Compton C W R, McDougall S, Young L, Bryan M A
a Cognosco, Anexa Animal Health , PO Box 21, Morrinsville 3340 , NZ.
N Z Vet J. 2014 Jan;62(1):30-7. doi: 10.1080/00480169.2013.823829. Epub 2013 Aug 28.
The main aim of this study was to describe the prevalence of primary subclinical ketosis (SCK) in mainly pasture-grazed dairy cows in three dairy-farming regions of New Zealand 7-12, and 35-40 days post-calving. A second aim was to investigate herd- and cow-level factors associated with the prevalence of SCK.
A cross-sectional longitudinal prevalence survey was undertaken in 1,620 dairy cows from 57 herds. A random sample of cows without disease in the prior 30 days were enrolled at one farm visit within 5 days of calving, and blood samples were collected 7 and 28 days later (7-12 and 35-40 days post-calving) for measurement of beta-hydroxy butyrate (BHBA) concentrations using an electronic cow-side meter. SCK was defined as blood BHBA concentration ≥1.4 mmol/L.
Mean cow-level prevalence of SCK varied with interval post-calving (16.8 and 3.2% at 7-12 days and 35-40 days post-calving, respectively) and age (13.0 and 13.1% of 2-year olds and ≥8-year olds, respectively, compared to 7.2% of 3-4-year-old cows). Mean herd-level prevalence of SCK was 14.3 (min 0, max 60.0)% and 2.6 (min 0, max 24.4)% at 7-12 days and 35-40 days post-calving, respectively, and was greater in Southland (13.3%) than Waikato and Canterbury herds (6.9 and 4.7%, respectively).
This is the first population-based report of the prevalence of SCK in New Zealand dairy herds and demonstrates that age and interval post-calving are important risk factors determining prevalence; and that there is wide variation in prevalence between herds.
Subclinical ketosis may be unrecognised but common in many New Zealand dairy cows in the first 2 weeks of lactation.
本研究的主要目的是描述新西兰三个奶牛养殖区主要以牧场放牧为主的奶牛在产犊后7 - 12天以及35 - 40天原发性亚临床酮病（SCK）的患病率。第二个目的是调查与SCK患病率相关的畜群和奶牛水平因素。
对来自57个畜群的1620头奶牛进行了横断面纵向患病率调查。在产犊后5天内的一次农场访视中，随机抽取在过去30天内无疾病的奶牛，在7天和28天后（产犊后7 - 12天和35 - 40天）采集血样，使用电子奶牛侧检测仪测量β-羟基丁酸（BHBA）浓度。SCK定义为血BHBA浓度≥1.4 mmol/L。
SCK的平均奶牛水平患病率随产犊后间隔时间而变化（产犊后7 - 12天和35 - 40天分别为16.8%和3.2%），且随年龄变化（2岁和≥8岁奶牛分别为13.0%和13.1%，而3 - 4岁奶牛为7.2%）。SCK的平均畜群水平患病率在产犊后7 - 12天和35 - 40天分别为14.3%（最小值0，最大值60.0%）和2.6%（最小值0，最大值24.4%）；南区（13.3%）高于怀卡托和坎特伯雷畜群（分别为6.9%和4.7%）。
这是新西兰奶牛畜群中SCK患病率的首份基于群体的报告，表明产犊后年龄和间隔时间是决定患病率的重要风险因素；且畜群间患病率存在广泛差异。
亚临床酮病在新西兰许多奶牛产犊后的前两周可能未被识别但很常见。
