Abstract

The main aim of our study was to assess changes in the somatic cell count (SCC) and total bacterial count (TBC) in the raw milk of White Short-haired (WSH) goats (n = 13) during lactation and their relationships to daily milk yield (DMY), basic milk components, the acidity of milk and California mastitis test (CMT). All monitored goats were in the second lactation and throughout the study, all these goats were clinically healthy. Individual milk recording and sampling of each goat during lactation were carried, from the end of April to October on the mean 54, 89, 124, 159, 194 and 229 day of lactation and all monitored goats were milked by hand. Throughout lactation, the mean values of Log SCC ranged from 5.60 to 5.91 and the mean values of Log TBC from 2.85 to 3.58, whilst the SL had no significant effect on any of these traits. The Log SCC had a significant positive correlation (p ≤ .01) only with CMT, which suggests that CMT may be a good predictor of the SCC. On the other hand, all correlations of Log TBC with all other traits were insignificant. Regarding the effect of the SL on all other monitored traits, it had a highly significant effect (p ≤ .01) on the DMY, contents of fat and total protein and titratable acidity. The SL had also a significant effect (p ≤ .05) on the pH. Nevertheless, the SL had no significant effect on lactose content and CMT. The results of our study suggest that in clinically healthy WSH goats, the SCCs in goat milk after milking should only rarely be higher than 1,000,000 cells/mL and if strict milking hygiene is applied, the TBCs should be significantly lower than 500,000 cfu/mL. The present study also suggests that the SCCs in milk in WSH goats are comparable to their counts in most other breeds.

• HIGHLIGHTS

• The stage of lactation had no significant effect on the SCC and TBC.

• In clinically healthy WSH goats, the SCCs in raw milk should rarely be higher than 1,000,000 cells/mL.

• When strict milking hygiene is applied in clinically healthy goats, the TBCs in milk after milking should be significantly lower than 500,000 cfu/mL.

摘要

我们研究的主要目的是评估白短毛 (WSH) 山羊 ( n ) 生奶中体细胞计数 (SCC) 和细菌总数 (TBC) 的变化。 = 13) 哺乳期及其与每日产奶量 (DMY)、基本牛奶成分、牛奶酸度和加州乳腺炎测试 (CMT) 的关系。所有被监测的山羊都处于第二次哺乳期，并且在整个研究过程中，所有这些山羊在临床上都是健康的。从4月底到10月，在泌乳期的平均第54天、第89天、第124天、第159天、第194天和第229天，对每只山羊在泌乳期间进行个体牛奶记录和取样，所有监测的山羊都是手工挤奶的。在整个哺乳期间，Log SCC 的平均值范围为 5.60 到 5.91，Log TBC 的平均值范围为 2.85 到 3.58，而 SL 对这些性状中的任何一个都没有显着影响。Log SCC 呈显着正相关（p ≤ .01) 仅适用于 CMT，这表明 CMT 可能是 SCC 的良好预测指标。另一方面，Log TBC 与所有其他性状的所有相关性都不显着。关于 SL 对所有其他监测性状的影响，它对 DMY、脂肪和总蛋白含量以及可滴定酸度有非常显着的影响 ( p ≤ .01)。SL 也有显着影响（p ≤ .05) 的 pH 值。尽管如此，SL 对乳糖含量和 CMT 没有显着影响。我们的研究结果表明，在临床健康的 WSH 山羊中，挤奶后山羊奶中的 SCC 很少会高于 1,000,000 个细胞/mL，如果采用严格的挤奶卫生，TBC 应显着低于 500,000 cfu/mL。本研究还表明，WSH 山羊牛奶中的 SCC 与大多数其他品种的数量相当。

• 强调

• 泌乳阶段对SCC和TBC没有显着影响。

• 在临床健康的 WSH 山羊中，生奶中的 SCC 很少会高于 1,000,000 个细胞/mL。

• 当对临床健康的山羊实行严格的挤奶卫生时，挤奶后牛奶中的 TBC 应显着低于 500,000 cfu/mL。