University of Calgary Faculty of Veterinary Medicine, 3330 Hospital Drive NW HSC 2559, Calgary, Alberta T2N 4N1, Canada.
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, VM3B 1089 Veterinary Medicine Drive, Davis, California 95616, USA.
J Wildl Dis. 2024 Apr 1;60(2):531-536. doi: 10.7589/JWD-D-23-00101.
Segmental analyses of hair may be useful for measuring biomarkers over several seasons to years from a single sample. To attribute hair segments to specific time periods, a known chronological marker, or a hair growth rate, is needed. We examined guard hair growth rates of captive muskoxen (Ovibos moschatus) in Fairbanks, Alaska, USA. We sought to determine if a general growth rate could be applied across muskox populations, thus facilitating the use of segmental analyses for various biomarkers. We used archived samples from 16 muskoxen that had guard hairs sampled at six, 14, and 30 wk after shaving. We measured the lengths of 10 guard hairs per sample, calculated weekly and annual growth rates, and then fitted linear mixed-effects models to assess the effect of different covariates on hair growth rate. The period in which hair had been grown had a significant effect (P<0.05) on growth rate. Extrapolated annual hair growth rates were 277±40 mm/yr (weeks 0-6), 248±47 mm/yr (weeks 7-14), and 165±36 mm/yr (weeks 15-30), with an overall average rate of 210±14 mm/yr. These rates were significantly faster than those of free-ranging Greenland muskoxen-78 mm/yr as measured by stable isotope analyses-and varied intra-annually. This suggests that a universal growth rate cannot be generalized across muskox populations and time.
毛发的分段分析可能有助于在单个样本中测量多个季节甚至数年的生物标志物。为了将毛发段归因于特定的时间段，需要一个已知的时间标记或毛发生长率。我们检查了美国阿拉斯加费尔班克斯圈养麝香牛（Ovibos moschatus）的护毛生长速度。我们试图确定是否可以在不同的麝香牛种群中应用一般的生长率，从而促进分段分析各种生物标志物的应用。我们使用了 16 只麝香牛的存档样本，这些样本在剃毛后 6、14 和 30 周时采集了护毛。我们测量了每个样本中的 10 根护毛的长度，计算了每周和每年的生长率，然后拟合了线性混合效应模型，以评估不同协变量对毛发生长率的影响。毛发生长的时期对生长率有显著影响（P<0.05）。推断的年毛发生长率分别为 277±40 mm/yr（0-6 周）、248±47 mm/yr（7-14 周）和 165±36 mm/yr（15-30 周），平均总生长率为 210±14 mm/yr。这些速率明显快于稳定同位素分析测量的自由放养格陵兰麝香牛的 78 mm/yr，并且每年都有变化。这表明，普遍的生长率不能在不同的麝香牛种群和时间中推广。
