effects of late gestation supplementation of rumen undegradable protein, vitamin e, zinc, and...

R. R. Redden, R. W. Kott, J. A. Boles, A. W. Layton and P. G. Hatfieldzinc, and chlortetracycline to ewes on indices of immune transfer and productivity

Effects of late gestation supplementation of rumen undegradable protein, vitamin E,

doi: 10.2527/jas.2009-2442 originally published online December 4, 20092010, 88:1125-1134.J ANIM SCI

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ABSTRACT: Late gestation supplementation of feed additives, such as rumen undegradable intake protein (RUIP), vitamin E, Zn, and chlortetracycline, has in-consistently improved ewe/lamb productivity. In 3 ex-periments, Western white-faced ewes were supplement-ed 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 × 2 fac-torial 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 (PI3) titers, milk production, ewe BW and BCS change, and lamb pro-

duction 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-PI3 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 ≤ 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.

Key words: chlortetracycline, immune transfer, lamb production, rumen undegradable intake protein, vitamin E, zinc

©2010 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2010. 88:1125–1134 doi:10.2527/jas.2009-2442

INTRODUCTION

In US sheep flocks, nonpredatory lamb loss in the range of 10 to 20% is not uncommon (Rook et al., 1990; Rowland et al., 1992). Improving lamb survival from birth to weaning could increase the weight of lamb crop and thereby increase producer income. Late gestation

supplementation of rumen undegraded intake protein (RUIP; Annett et al., 2005), vitamin E (Kott et al., 1998), Zn (Hatfield et al., 1995), and chlortetracycline (SID, 2002) have been reported to improve lamb sur-vival or productivity. It has been speculated that im-provements noted with supplementation depend on a certain level of animal stressors, such as harsh weather conditions. The impact of stressors may become more apparent in aged and poor-conditioned ewes. Further-more, older ewes (Dickerson and Glimp, 1975) and ewes in poor body condition (Al-Sabbagh et al., 1995) are typically less productive.

Our objective was to compare a late gestation sup-plement that contained additional RUIP, vitamin E, Zn, and chlortetracycline with an isocaloric, isonitrog-enous supplement that was low in RUIP and did not supply extra vitamin E, Zn, or antibiotic. In addition,

Effects of late gestation supplementation of rumen undegradable protein, vitamin E, zinc, and chlortetracycline to ewes on indices

of immune transfer and productivity1,2

R. R. Redden,* R. W. Kott,* J. A. Boles,* A. W. Layton,† and P. G. Hatfield*3

*Department of Animal and Range Sciences, Montana State University, Bozeman 59717; and †Montana Department of Livestock, Bozeman 59717

1 Research was funded by the Montana Sheep Inst., Bozeman.2 The authors thank D. M. Hallford at the New Mexico State Uni-

versity’s Endocrinology Laboratory (Las Cruces) for RIA of colostral IgG and J. M. Martin (Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman) for his assistance with statistical analyses.

3 Corresponding author: [email protected] August 28, 2009.Accepted November 23, 2009.

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the potential interaction of supplement type with ewes at greatest and least risk of decreased productivity (i.e., young vs. old and good vs. poor BCS) was investigated. We hypothesized that supplementation of feed addi-tives listed above would improve immune transfer, milk production, ewe BW stasis, or overall lamb production of old and poor conditioned ewes.

MATERIALS AND METHODS

Activities involving the live animals were approved by the Institutional Animal Care and Use Committee at Montana State University.

Animals, Facilities, and Treatments

Three experiments were conducted using 2- to 6-yr-old Rambouillet, Targhee, and Columbia ewes from the flock at the Montana State University Red Bluff Research Ranch (latitude 45°35′ N, longitude 111°38′ W, altitude 1,450 m). Vegetation is a typical foothill bunchgrass type. Bluebunch wheatgrass (Pseudoroeg-neria spicata) and Idaho fescue (Festuca idahoensis) are the major grasses. Rubber rabbit brush (Ericameria nauseosus), prairie sagewort (Artemisia frigida), lupine (Lupinus spp.), milkvetch (Astragalus spp.), and west-ern yarrow (Achillea millefolium) are commonly occur-ring shrubs and forbs (Harris et al., 1989).

One month before lambing (March 10), feeding of supplement treatments was initiated. Ewes were sup-plemented with 204 g/(ewe·d) on a DM basis of high [HS; 12.5% RUIP, 880 IU/kg of supplemental vitamin

E, 176 mg/kg of AA-linked Zn (Availa-Zn 100, Zinpro, Eden Prairie, MN), and 352 mg/kg of chlortetracycline (Aureomycin, Alpharma, Bridgewater, NJ)] or low (LS; 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline) supplements (Table 1). The 2 supplements were pelleted and were formulated to be isocaloric (64% TDN) and isonitrogenous (25% CP). Energy portions of the supplements were mainly ground corn, wheat middlings, and malt sprouts. Con-centration of RUIP in supplements was determined by NRC values for RUIP of feed ingredients. Concentra-tion of RUIP in the LS was consistent with traditional range protein supplements, whereas the HS was de-veloped with as much RUIP as possible without di-minishing the palatability of the supplements. Greater concentration of RUIP in the HS was accomplished by substitution of hydrolyzed feather meal for canola meal as the protein source. Supplemental concentrations of vitamin E and Zn in the HS were consistent with previ-ous literature (Hatfield et al., 1995; Kott et al., 1998) that reported improvements in productivity. Chlortet-racycline was included in the supplement at 352 mg/kg, the maximum dose allowed (FDA, 1996).

Ewes were sheared 10 d after initiation of supplemen-tal treatments. In accordance with our routine health management protocol, ewes were vaccinated with a Clostridium perfringens type C & D preparation (Bar-Vac CDT, Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO) and treated for internal (Valbazen, Pfizer Animal Health, Exton, PA) and external (Permectrin, Boehringer Ingelheim Vetmedica) parasites immediate-ly after shearing.

Table 1. Chemical composition of long-stem hays and supplements fed to ewes during late gestation on a DM basis

Item

Hay1 Supplement2

Grass Alfalfa Barley High Low

DM, % 87.7 87.3 85.6 90.1 90.0CP, % 9.39 14.7 13.9 25.0 25.0RUIP, % 12.5 7.56ADF, % 37.6 37.5 33.2 7.45 12.2TDN, % 59.7 58.2 64.7 64.0 64.4S, % 0.14 0.27 0.17 0.42 0.52P, % 0.22 0.21 0.22 0.75 0.75K, % 1.97 2.61 2.00 0.84 1.10Mg, % 0.22 0.27 0.14 0.24 0.36Ca, % 0.68 1.45 0.42 1.50 1.49Na, % 0.01 0.06 0.15 0.91 0.91Fe, mg/kg 84 417 71 130 136Mg, mg/kg 58 40 34 158 150Cu, mg/kg 6 20 5 10 8Zn, mg/kg 12 13 17 343 166Se, mg/kg 0.3 0.3Supplemental vitamin E, IU/kg 880 0Chlortetracycline, mg/kg 352 0

1Chemical analysis conducted by Midwest Laboratory Inc., Omaha, NE.2Chemical composition of high and low supplements was calculated from NRC values of feed ingredients used to construct supplements. Ewes

were fed supplement treatments at 204 g/(ewe·d) on a DM basis for at a least 30 d before lambing in Exp. 1, 2, and 3. High = 12.5% undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of chelated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.

Redden et al.1126



Immediately after birth, ewes and lambs were placed in individual pens (1.5 m2) with water for 12 to 36 h to allow maternal bonding. Within 3 h of birth, lamb sex and birth weight were recorded, and the umbilical cords of lambs were clipped and dipped in iodine. At 24 to 36 h after parturition, lambs were ear-tagged for individual identification and their tails were docked. In accordance with ranch operating procedure, ram lambs from regis-tered Targhee and purebred Rambouillet matings were left intact, whereas commercial Targhee, Rambouillet, and Columbia matings were castrated with an elastra-tor. The ewe and her lamb(s) were moved to single or twin mixing pens at 12 to 36 h of age. For 1 wk (±2 d), ewes and lambs remained in mixing pens with ad libitum access to long-stem alfalfa hay (Table 1) that was fed in an open bunk and water. After 7 d in mixing pens, ewe and lambs were moved to larger paddocks and fed alfalfa hay (Table 1) ad libitum until late May. On May 23 and 20 in 2007 and 2008, respectively, all ewes and lambs were moved to native range where they were herded as 1 contiguous flock (this date is subse-quently referred to as turnout). On August 23 and 28, 2007 and 2008, respectively, all lambs were weaned.

Exp. 1

Fifty-two Targhee ewes were moved March 8, 2007 (2 d before initiation of 29 d of supplement treatment) from the range flock at the Red Bluff Research Ranch to the Montana State University Fort Ellis Research and Teaching Farm (latitude 45°38′ N, longitude 110°58′ W, altitude 1,505 m). Ewes were housed in a 3,721 m2 pen with ad libitum access to long-stem grass hay (Table 1) and water. On March 9, 2007, ewes were not allowed access to feed and water for 12 h and then weighed the following day at 0800 h to obtain a shrunk BW mea-surement. Body condition scores were assigned to each ewe as described by Russel et al. (1969).

Ewes were assigned randomly to a 2 × 2 factorial arrangement of treatments. Factors consisted of type of protein supplement (the HS or LS described pre-viously) and ewe age [one-half were 6-yr-old (6YR) and one-half were 3-yr-old (3YR) Targhee ewes from the Red Bluff Research Ranch]. Thus, the 4 treatment combinations (13 ewes/treatment) were 1) HS 3YR, (2) LS 3YR, (3) HS 6YR, and (4) LS 6YR. The 3YR and 6YR ewes had average BCS of 2.3 and 2.1 ± 0.5, respectively. For 29 d, ewes were individually supple-mented (March 10 to April 7, 2007) in pens (1.5 m2) every other day at 409 g/ewe on a DM basis. On April 9, 2007, ewes were weighed after a 12-h shrink and re-turned to the Red Bluff Research Ranch approximately 5 d before lambing began. Ewes were held in a drylot at Red Bluff and group fed 1 kg/(ewe·d) each of long-stem alfalfa hay and long-stem barley hay (Table 1). Ewes were group fed their respective supplement throughout lambing (14 ± 6 d). After parturition, ewes no longer received supplements.

Exp. 2

Similar to Exp. 1, 40 Targhee and Rambouillet ewes were moved to the Fort Ellis Research and Teaching Farm and assigned randomly to a 2 × 2 factorial ar-rangement of treatments. Factors were ewes randomly selected from good (GBC) and poor (PBC) BCS pop-ulations and the HS or LS treatments. The 4 treatment combinations (10 ewes/treatment) were 1) HS GBC, 2) LS GBC, 3) HS PBC, and 4) LS PBC. The GBC and PBC ewes averaged 3.0 and 1.7 ± 0.5 BCS, respec-tively. Ewes were supplemented and managed similar to ewes in Exp. 1.

Exp. 3

The ewe flock at Red Bluff in 2007 and 2008 (606 and 657 ewes, respectively) were divided randomly into 2 groups, and groups were assigned to the HS or LS treatment (n = 2 groups/treatment). Ewes were group fed their assigned supplement treatments from March 10 throughout lambing. From March 10 to 20, ewes were maintained on native range, whereas after shear-ing (March 20), the ewes were held in a drylot and group fed 1 kg/(ewe·d) each of long-stem alfalfa hay and long-stem barley hay (Table 1) in addition to their supplement treatment.

Data Collection

Ewe/Lamb Production Data. Lamb BW data were recorded at birth, turnout (32 and 27 d of age ± 6 d in 2007 and 2008, respectively), and weaning (117 and 127 ± 6 d of age in 2007 and 2008, respectively). Ewe BW and BCS data also were recorded at turnout and weaning. Ewe performance was calculated as kilo-grams of lamb/ewe, with lambs that died included in the analysis as a 0-kg lamb BW. Only ewes that lambed were included in production data.

Parainfluenza Type 3 (Exp. 1 and 2). Parain-fluenza type 3 (PI3) vaccinations were used to evaluate the effects of dietary supplements on specific passive transfer of immunity from ewes to lambs. We selected PI3 because it is not a common pathogen in sheep and assays are readily available for the specific titer. This procedure was previously used by Reffett et al. (1988) and Daniels et al. (2000).

In Exp. 1 and 2, all ewes were treated with an intra-nasal injection of bovine rhinotracheitis-parainfluenza3 vaccine (Pfizer Animal Health, New York, NY) 2 d be-fore feeding of supplement treatments was started, and a booster was given 2 wk later. After the individual feeding period, ewe blood samples were taken, and 3 d after parturition, lamb blood samples were taken. Blood samples (5 mL) from a jugular vein were collected with evacuated tubes and centrifuged at 1,000 × g for 20 min at 4°C. Serum was decanted into 10-mL plastic tubes and stored at −20°C. Lamb serum was analyzed for PI3 titers at the Montana Veterinary Diagnostic Laborato-

Late gestation supplementation 1127



ry (Bozeman) by the hema-absorption method using an end-point titer assay described by Daniels et al. (2000) modified for use in a 96-well plate. A greater dilution giving positive hema-absorption equates to a greater amount of PI3 antibody in the sample.

Intake and Digestion (Exp. 1 and 2). Four days after starting supplementation, a chromic oxide bolus (Sheep Chrome, Captec, Armidale, New South Wales, Australia) was administered to each ewe. Five days were allowed for the release rate of the chromic ox-ide bolus to equalize, with fecal collections obtained at 0900 h every other day thereafter for 6 d. Fecal samples were stored frozen at −20°C. One ewe was removed from analysis as a result of a lost bolus before fecal col-lections were concluded. After thawing, fecal samples were composited over the 6-d collection period by ewe and dried at 60°C for 24 h. Fecal samples were then ground to pass a 1-mm screen in a Wiley mill and dried at 100°C for 12 h.

Fecal samples were then prepared for Cr analysis using a modified version of the method described by Williams et al. (1962). Duplicate 1.0-g samples of fe-ces were ashed in a silica basin for 90 min at 600°C. Samples were digested in 3 mL of a phosphoric acid-manganese sulfate solution and 4.5% (wt/vol) potas-sium bromate solution until effervescence ceased or a light purple color appeared. Samples were brought to volume in a 100-mL volumetric flask with deionized water and mixed thoroughly. Chromium concentration was determined by atomic absorption spectroscopy us-ing air-plus-acetylene flame. Daily fecal output (FO) was estimated by dividing the concentration of fecal Cr into the quantity of Cr released daily from the bolus (0.195 g of Cr2O3/d).

Grass hay and supplement samples (Table 1) were ground to pass a 1-mm screen in a Wiley mill. Dry matter was determined on these samples after heating for 12-h at 100°C. Hay, supplement, and fecal samples were analyzed for indigestible ADF (IADF) similar to procedures described by Bohnert et al. (2002). Briefly, duplicate samples (0.5 g) of hay, supplement, and feces were weighed into Ankom filter bags (F57, Ankom Co., Fairport, NY). Samples were then incubated for 96 h in a ruminally cannulated cow consuming low-quality forage ad libitum. The sample bags were then removed from the rumen, rinsed with warm (39°C) tap water until the rinse water was clear, and analyzed for ADF as described by (Goering and Van Soest, 1970) using procedures modified for use in an Ankom 200 Fiber Analyzer (Ankom Co.). Indigestible ADF was used as a marker to estimate daily ewe hay intake: daily ewe hay intake = [(FO × % fecal IADF) – (supplement × % supplement IADF)]/% hay IADF. Ewe DM digestibil-ity (DMD) was calculated as DMD = 1 − [FO/(hay + supplement intake)].

Milk Collection and Analysis (Exp. 1 and 2). Within 2 h of birth, colostrum samples were taken from ewes, placed in a 100-mL container, and stored frozen. Three and ten days after lambing, ewes and

lambs were separated for a 2-h period. At the begin-ning and end of this period, ewes were hand-milked af-ter an intravenous injection of oxytocin (20 USP units of oxytocin principle; Vedco, St. Joseph, MO). Milk volume was recorded from the second milking, and a milk sample was collected in a 100-mL container and stored frozen. Milk protein, fat, lactose, total solids, and nonfat solids were determined by infrared analysis (MilkoScan FT120, Foss America, Eden Prairie, MN) at the Montana Veterinary Diagnostic Laboratory. So-matic cell count (SCC) was determined by the same laboratory using a Soma-Scope MKII counter (Delta Instruments, Norwood, MA). Colostral IgG concentra-tions were measured by RIA at the New Mexico State University Endocrinology Laboratory (Las Cruces) as described by Richards et al. (1999).

Statistical Analyses

All 3 experiments were completely randomized de-signs. In Exp. 1 and 2, ewe was the experimental unit, whereas in Exp. 3, pen was the experimental unit. The statistical model for Exp. 1 and 2 included the fixed ef-fects of supplement, age or BCS, and supplement × age or BCS, with the model for Exp. 3 including only the fixed effect of supplement. End point PI3 titer dilutions and somatic cells were transformed with a log base-10 transformation. Data were analyzed using PROC GLM procedures (SAS Inst. Inc., Cary, NC) and are present-ed as least squares means with differences considered significant at P < 0.10. Birth date was added as a co-variate for lamb turnout and weaning BW to account for differences in age of lambs for Exp. 1 and 2. When an interaction occurred (P < 0.10) between supplement and ewe age or BCS, the effect of supplement was re-ported within age or condition groups. When an inter-action was not detected (P > 0.10), main effects were reported for supplement and ewe age or BCS.

RESULTS

Exp. 1

No supplement × age interactions were detected for DMD, DMI, and DMI as a percentage of ewe initial BW (Table 2). Dry matter intake and DMD did not dif-fer between ewes consuming the HS and LS. The 3YR ewes had greater (P < 0.01) DMD, DMI, and DMI as a percentage of ewe BW than 6YR ewes.

No effects of age, supplement, or age × supplement were detected for colostrum IgG or ewe PI3 titer con-centrations (Table 2); however, an age × supplement interaction (P < 0.01) was detected for lamb PI3 titers. Within 3YR ewes, lambs born to HS ewes had greater (P = 0.01) PI3 antibody titers than lambs born to LS ewes. Lamb PI3 titers from 6YR ewes did not differ (P = 0.16) between supplemental treatments.

On d 3, supplement × age interactions were not de-tected for 2-h milk production, concentrations of fat,

Redden et al.1128



lactose, and total solids, and SCC (Table 3). In ad-dition, ewe age and type of supplement did not affect these variables. Supplement × age interactions were de-tected (P ≤ 0.07) for milk protein concentrations and milk nonfat solids concentrations. Within 6YR ewes, milk concentrations of protein and nonfat solids were

greater (P ≤ 0.10) in ewes fed the LS than HS. Within 3YR ewes, supplement had no effect (P ≥ 0.21) on milk concentrations of protein and nonfat solids.

On d 10, a supplement × age interaction was de-tected (P = 0.06) for concentrations of milk nonfat solids (Table 3); however, within 3YR and 6YR ewes

Table 2. Least squares means of fecal output, DM digestibility (DMD), DMI, log base-10 transformation of ewe and lamb serum parainfluenza type 3 (PI3) titers, and colostrum IgG of 3- and 6-yr-old ewes fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vitamin E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 11

Item

Treatment

SEM2

P-value3-yr-old 6-yr-old

High Low High Low S × A3 3- vs. 6-yr-old High vs. low

Fecal output, kg/d 0.89 1.00 0.87 0.90 0.06 0.58 0.29 0.29DMD, % 51.1a 50.2a 46.5b 44.2c 0.99 0.48 <0.01 0.11DMI, kg/d 1.40ab 1.55a 1.20b 1.19b 0.09 0.40 <0.01 0.52DMI:BW,4 % 2.52a 2.78a 2.00b 2.00b 0.16 0.40 <0.01 0.42Ewe serum PI3 titers

5 0.95 0.76 0.67 0.76 0.14 0.34 0.34 0.75Lamb serum PI3 titers

5 1.25a 0.87b 1.07ab 1.29a 0.11 <0.01Colostral IgG, mg/mL 54.1 56.8 45.9 50.8 5.49 0.83 0.15 0.43

a–cWithin a row, means that do not have a common superscript differ, P < 0.10.1Ewes were 3 or 6 yr of age. High = 12.5% rumen undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of che-

lated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.2n = 13, 13, 13, 13, 13, 6, and 9 samples/treatment for fecal output, DMD, DMI, DMI:BW, ewe serum PI3 titers, lamb serum PI3 titers, and

colostral IgG, respectively. In cases where n varied by treatment, the smallest value is reported.3S × A = interaction between type of supplement and age of ewe.4DMI:BW = DMI divided by ewe initial BW.5Analyzed using an end-point titer assay. The last culture PI3 virus to medium dilution giving a visible positive hema-absorption was recorded

as the end-point titer. A greater dilution giving positive hema-absorption equates to a greater amount of PI3 antibody in the sample.

Table 3. Least squares means of milk volume and composition from 3- and 6-yr-old ewes fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vitamin E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 11

Day and item

Treatment

SEM2



d 3 2-h milk production, mL 190 210 174 230 26.2 0.48 0.95 0.14 Fat, % 11.5a 9.85b 11.6a 11.0ab 0.71 0.43 0.36 0.12 Protein, % 5.55a 5.31a 5.61a 6.07b 0.19 0.07 Lactose, % 4.29 4.24 4.25 4.34 0.09 0.45 0.76 0.81 Total solids, % 22.5a 20.6b 22.6a 22.6a 0.68 0.15 0.11 0.14 Nonfat solids, % 10.9a 10.6a 10.9a 11.4b 0.18 0.03 SCC4 5.25a 5.34ab 5.74b 5.41ab 0.18 0.24 0.16 0.49d 10 2-h milk production, mL 155a 191ab 165ab 217b 25.5 0.73 0.47 0.07 Fat, % 9.78 9.13 10.3 10.1 0.75 0.80 0.31 0.52 Protein, % 5.03a 4.84a 5.15ab 5.34b 0.13 0.14 0.02 0.98 Lactose, % 4.63 4.72 4.72 4.70 0.09 0.57 0.72 0.73 Total solids, % 20.7 19.9 21.0 21.3 0.75 0.45 0.23 0.74 Nonfat solids, % 10.8ac 10.7a 10.9bc 11.2b 0.09 0.06 SCC4 5.23 5.19 5.57 5.37 0.19 0.73 0.17 0.49

a–cWithin a row, means that do not have a common superscript differ, P < 0.10.1Ewes were 3 or 6 yr of age. High = 12.5% rumen undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of che-

lated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.2n = 10 samples/treatment. In cases where n varied by treatment, the smallest value is reported.3S × A = interaction between type of supplement and age of ewe.4SCC = log-transformation of somatic cell counts.




no differences were detected between supplements (P ≥ 0.11). Interactions were not detected for any of the other d-10 milk variables. Ewes supplemented the LS had greater (P = 0.07) 2-h milk production than ewes fed the HS. The 3YR ewes had greater (P = 0.02) milk protein concentrations than the 6YR ewes. Day 10 milk fat, lactose, solids, and SCC did not differ between age and supplement treatments.

Supplement × age interactions were not detected for any of the ewe BW or BCS variables. Initial shrunk BW was greater (P < 0.01) for 6YR than for 3YR ewes (Table 4); however, ewes fed the HS lost more BW (P = 0.07) than those fed the LS from the start of supplementation until turnout. No differences were detected in ewe BW change from supplementation to weaning. Initial BCS did not differ among treatments at the start of the experiment (Table 4), and no dif-ferences were measured for BCS change after the indi-vidual supplementation period. Ewe BCS did not differ between the HS and LS ewes at turnout; however, 3YR ewes lost more BCS (P = 0.08) than 6YR ewes. No differences in ewe BCS change were detected among treatments at weaning, but there was a tendency (P = 0.11) for 3YR ewes to gain BCS, whereas 6YR ewes maintained or slightly lost BCS.

No supplement × age or age effects were detected for lamb birth, turnout, or weaning BW of single- or twin-bearing ewes (Table 4). Birth BW of single lambs born to ewes fed the LS ewes was greater (P = 0.10) than single lambs born to ewes fed the HS. In contrast, birth BW of twin lambs born to HS ewes was greater (P = 0.07) than birth BW of twin lambs born to ewes in the LS treatment. No supplement or age differences were detected for turnout or weaning BW of lambs born to single- or twin-bearing ewes.

Exp. 2

No BCS, supplement type, or supplement × BCS interactions were detected for ewe intake or DMD of grass hay and supplement. Dry matter intake as a per-centage of initial BW did not differ among treatments. There was a tendency (P = 0.11) for GBC ewes to have greater diet DMD than PBC ewes (Table 5). No BCS, supplement type, or supplement × BCS interactions were detected for colostrum IgG concentrations (Table 5). In addition, ewe and lamb anti-PI3 titers did not differ among treatments.

On d 3, supplement × BCS interactions were not detected for 2-h milk production, concentration of milk

Table 4. Least squares means of 3- and 6-yr-old ewe BW and BCS and their respective lamb BW when fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vitamin E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 11

Item2

Treatment

SEM3



Initial ewe BW, kg 64.7a 64.3a 70.2b 70.3b 1.86 0.89 <0.01 0.96Ewe BW change, kg Prelambing 2.4 1.9 1.6 2.8 1.01 0.34 0.99 0.67 Turnout −7.6a −5.6ab −6.1ab −4.0b 1.21 0.98 0.16 0.07 Weaning −3.8a 0.4b −3.2ab −2.0ab 1.92 0.38 0.60 0.14Initial ewe BCS 2.3 2.3 2.2 2.2 0.12 0.87 0.44 0.55Ewe BCS change5

Prelambing −0.2 −0.1 0.0 0.1 0.13 0.90 0.18 0.79 Turnout −0.2a −0.1ab 0.2b 0.0ab 0.15 0.26 0.08 0.70 Weaning 0.1ab 0.3a −0.1b 0.0ab 0.17 0.74 0.11 0.39Single-born lamb Birth BW, kg 5.4 5.8 5.4 6.2 0.35 0.50 0.51 0.10 Turnout BW, kg 15.2 14.7 13.5 13.5 1.50 0.84 0.31 0.86 Weaning BW, kg 31.7 31.7 31.2 32.5 4.76 0.86 0.99 0.87Twin-born lamb Birth BW, kg 9.4 8.5 9.7 8.9 0.53 0.93 0.42 0.07 Turnout BW, kg 19.5 18.5 17.9 22.7 2.90 0.18 0.58 0.44 Weaning BW, kg 43.9 48.8 34.3 54.0 12.7 0.42 0.82 0.26

a,bWithin a row, means that do not have a common superscript differ, P < 0.10.1Ewes were 3 or 6 yr of age. High = 12.5% rumen undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of che-

lated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.2Initial, prelambing, turnout, and weaning ewe BW and BCS were taken at −44, −9, 32, and 117 d, respectively, relative to average lambing

(April 22, 2007).3n = 9, 6, and 2 samples/treatment for ewe BW and BCS, single-born lambs, and twin-born lambs, respectively. In cases where n varied by

treatment, the smallest value is reported.4S × A = interaction between type of supplement and age of ewe.5Ewe BCS was evaluated by a trained technician (1 = emaciated; 5 = obese).

Redden et al.1130



fat, protein, lactose, total solids, and nonfat solids (Ta-ble 6). Concentration of milk fat and lactose was great-er (P ≤ 0.10) in GBC than in PBC ewes, and ewes fed the HS had less (P = 0.03) SCC than ewes fed the LS.

On d 10, supplement × BCS interactions were de-tected (P ≤ 0.06) for concentrations of milk protein

and nonfat solids (Table 6). Supplement × BCS inter-actions were not detected for 2-h milk production on d-10 milk concentrations of fat, lactose, total solids, or somatic cells. Ewes in GBC on the HS had greater (P ≤ 0.07) milk protein and nonfat solids concentrations than ewes in GBC on the LS. Protein and nonfat solids

Table 5. Least squares means of fecal output, DM digestibility (DMD), DMI, log base-10 transformation of ewe and lamb serum parainfluenza type 3 (PI3) titers, and colostrum IgG of ewes that differed in BCS (good and poor) that were fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vita-min E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 21

Item

Treatment

SEM2

P-valueGood Poor

High Low High Low S × C3 Good vs. poor High vs. low

Fecal output, kg/d 0.87 0.86 0.82 0.89 0.08 0.53 0.88 0.53DMD, % 51.2 50.1 49.2 48.7 1.32 0.79 0.19 0.52DMI, kg/d 1.36 1.30 1.19 1.29 0.11 0.47 0.47 0.85DMI:BW,4 % 2.31 2.24 2.26 2.46 0.19 0.45 0.65 0.73Ewe serum PI3 titers

5 1.00 0.76 0.71 0.87 0.18 0.26 0.57 0.81Lamb serum PI3 titers

5 1.28 0.94 0.93 1.01 0.23 0.31 0.51 0.54Colostral IgG, mg/mL 57.7 53.3 59.6 54.6 5.63 0.95 0.78 0.41

1Good = average BCS = 3, range of 2.5 to 3.5; poor = average BCS = 1.7, range of 1.5 to 2. High = 12.5% rumen undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of chelated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.

2n = 9, 9, 9, 9, 9, 6, and 6 samples/treatment for fecal output, DMD, DMI, DMI:BW, ewe serum PI3 titers, lamb serum PI3 titers, and colostral IgG, respectively. In cases where n varied by treatment, the smallest value is reported.

3S × C = interaction between type of supplement and condition of ewe.4DMI:BW = DMI divided by initial ewe BW.5Analyzed using an end-point titer assay. The last culture PI3 virus to medium dilution giving a visible positive hema-absorption was recorded

as the end-point titer. A greater dilution giving positive hema-absorption equates to a greater amount of PI3 antibody in the sample.

Table 6. Least squares means of milk volume and composition from ewes that differed in BCS (good and poor) that were fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vita-min E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 21

Day and item

Treatment

SEM2

P-valueGood Poor


d 3 2-h milk production, mL 163 182 194 158 30.0 0.31 0.90 0.75 Fat, % 11.1ab 11.8a 9.34b 10.5ab 0.96 0.79 0.10 0.28 Protein, % 5.88 4.99 5.56 6.05 0.51 0.15 0.42 0.67 Lactose, % 4.55a 4.47a 4.39ab 4.23b 0.10 0.66 0.04 0.21 Total solids, % 22.6 22.4 20.5 22.0 1.25 0.46 0.28 0.53 Nonfat solids, % 11.4a 10.5b 11.1ab 11.4ab 0.41 0.12 0.44 0.48 SCC4 5.02a 5.27b 5.14ab 5.53b 0.16 0.62 0.20 0.03d 10 2-h milk production, mL 166a 168a 108b 134ab 18.9 0.51 0.02 0.41 Fat, % 9.38 10.5 10.7 9.48 1.56 0.41 0.90 0.95 Protein, % 5.15a 4.48b 4.64ab 4.93ab 0.27 0.06 Lactose, % 4.77 4.72 4.29 4.75 0.32 0.39 0.44 0.48 Total solids, % 20.43 20.9 21.2 20.4 1.46 0.61 0.91 0.89 Nonfat solids, % 10.9a 10.4b 10.5ab 10.8ab 0.26 0.05 SCC4 6.19 2.94 6.09 2.26 3.41 0.50 0.88 0.63

a,bWithin a row, means without a common superscript differ, P < 0.10.1Good = average BCS = 3, range of 2.5 to 3.5; poor = average BCS = 1.7, range of 1.5 to 2. High = 12.5% rumen undegraded intake protein

(RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of chelated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.

2n = 8 samples/treatment. In cases where n varied by treatment, the smallest value is reported.3S × C = interaction between type of supplement and condition of ewe.4SCC = log-transformation of somatic cell counts.




concentrations did not differ between HS and LS ewes in PBC BCS. Ewes in GBC BCS had greater (P = 0.02) 2-h milk production than ewes in PBC BCS.

Initial shrunk BW was greater (P = 0.06) for GBC than for PBC ewes (Table 7). No BCS, supplement, or BCS × supplement differences were detected for ewe BW change during the individual supplementation period. Likewise, no differences were detected among treatments in ewe BW change from start of supplemen-tation to turnout. No differences were detected in ewe BW change from supplementation to weaning. Initial BCS were greater (P = 0.01) for GBC than for PBC ewes. Supplement × BCS interactions were noted (P = 0.09) for BCS change during the individual supplemen-tation period. The HS and LS GBC ewes had greater (P < 0.01) BCS loss than did HS and LS PBC ewes. Ewe BCS and BCS × age differences in BCS changes were not detected at turnout; however, GBC ewes lost more BCS (P < 0.01) than PBC ewes. Similarly, GBC ewes lost more BCS (P < 0.01) than PBC ewes at wean-ing. No supplement, BCS, or supplement × BCS effects were detected for single- or twin-born lamb birth, turn-out, or weaning BW (Table 7).

Exp. 3

Ewe BW and BCS at turnout and weaning did not differ between supplement treatments (Table 8). More-

over, birth, turnout, and weaning BW did not differ between single and twin lambs born to ewes consum-ing HS or LS (Table 8). Percentage of lambs alive at turnout and weaning BW did not differ between single and twin lambs born to ewes consuming the 2 different supplements (Table 8).

DISCUSSION

The overall goal of this project was to develop a late gestation supplement that improved lamb production, particularly in thin and old ewes. Supplementation of RUIP has been shown to increase ewe BW (Roeder et al., 2000), improve indices of immunity (Annett et al., 2005), and increase lamb production (Annett et al., 2005). In addition, Zn supplementation has increased indices of immune function (Spears, 1989) and lamb production (Hatfield et al., 1995), and vitamin E supple-mentation has been reported to improve immune trans-fer from ewe to lamb (Ritacco et al., 1986; Reffett et al., 1988; Gentry et al., 1992) and enhance lamb produc-tion (Gentry et al., 1992; Kott et al., 1998). Chlortetra-cycline supplementation is commonly recommended in late gestation to decrease pathogen proliferation (SID, 2002), and it has been shown to improve piglet survival and growth (Maxwell et al., 1994). Furthermore, ewe age and BCS are known to affect lamb survival and growth (Al-Sabbagh et al., 1995). Nonetheless, research

Table 7. Least squares means of ewe BW and BCS change and lamb BW from ewes that differed in BCS (good and poor) that were fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in undegraded intake protein, vitamin E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 21

Item

Treatment

SEM2

P-valueGood Poor


Initial BW 68.6a 67.1a 62.0b 61.9b 2.72 0.74 0.06 0.76Ewe BW change, kg Prelambing 0.3 0.1 0.7 0.9 0.79 0.77 0.38 0.95 Turnout −9.2a −6.8ab −5.4b −7.3ab 1.73 0.18 0.31 0.88 Weaning −6.5 −7.3 −2.2 −5.0 3.16 0.70 0.21 0.50Initial BCS 3.1a 3.0a 1.7b 1.8b 0.08 0.11 <0.01 0.69Ewe BCS change Prelambing −0.7a −0.5a 0.4b 0.2b 0.12 0.09 Turnout −0.7a −0.4a 0.3b 0.1b 0.59 0.16 <0.01 0.84 Weaning −0.6a −0.3ac 0.3b 0.0bc 0.20 0.19 <0.01 0.94Single-born Birth BW, kg 5.4 5.3 4.1 5.2 0.79 0.41 0.28 0.43 Turnout BW, kg 12.9 13.7 11.5 8.8 2.98 0.50 0.19 0.68 Weaning BW, kg 36.4 29.6 30.6 20.2 9.12 0.62 0.29 0.24Twin-born Birth BW, kg 9.3 11.6 8.2 9.5 1.7 0.68 0.15 0.12 Turnout BW, kg 17.1 24.4 18.8 17.5 4.9 0.21 0.40 0.34 Weaning BW, kg 37.3 62.1 43.6 36.9 16.6 0.18 0.37 0.40

a–cWithin a row, means that do not have a common superscript differ, P < 0.10.1Good = average BCS = 3, range of 2.5 to 3.5; poor = average BCS = 1.7, range of 1.5 to 2. High = 12.5% rumen undegraded intake protein

(RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of chelated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.

2n = 7, 2, and 2 samples/treatment for ewe BW and BCS, single-born lambs, and twin-born lambs, respectively. In cases where n varied by treatment, the smallest value is reported.

3S × C = interaction between type of supplement and condition of ewe.

Redden et al.1132



that has investigated the effects of these supplements has been inconsistent. Late gestation supplementation of RUIP (Ramsey et al., 2000; Roeder et al., 2000), Zn (Spears, 1989), and vitamin E (Daniels et al., 2000; Dafoe et al., 2008) were all found to have no effect on livestock production. It is also important to note, how-ever, that to our knowledge, no research has indicated negative biological responses as a result of incorporat-ing these additives into a late gestation supplement.

Ewe DMD estimates in Exp. 1 and 2 were relatively small compared with estimates of DMD based on ADF concentrations as described by Rohweder et al. (1978). Similar studies have found that IADF used as internal marker typically underestimated actual grass hay DMD (Cochran et al., 1986; Judkins et al., 1990; Sunvold and Cochran, 1991). Nonetheless, supplemental treatments did not appear to influence ewe DMD.

Because differences were not detected in lamb PI3 ti-ters of 6YR ewes on HS or LS, we reject our hypothesis that HS would improve immune transfer in high-risk 6YR ewes. In contrast, 3YR ewe immune transfer to lambs seemed to be improved with the HS. Because ewe PI3 titers and colostral IgG concentrations did not differ among treatments and lamb production was not altered, these data do not provide evidence that supple-mentation or age had a major effect on immune trans-fer from ewe to lamb.

Neither age nor supplement treatments enhanced d 3 or 10 milk production or milk composition in a consistent pattern that translated into improved lamb production. Although differences were not detected, it should be noted that 3YR HS and GBC HS ewes nu-merically had the least SCC and the greatest ewe serum PI3 titers. Elevated milk SCC mainly reflect the num-ber of leukocytes that migrate from blood to the mam-mary gland in response to an infection in the mammary gland (Rupp et al., 2009) and are indicative of chronic mastitis. Greater PI3 titers and less SCC might indicate that 3YR ewes on the HS had improved immunological protection. However, further research is needed to iden-tify if titer levels and SCC are related to and indicative of improved immune function. Furthermore, results of Exp. 1 and 2 refuted our original hypothesis that im-mune function would be improved by RUIP supplemen-tation of high-risk 6YR and PBC ewes.

Trends in BW and BCS change for age or supplement treatment did not indicate that any treatment affected ewe BW and BCS stasis to any great extent. Moreover, differences in ewe productivity were not detected for age or supplement treatments. Although, lamb survival was not analyzed in Exp. 1 or 2, lamb loss was factored into the calculation of kilograms of lamb weaned per ewe. Therefore, if a lamb loss difference was present among treatments, it should have been reflected in the

Table 8. Least squares means of ewe BW and BCS, lamb BW, and lamb survival rates when fed 204 g/(ewe·d) on a DM basis of protein supplements that varied in unde-graded intake protein, vitamin E, Zn, and chlortetracycline (high or low) the last 30 d of gestation in Exp. 31

Item2

Treatment

SEM3 P-valueHigh Low

Ewes Turnout BW, kg 58.2 58.2 0.47 0.95 Weaning BW, kg 61.4 60.9 0.47 0.33 Turnout BCS 2.5 2.4 0.08 0.19 Weaning BCS 2.8 2.8 0.10 0.64Single lambs Birth BW, kg 5.3 5.4 0.05 0.63 Turnout BW, kg 12.9 12.8 0.80 0.95 Weaning BW, kg 30.1 30.6 1.18 0.80Twin lambs Birth BW, kg 8.7 8.6 0.07 0.31 Turnout BW, kg 17.1 17.2 0.83 0.96 Weaning BW, kg 42.1 41.4 1.27 0.73Single survival Birth, % 100 100 — — Turnout, % 92.4 92.7 0.01 0.85 Weaning, % 86.1 87.6 0.02 0.75Twin survival Birth, % 200 200 — — Turnout, % 172 170 0.05 0.90 Weaning, % 156 155 0.07 0.91

1High = 12.5% rumen undegraded intake protein (RUIP), 880 IU/kg of supplemental vitamin E, 176 mg/kg of chelated Zn, and 352 mg/kg of chlortetracycline; low = 7.56% RUIP, no supplemental vitamin E, no chelated Zn, and no chlortetracycline.

2Turnout BW were taken 32 and 27 d after average lambing date in 2007 and 2008, respectively. Weaning BW were taken 117 and 127 d after average lambing in 2007 and 2008, respectively.

3n = 2 groups/treatment.




lamb BW data. Supplementation of ewes in Exp. 3 did not indicate that supplementation of the HS treatment affected measures of ewe productivity. Thus, the results of Exp. 3 were consistent with the 2 previous experi-ments.

Conclusions

Under the conditions of our study, the HS (containing additional RUIP, vitamin E, AA-linked Zn, and chlor-tetracycline) did not improve ewe or lamb production or affect indices of immune function. Although supple-ment treatment altered immune transfer from ewe to lamb, the response was not consistent across age or type of supplement. Moreover, there were no meaning-ful interactions for immune transfer between age or BCS and the type of supplement. We had anticipated that the HS would benefit the at-risk ewes (old or PBC), but this was not the case. Thus, with the indices of ewe and lamb performance and immune function that we evaluated, the additional cost typically associated with supplements similar to our HS, even for at-risk ewes, were not warranted under our conditions.

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