부산대학교 도서관

• NIRS can be used to predict cow-specific diet digestibility from faecal samples. • Genetic variation in digestibility can be determined from iNDF content in the faeces. • Protocols with sizable contemporaries of cows are required for genetic analyses. • Heritability estimates ranged from 0.13 to 0.51 depending on the sampling protocol. • The coefficient of genetic variation for dry matter digestibility was 1.7%. Digestibility traits included in this study were dry matter digestibility (DMD, g/kg), which was calculated based on the indigestible neutral detergent fibre (iNDF, g/kg of dry matter) content in faeces (iNDF f) and in diet (iNDF d), and iNDF f predicted directly from faecal samples by near infrared reflectance spectroscopy (NIRS). The data set was collected at three research herds in Finland and one in Norway including in total 931 records from 328 lactating Nordic Red Cattle and Holstein cows. Observations were associated with different accuracy, due to the differences in sampling protocols used for collecting faecal samples. Heritability estimates varied between different sampling protocols and ranged from 0.14 ± 0.06 to 0.51 ± 0.24 for DMD and from 0.13 ± 0.05 to 0.48 ± 0.18 for iNDF f. Estimated genetic standard deviations were 10.5 g/kg and 6.2 g/kg dry matter for DMD and iNDF f , respectively. Results of our study indicated that recording only the iNDF content in the faeces is sufficient to determine genetic variation in cows' ability to digest feed. The coefficient of genetic variation for DMD was rather small (1.7%), but could be utilized if it is supported by a positive analysis of benefits over costs. [ABSTRACT FROM AUTHOR]