Late gestation supplementation of feed additives, such as rumen undegradable intake protein (RUIP), vitamin E, Zn, and chlortetracycline, has inconsistently improved ewe/lamb productivity. In 3 experiments, Western white-faced ewes were supplemented for at least 30 d during late gestation with 204 g/(ewe.d) on a DM basis of high (HS; 12.5% RUIP, 880 IU/kg of vitamin E, 176 mg/kg of Zn supplied by an AA complex, and 352 mg/kg of chlortetracycline) or low (LS; 7.56% RUIP and no supplemental vitamin E, Zn, or chlortetracycline) supplements. Ewes of different age (Exp. 1; 3- vs. 6-yr-old; n = 52) and BCS (Exp. 2; good vs. poor BCS; 3.0 and 1.7 +/- 0.5, respectively; n = 40) were supplemented individually in a 2 x 2 factorial arrangement of treatments for 29 d. Thereafter, each ewe was group fed the appropriate supplement until lambing (14 +/- 7 d). Ewe intake, colostral IgG, ewe and lamb parainfluenza type 3 (PI(3)) titers, milk production, ewe BW and BCS change, and lamb production were measured in both experiments. In Exp. 3, approximately 600 ewes were group fed HS or LS over 2 yr. Ewe BW, ewe BCS, lamb production, and lamb survival was measured in Exp. 3 with groups within year as the experimental unit. In Exp. 1, lambs born to 3-yr-old ewes fed the HS had greater (P = 0.01) anti-PI(3) antibody titers than lambs born to 3-yr-old ewes fed the LS. Three-year-old ewes had greater (P < 0.01) DMI than 6-yr-old ewes. In Exp. 1 and 2, d 3 and 10 milk production differences (P <or= 0.10) were detected among treatments; however, lamb production did not differ among treatments in either experiment. In Exp. 3, late gestation supplementation did not affect indices of ewe or lamb production. Under the condition of these 3 studies, late gestation supplementation of HS or LS did not affect ewe productivity. Similarly, ewe age and BCS did not affect productivity, nor did ewe age or BCS interact with type of late gestation supplement.

Summary Backgrounding lambs on forage-based diets after weaningmay provide producers with alternatives to traditional market-ing of lambs directly to feedlots. Our objective was to evaluatefeedlot performance of lambs from different backgroundingtreatments. Seventy-two crossbred lambs were randomlyassigned to one of four backgrounding treatments. Treatmentswere imposed after traditional, range-weaning practice (140 dof age). Treatments were: 1) drylot ad libitum access to 80:20alfalfa:barley pellets (PELLET); 2) cool-season, grass-paddockgrazing (GRASS); 3) unweaned, dormant-range grazing (LATEWEAN); and 4) weaned, dormant-range grazing (RANGE).After 29 d of backgrounding, lambs within backgroundingtreatment were assigned to feedlot pens (3 pens/treatment).Lamb-BW and ultrasound measurements were taken at wean-ing (d-29), after backgrounding (d 0), after transition to 70 per-cent grain diet (d 19), and at the end of the feedlot period (d 68). Lambs backgrounded on PELLET had greater BW

Western White face ewes were used in two experiments to compare production responses of lambs to HIGH (12.5% rumen by-pass protein, 400 IU of supplemental Vitamin E, 176 ppm chelated Zn, and 72.7 mg/kg chlortetracycline) or LOW (7.56% rumen by-pass protein, with no supplemental Vitamin E, chelated Zn, or chlortetracycline) iso-caloric, iso-nitrogenous supplement fed to ewes of different age (Exp. 1; 3 vs 6 yr old; n = 52) and different body condition score (Exp. 2; GOOD vs POOR; 3.0 and 1.7 + 0.5, respectively; n = 40). Supplement was individually fed 0.227 kg·ewe -1 ·d -1 for 29 d prior to expected lambing. Thereafter, each ewe was mass fed the appropriate supplement until lambing. Exp. 3 group fed HIGH or LOW supplements to the Red Bluff Research Ranch ewe flock. Total weight of lambs per ewe was measured at birth, turnout, and weaning. Colostrum was collected 4 h postpartum and analyzed for IgG. Two parainfluenza type 3 (PI3) intranasal vaccinations were administered to ewes 31 and 17 d prior to expected lambing. Day 3 postpartum lamb sera was collected and analyzed for anti-PI3 antibody titers. Exp. 1: Lambs born to 3 yr old ewes on HIGH supplement had greater (P < 0.05) anti-PI3 antibody titers than lambs born to 3 yr old ewes on LOW supplement. Exp. 2: Lambs born to GOOD ewes on HIGH supplement had greater (P < 0.10) anti-PI3 antibody titers than other treatments. Exp. 3: Kilograms of lamb per ewe at weaning were greater (P < 0.10) for HIGH than LOW supplemented ewes. We detected improvements in PI3 immune transfer dependent of age and condition of ewe and production of weaned lamb was improved when the HIGH supplement is fed to ewes during late gestation. .