The aim was to study the variations of somatic cell counts (SCC) of goat milk according to pathological and physiological variables. Aseptic samples of foremilk were collected every 20 d from both udder halves (UH) during entire lactation from 87 goats, resulting in a total of 929 samples. The infectious status was assessed by bacteriological cultures, and the SCC (cells/mL) by a Fossomatic counter. Chi-squared, ANOVA, and regression analysis (positive cultures transformed into dummy variable) were carried out to analyze the relationship between variables. Prevalence of intramammary infection (IMI) was 14.2% of all UH samples examined. The prevalent mastitis agents were coagulase-negative staphylococci (CNS, 10.6%) and Staphylococcus aureus (3.6%). Pathogens increased (P < 0.001) the SCC. The average values for SCC of uninfected UH, CNS and S. aureus are shown in Table 1. Uninfected SCC averages for the first (≤90 d), second (91–180 d) and third (>180 d) lactation stages were 674 ± 1087 × 10³, 995 ± 1300 × 10³ and 1637 ± 2424 × 10³, respectively. Uninfected UH of goats with more than 3 lactations (n = 295 samples) had more (P = 0.004) SCC average (1075 ± 1752 × 10³) than those of 1 or 2 lactations (n = 501 samples; 792 ± 664 × 10³). The SCC regression with IMI and days in lactation were R² = 0.19 (P < 0.001) and R² = 0.10 (P < 0.001), respectively. The SCC averages of negative UH were 1946 × 10³, 1004 × 10³, 647 × 10³, and 335 × 10³ for daily milk yields less than 0.5 L, between 0.51 and 1.0 L, between 1.01 and 2.0 L, and more than 2.01 L, respectively. Although subclinical mastitis was the principal factor for SCC increases, these results showed that there are other non-infectious factors (lactation stage, parity number and milk yield) that cause variation in SCC, and must be considered when monitoring udder health and milk quality of dairy goats. Table 1 (Abstr. T190). SCC values from uninfected UH (UI) and with subclinical infections due to SCN and S. aureus.

Udder half health	n	Mean	SD	95% CI		Median
IL	SL
UI	796	789,427	1,139,886	710,118	868,734	381,000
CNS	99	1,891,432	1,521,385	1,384,177	2,398,687	1,619,000
S.aureus	34	5,296,615	3,806,640	3,118,445	7,290,169	4,431,000