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Abstract: Sixty Spanish (S) and 40 Boer×Spanish (BS) doelings (14.9±3.8kg and 21.9±3.8kg initial BW, respectively, and approximately 6 months of age) were used in an experiment with four 3-week periods to determine effects of dietary broiler litter (L) level on growth performance. There were two groups per treatment with six S and four BS doelings in each. Dietary treatments were 20% coarsely ground millet hay and 80% concentrate, which consisted of 0 (0L), 20 (20L), 40 (40L), or 60% L (60L; total dietary level). An additional treatment was 80% hay and 20% concentrate (80F). Concentrate (primarily corn and L when included) DM intake (DMI) was 700, 593, 652, 387, and 165g/d (S.E.=20.3) and total DMI was 883, 755, 825, 490, and 696g/d (S.E.=35.5) for 0L, 20L, 40L, 60L, and 80F, respectively. There was a dietary treatment×period interaction in ADG (period 1: 104, 29, 36, −44, and 47g; period 2: 124, 102, 53, −74, and 12g; period 3: 175, 126, 126, 87, and 80g; period 4: 161, 151, 136, 66, and 51g for 0L, 20L, 40L, 60L, and 80F, respectively (S.E.=12.2)). Treatment and genotype also interacted in ADG (S: 107, 85, 72, 8, and 36g; BS: 174, 118, 103, 10, and 60g for 0L, 20L, 40L, 60L, and 80F, respectively (S.E.=9.2)). ADG:DMI ranked (P <0.06) 0L>20L>40L>80F>60L (152, 130, 102, 18, and 65g/kg for 0L, 20L, 40L, 60L, and 80F, respectively; S.E.=6.12). The acetate:propionate ratio in ruminal fluid was greater (P <0.05) for 60L and 80F than for other treatments (1.60, 1.73, 2.18, 3.80, and 3.67 for 0L, 20L, 40L, 60L, and 80F, respectively; S.E.=0.27). Liver Cu concentration at the end of the experiment was influenced by dietary treatment (88, 275, 478, 286, and 47ppm for 0L, 20L, 40L, 60L, and 80F, respectively; S.E.=53.2). In conclusion, L can be effectively used in diets for growing meat goats, but high levels, such as above 40% of dietary DM, may restrict performance primarily via limited feed intake. However, the level of L below this threshold impacts efficiency of feed utilization. [Copyright &y& Elsevier]

Abstract: Eight nonlactating Alpine does (2.5–6.5 year of age; 46±2.9kg BW) were used to determine effects of standing versus walking at different speeds and interactions between walking speed and forage ingestion on energy expenditure (EE), heart rate (HR), and their ratio. Coarsely ground alfalfa hay was fed at a maintenance level of intake, and measures were performed in a head-box respiration calorimetry system. In experiment 1, measures occurred at least 3h after feeding for 20min after the plateau in EE sequentially, while standing (0m/s) on a treadmill and thereafter walking at 0.14, 0.28, and 0.42m/s at a +5% slope. HR and EE ranked (P <0.05) 0<0.14<0.28<0.42m/s (HR: 79, 95, 108, and 125beats/min; EE: 20.6, 25.8, 29.6, and 34.1kJ/(kg BW0.75 ×h)). The ratio of EE:HR was lowest among treatments (P <0.05) for 0m/s (6.26, 6.54, 6.58, and 6.56 (kJ/(kg BW0.75 ×day)/(beats/min) for 0, 0.14, 0.28, and 0.42m/s, respectively). In experiment 2, EE and HR were first determined while standing, followed by measures when walking at 0.07, 0.14, or 0.21m/s at a +5% slope; measurements also occurred while consuming 50% of the daily allocation of forage when standing or walking at the different speeds immediately after measures without forage ingestion. Differences between values for forage consumption plus walking or standing and walking or standing without forage were calculated to determine the origin of, or factor responsible for, change in EE (i.e., walking (W) versus forage consumption (F)), with the previous standing estimate without forage used as a covariate. There was an interaction (P <0.05) between walking speed and origin of EE. EE due to W ranked (P <0.05) 0<0.07<0.14, and 0.21m/s (−0.3, 3.4, 4.8, and 5.9kJ/(kg BW0.75 ×h)). Conversely, EE attributable to F was lower (P <0.05) for 0 than for 0.07 and 0.21m/s (9.0, 10.7, 10.3, and 10.7kJ/(kg BW0.75 ×h) for 0, 0.07, 0.14, and 0.21m/s, respectively). Differences in HR were generally similar in magnitude to those in EE (−1, 9, 17, and 20beats/min for W, and 35, 51, 40, and 42beats/min for F, at 0, 0.07, 0.14, and 0.21m/s, respectively (S.E.=2.1)). In summary, these results suggest potential use of HR to predict EE while grazing. Forage consumption increased EE to a greater extent than walking and may lessen effects of walking and walking speed on the grazing activity energy cost. [Copyright &y& Elsevier]

Abstract: Differences among ruminant species in forage selectivity offer potential for efficient utilization of pastures with diverse arrays of plant species. One common management strategy that may influence forage selectivity is stocking rate (SR). Therefore, this experiment was conducted to determine effects of SR on performance and forage selectivity of growing sheep and goat wethers co-grazing grass/forb pastures. Grazing was for 16 weeks in 2002 and 2003. Pastures consisted of various grasses, primarily bermudagrass (Cynodon dactylon) and johnsongrass (Sorghum halepense), and forbs (e.g., ragweed; Ambrosia spp.). Sheep (Khatadin) and goats (75% Boer) averaged 21±0.7 and 21±0.5kg initial BW, respectively, and were 4–5 months of age when grazing began. Stocking rates were four (SR4), six (SR6), and eight (SR8) animals per 0.4-ha pasture, with equal numbers of sheep and goats. The nine pastures (three/treatment) were divided into four paddocks for rotational grazing in 2-week periods. Forage mass (pre- and post-grazed) and composition of grass versus forbs were determined by quadrat samples and transect analysis, respectively. BW was measured every 4 weeks and preference values for grass, forbs, and ragweed (10: highest possible preference; 0: consumption in proportion to availability; −10: no consumption) were determined from fecal microhistology and transect measures. There was a year×SR interaction (P &#60;0.05) in herbage DM mass before grazing (year 1: 2937, 3298, and 3351kg/ha; year 2: 3033, 2928, and 2752kg/ha for SR4, SR6, and SR8, respectively (S.E.=174.4)). Post-grazed forage mass decreased linearly (P &#60;0.05) as SR increased (2279, 1693, and 1288kg/ha for SR4, SR6, and SR8, respectively (S.E.=102.6)). In vitro true DM digestibility of pre-grazed forage samples was similar among SR, but SR×year interacted (P &#60;0.05) for post-grazed samples (year 1: 57.0, 54.4, and 53.5; year 2: 56.8, 49.0, and 48.3 for SR4, SR6, and SR8, respectively (S.E.=2.16). Year and SR interacted (P &#60;0.05) in the percentage of grass in pastures post-grazing determined by transect (year 1: 64, 69, and 74%; year 2: 50, 66, and 73% for SR4, SR6, and SR8, respectively (S.E.=8.4)). The preference for grasses was higher and that for total forbs lower for sheep than for goats (P &#60;0.05). The preference value for ragweed, measured in year 2, was lower (P &#60;0.05) for sheep than for goats (−1.6 versus 0.2) and increased linearly with increasing SR. Average daily gain tended (P &#60;0.10) to decrease linearly as SR increased (61, 51, and 47g/day), and total BW gain per hectare increased linearly (P &#60;0.05; 610, 759, and 933g/day for SR4, SR6, and SR8, respectively). In conclusion, post-grazing herbage mass >1000kg/ha at most measurement times suggests that decreasing forage availability with increasing SR may not have been primarily or solely responsible for the effect on ADG by limiting DM intake. Rather, the effect of SR on available forage mass could have limited the ability of both sheep and goats to compensate for the effect of SR on forage nutritive value. [Copyright &y& Elsevier]

Abstract: A study was conducted to assess effects of stocking rate (SR) on grazing behavior and energy expenditure (EE) by growing sheep and goat wethers co-grazing grass/forb pastures. Grazing was for 16-week periods in 2002 and 2003. Pastures consisted of various grasses, primarily bermudagrass (Cynodon dactylon) and johnsongrass (Sorghum halepense), and forbs (e.g., ragweed; Ambrosia spp.). Sheep (Khatadin) and goats (≥75% Boer) averaged 21±0.7 and 21±0.5kg initial BW, respectively, and were 4–5 months of age when grazing began. Stocking rates were four (SR4), six (SR6), and eight (SR8) animals per 0.4-ha pasture, with equal numbers of sheep and goats. The nine pastures (three/treatment) were divided into four paddocks that were rotationally grazed in 2-week periods. In weeks 3, 8, and 13 of both years, EE was determined on one goat and one sheep in each pasture via heart rate. In the same weeks, behavioral observations (position and activity) were made every 30min of 13.5h of daylight on two goats and two sheep in each pasture. Grazing behavior using IGER Grazing Behavior Monitoring System units was also measured over 24-h periods on animals used for EE measurement. Based on visual observations, grazing (52.7, 57.1, and 61.4%) and standing time (61.1, 66.3, and 69.8%) increased and idle time in daylight (24.2, 21.1, and 15.9% for SR4, SR6, and SR8, respectively) decreased linearly (P &#60;0.05) as SR increased. Species interacted (P &#60;0.05) with year in daylight time spent standing and ruminating. Grazing time during daylight was similar between species (56.1 and 58.0% for sheep and goats, respectively), although idle time was greater (P &#60;0.05) for goats (23.6% versus 17.2%; S.E.=1.41). Time spent ruminating in daylight was similar among SR but was greater for sheep in year 2 but not year 1 (year 1, 22.3% versus 19.0%; year 2, 27.8% versus 15.1% for sheep and goats, respectively; S.E.=1.44). Based on the IGER units, the number of steps increased linearly (P &#60;0.05) with increasing SR (2279, 2707, and 2788 for SR4, SR6, and SR8, respectively (S.E.=96.4)), but was similar for the two species. As SR increased, time spent eating increased (7.4, 8.4, and 9.6h) and time spent lying (11.0, 10.2, and 8.9h), ruminating (7.9, 7.7, and 6.8h), and idle (8.6, 8.0, and 7.6h for SR4, SR6, and SR8, respectively) decreased (P &#60;0.05). Goats spent less time eating (1.1h) and more time idle (0.7h) than did sheep (P &#60;0.05). SR, species, and year interacted (P &#60;0.05) in EE of wethers (year 1, sheep: 510, 569, and 572kJ/kg BW0.75; year 2, sheep: 572, 597, and 648kJ/kg BW0.75; year 1, goat: 524, 524, and 640kJ/kg BW0.75; year 2, goat: 499, 496, and 551kJ/kg BW0.75 for SR4, SR6, and SR8, respectively; S.E.=17.0). In summary, influences of SR on grazing time and EE can vary with grazing season. With forage conditions of this study, SR had similar effects on grazing behavior of sheep and goats when co-grazing. Effects of SR on EE may contribute to impact on ADG by small ruminants. [Copyright &y& Elsevier]