Survey on milk quality at late lactation and presence of ancient Zebu whey protein marker in Podolic cattle of Basilicata region

More than 800 milk samples from 13 farms were collected in Basilicata region (South-Italy) to make a survey on milk quality of Podolic cattle. The gross composition showed fluctuating variability, influenced both by sampling and endogenous parameter of the animal. The fat content had the highest variability, probably as a consequence of manual milking. Protein ranged from a minimum of 3.4 to a maximum of 3.8% (±0.13 sd), while lactose ranged from 4.9 to 5.2% (±0.12 sd); in contrast to the fat content, these parameters had very low variability. Somatic cell counts (SCC) and differential somatic cell count (DSCC) showed good udder health for all farms (except 1 farm), having a SCC mean value of 318.3 Colony Forming Unit (CFU)/mL value, but DSCC below 66.3%. The urea content fell within the range of 13.9 and 36.9 mg/dl, 6 farms fell out the normal range (20–46 mg/dl) meaning that animals were supplied with unbalanced protein food, which in turn could affect the milk production (if low) or have impact on cow fertility (when high). Acetone and β-hydroxybutyric acid (BHB) are considered useful indicators of subclinical ketosis (SCK), 0.15 mM for milk acetone and 0.1 mM for milk BHB have been proposed as threshold for SCK. Our results showed only 1 farm subject to SCK. Considering the casein content, the mean value represents the 78.4% of the total protein content, which is within the normal range. The coagulation properties of milk showed mean value of coagulation time slightly above the normal range, this implies a slow reaction of milk to rennet action (r = 23.6 min vs normal range 11 < r < 17 min); similarly, the coagulation rate (k20) was slight high (5.1 min), it reflects in a slower rate of aggregation of micelles. On the other hand, A30 mean value (39.7 mm) showed good curd firmness at 30 min after the addition of calf rennet on milk. According to the correlation matrix SCC had negative correlation with urea content (r = −0.587, p < 0.05); then, acetone had high significative correlation with BHB (r = 0.877, p < 0.0001). The research of the ancient marker of Zebu whey protein was based on the detection of the α-lactalbumin variant A by RP-HPLC analysis of 239 individual milk samples. The variant was found only in the 13.8% of the population studied. The most of them were heterozygotes (both containing variant B, the most common in taurine breeds, and variant A), while only the 6.1% were, surprisingly, homozygotes containing only the variant A.