Experimental determination of dietary carbon turnover in bovine hair and hoof

Abstract

Stable isotopes measured in keratinized tissues like hair or hoof have proven to be a useful tool for reconstructing the dietary history of animals with a weekly to daily resolution. Quantitative reconstruction of dietary preferences requires a precise estimate of tissue turnover by means of controlled feeding experiments. We determined the turnover rates of carbon in hoof and tail hair of growing steers ( Bos taurus L., 1758) fed a C3-based diet, followed by a C4-based diet, for 168 d. As with horses, turnover in steer hair was successfully described by a three-pool modelling approach, with apparent half-lives of 1.7, 7.7, and 69.1 d for each of the pools, each contributing 53%, 20%, and 28% of the total signal, respectively. Two pools only were identified in bovine hoof, which recorded the diet switch more slowly than hair with a reduction in the amplitude of short-term isotope changes. We interpreted this result as a sampling artefact and found that the hooves reflected the same pools as the hair if growth geometry is taken into account. The model parameters defined in this study allowed us to quantitatively reconstruct previous diets of steers of different breeds and individual history with a precision of ±1‰.

Responses of herbage and cattle tail switch hair δ15N value to long-term stocking rates on a rough fescue grassland

“…This portion was divided into five sections of 2.3 cm each to represent hair growth in one month (Zazzo et al 2007). Hair longer than 11.5 cm was not used as this portion was assumed to represent growth prior to the current grazing season.…”

Influence of forage preferences and habitat use on13C and15N abundance in wild caribou (Rangifer tarandus caribou) and moose (Alces alces) from Canada

“…These studies suggest a diet-keratin δ 13 C discrimination of ca. +3 ‰ based on measurement on the hair (experimental conditions in [35][36][37][38]; natural environments in [32,37]), the horn (natural environments in [39]), and the hoof (experimental conditions in [12,38]). The 15 N discrimination value between diet and keratin is more difficult to decipher since it can be influenced by factors like the dietary protein content and nutrient requirement of the animal [40].…”

An ancient bison from the mouth of the Rauchua River (Chukotka, Russia)

“…This suggests that the floccus hairs increased in length by at least 10 cm since the last moult. Bison have a single late-spring moult (Sokolov, 1979) and the floccus hair growth rate of large herbivores amounts to about 1 mm per day (Schwertl et al, 2003;Zazzo et al, 2007). It follows that the death occurred at least 100 days after the last moult date, although the maximum time period cannot be defined.…”