particular, low coefficients of faecal egg count underline the needs of further significant investigations.
La resistenza genetica alle parassitosi gastrointestinali: esperienze condotte sulla razza ovina Massese
GIULIOTTI, LORELLA;BENVENUTI, MARIA NOVELLA;CECCHI, FRANCESCA;
2003-01-01
Abstract
In small ruminants gastrointestinal parasitosis represent a severe limit to the quality of productions and animal welfare. The difference between the dissimilar levels of sheep’s infection in the flock is a relevant marker of the high variability about the gastrointestinal parasite resistance. In fact, there is considerable interest in the assessment of the resistance of a parasitised host, especially for nutrition and breeding studies. The aim of this work is the evaluation, in a farm of ovine Massese’s breed, of heritability and repeatability coefficients about the main phaenotipic traits connected with resistance to gastrointestinal strongylosis: faecal egg count and packed cell volume. Animals were tested eight times, during periods of moderate and high elmints infestations. One faecal sample per animal was collected and processed in order to determine the faecal egg count, using the modified McMaster tecnique by Permin and Hansen, transforming the values obtained into natural logarithm log (FEC+25). At the time of faecal collection, the animal also underwent blood analyses for determination of haematocrit. This preliminary results show that heritability coefficient of faecal egg count was quite low, with a value of 0.10; repeatability coefficient was little higher, with a value of 0.16. Packed cell volume genetic values were clearly more favourable, presenting respectively 0.22 (heritability) and 0.58 (repeatability). These results, derivate from first Italian studies on Massese’s breed, can give an interesting direction on the possibility to adopt suitable genetic improvement plans for gastrointestinal parasite resistance and, in particular, low coefficients of faecal egg count underline the needs of further significant investigations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
