Breeding options for nematode resistance in Lacaune dairy sheep.

Due to progressing anthelmintic resistance of gastrointestinal nematodes (GIN), supportive measures are needed to control these parasites. In sheep, it has been shown that selection towards an increased nematode resistance is feasible and that faecal egg count (FEC) is the generally acknowledged trait for selection. However, a selection based on FEC would come with certain costs, therefore auxiliary, cheaper resistance traits would be most welcome. FAMACHA©, a colour classification of the eyelid, usually used to determine the manifestation of an infection with Haemonchus contortus, could serve as such. Therefore, we collected FAMACHA©, packed cell volume (PVC) and FEC phenotypes of approx. 1150 naturally infected Lacaune ewes on 15 commercial farms in Switzerland. The Haemonchus-proportion was determined on farm level. Phenotypic correlations of FEC and FAMACHA© as well as FAMACHA© and PCV were 0.25 (SE 0.03) and -0.35 (SE 0.08), respectively, and correspond well with the results of other studies. A multi-trait animal model was applied to estimate genetic parameters with FEC, FAMACHA©, PVC and milk yield as dependent variables. The heritabilities of FEC, FAMACHA©, PCV and milk yield were estimated to be moderate with values of 0.33 (SE 0.08), 0.30 (SE 0.08), 0.36 (SE 0.08) and 0.34 (SE 0.08), respectively. The genetic correlations between FEC and FAMACHA© and between FEC and PCV were estimated to be close to zero with values of 0.03 (SE 0.22) and 0.01 (SE 0.21), respectively. The average Haemonchus-proportion compared to other GIN was found to be 43%. The FAMACHA© classification of the Lacaune ewes seems to indicate a rather high worm challenge, with 38, 14 and 2% of observations classified to scores 3, 4 and 5, respectively. However, the worm challenge according to FEC was moderate. It has been suggested that the genetic correlation between FAMACHA© and FEC is more pronounced when FEC was high. It could therefore be that the lack of genetic correlation was due to an insufficient worm challenge, even though the Lacaune were grazing at least 70 days before phenotyping. The genetic correlation between FEC and milk yield was estimated to be 0.07 (SE 0.22, slightly unfavourable). We conclude that if FEC is used as trait, the Lacaune could be selected for lower susceptibility towards nematode infection. The use of FAMACHA© as an auxiliary trait for FEC is not feasible, due to an inexistent genetic correlation between these two traits.

[Influence of local anaesthesia on pain and distress induced by bloodless castration methods in young lambs]. / Einfluss der Lokalanästhesie auf Schmerz und Stress verursacht durch unblutige Kastrationsmethoden beim jungen Lamm.

Behavioural and cortisol responses of lambs were used as indicators of pain and distress to assess short- and long-term effects of bloodless castration methods with and without local anaesthesia. Eighty lambs, aged 2-7 days, were control handled or castrated by crushing- Burdizzo- or rubber ring method with and without local anaesthesia. Either 4 mg/kg diluted lidocaine, or corresponding volumes of physiologic sodium chloride solution were distributed in both spermatic cords and the scrotal neck. The serum cortisol response was monitored for 48 h, behavioural- and clinical traits over a 3-month period. The crushing castration method was excluded from the study after 10 lambs had been castrated, since this method showed severe local reactions. Local anaesthesia significantly reduced behavioural and cortisol responses after rubber ring castration and tendentially after Burdizzo castration. Prolonged or chronic pain after rubber ring castration with anaesthesia was not evident. If combined with local anaesthesia, both the rubber ring and the Burdizzo method are acceptable methods for castration of lambs up to one week of age.

[Influence of local anaesthesia on short- and long-term pain induced in calves by three bloodless castration methods]. / Einfluss der Lokalanästhesie auf Kurz- und Langzeitschmerzen verursacht durch drei unblutige Kastrationsmethoden beim Kalb.

Behavioural and cortisol responses of calves were used as indicators of pain to assess short- and long-term effects of three bloodless castration methods with and without local anaesthesia. Eighty calves, aged 21 to 28 days, were control handled (20) or castrated by Burdizzo (25), rubber ring (25), or crushing technique (10). Either a total volume of 10 ml of Lidocaine or NaCl was distributed in both spermatic cords and the scrotal neck. The plasma cortisol response was monitored for 72 hours, and behavioural and clinical traits over a three-month period. Castration success was assessed by degree of atrophy and histological tissue examination. The crushing technique cannot be recommended due to incomplete castration success, and the evaluation was stopped after 10 animals. Local anaesthesia reduced the level of indicators of acute pain after Burdizzo and rubber ring technique. It did, however, not result in a totally painless castration. When castration is performed at the age of 3 to 4 weeks, the rubber ring but not the Burdizzo method showed evidence of chronic pain lasting for several weeks.