Five male castrated Holstein-Friesian calves 133 to 149 days old (weight range = 82–112
kg) were included in the study. The animals were sourced from a commercial high health
herd and confirmed as negative for BVDV via PCR prior to study commencement. The animals
were housed in 1 room (22m2 (link)) in a high-containment (SAPO4) animal facility at the Pirbright Institute. Bedding
material was provided (https://www.mayofarmsystems.co.uk/mayo-mattress-stable-mat/ ), light/dark
cycle was 12:12 h, temperature was held between 10°C to 24°C, and humidity 40% to 70%.
Animals were fed concentrated rations twice daily and given ad lib access to hay and
water. Environmental enrichment was provided, including rubber toys and a hollow ball
stuffed with hay.
Four of the 5 animals (calves Nos. 2–5) were randomly assigned to the treatment group and
the remaining animal (calf No. 1) to the untreated group. The 4 treated animals were each
inoculated with 3 ml of a LSDV suspension at a concentration of 1 × 106 PFU/ml;
2 ml (2 × 106 PFU) was inoculated intravenously (IV) into the jugular vein, and
1 ml (1 × 106 PFU) injected intradermally (ID) into 2 sites on each side of the
neck (0.25 ml in each site). The untreated animal was not inoculated. Each animal was
examined daily for clinical signs, including fever, anorexia, depression, and for gross
lesions, including cutaneous nodules and lymphadenopathy.
Skin biopsies were carried out on the 4 inoculated animals at 5, 9, 11, 15, 17, and 19
days postinoculation (DPI). Hair was removed from the biopsy site with electric clippers
and cleaned with skin wipes containing 2% chlorhexidine in 70% alcohol (Clinell, GAMA
Healthcare); 2.5 ml of lignocaine (Lidocaine Hydrochloride injection 2%, Hameln
Pharmaceuticals) was injected subcutaneously, and after 10 minutes, a 0.8 cm punch biopsy
was taken using a disposable biopsy punch (Integra Miltex). One half of the biopsy tissue
was placed into 10% sterile buffered formalin (Merck) for a minimum of 48 hours. One
quarter was placed into 4% paraformaldehyde (Santa Cruz Biotechnology, sc-281692). The
remaining quarter was stored at –80°C for future studies. Insects were fed on the skin of
the 4 inoculated cattle at up to 7 time points during the study. The results of this
procedure are reported separately (manuscript in preparation).
The 5 animals were euthanized at 19 to 21 DPI with an overdose of barbiturate solution
(Dolethal 200mg/ml Solution for injection, Vetoquinol). A postmortem examination was
carried out and tissue samples collected into 10% sterile buffered formalin for a minimum
of 48 hours before processing.
kg) were included in the study. The animals were sourced from a commercial high health
herd and confirmed as negative for BVDV via PCR prior to study commencement. The animals
were housed in 1 room (22m2 (link)) in a high-containment (SAPO4) animal facility at the Pirbright Institute. Bedding
material was provided (
cycle was 12:12 h, temperature was held between 10°C to 24°C, and humidity 40% to 70%.
Animals were fed concentrated rations twice daily and given ad lib access to hay and
water. Environmental enrichment was provided, including rubber toys and a hollow ball
stuffed with hay.
Four of the 5 animals (calves Nos. 2–5) were randomly assigned to the treatment group and
the remaining animal (calf No. 1) to the untreated group. The 4 treated animals were each
inoculated with 3 ml of a LSDV suspension at a concentration of 1 × 106 PFU/ml;
2 ml (2 × 106 PFU) was inoculated intravenously (IV) into the jugular vein, and
1 ml (1 × 106 PFU) injected intradermally (ID) into 2 sites on each side of the
neck (0.25 ml in each site). The untreated animal was not inoculated. Each animal was
examined daily for clinical signs, including fever, anorexia, depression, and for gross
lesions, including cutaneous nodules and lymphadenopathy.
Skin biopsies were carried out on the 4 inoculated animals at 5, 9, 11, 15, 17, and 19
days postinoculation (DPI). Hair was removed from the biopsy site with electric clippers
and cleaned with skin wipes containing 2% chlorhexidine in 70% alcohol (Clinell, GAMA
Healthcare); 2.5 ml of lignocaine (Lidocaine Hydrochloride injection 2%, Hameln
Pharmaceuticals) was injected subcutaneously, and after 10 minutes, a 0.8 cm punch biopsy
was taken using a disposable biopsy punch (Integra Miltex). One half of the biopsy tissue
was placed into 10% sterile buffered formalin (Merck) for a minimum of 48 hours. One
quarter was placed into 4% paraformaldehyde (Santa Cruz Biotechnology, sc-281692). The
remaining quarter was stored at –80°C for future studies. Insects were fed on the skin of
the 4 inoculated cattle at up to 7 time points during the study. The results of this
procedure are reported separately (manuscript in preparation).
The 5 animals were euthanized at 19 to 21 DPI with an overdose of barbiturate solution
(Dolethal 200mg/ml Solution for injection, Vetoquinol). A postmortem examination was
carried out and tissue samples collected into 10% sterile buffered formalin for a minimum
of 48 hours before processing.
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