title: Measurement of fecal glucocorticoid metabolites and evaluation of udder characteristics to estimate stress after sudden dry-off in dairy cows with different milk yields.
abstract: Sudden dry-off is an established management practice in the dairy industry. But milk yield has been increasing continuously during the last decades. There is no information whether the dry-off procedure, which often results in swollen and firm udders, causes stress, particularly in high-producing dairy cows. Therefore, we evaluated the effect of a sudden dry-off on extramammary udder pressure and the concentration of fecal glucocorticoid metabolites (i.e., 11,17-dioxoandrostane, 11,17-DOA) as an indirect stress parameter. Measurements were carried out within the last week before dry-off and until 9d after dry-off considering 3 groups of milk yield (i.e., low: <15 kg/d, medium: 15-20 kg/d, and high: >20 kg/d). Udder pressure increased in all yield groups after dry-off, peaked at d 2 after dry-off and decreased afterwards. Pressures were highest in high-yielding cows and lowest in low-yielding cows. But only in high-yielding cows was udder pressure after dry-off higher than before dry-off. Baseline 11,17-DOA concentrations depended on milk yield. They were highest in low-yielding (121.7 ± 33.3 ng/g) and lowest in high-yielding cows (71.1 ± 30.0 ng/g). After dry-off, 11,17-DOA increased in all yield groups and peaked at d 3. Whereas in medium- and high-yielding cows 11,17-DOA levels differed significantly from their respective baseline during the whole 9-d measuring period, low-yielding cows showed elevated 11,17-DOA levels only on d 3 after dry-off. However, especially the increase in 11,17-DOA after dry-off between the 3 yield groups was considerably different. Mean 11,17-DOA increase from baseline to d 3 was highest in high-yielding cows (129.1%) and considerably lower in low-yielding cows (40.1%). The highest fecal 11,17-DOA concentrations were measured on d 3 after dry-off, indicating that the stress was most intense on d 2, which is due to an 18-h time lag; at about the same time, udder pressure peaked. Our results showed a negligible effect of a sudden dry-off on low-yielding cows. High-yielding cows, however, faced high extramammary pressures and increased glucocorticoid production. Considering animal welfare aspects, a review of the current dry-off strategies might be warranted.
authors.affiliation: Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Koenigsweg 65, 14163 Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bertulat
authors.forename: C
authors.initials: C
authors.lastname: Fischer-Tenhagen
authors.forename: V
authors.initials: V
authors.lastname: Suthar
authors.forename: E
authors.initials: E
authors.lastname: Möstl
authors.forename: N
authors.initials: N
authors.lastname: Isaka
authors.forename: W
authors.initials: W
authors.lastname: Heuwieser
mesh_terms: D000731:Androstanes / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003612:Dairying / Q000379:methods; D005243:Feces / Q000737:chemistry*; D005260:Female; D005938:Glucocorticoids / Q000032:analysis*; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism; D007774:Lactation / Q000502:physiology*; D008321:Mammary Glands, Animal / Q000502:physiology*; D011312:Pressure; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D000731:Androstanes; D005938:Glucocorticoids; D006854:Hydrocortisone