Evaluation of factors inducing variability of faecal nutrients in captive red deer under variable demands

Based on the assumption that dietary and faecal nitrogen correlate, the number of studies using faecal samples collected in the wild to understand diet selection by wild herbivores and other ecological patterns has been growing during the last years, especially due to the recent development of cheap tools for analysis of nutrients like Near-Infrared Reflectance Spectroscopy (NIRS). Within the annual reproductive cycle, cervids (members of the family Cervidae) face strong seasonal variations in nutritional demands, different for hinds (gestation and lactation) and stags (antler growth) and reflected in differential patterns of seasonal diet selection. In this study we aimed to quantify how pasture availability, season and individual factors like sex, age, reproductive status, body mass and body condition affect faecal nutrients in captive red deer with the goal of understanding how these factors may influence the interpretation of results from samples obtained in the wild with little or no information about the animals who dropped those faeces. We used NIRS for analysing nitrogen, neutral and acid detergent fibres in faeces. The relative influence of some individual factors like pregnancy was low (around 4%), while age and weight may induce a variability up to 18%. The presence or absence of pasture contributed to a variability around 13%, while the season contributed to an average variability around 17% (and up to 21% in certain situations). This high variability in faecal nutrients was observed in a controlled setting with captive animals and controlled diets. Thus, in natural situations we suspect that there would be even greater variation. According to the results, we recommend that preliminary research with captive animals of the species of interest should be conducted before collecting samples in the wild, which should help in the interpretation of results.

Feed storage and handling.

This chapter highlights some important tips on feed storage and handling which includes topics on concentrate feed storage equipment, storing roughage, calculating the amount of storage capacity needed, feed storage hygiene, and reducing diet selection by animals fed a formulated mixed ration.

Grazing behaviour - diet selection and pasture intake.

In this chapter the nutritional environment, foraging behaviour, feed intake, and diet selection of grazing animals are discussed.

PSV-10 Free-choice diet selection by sheep during peripartum

Our objective was to explore diet selection and productive performance by sheep during peripartum. Pregnant Saint-Croix and Katahdin ewes were housed in individual pens from 100 days of gestation to 60 days of lactation and assigned to two groups: Free-choice-FC and Mixed-ration-MR (n = 12/group). Sheep in FC received ad-libitum amounts of soybean meal, sorghum grain, alfalfa and oat hays, presented in individual troughs. Animals in MR received a total-mixed-ration with these feeds, balanced for gestation or lactation according to NRC. Dry matter (and nutrient) intake/kg BW was measured daily, whereas BW and BCS were measured every 7 and 14 d, respectively. Data was analyzed as a Linear Mixed Model with repeated measures; group, breed, litter size (single, twins) and parity (primiparous, multiparous) were the fixed factors and sheep (random factor) was nested within group. Overall dry matter and ME intake did not differ between groups (P > 0.05), without breed, litter size or parity effects (P > 0.05), but protein intake was greater and NDF and ADF intakes were lower in FC than in MR (P < 0.001). During gestation, FC sheep consumed soy=alfalfa >sorghum >oats, and during lactation they increased (2X) soy intake (P < 0.001). Body weight was similar between groups (73.3±1.3, and 70.6±1.3 kg, for FC and MR, respectively; P=0.148), whereas BCS was greater for FC than for MR (3.9±0.2 vs. 3.3 ±0.1; P = 0.01). During lactation, ewe BW (67.3±1.3 vs. 61.92±1.3 kg; P = 0.01) and BCS (3.83±0.1 vs. 3.03±0.1; P < 0.001) were greater for FC than for MR. Offspring BW was similar between groups (11.5±0.6, and 11.4±0.5 kg, for FC and MR, respectively; P = 0.804). In conclusion, the free-choice treatment enhanced ewe nutrition, reducing BW and BCS losses during lactation without influencing offspring growth. Free-choice may enable ewes to meet their individual nutrient needs, with benefits to their welfare and postpartum ovarian activity.