Author:
Ivanov Martin,Nohálová Hana,Nývltová Fišáková Miriam,Dresler Petr,Dreslerová Gabriela
Abstract
In this essay, we focused on the evaluation of isotope analyses (δ13Ccoll and δ15Ncoll) of the first lower molars (m1) of domestic cattle (Bostaurus) from two early medieval Pohansko-Southern bailey (Pohansko-JP) and Kostice-”Zadní hrúd” (Kostice-ZH) sites. The aim of the study is the evidence of the breast-feeding effect of calves and subsequent weaning on the dentine average isotope composition. Results from both sites are compared with the data obtained from recent experimental cattle breeding. Possible differences in the cattle breeding between both studied localities are evaluated. The first lower molars of the domestic cattle (n = 15) were selected for analyses from both sites supplemented by a sample of the compact bone of the shinbone of an adult individual from the Pohansko-JP site. The determination of the ontogenetic age of the analyzed individuals is based on the dentition development stage. For the purpose of isotope analyzes (δ13Ccoll and δ15Ncoll), dentine collagen was extracted from all tooth crowns. The δ13Ccoll dentine values of the m1 of cattle from the Pohansko-JP ranged from -17.75‰ to -21.8‰ (n = 11) with mean value of -19.81 ± 1.03‰. δ15Ncoll values for dentine of all m1 samples from Pohansko-JP range from 6.2‰ to 11.87‰ with mean value of 8.29 ± 1.71‰ (n = 11). The highest δ15Ncoll values were observed primarily in samples of juvenile individuals, with the exception of one adult specimen (10.90 ‰). δ13Ccoll values in m1 of adult individuals from the Kostice-ZH site range from -19.30‰ to -20.91‰ (n = 4). The mean value -19.83 ± 1.01‰ is lower if compared to results from recent experimental breedings. The volume of 15N isotope is significantly lower contrary to those in Pohansko-JP and aforementioned experimental study. It can be assumed that the diet of the cattle in both studied sites was primarily based on C3 plants; however, we cannot exclude a small admixture of C4 plants (millet) in the diet of some observed individuals. The cattle from the Pohansko-JP could be driven to graze from the open meadows up to the ecotones in the vicinity of the forest which is partly supported by the palaeobotanic record. In Kostice-ZH site, the grazing in open meadows was most prevalent. The volume of 15N from the Pohansko-JP site shows that in most cases, calves were not prematurely weaned. In samples from Kostice-ZH, the 15N content in adult individuals was significantly lower contrary to values from Pohansko-JP. A present stage of the knowledge indicates that the cattle (i. e., including mother cows) was probably fed plants characterized by low δ15N values; however, a premature weaning to increase the milk production cannot be excluded.