Liu Guanglei, Done Eryl, Ip Joyce, Li Cheuk Ming, Flay Kate, Kenéz Ákos
Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong SAR, China.
CityU Farm, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong SAR, China.
Front Vet Sci. 2025 May 22;12:1601524. doi: 10.3389/fvets.2025.1601524. eCollection 2025.
The establishment of a new teaching and research dairy farm at City University of Hong Kong (Hong Kong SAR, China) necessitated the importation of pregnant dairy heifers from Australia. On 20 September 2022, a cohort of 24 pregnant heifers arrived by air to CityU Farm. Commencing shortly after arrival, during the subsequent month all heifers exhibited abnormal udder development resembling cows within 2 weeks pre-parturition, despite being 10-17 weeks from calving. Further clinical examination showed excessive teat edema, ventral abdominal edema and milk leakage. Additionally, serum biochemical analysis identified elevated cortisol and prolactin levels, accompanied by reduced cholesterol and triglyceride levels. These observations indicated that premature lactation in the heifers could be associated with transport-induced stress, hormonal imbalances, and potential zearalenone contamination in the feed. Interventions were implemented upon the appearance of clinical signs, including the reduction of artificial lighting in the barns to reduce solar-induced stress, removal of concentrate from the diet with only timothy hay retained, and implementing timely monitoring and treatment of mastitis cases. The majority of the heifers calved successfully as expected, with the exception of one premature calving case (approximately 6 weeks early). Notably, half of the heifers that experienced premature lactation exhibited reduced colostrum quality at calving post-recovery with 50% (of 20 sampled) having a %Brix value of <22, (mean %Brix value of 22.13 ± 4.20). The findings emphasize the physiological challenges associated with international cattle transport and underscore the need for research-driven strategies to improve livestock acclimatization, welfare, and management during and after transportation.
香港城市大学（中国香港特别行政区）新建了一个教学与科研奶牛场，因此需要从澳大利亚进口怀孕的奶牛小母牛。2022年9月20日，一群24头怀孕的小母牛空运抵达城大农场。到达后不久开始，在随后的一个月里，所有小母牛都出现了异常的乳房发育，类似于产前2周内的母牛，尽管它们距离产犊还有10 - 17周。进一步的临床检查发现乳头水肿过度、腹侧腹部水肿和乳汁泄漏。此外，血清生化分析显示皮质醇和催乳素水平升高，同时胆固醇和甘油三酯水平降低。这些观察结果表明，小母牛过早泌乳可能与运输引起的应激、激素失衡以及饲料中潜在的玉米赤霉烯酮污染有关。临床症状出现后采取了干预措施，包括减少牛舍中的人工照明以减轻阳光引起的应激，从日粮中去除精饲料，仅保留提摩西干草，并及时监测和治疗乳腺炎病例。除了一例早产犊病例（提前约6周）外，大多数小母牛按预期成功产犊。值得注意的是，经历过早泌乳的小母牛中有一半在产后恢复时初乳质量下降，20份采样中有50%的乳清浓度值<22（平均乳清浓度值为22.13±4.20）。这些发现强调了国际运输牛所面临的生理挑战，并强调需要研究驱动的策略来改善运输期间及之后牲畜的适应、福利和管理。
