Relationship Between Somatic Cell Count and lntramammary Infection of the Half Udder in Dairy Ewes

Abstract

A total of 1382 milk samples from half udders of three breeds of ewes (686 Assaf, 422 Churra, and 274 Castellana) were collected aseptically at midlactation from 18 flocks in the Castile-León region of Spain. Bacteriological tests were carried out on the samples to ascertain the status and type of IMI. Somatic cell counts were determined for all samples after bacteriological analysis. Analysis of variance showed significant effects of breed, IMI status, flock nested within breed by milking type, organism within IMI status, and interactions of breed by milking type and of breed by organism. The most frequent bacterial groups were staphylococci, especially coagulase-negative staphylococci, followed by streptococci, micrococci, and yeasts. The SCC response was related to the bacterial group involved in the IMI; coagulase-negative staphylococci showed significantly lower SCC values than those for coagulase-positive staphylococci and streptococci. Highest percentages of IMI by major pathogens and highest SCC, both in the absence of IMI and in staphylococcal IMI, were in Assaf ewes. The threshold of 300,000 cells/ml allowed 81% of the half udders to be correctly classified according to IMI status. However, the existence of breed differences in SCC response and IMI type could make the use of specific SCC thresholds for each breed advisable.

Genetic selection for reduced somatic cell counts in sheep milk: A review

“…Some evidence has been provided that healthy ewes have normally higher SCC than cows (Maisi et al, 1987;Fthenakis et al, 1991;González-Rodríguez et al, 1995). Bufano et al (1996) showed that a high SSC (>1 million/mL) occurs in healthy sheep and goat milk, especially towards the end of lactation.…”

“…Some researchers (Fthenakis et al, 1991;Jones, 1991) reported discrimination values between healthy and infected glands ranging from 500 to 1600 × 10 3 cells/mL, while others (Bergonier et al, 1994;De la Cruz et al, 1994;Pengov, 2001) reported values similar to those for cows (200-300 × 10 3 cells/mL). González-Rodríguez et al (1995) suggested that breed differences in SCC do exist. Considering several breeds, these researchers reported the value of 300 × 10 3 cells/mL as the most suitable threshold of discrimination for total SCC data.…”

Efficacy of vaccination and nisin Z treatments to eliminate intramammary Staphylococcus aureus infection in lactating cows

“…IMI is the major factor inducing high milk SCCs (González-RodríGuez et al, 1995). A high SCC is usually taken as an indicator of an IMI caused by bacteria, and a low SCC (<1.50×10 5 cells/ml) in general implies freedom from such infections (Sordillo et al, 1997).…”

Management and sanitary practices in ewe dairy farms and bulk milk somatic cell count

“…Factors such as breed, flock, animal's age, lactation stage, udder health and hygiene, and handling during milking, all influence SCC values (Bergonier and Berthelot, 2003;Gonzalo et al, 2005). Consequently, these values are not only necessary indicators of milk quality in sanitary terms, but also indirectly reveal parameters for sanitary control and management practices on small ruminant dairy farms (González-Rodríguez et al, 1995;Gonzalo et al, 2005). On 42.7% of the farms surveyed, the BMSCC was < 600 × 10 3 cells mL -1 , and these results coincide with other studies done previously on the Manchegan breed (Serrano et al, 2003).…”

“…Currently, there is a regulatory limit set for this species by Council Directives 92/46/EC and 94/71/EC. However, despite there being no set maximum BMSCC or individual SCC values for the milk of small ruminants, there appears to be good agreement (De la Cruz et al, 1994;González-Rodríguez et al, 1995;Gonzalo et al, 2005) as to considering that BMSCC values over 500-600 × 10 3 cell mL -1 would be associated with an increased prevalence of mammary infections and with significant losses in the milk production of small ruminants. Therefore it is necessary to conduct studies which could help improve the hygiene-sanitary quality of ewe's milk by f irstly improving the BMSCC.…”