Angus, Hereford, and Angus-cross yearling beef heifers (409 ± 35 kg; n = 39) were used to evaluate protein supplementation strategies in low- to medium-quality forage diets on circulating AA concentrations. Heifers were stratified by BW and BCS and then randomly assigned to 1 of 4 protein supplements: 1) no supplementation (CON), 2) low-fat dried distiller's grains (LDG; 7.4% fat; 0.8% BW), 3) high-fat dried distiller's grains (HDG; 9.5% fat; 0.8% BW), and 4) cottonseed meal (CSM; 2.2% fat; 0.4% BW) to provide similar CP intake. Heifers were individually fed by means of a Calan gate system (American Calan Inc., Northwood, NH). Hay was fed twice daily 7 h apart to provide low- to medium-quality chopped grass hay (8.6% CP and 70% NDF; 1.13 Mcal NEm/kg) ad libitum, and 1 h prior to hay feeding, supplements were provided. Supplementation began 7 d prior to timed AI (d 0) and ended 30 d later. A subset of heifers (3 per treatment) were randomly selected to evaluate circulating AA concentrations after feeding on d 26 and were fed protein supplements prior to AM hay feeding, and then coccygeal blood samples were collected at −2, 2, 4, 6, 8, 10, 12, and 14 h after supplementation. Overall plasma total AA (TAA), branched-chain AA (BCAA), and essential AA (EAA) concentrations were lower (P ≤ 0.003) for CON than for CSM, HDG, and LDG, whereas overall plasma nonessential AA (NEAA) concentrations were not different (P = 0.22) among treatments. At 8 h after feeding, plasma TAA, BCAA, and EAA concentrations were lowest (P ≤ 0.03) compared with all other hours. Within h 8, HDG had greater (P ≤ 0.04) plasma TAA, BCAA, NEAA, and EAA concentrations compared with CON, CSM, and LDG. Plasma EAA concentrations were lower (P ≤ 0.03) for h 6, 12, and 14 and plasma BCAA concentrations were lower for h 2, 4 10, 12, and 14 in CON heifers compared with LDG- and HDG-supplemented heifers; however, plasma NEAA concentrations were not different (P ≥ 0.05) among treatments 4 and 14 h after feeding. Plasma Asp and Trp were not different (P ≥ 0.33) among supplementation strategies for treatment or treatment × hour. Greater plasma Arg concentrations were observed (P ≤ 0.03) in CSM vs. HDG, LDG, and CON at h 6, 10, 12, and 14 h after feeding. Overall, protein supplementation increased circulating AA concentrations compared with no supplementation and the lowest AA concentrations were observed at 8 h after feeding.
Lambs born from feed-restricted or overfed ewes can be lighter at birth, whereas maternal Se supplementation can increase fetal size near term. We hypothesized that birth weight would be inversely related to feed efficiency and growth rates during postnatal development. To examine the effects of maternal dietary Se and nutrient restriction or excess on postnatal lamb growth, diet digestibility, and N retention, 82 ewe lambs (52.2 ± 0.8 kg) were allotted randomly to 1 of 6 treatments in a 2 × 3 factorial arrangement. Factors were dietary Se [adequate Se (9.5 μg/kg of BW; ASe) vs. high Se (Se-enriched yeast; 81.8 μg/kg of BW; HSe)] and maternal nutritional intake [60% (restricted, RES), 100% (control, CON), or 140% (high, HI) of NRC requirements]. Selenium treatments began at breeding. Nutritional treatments began on d 50 of gestation. Lambs were immediately removed from their dams at parturition, provided artificial colostrum, and fed milk replacer until weaning. After weaning, lambs were maintained using common management and on common diets until necropsy at 180 d. Male and female lambs from RES-fed ewes were lighter (P ≤ 0.03) at birth than lambs from CON-fed ewes, with lambs from HI-fed ewes being intermediate. Although maternal nutritional intake influenced (P < 0.06) BW gain before weaning on d 57, both maternal nutritional intake and sex of offspring influenced (P ≤ 0.09) BW gain from d 57 to 180. Although maternal nutritional intake did not influence (P ≥ 0.35) female lamb BW gain, male lambs from RES-fed ewes were lighter (P ≤ 0.09) than those from CON-fed ewes until d 162. By d 180, male lambs from RES- and HI-fed ewes were lighter (P ≤ 0.09) than those from CON-fed ewes. In a subset of lambs used in a feed efficiency study, namely, those born to ASe ewes, HI maternal nutritional intake decreased (P ≤ 0.09) ADG and G:F compared with lambs born to RES- and CON-fed ewes, which did not differ (P ≥ 0.60). Conversely, when lambs were born to HSe ewes, HI maternal nutritional intake increased (P ≤ 0.01) ADG and G:F compared with CON, with RES being intermediate. Moreover, lambs born to ASe-HI ewes had decreased (P < 0.01) ADG and G:F compared with lambs born to HSe-HI ewes. Furthermore, male lambs had a greater (P < 0.01) G:F than female lambs. Maternal diet did not affect (P ≥ 0.11) N retention in male lambs. These data indicate that maternal nutrition during gestation and sex of the offspring alter postnatal growth and efficiency of growth in offspring despite similar postnatal management.
To investigate the influence of maternal Se supply and plane of nutrition on lamb morbidity, mortality, and passive transfer of IgG, pregnant ewe lambs were used in 2 experiments with 2 × 3 factorial treatment arrangements. Supplementation of Se began at breeding and was either adequate Se (ASe, 9.5 μg/kg of BW) or high Se (HSe, 81.8 μg/kg of BW) in Exp. 1 or ASe (11.5 µg/kg of BW) or HSe (77.0 µg/kg of BW) in Exp. 2. On d 50 or 40 of gestation for Exp. 1 or 2, respectively, ewes were assigned randomly to 1 of 3 nutritional planes: 60% (RES), 100% (control, CON), or 140% (HI) of NRC requirements. This resulted in the following treatments: ASe-RES, ASe-CON, ASe-HI, HSe-RES, HSe-CON, and HSe-HI. Upon parturition, lambs were separated from their dams and serum samples obtained. Lambs were fed artificial colostrum for the first 20 h and then placed on milk replacer and grain pellets until completion of the study (Exp. 1, 57 d; Exp. 2, 21 d). Twenty-four hours after parturition, lamb serum samples were collected for IgG analysis. All lambs were reared similarly and morbidity and mortality assessed. Main effects were considered significant when P ≤ 0.05. In Exp. 1, there was a Se × plane of nutrition interaction (P ≤ 0.01) for lamb morbidity from birth to weaning and for 24-h IgG concentration. Lambs from ASe-RES and HSe-HI ewes were treated more frequently (P < 0.01) for respiratory and gastrointestinal disease, and lambs from HSe-HI ewes had the smallest (P < 0.01) 24-h serum IgG concentration. In Exp. 1, lambs from HI ewes also had the greatest (P < 0.01) mortality rates from birth to weaning compared with lambs from CON and RES ewes. In Exp. 2, there was an effect (P < 0.01) of maternal plane of nutrition with lambs from RES ewes having increased 24-h IgG compared with lambs from CON and HI ewes. There was no effect of maternal Se supplementation on lamb 24-h IgG in Exp. 2; however, there was a Se × plane of nutrition interaction (P < 0.01) for morbidity. From birth to 21 d of age, lambs from ASe-CON ewes had fewer (P < 0.01) treatment days compared with lambs from any of the other treatment groups. There also tended (P = 0.08) to be an effect of maternal Se supplementation on lamb mortality with increased mortality observed in lambs from HSe ewes. Results from the studies show a restricted maternal plane of nutrition can increase lamb serum IgG concentration. Selenium results were not consistent between the 2 experiments and may be due to differences in maternal Se.
The effects of maternal nutrition on offspring wool production (quality and quantity) were evaluated. Primiparous Rambouillet ewes (n = 84) were randomly allocated to 1 of 6 treatments in a 2 × 3 factorial design. Selenium treatment [adequate Se (ASe, 9.5 μg/kg of BW) vs. high Se (HSe, 81.8 μg/kg of BW)] was initiated at breeding, and maternal nutritional intake [control (CON, 100% of requirements) vs. restricted (60% of CON) vs. overfed (140% of CON)] was initiated at d 50 of gestation. Lamb birth weight was recorded at delivery, and all lambs were placed on the same diet immediately after birth to determine the effects of prenatal nutrition on postnatal wool production and follicle development. At 180 ± 2.2 d of age, lambs were necropsied and pelt weights were recorded. Wool samples were collected from the side and britch areas, whereas skin samples were collected from the side of each lamb only. Although Se status did not influence side staple length in males, female lambs born from ewes on the ASe treatment had a shorter staple length (P < 0.05) when compared with females from ewes on the HSe treatment. Maternal nutritional intake and Se status did not influence (P ≥ 0.23) wool characteristics on the britch. However, at the britch, wool from female lambs had a reduced comfort factor (P = 0.01) and a greater (P = 0.02) fiber diameter compared with wool from male lambs. Maternal Se supplementation, maternal nutritional plane, sex of the offspring, or their interactions had no effect (P > 0.13) on primary (29.10 ± 1.40/100 µm2) and secondary (529.84 ± 21.57/100 µm2) wool follicle numbers. Lambs from ASe ewes had a greater (P = 0.03) secondary:primary wool follicle ratio compared with lambs from HSe ewes (20.93 vs. 18.01 ± 1.00). Despite similar postnatal diets, wool quality was affected by maternal Se status and the maternal nutritional plane.
To determine similarities and differences between nonsuperovulated and superovulated ewe models, data collected from several experiments (1989 through 2005) were analyzed. Mature non-pregnant non-superovulated (n = 91) or superovulated (n = 299) Western range-type ewes were used for evaluation of luteal function. To induce superovulation, ewes were injected twice daily with FSH on days 13 to 15 of the estrous cycle. At corpora lutea (CL) collection on day 5 or 10 of the estrous cycle, the number of CL was determined. For selected ewes, the CL were weighed and blood samples were collected for determination of progesterone (P4) concentration in serum. Each year, a similar (P > 0.1) number of ovulations/ewe was induced by FSH treatment (range from 12.4 ± 2.0 to 20 ± 2.5/year). Superovulated ewes had greater (P 0.1) for superovulated vs. non-superovulated ewes (2.3 ± 1.1 vs. 1.3 ± 0.1 ng/ml), but on day 10 tended to be greater (P < 0.06) in superovulated than non-superovulated ewes (5.8 ± 1.3 vs. 3.8 ± 0.3 ng/ml). When P4 concentration in serum was expressed per g of luteal tissue mass, values were similar for non-superovulated and superovulated ewes on days 5 and 10 of the estrous cycle. Moreover, all P4 values were greater (P < 0.05) on day 10 than on day 5 of the estrous cycle. Thus, despite some differences in CL number and CL weight, the major function of the CL, P4 production does not seem to be altered in superovulated ewes compared with non-superovulated ewes. Therefore, these data indicate that our superovulated ewe model may be used for studies of luteal function.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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