G. Detweiler

Dairy goat performance with different dietary concentrate levels in late lactation

Alpine yearling doelings (22; 44+/-1.0kg) and mature does (25; 59+/-1.7kg) were used in an experiment with 16 weeks in late lactation, 8-13 weeks dry and 12 weeks in the subsequent lactation. Diets of 20, 35, 50 or 65% concentrate and 2.18, 2.34, 2.49 and 2.62Mcal/kg ME, respectively (20C, 35C, 50C and 65C treatments, respectively), were consumed ad libitum in late lactation, with a 35% concentrate diet (2.18Mcal/kg ME) in the first 4 weeks of the dry phase and 50% concentrate (2.65Mcal/kg ME) until kidding. Other goats consuming 20 or 35% concentrate in late lactation received 65 (2.65Mcal/kg ME) or 50% concentrate, respectively, in the dry phase (20A and 35A treatments, respectively). All goats consumed a 50% concentrate diet (2.42Mcal/kg ME) in the subsequent early lactation. DM intake in late lactation was similar among treatments (1.95, 2.21, 2.17, 2.10, 1.99 and 2.00kg per day for 20C, 35C, 50C, 65C, 20A and 35A, respectively; S.E.=0.098) and greater (P<0.05) for does versus doelings (2.16 versus 1.98kg per day; S.E.=0.058); DM intake in the dry phase was similar among treatments. Relative to BW, DM intake was greater (P<0.05) for doelings than for does in late lactation (4.16 versus 3.43% BW) and early lactation (4.56 versus 3.80% BW). The effect of dietary treatment on milk production in late lactation varied with parity (P<0.05); milk production by doelings was 1.39, 1.49, 1.43, 1.57, 1.29 and 1.52kg per day and by does was 1.01, 1.89, 2.38, 1.63, 1.17 and 1.34kg per day for 20C, 35C, 50C, 65C, 20A and 35A, respectively; S.E.=0.200). BW change during the entire 16 weeks late lactation phase was greater (P<0.05) for 65C than for other treatments except 50C (6.9, 5.6, 9.1, 10.4, 5.8 and 4.0kg for 20C, 35C, 50C, 65C, 20A and 35A, respectively; S.E.=1.28), although BW at kidding and litter weight were similar among treatments. BW, DM intake and milk production in the first 12 weeks of the subsequent lactation were not affected by dietary treatment or parity. In conclusion, with moderate to high quality forage in late lactation and a moderate level of concentrate in the dry period, the level of concentrate fed in late lactation and in the dry period may not affect subsequent lactation performance regardless of parity. Milk production by doelings in late lactation appears relatively less responsive to dietary concentrate level than that by does.

Effects of different management practices on preweaning and early postweaning growth of Alpine kids

Two sets of 40 dairy goat Alpine kids (3-9 days of age) were used to determine effects of group versus individual pens, preweaning access to forage and different milk feeding restriction regimens on preweaning and early postweaning growth. Treatments in the first experiment were: C1: individual pens; C2: two kids per pen; P: group pen; and PF: P plus free access to alfalfa hay. Treatment did not affect ADG gain in the 8-week preweaning phase (167, 173, 167 and 168g per day; S.E.=4.5) or in week 1-12 (137, 134, 149 and 128g per day for C1, C2, P and PF, respectively; S.E.=6.7). Treatments in the second experiment were: AL: ad libitum milk intake with two meals in week 3-8, then 50% of intake on the preceding few days with one meal in week 9-10; R-1X and R-2X: 75% of intake on the last few days of week 2 with one or two meals, respectively, in week 3-8, then, 50% intake with one meal in week 9-10; and R-2X-1X: 75% intake with two meals in week 3-6, then 37.5% intake with one meal in week 7-10. Milk DM intake in week 1-10 was greatest (P<0.05) among treatments for AL (174, 115, 128 and 113g per day for AL, R-2X, R-1X and R-2X-1X, respectively). Starter diet DM intake (g per day) was 51, 78, 72 and 143 in week 7-8 (S.E.=16); 138, 194, 165 and 249 in week 9-10 (S.E.=15); 343, 396, 388 and 417 in week 11-12 (S.E.=47); and 508, 530, 489 and 539 in week 13-14 (S.E.=38) for AL, R-2X, R-1X and R-2X-1X, respectively. ADG (g per day) was 139, 120, 119 and 131 in week 1-10 (S.E.=7) and 105, 109, 123 and 117 in week 11-14 (S.E.=16) for AL, R-2X, R-1X and R-2X-1X, respectively. In conclusion, although group pens and forage access may not enhance ADG of artificially reared dairy goat kids by promoting early dry feed consumption restricted feeding regimens can yield preweaning and early postweaning ADG comparable to ad libitum milk intake. Also, feeding milk in restricted amounts once daily appears feasible, and a second reduction in milk intake in the latter part of the suckling phase may further stimulate dry feed intake.

Effects of breed and diet on growth and body composition of crossbred Boer and Spanish wether goats.

Sixty growing 3/4 Boer x 1/4 Spanish (BS) and Spanish (SP) wethers were used to determine influences of diet and breed on growth and body composition. A pelleted 50% concentrate diet (CD) and a diet based on grass hay (HD) were fed for ad libitum intake. Six wethers of each breed were slaughtered at 0 wk (total of 12). Six wethers of each diet-breed combination were slaughtered at 14 and 28 wk (24 per time) after consumption of the CD or HD. Initial BW of fed wethers were 21.6 and 18.8 kg for BS and SP, respectively (SEM = 0.7). Average daily gain during the entire experiment was influenced by an interaction (P < 0.05) between breed and diet (199, 142, 44, and 50 g/d for BS:CD, SP:CD, BS:HD, and SP:HD, respectively). Carcass mass was greater (P < 0.05) for CD vs. HD (56.2, 56.2, 53.2, and 54.0% of empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively). Mass of the liver (2.11, 1.92, 2.00, and 1.98% of empty BW; SEM = 0.05) and gastrointestinal tract (5.50, 4.83, 8.43, and 8.36% of empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively; SEM = 0.16) tended (P < 0.07) to be influenced by an interaction between breed and diet. Mass of internal fat (12.2, 12.1, 3.4, and 3.4% empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively; SEM = 0.3) differed (P < 0.05) between diets. Energy in the carcass (320, 236, 87, and 79 MJ), noncarcass tissues (318, 237, 77, and 72 MJ), and empty body (638, 472, 164, and 150 MJ) ranked (P < 0.05) BS:CD > SP:CD > BS:HD and SP:HD. Empty body concentration of protein was 18.3, 17.5, 18.3, and 19.7% (SEM = 0.3) and of fat was 24.0, 23.4, 10.8, and 10.3% for BS:CD, SP:CD, BS:HD, and SP:HD, respectively (SEM = 0.6). Energy concentration in accreted tissue was 17.0, 18.7, 16.3, and 6.4 MJ/kg for CD:wk 1 to 14, CD:wk 15 to 28, HD:wk 1 to 14, and HD:wk 15 to 28, respectively (SEM = 1.4). In conclusion, relatively high growth potential of growing Boer crossbred goats with a moderate to high nutritional plane does not entail a penalty in realized growth when the nutritional plane is low. Body composition of growing Boer and Spanish goats is fairly similar regardless of growth rate. For growing meat goats other than with a prolonged limited nutritional plane, an average energy concentration in accreted tissue is 17.3 MJ/kg.

Determination of fetal numbers in Alpine does by real-time ultrasonography

Abstract Pregnancy diagnosis was carried out in Alpine does using a real-time ultrasound instrument equipped with a 5 MHz sector array probe. Eighty Alpine does were examined 5 and 7 wk after breeding. Does were restrained while standing, and the transducer probe was placed on the hairless caudal ventral abdominal wall cranial to the udder. Non-pregnant does were readily and accurately recognized at 5 and 7 wk after breeding. Number of fetuses per doe at 5 wk of gestation was different (P 0.2) to the number born. Accuracy for determining singles, twins, and triplets at 5 wk of gestation was 44, 73, and 67%, respectively; at 7 wk of gestation it was 82, 89 and 100%, respectively. This accuracy is similar to that reported in ewes. It was concluded that real-time ultrasonography scanning by the transabdominal route is a reliable method for early pregnancy diagnoses in goats. The technique also enables accurate separation of does carrying singles, twins, and triplets as early as 7 wk in gestation. Such information can be useful for improved nutritional management.

Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer × Spanish goats1

Twenty-four yearling Boer × Spanish wethers were used to assess effects of different forages, either fresh (Exp. 1) or as hay (Exp. 2), on feed intake, digestibilities, heat production, and ruminal methane emission. Treatments were: 1) Sericea lespedeza (SER; Lespedeza cuneata), a legume high in condensed tannins (CT; 20% and 15% in fresh forage and hay, respectively), 2) SER supplemented with polyethylene glycol (SER-PEG; 25 g/d), 3) alfalfa (Medicago sativa), a legume low in CT (ALF), and 4) sorghum-sudangrass (Sorghum bicolor), a grass low in CT (GRASS). Experiments were 22 d, which included 16 d for acclimatization followed by a 6-d period for fecal and urine collection, and gas exchange measurement (last 2 d). Intake of OM was 867, 823, 694, and 691 g/d (SEM = 20.1) with fresh forage, and 806, 887, 681, and 607 g/d with hay for SER, SER-PEG, ALF, and GRASS, respectively (SEM = 46.6). Apparent total tract N digestion was greater for SER-PEG vs. SER (P < 0.001) with fresh forage (46.3%, 66.5%, 81.7%, and 73.2%; SEM = 1.71) and hay (49.7%, 71.4%, 65.4%, and 54.8% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.57). Intake of ME was similar among treatments with fresh forage (8.24, 8.06, 7.42, and 7.70 MJ/d; SEM = 0.434) and with hay was greater for SER-PEG than ALF (P < 0.03) and GRASS (P < 0.001) (8.63, 10.40, 8.15, and 6.74 MJ/d for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.655). The number of ciliate protozoa in ruminal fluid was least for SER with fresh forage (P < 0.01) (9.8, 20.1, 21.0, and 33.6 × 10(5)/ml; SEM = 2.76) and hay (P < 0.02) (6.3, 11.4, 13.6, and 12.5 × 10(5)/ml for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.43). Methane emission as a percentage of DE intake was lower (P < 0.01) for SER vs. ALF and GRASS with fresh forage (6.6, 8.3, 9.4, and 9.2%; SEM = 0.64) and hay (4.3, 4.9, 6.4, and 6.7% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.38). In summary, methane emission in this short-term experiment was similar between a legume and grass low in CT as fresh forage and hay. The CT in SER markedly decreased N digestibility and elicited a moderate decline in ruminal methane emission. Supplementation with PEG alleviated the effect of CT on N digestibility but not ruminal methane emission, presumably because of different modes of action. In conclusion, potential of using CT-containing forage as a means of decreasing ruminal methane emission requires further study, such as with longer feeding periods.

Technical Note: Effects of tethering on herbage selection, intake and digestibility, grazing behavior, and energy expenditure by Boer × Spanish goats grazing high-quality herbage1

Twenty-four yearling Boer x Spanish goats were used in a crossover experiment to determine the effects of tethering on herbage selection, intake and digestibility, grazing behavior, and energy expenditure (EE) with high-quality herbage. Four 0.72-ha paddocks of wheat (Triticum aestivum) and berseem clover (Trifolium alexandrium) were grazed in the spring. Each paddock hosted 6 animals, 3 with free movement and 3 attached to a 3-m tether that was moved daily and provided access to an area of 28.3 m(2). One animal of each treatment and paddock was used to determine herbage selection, fecal output, or grazing behavior and EE. Herbage DM mass in tethered areas before grazing averaged 2,649 and 2,981 kg/ha in periods 1 and 2, respectively. The CP concentration in ingesta was greater (P < 0.05; 23.1 and 20.3 +/- 0.82%) for free vs. tethered animals, although in vitro true DM digestion (75.7 and 76.5 +/- 1.20%, respectively) did not differ (P > 0.05) between treatments. Intake of ME based on in vitro true DM digestion and fecal output was greater (P < 0.05) for free vs. tethered animals (12.7 and 10.4 +/- 0.89 MJ/d). No treatment effects were observed (P > 0.05) for time spent ruminating or grazing (405 and 366 +/- 42.5 min/d, respectively), although mean EE was greater (P < 0.05) for free vs. tethered animals (633 and 512 +/- 27.4 kJ/kg of BW(0.75) for free and tethered, respectively), with differences (P < 0.05) between treatments at each hour of the day. Tethering animals may be acceptable to model those with free movement for some measures such as ingesta composition but appears inappropriate for others, such as energy metabolism.

Energy expenditure and activity of different types of small ruminants grazing varying pastures in the summer.

Abstract Beker, A., Gipson, T.A., Puchala, R., Askar, A.R., Tesfai, K., Detweiler, G.D., Asmare, A. and Goetsch, A.L., 2009. Energy expenditure and activity of different types of small ruminants grazing varying pastures in the summer. J. Appl. Anim. Res., 37: 1–14. Objectives were to determine the activity energy cost for different types of goats as well as a breed of sheep and to evaluate methods of prediction. Eight animals each of yearling Angora, doeling goats, yearling Boer wether goats, yearling Spanish wether goats and Rambouillet wether sheep slightly more than 2 yr of age were used. Two animals of each type were randomly allocated to one of the four pastures 9.3, 12.3, 4.6 and 1.2 ha in area. Forage conditions varied markedly among pastures. The experiment was conducted in the summer with three periods, 30, 26 and 26 d in length. Energy expenditure (EE) was estimated from heart rate (HR) on pasture and EE:HR for each animal determined in a calorimetry system. A leg position/movement monitoring system and a GPS collar with position and movement sensors were used to estimate distance traveled and. time spent grazing/eating, resting while lying, resting while standing and walking without grazing/eating. EE attributable to activity (EEa%), expressed as a percentage of the ME requirement for maintenance plus activity in confinement, was determined based on total EE, BW and ADG. ADG was similar among animal types. Distance traveled was affected by an interaction (P<0.05) between animal type and period (Angora goats: 2.98, 2.33 and 2.47; Boer goats: 3.17, 3.46 and 2.68; Spanish goats: 2.85, 5.28 and 3.30; sheep: 3.04, 3.43 and 2.25 km in periods 1, 2 and 3, respectively (SE = 0.423). Time spent grazing was lowest among animal types (P<0.05) for Angora goats (4.3, 8.4, 7.8 and 6.8 h/day) and time spent walking without grazing was lower (P<0.05) for Angora goats and sheep than for Boer goats (1.7, 2.4, 2.1 and 1.2 h/day for Angora goats, Boer goats, Spanish goats and sheep, respectively). Total EE was affected by an interaction (P<0.05) between animal type and period (Angora, goats: 5.89, 5.55, and 5.16; Boer goats: 9.63, 10.92 and 8.55; Spanish goats: 6.73, 8.17 and 7.02; sheep: 12.54, 11.84 and 12.93 MJ/day in periods 1, 2, and 3, respectively (SE = 0.442). EEa% was affected by an interaction (P<0.05) between animal type and period (Angora goats: 15.7, 17.4 and 15.1; Boer goats: 59.7, 67.4 and 34.4; Spanish goats: 46.2, 61.7 and 41.6; sheep: 22.3, 11.8 and 21.9% in periods 1, 2 and 3, respectively (SE = 6.07). EEa% of goats was predicted with moderate accuracy (R2 = 0.40–0.41) and without bias from estimates of 5.79 and 5.05%/h spent grazing/eating and grazing/eating plus walking, respectively, determined in a companion experiment; however, these methods were not suitable for sheep.

Effects of different quality diets consumed continuously or after a lower quality diet on characteristics of growth of young Spanish goats

Spanish wether and doeling kids (4.5 months of age; 13.4 kg initial BW) were used to determine influences of different quality diets consumed continuously or after a lower quality diet on characteristics of growth. The experiment consisted of two 9-week periods. Diets were low quality forage (L, prairie hay supplemented with soybean meal), high quality forage (H, dehydrated alfalfa pellets) and 70% concentrate (C). Kids on two treatments consumed L in Period 1, with half switched to C and half to H in Period 2 (LC and LH, respectively). The CC treatment entailed C consumption in both periods, and HH kids were fed H in both periods. For HC, H was fed in Period 1 followed by C in Period 2. DM intake ranked (P<0.05) LC and LH<CC<HC and HH in Period 1 (502, 352, 386, 610 and 636 g per day) and CC and LC<LH, HC and HH in Period 2 (652, 621, 833, 808 and 836 g per day for CC, LC, LH, HC and HH, respectively). ADG was lowest among treatments (P<0.05) for LC and LH in Period 1 (78, 1, −1, 84 and 80 g per day) and was 53, 82, 112, 92 and 73 g per day in Period 2 for CC, LC, LH, HC and HH, respectively (S.E. = 11). Empty body fat concentration at the end of Period 1 was greatest for the C diet and lowest for L (P<0.05; 12.2, 6.4 and 9.0% for C, L and H, respectively), and protein concentration was greatest among treatments (P<0.05) for L (16.8, 20.1 and 18.1% for C, L and H, respectively). At the end of Period 2, empty body fat concentration was 22.0, 15.9, 14.4, 20.1 and 15.2% (S.E.=1.94), and protein concentration was 16.8, 16.9, 17.9, 16.5 and 17.6% (S.E.=0.35) for CC, LC, LH, HC and HH, respectively). In summary, kids on the L diet in Period 1 mobilized fat to accrete a small amount of protein. Continuous consumption of C resulted in high fat accretion relative to H in both periods. Consumption of H in Period 1 followed by C in Period 2 resulted in growth characteristics slightly different from those with continual intake of C, with a lower concentration of protein in accreted tissue for HC. The diet in Period 2 for kids previously consuming L did not markedly affect tissue accretion. In conclusion, the nature of the diet consumed by young Spanish goats can impact current and subsequent rate and composition of BW gain.

Effects of Stocking Rate, Breed and Stage of Production on Energy Expenditure and Activity of Meat Goat Does on Pasture

Abstract Beker, A., Gipson, T.A., Puchala, R., Askar, A.R., Tesfai, K., Detweiler, G.D., Asmare, A. and Goetsch, A.L. 2009. Effects of stocking rate, breed and stage of production on energy expenditure and activity of meat goat does on pasture. J. Appl. Anim. Res., 36: 159–174. Sixteen Boer and 16 Spanish multiparous does were used to determine how stocking rate (SR), breed and stage of production influence energy expenditure and behavioral activities on pasture and to develop a simple method of predicting energy used for activity. The experiment began in late spring at an average of 24 d after kidding. Litter size was two and kids were Boer and Spanish. Two does of each breed resided in eight 0.5-ha grass/forb pastures. There were five periods, 56, 60, 63, 64 and 73 d in length, corresponding to mid-lactation, early post-weaning, the late dry period, early gestation and mid-gestation. During period 1 and the first part of period 2, two additional does with kids of each breed grazed in four High SR pastures, with other pastures designated as Low SR. Because of low available forage mass in period 3, grass hay was offered for ad libitum consumption in periods 3–5 and a concentrate supplement was provided in periods 4 and 5. Energy expenditure (EE) was estimated from heart rate (HR) on pasture and EE.HR for each doe determined in a calorimetry system. A leg position I movement monitoring system and a GPS collar with position and movement sensors were used to estimate distance traveled and time spent grazing/eating, resting while lying, resting while standing and walking without grazing I eating. EE attributable to activity (EEa%), expressed as a percentage of the ME requirement for maintenance plus activity in confinement, was determined based on total EE, estimated milk production and doe BW and ADG. Forage DM mass in the middle of periods was 696, 246, 125 and 196 kg/ha for the High SR and 1362, 967, 479 and 610 kg/ha for the Low SR in periods 1, 2, 3 and 4, respectively. Kid ADG at weaning after 73 d was lower (P<0.05) for the High vs. Low SR (87 vs. 112 g). Distance traveled was not influenced by SR or breed but varied among periods (3.54, 3.76, 3.09, 3.08 and 4.10 km/d in periods 1, 2, 3, 4 and 5, respectively; SE = 0.193). Time spent grazing/eating tended (P < 0.07) to be greater for Boer vs. Spanish does (7.9 vs. 6.7 h/d) and differed among periods (8.0, 7.8, 7.6, 5.3 and 8.0 h I day in periods 1, 2, 3, 4 and 5, respectively; SE = 0.72). Total EE was greater (P <0.05) for Boer than for Spanish does (13.4 vs. 11.4 MJ/d) and differed among periods (13.5, 11.6, 11.7, 11.8 and 13.4 MJ I day in periods 1, 2, 3, 4 and 5, respectively; SE = 0.41). Likewise, predicted ME intake was greater (P<0.05) for Boer vs. Spanish does (14.2 vs. 12.2 MJ/d) and varied with period (16.1, 10.6, 12.8, 12.6 and 14.0 MJ/day in periods 1, 2, 3, 4 and 5, respectively; SE = 0.47). EEa% was not influenced by SR, breed or period, averaging 49%. Behavioral activities were not highly related to EEa%, although no-intercept regressions against time spent grazing/eating and grazing/eating plus walking indicated an increase in EEa% of 5.79 and 5.05%/h, respectively. In conclusion, although EEa% was not affected by trea tments of this experiment or highly related to behavioral activities monitored, it represents a sizeable cost of energy deserved of further study.

Effects of stage of lactation and dietary forage level on body composition of Alpine dairy goats.

Multiparous Alpine does (42) were used to determine how stage of lactation and dietary forage level affect body composition. The feeding and body composition portion of the study had a 2 x 3 factorial arrangement of treatments. Eighteen does were fed a 40% forage diet (40F) and 18 received a diet with 60% forage (60F) for approximately 2, 4, or 6 mo of lactation (59 +/- 1.3, 116 +/- 1.0, and 184 +/- 1.4 d, respectively), followed by determination of body composition (6 does per diet at each time of slaughter). Does were assigned sequentially to treatments as kidding occurred. The 60F diet had 20% more dehydrated alfalfa pellets than the 40F diet, with higher levels of corn and soybean meal and inclusion of supplemental fat in the 40F diet. Initial body composition measures were made with 6 other does a few days after kidding (0 mo; 4 +/- 0.6 d). Before parturition, does were fed a 50% concentrate diet free choice. Intake of dry matter was greater for 60F than for 40F, average daily gain tended to be affected by an interaction between diet and month (0, 24, 121, -61, 46, and 73 g), and 4% fat-corrected milk was less in mo 5 to 6 than earlier. Internal fat mass was greatest among times at 6 mo and greater for 40F than for 60F. Mass of the gastrointestinal tract was less for 40F than for 60F and decreased with increasing time in lactation. Concentrations of fat in the carcass (13.8, 13.1, 16.5, 11.2, 11.5, and 14.4%), noncarcass tissues (18.6, 24.2, 33.3, 14.3, 16.5, and 24.5%), and empty body (16.5, 18.7, 25.2, 12.9, 14.1, and 19.5% for 40F at 2 mo, 40F at 4 mo, 40F at 6 mo, 60F at 2 mo, 60F at 4 mo, and 60F at 6 mo, respectively) were affected by stage of lactation and diet. Based on daily change in tissue mass and energy, energy concentration in tissue mobilized or accreted was 16, 20, and 32 MJ/kg in 1 to 2, 3 to 4, and 5 to 6 mo of lactation, respectively. In conclusion, based on tissue mass, more energy was expended by the gastrointestinal tract with 60F than with 40F. Considerable internal fat appeared to be mobilized in early lactation, particularly with the diet moderate to high in forage, with more rapid and a greater magnitude of repletion by does consuming the diet lower in forage. The concentration of energy in tissue mobilized or accreted varied with stage of lactation, being considerably greater at 5 to 6 mo of lactation than earlier.