Effects of Infection by Caprine Arthritis-Encephalitis Virus on Milk Production of Goats

Nord, K.; Ådnøy, Tormod

doi:10.3168/jds.s0022-0302(97)76190-3

Cited by 40 publications

(25 citation statements)

References 12 publications

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“…This was attributed to a selective immunosuppression due to altered macrophage function during CAEV infection. In seropositive goats, an increase of SCC was mostly reported as far as bacteriologically uninfected halves are concerned [82,105,127,130]. This could be related to the larger number of macrophages in the milk of CAEV contaminated goats [82].…”

Section: Lentiviral Variation Factors Of Somatic Cell Countsmentioning

confidence: 98%

Mastitis of dairy small ruminants

et al. 2003

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-Staphylococci are the main aetiological agents of small ruminants intramammary infections (IMI), the more frequent isolates being S. aureus in clinical cases and coagulase negative species in subclinical IMI. The clinical IMI, whose annual incidence is usually lower than 5%, mainly occur at the beginning of machine milking and during the first third of lactation. These features constitute small ruminant peculiarities compared to dairy cattle. Small ruminant mastitis is generally a chronic and contagious infection: the primary sources are mammary and cutaneous carriages, and spreading mainly occurs during milking. Somatic cell counts (SCC) represent a valuable tool for prevalence assessment and screening, but predictive values are better in ewes than in goats. Prevention is most often based on milking machine management, sanitation and annual control, and milking technique optimisation. Elimination mainly relies on culling animals exhibiting clinical, chronic and recurrent IMI, and on drying-off intramammary antibiotherapy; this treatment allows a good efficacy and may be used selectively by targeting infected udders only. Heritability values for lactation mean SCC scores are between 0.11 and 0.15. Effective inclusion of ewe's mastitis resistance in the breeding goal has recently been implemented in France following experimental and large scale estimations of genetic parameters for SCC scores.ewe / goat / mastitis / somatic cell count / epizootiology

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Section: Lentiviral Variation Factors Of Somatic Cell Countsmentioning

confidence: 98%

Mastitis of dairy small ruminants

et al. 2003

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“…The impact of SRLV-induced mastitis on production is also a controversial issue. Some studies do not detect differences in the quantity and quality of milk from infected and uninfected goats [10,11,12]. Other reports show a reduction in milk production (9% in goats of the Murciano-Grenadine breed) without altering milk quality [13].…”

Section: Introductionmentioning

confidence: 99%

Small Ruminant Lentiviruses: Genetic Variability, Tropism and Diagnosis

Ramírez

Reina

Amorena

et al. 2013

Viruses

126

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Small ruminant lentiviruses (SRLV) cause a multisystemic chronic disease affecting animal production and welfare. SRLV infections are spread across the world with the exception of Iceland. Success in controlling SRLV spread depends largely on the use of appropriate diagnostic tools, but the existence of a high genetic/antigenic variability among these viruses, the fluctuant levels of antibody against them and the low viral loads found in infected individuals hamper the diagnostic efficacy. SRLV have a marked in vivo tropism towards the monocyte/macrophage lineage and attempts have been made to identify the genome regions involved in tropism, with two main candidates, the LTR and env gene, since LTR contains primer binding sites for viral replication and the env-encoded protein (SU ENV), which mediates the binding of the virus to the host’s cell and has hypervariable regions to escape the humoral immune response. Once inside the host cell, innate immunity may interfere with SRLV replication, but the virus develops counteraction mechanisms to escape, multiply and survive, creating a quasi-species and undergoing compartmentalization events. So far, the mechanisms of organ tropism involved in the development of different disease forms (neurological, arthritic, pulmonary and mammary) are unknown, but different alternatives are proposed. This is an overview of the current state of knowledge on SRLV genetic variability and its implications in tropism as well as in the development of alternative diagnostic assays.

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“…However, Ryan and others (1993) found that CAEV infection was a risk factor for intramammary bacterial infection in spite of the fact that this relationship was not observed in herds with a low prevalence of subclinical intramammary infection Cutlip 1988, Nord 1997). Furthermore, CAEV infection increases scc and N-acetyl-beta-glucosaminidase activity in milk from udder halves which are not infected with bacteria (Lerondelle and others 1992, 1995, Ryan and others 1993, Nord and Adnoy 1997, and the increases in the scc are lower or similar to those induced by coagulase-negative staphylococci (Lerondelle andothers 1992, Ryan andothers 1993). In goats, subclinical intramammary bacterial infection can cause a reduction in milk yield of up to 23 per cent (Dulin and others 1983, Sanchez and others 1997) and scc are a useful tool for predicting subclinical intramammary infections in mastitis control plans.…”

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confidence: 99%

Relationships between infection with caprine arthritis encephalitis virus, intramammary bacterial infection and somatic cell counts in dairy goats

et al. 2001

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Somatic cell counts, the bacteriological condition of the milk and antibodies against caprine arthritis encephalitis virus (CAEV) were measured monthly throughout lactation in 121 lactating goats of the Murcia-Granada breed in four commercial dairy goat herds. The prevalence of bacterial intramammary infection was 5.6 per cent and the prevalence of CAEV infection was 20.6 per cent. An analysis of variance revealed a significant effect of herd, intramammary infection and the interaction between intramammary infection and CAEV on the somatic cell count. In udder halves free of intramammary infection, the somatic cell counts were significantly lower in seronegative goats than in seropositive goats (P<0.05), but the difference was not significant in udder halves persistently infected by bacteria. There was a significant increase in somatic cell counts due to bacterial intramammary infection (P<0.01) in the seronegative goats, but this effect was not present in the seropositive animals.

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Effects of Infection by Caprine Arthritis-Encephalitis Virus on Milk Production of Goats

Cited by 40 publications

References 12 publications

Mastitis of dairy small ruminants

Mastitis of dairy small ruminants

Small Ruminant Lentiviruses: Genetic Variability, Tropism and Diagnosis

Relationships between infection with caprine arthritis encephalitis virus, intramammary bacterial infection and somatic cell counts in dairy goats

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