Foraging behaviour and intake in wapiti hinds (Cervus elaphus canadensis).

摘要

There is an urgent need for feeding standards for farmed deer and knowledge of seasonal intake is essential in achieving this. Use of n-alkane markers for estimating dry matter digestibility and intake (DMI) of wapiti hinds (n = 8), administered via intra-ruminal controlled release device, were evaluated in pen trials. Foraging behaviour and DMI of hinds (n = 10) on two planes of nutrition (heavily (H) and lightly (L) grazed pasture) were studied during gestation and lactation. Seasonal consistency of natural C₃₁ and C₃₃ n-alkane recoveries made them dependable compounds to pair with dosed C₃₂. DMI estimates using C₃₃ :C₃₂ were slightly more accurate, while those using C ₃₁:C₃₂ were more precise. The bite count method provided field validation of marker technique.; Spring weight loss (−2.9 ± 0.8 g/kg0.75/day) reflected the inability of hinds to meet nutritional requirements of late gestation, even though herbage quality was at its seasonal peak. Augmented bite rates (47.7 ± 1.0 bites/min) and grazing time (10.85 ± 1.23 h/day) did not afford sufficient compensation. Although metabolizable energy requirements peaked during early lactation, hinds were able to consume enough high quality forage (5.38 ± 0.25 kg DM/day) to achieve compensatory growth (12.5 ± 1.4 g/kg0.75/day). This was accomplished by increasing bite size (280 ± 28 mg). Continued elevated intakes through late summer (5.32 ± 0.41 kg DM/day) and autumn (4.41 ± 0.24 kg DM/day), ensured hinds regained adequate condition in time for the oncoming breeding season and winter, respectively. In autumn, reduced bite rates (37.2 ± 1.5 bites/min) and feeding bouts of shorter duration (59.9 ± 11.1 min), reflected diminishing forage quality.; Maternal care disrupted normal patterns of foraging and bedding in June/July. This occurred, most notably, through reductions in length of foraging bouts (H: 83.3 ± 7.9 min, L: 50.2 ± 2.1 min) and hinds spending less active time foraging (78.8 ± 9.8%). To achieve satisfactory nutrient intake, hinds attempted to compensate by increasing frequency of grazing sessions (H: 8.4 ± 0.8 bouts/day, L: 12.0 ± 0.6 bouts/day). Lactating hinds were able to reduce daily foraging in lightly grazed pasture without comprising intake levels.; This study presented evidence that the double n-alkane ratio technique can provide accurate and precise assessment of DMI in wapiti, at least on known diets. Contributions of empirical information on activity and intake of reproductive female wapiti improved the predictive capabilities of an existing computer simulation model linking wapiti bioenergetics with behaviour.