. The Canadian field-naturalist. Natural history; Sciences naturelles. 2006 RosAiTi-; ANi:» Niiuioiix Late-born Elk Caij- 189. Figure 1. Late born elk calf with spots photographed by J. Neuhold near Hartsmere, Ontario, on October 5, 2004. of calving for Elk is such that inclement winter/spring weather is avoided but is early enough ( June) so that calves can attain sufficient weight and size to sur- vive the winter (Hudson et al. 2002). Juvenile Elk have evolved to reduce or cease growth during fall and win- ter, when the nutritive value of forage declines. Cook et al. (1996) reported that
. The Canadian field-naturalist. Natural history; Sciences naturelles. 2006 RosAiTi-; ANi:» Niiuioiix Late-born Elk Caij- 189. Figure 1. Late born elk calf with spots photographed by J. Neuhold near Hartsmere, Ontario, on October 5, 2004. of calving for Elk is such that inclement winter/spring weather is avoided but is early enough ( June) so that calves can attain sufficient weight and size to sur- vive the winter (Hudson et al. 2002). Juvenile Elk have evolved to reduce or cease growth during fall and win- ter, when the nutritive value of forage declines. Cook et al. (1996) reported that calf growth in mid-Novem- ber was 50% of that found in September and hypoth- esized that the nutritional strategy of Elk calves during the late fall/early winter was primarily to maintain con- dition rather than maximizing growth. Inevitably, ener- gy acquisition for rapid growth becomes a problem for late-bom calves, as not only is forage less nutri- tious during the fall and winter, but milk production in lactating cow Elk also declines during that period due to poor quality forage (Cook et al. 1996; Cook 2002). In addition, survival was found to be lower for late-bom Elk calves in Yellowstone National Park than for earlier-bom calves (Singer et al. 1997), and calf mortality during winter was primarily due to mal- nutrition. The calf in this study was observed nursing in mid-January 2005 and supplemental feeding by peo- ple in the area may have provided sufficient energy for the cow to continue milk production during the winter period. Nutrition and lactation can affect the timing of es- trous in Elk and subsequently the parturition date (Cook 2002). Generally, cows that are suckling a calf during the mt come into estrous later than cows that do not have a calf (Hudson et al. 2002). During the early part of mt, estrous approximates 21 days but is variable (19-25 days) (Bubenik 1982) and estrous length in- creases and becomes irregular during the later stages of the breeding
Size: 1881px × 1329px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, books, booksubjectnaturalhistory
