Abstract

SUAREZ, V.H et al. Relaciones entre el recuento de células somáticas, test de mastitis California, conductividad eléctrica y el diagnóstico de mastitis subclínicas en cabras lecheras. RIA. Rev. investig. agropecu. [online]. 2014, vol.40, n.2, pp.145-153. ISSN 1669-2314.

Mastitis in udders is a major health problem, affecting productivity, safety and product quality in the dairy goat. Because the diagnosis of subclinical mastitis is problematic for accurate monitoring, the objective of this study is to evaluate the relationships among the infectious status of half udder and different diagnosis methods: somatic cell count (SCC), California mastitis test (CMT) and electric conductivity (CE) and its diagnostic possibilities in the real dairy goat systems. From milked goats (Saanen, 76%) during Sept/2010-March/2011 and June/2011-Dec/2011 periods, monthly samples (n=846) of milk were taken from each half udder. Udder halves infectious status was assessed by bacteriological cultures and classified in three groups: negative culture (NI), and intrammary infections by minor pathogens and by major pathogens. Chi square, analysis of variance and correlation and regression analysis were carried out to analyse interrelations between variables. Sensitivity (S), specificity (SP) and predictive values (VP) were calculated. Coagulase-negative Staphylococcus sp SCN (n=37), were the minor pathogen and Staphylococcus aureus (n=13), was the only major pathogen isolated. Pathogen increase CCS (P<0001) and CMT (P<0.0001) but not CE (0.09). The average values for CCS of NI, SCN y S. aureus were respectively 789427±1139886, 1891432±1521385 y 5296615±3806640. The correlation obtained between CCS and CE was respectively r=0.41 (P<0.0001) and r=0.12 (P<0,03). The CCS had significative (p<0.0001) correlations of r=0.86 with VMYP, r=0.64 with CMT, r=0.24 with CE and 0.47 with PortaSCC. The VMYP cell counts was 20.8% lesser than Breed counts. CCS averages were for the CMT scores of 326823 (0), 494294 (traces), 741670 (1), 1680557 (2) and 3842440 (3) cells/ml. S and SP were of 70% and 79% for CCS, 68% and 80% for CMT and 58% y 60% for CE respectively. The study shows that both the CCS (cut line <1000000) and CMT (0, T, 1) can be used to monitor the presence of subclinical mastitis, considering that exhibit good high negative VP (98% ) and good SP for the diagnosis of healthy udders and acceptable S for infections (specially major pathogens), provided that the bacteriological diagnosis, recurrence of diagnosis and other no infectious factors associated to elevated CCS are taken into account.

Keywords : Subclinical mastitis; Dairy goat; Aetiology; Diagnostic test.

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