Nutrient digestion and performance by lambs and steers fed thermochemically treated crop residues.

Five studies were conducted to determine nutrient digestibility and performance of lambs and steers fed thermochemically treated crop residues and distillers dried grains with solubles (DDGS) as a corn replacement pellet (CRP; 75% residue:25% DDGS, DM basis). Fifteen Hampshire, Suffolk, or Dorset wethers (BW 33.3 +/- 5.0 kg) were utilized to evaluate nutrient digestibility of the unprocessed native (NAT) and CRP [Exp. 1: wheat straw (WS); Exp. 2: corn stover (CS); Exp. 3: switchgrass (SWG) and corn fiber:wheat chaff (CFWC)] when limit fed (Exp. 1 and 2: 1.8% of BW daily; Exp. 3: 2.5% of BW daily) compared with a 60% corn diet. In Exp. 4, 56 individually fed Dorset-cross wether lambs (BW 32.0 +/- 1.4 kg) were utilized to compare performance and digestibility of WS, wheat chaff (WC), corn fiber (CF), a 3:1 blend of corn fiber:wheat straw (CFWS), a 3:1 blend of CFWC, and SWG-CRP fed for ad libitum intake compared with a 45% corn diet. In Exp. 5, 32 individually fed Holstein steers (BW 185.2 +/- 0.9 kg) were used to evaluate performance and digestibility of diets containing corn, WS-CRP, CFWC-CRP, or NAT-WS fed for ad libitum intake. Crop residues were processed with 5% calcium oxide (DM basis) and 35% water in a double-shaft enclosed mixer (Readco Kurimoto Continuous Processor, York, PA) and subsequently pelleted with DDGS to form CRP. Feeding lambs WS-CRP (Exp. 1) or CS-CRP (Exp. 2) increased digestion of DM, NDF, and ADF compared with NAT (P < 0.05). In Exp. 3, feeding CFWC-CRP increased total tract NDF digestibility and ADF digestibility (P < 0.05). Experiment 4 final BW were greatest for control lambs and least for lambs fed CFWS-CRP or SWG-CRP. Body weight gains for lambs fed CRP averaged 15.9% less than control (P < 0.05). Lambs fed CRP diets had greater (P < 0.05) NDF and ADF intake and output. In Exp. 5, steers fed the corn or 2 CRP diets gained similarly and faster (P < 0.05) than those fed the NAT-WS diet. Steers fed the control corn diet were more efficient (P < 0.05) than steers fed other treatments. Steers fed the corn diet, CFWC-CRP, and WS-CRP had greater (P < 0.01) DM digestibility than NAT. The results confirm benefits for nutrient digestion and subsequent animal performance when crop residues are thermochemically processed. Processed crop residues may be fed in combination with DDGS to partially replace corn in ruminant diets.

Effects of restricted and ad libitum intake of diets containing wheat middlings on site and extent of digestion in steers.

A 5 x 5 Latin square design was used to determine the effects of restricted and ad libitum intake of diets containing wheat middlings on the site and extent of digestion compared to ad libitum intake of a corn-based diet and ad libitum intake of chopped alfalfa hay. Five ruminally and duodenally cannulated Angus steers (519 +/- 41.5 kg BW) were used to compare five dietary treatments. The five treatments were as follows: ad libitum access to a corn-based finishing diet (control), the control diet with 25 percentage units of the corn and soybean meal replaced with wheat middlings offered ad libitum (WM), the WM diet restricted to 75% of predicted ad libitum intake (RWM), the RWM diet with wheat middlings replaced with ammoniated wheat middlings (RNWM), and ad libitum access to a chopped alfalfa hay diet. Although RWM steers were fed to consume 75% of ad libitum intake, RWM steers consumed 15.5% less DM than WM. Steers fed ad libitum hay consumed 28.6, 31.7, and 37.2% less (P < 0.01) DM, OM, and nitrogen than RWM steers. No differences in apparent or true ruminal digestibility were observed among steers fed the control vs WM, WM vs RWM, RWM vs RNWM, or RWM vs hay diets. However, the steers fed the hay diet had 32.5, 33.4, and 36.9% lower (P < 0.01) apparent total tract digestibilities of DM, OM, and N than those fed the RWM diet. Average ruminal pH was lower (P < 0.01) for control steers than those fed the WM diet and for those fed RWM compared to the hay diet. The acetate:propionate ratio was higher for cattle fed hay vs the RWM diet. Microbial DM and OM flow to the small intestine was higher (P < 0.02) for steers fed the RWM diet than those fed the hay diet. In addition, bacterial N flow to the small intestine was higher (P < 0.01) for cattle receiving the RWM diet than the hay diet. Feeding diets containing 25 percentage units of wheat middlings at 75% ad libitum intake had no effect on ruminal digestibility.

Intake restriction strategies and sources of energy and protein during the growing period affect nutrient disappearance, feedlot performance, and carcass characteristics of crossbred heifers.

Two trials were conducted to evaluate intake restriction, energy, and protein source on the performance and carcass merit of heifers limit-fed corn gluten feed. Trial 1 crossbred heifers (n = 140) were allotted to ad libitum wet corn gluten feed (WCGF)-hay, ad libitum WCGF-corn, WCGF-corn continuously limit-fed to achieve a gain of 1.1 kg/d or WCGF-corn fed in the following sequence: 70% of ad libitum for 20 d, ad libitum for 20 d, and 2 d common intake during the 84-d growing period. One-half of these restricted-refed heifers received a rumen-undegraded protein supplement, and the other half received a rumen degraded protein supplement. Heifers were fed a common finishing diet ad libitum subsequent to the growing period. Heifers offered ad libitum WCGF-hay and WCGF-corn were slaughtered at a common compositional fat end point. Heifers limit-fed WCGF-corn were slaughtered at the same time as heifers offered ad libitum WCGF-corn, regardless of subcutaneous fat cover. Limit-feeding WCGF-corn diets to growing heifers reduced ADG (P < or = 0.01) but did not compromise feed efficiency. Method of intake restriction, continuous or ad libitum-interrupted, and supplemental protein source did not affect combined growing-finishing performance. However, when fed for a common length of time, the average of the limit-fed heifers had lighter carcass weights (P < or = 0.01) and lower (P = 0.04) marbling scores. Heifers offered ad libitum WCGF-hay gained slower (P < or = 0.01) and less efficiently (P < or = 0.01) than heifers offered WCGF-corn. Trial 2 crossbred heifers (n = 222) were allotted to dry corn gluten feed (DCGF)-corn ad libitum or restricted to 80% of ad libitum for 42, 84, or 126 d; or ad libitum corn silage or DCGF-corn silage at 80% of ad libitum for 84 d. Feed efficiency (P = 0.07) and ADG (P = 0.08) tended to behave quadratically, being poorer for heifers limit-fed for 126 d during the growing period. Heifers limit-fed DCGF-corn gained more efficiently (P = 0.05) than heifers grown on ad libitum corn silage. Limit-feeding CGF-corn to growing beef heifers can be used to achieve moderate rates of gain without compromising feed efficiency. However, limit-feeding during the growing period may result in lighter weight carcasses with lower quality grades if not fed to the same fat end point as heifers grown with free access to concentrate.

Effects of energy intake, implantation, and subcutaneous fat end point on feedlot steer performance and carcass composition.

The purpose of this experiment was to evaluate the effects of energy intake, implantation, and fat end point on feedlot performance and carcass composition of steers. Three hundred eighty-four yearling crossbred steers (368 +/- 23.1 kg) were allotted in a completely randomized design. Treatments were arranged in a 2 x 3 x 2 factorial experiment. Main effect factors were two levels of intake, three implant strategies, and two compositional fat end points at slaughter. The levels of intake were ad libitum (AL) and restricted (RS) intake (90% ad libitum). The three implant strategies were Revalor-S (REV) (120 mg trenbolone acetate, 24 mg estradiol), Synovex-Plus (SYN) (200 mg trenbolone acetate, 28 mg estradiol benzoate), and no implant (control). The compositional target end points were 1.0 and 1.4 cm s.c. fat cover over the 12th and 13th rib. Restricted-intake steers consumed 9.2% less (P < .01) DM than AL steers. Ad libitum-intake steers gained weight 15.5% more rapidly (P < .01) than RS-intake steers. Steers implanted with REV tended (P < .07) to gain faster than SYN steers, who in turn gained 15.2% more (P < .01) than control steers. Ad libitum-intake steers were 4.8% more (P < .01) efficient than RS steers. Steers fed to a targeted 1.4 cm s.c. backfat cover were 2.9% less (P < .05) efficient than steers fed to 1.0 cm, and steers implanted with either REV or SYN had similar (P = .47) feed efficiencies, whereas control steers had lower (P < .01) feed efficiencies. Steers fed to a targeted compositional fat end point of 1.4 cm had 1.3% higher (P < .01) dressing percentage (DP) than steers fed to 1.0 cm. Control and SYN steers had similar (P = .13) DP; however, REV steers had 6.1% greater (P < .01) DP than SYN steers. Steers fed to 1.4 cm s.c. fat end point had higher (P < .01) numerical yield grades than steers fed to 1.0 cm (3.34 vs 2.71). There was an interaction (P < .01) for intake level and implant for marbling score. Marbling scores were lower (P < .05) for RS x SYN and AL x REV than in other treatments. Steers on the RS x REV treatment were intermediate in marbling to all treatments except AL control, which was higher (P < .01) than RS x SYN, AL x REV, and RS x REV. No interaction for dry matter intake level and anabolic implants was observed for growth performance. The depression in carcass quality resulting from implanting is reduced as backfat increases from 1.0 to 1.4 cm at slaughter.

The effects of corn milling coproducts on growth performance and diet digestibility by beef cattle.

Simmental x Angus weanling heifers (n = 96; 239 +/- 2.3 kg) were used in four replications to evaluate three dietary treatments in Trial 1. Treatments were cracked corn-hay diets supplemented with one of three corn milling industry coproducts: dry corn gluten feed (DCGF), dried distillers grains (DDG), and a new modified corn fiber (MCF). In Trial 2, ruminally cannulated mature crossbred beef steers (n = 4; 606 +/-60 kg) were used in a 4 x 4 Latin square with 11-d periods to determine digestibility and ruminal metabolism of limit-fed cracked corn-alfalfa haylage diets supplemented with cornstarch (CON), DCGF, DDG, or MCF. During Periods 3 and 4, an in situ study was conducted to compare the rate and extent of CP degradation of DCGF, DDG, and MCF. In Trial 1, there were no differences (P > .10) in initial weights or DM intake. Average daily gain and feed efficiency (G/F) were improved (P < .01) for heifers fed DCGF or DDG vs heifers fed MCF. In Trial 2, no differences (P > . 10) in digestibilities of any nutrients or in ruminal VFA concentrations were observed for steers fed coproducts. The CON supplementation decreased (P < .05) total dietary fiber (TDF) digestibility, improved (P < .10) digestibilities of DM and OM, increased (P < .05) total VFA concentrations and concentrations of propionate and valerate, and decreased (P < .05) concentrations of butyrate, isobutyrate, and isovalerate when compared with the coproducts. Dry corn gluten feed increased (P < .05) and DDG tended (P < .10) to increase percentages of the immediately soluble fraction of CP, and both had increased (P < .05) rates (Kd) and greater (P < .05) extent of ruminal CP degradation than MCF. These data suggest that DCGF and DDG may be utilized in limit-fed high-energy diets without sacrificing performance. Feeding of MCF resulted in poorer performance of heifers, suggesting a limited feeding value that results from high ADIN content and slow in situ protein digestion.

Performance and carcass traits of early-weaned steers receiving either a pasture growing period or a finishing diet at weaning.

A 2-yr study was conducted to evaluate 1) steers fed ad libitum high concentrate after weaning (CONC), or 2) steers grown on pasture for 82 d, followed by high-concentrate finishing (PAST), on the performance and carcass traits of 74 early-weaned (117 d of age) steers. Potential breed differences were evaluated using crossbred steers of three types: 1) 3/4 Angus x 1/4 Simmental (BRI), 2) 3/4 Simmental x 1/4 Angus (CON), and 3) 1/2 Wagyu x 1/4 Angus x 1/4 Simmental (WAG). Steers were randomly assigned within breed to the two treatments. There was no interactions (P > .10), so the data were pooled over years. The CONC steers had an ADG that was .17 kg/d higher (P = .0001), intake 1.09 kg/d lower (P = .0001), and gain:feed ratio .013 unit better (.190 vs .177, P = .008) than PAST steers overall. Growing treatment did not affect total concentrate consumed (P = .97). The BRI steers required 31 d less than did CON steers (P = .008), and 23 d less than WAG steers (P = .05) when fed to a constant fat end point (1.1 cm). The BRI steers exhibited an ADG .16 kg/d higher (P = .0003), tended (P = .07) to have an ADG intake .49 kg/d higher, and exhibited gain:feed .01 unit better (.189 vs 180) than WAG steers. When compared with CON steers, BRI steers consumed 310 kg less total concentrate (P = .0003). No differences (P > .38) were observed between growing treatments for carcass characteristics or sensory attributes except that CONC steers tended (P = .11) to improve percentage of steers grading Average Choice or higher by 47% over PAST steers. The WAG steers had a 76-unit higher marbling score (1,000 = Small00, 1,100 = Modest00) (P = .006) than BRI steers, resulting in 19% more (P = .09) steers grading > or = Choice and 82% more (P = .03) grading > or = Average Choice. Liver (P = .15) and rumen (P = .01) weights as a percentage of hot carcass weight were reduced for CONC steers. The CONC steers had higher gain, lower intake, better efficiency, reduced liver and rumen weights, and consumed the same amount of total concentrate when compared with PAST steers. The BRI steers had less finishing days and lower daily intake compared with CON steers. The WAG steers had more days finishing, lower gain, lower intake, more undesirable efficiencies, consumed the same amount of total concentrate, and improved quality grades compared with BRI steers.

Effect of prostaglandin F2 alpha treatment before norgestomet and estradiol valerate treatment on regression, formation, and function of corpora lutea in beef heifers.

Two experiments were conducted to determine if corpus luteum regression, formation, and function were associated with the decreased calving rate observed in beef females administered PGF2 alpha 5 days before Syncro-Mate B (SMB) treatment. Experiment 1 included 31 beef heifers 11 to 13 months old and experiment 2 included 31 beef heifers 19 to 21 months old. Heifers were randomly assigned to 1 of 2 groups (control and PGF2 alpha 5 days before SMB treatment). Heifers were bled 10 days before PGF2 alpha treatment, immediately before PGF2 alpha and SMB treatments, at the time of implant removal, and twice weekly after implant removal. Heifers in experiment 2 were observed twice daily for estrus for 5 days after PGF2 alpha treatment and for 3 days after norgestomet implant removal. Based on the blood samples collected before SMB treatment, 15 heifers in experiment 1 and every heifer in experiment 2 were with estrous cycles. All heifers in experiment 1 had progesterone concentrations < 0.5 ng/ml 2 days after implant removal. However, progesterone concentrations during the luteal phase in control heifers with estrous cycles were higher (P < 0.05) than in PGF2 alpha treated heifers with estrous cycles and in heifers previously without estrous cycles. In experiment 2, based on the occurrence of estrus and progesterone concentrations, heifers were also classified as metestrus or diestrus at the time of SMB treatment. The data were analyzed as a 2 x 2 factorial with treatment (control or PGF2 alpha) and stage of the cycle (metestrus and diestrus) as main effects. More metestrus heifers (40%) had progesterone concentrations > 1.0 ng/ml 2 days after implant removal than diestrus heifers (0%). In addition, progesterone concentrations during the luteal phase in metestrus heifers were lower (P < 0.05) than in diestrus heifers. PGF2 alpha treatment had no effect (P > 0.25) on the number of heifers with > 1.0 ng/ml progesterone 2 days after implant removal and progesterone concentrations during the luteal phase. There was no treatment by stage of the estrous cycle interactions. In summary, the administration of PGF2 alpha 5 days before SMB decreased the calving rate by causing more heifers to be metestrus at SMB treatment. Fewer metestrus heifers (than diestrus heifers) were synchronized (with < 1.0 ng/ml of progesterone 2 days after implant removal) to SMB treatment and those synchronized had lower progesterone concentrations during the luteal phase.

Growth, reproductive performance, mammary development, and milk production of beef heifers as influenced by prepubertal dietary energy and administration of bovine somatotropin.

Three trials with 156 crossbred heifers were used to determine the effects of dietary energy and bovine somatotropin administration on subsequent heifer productivity. In Trial 1, heifer calves were weaned from their dams (n = 28; 113 +/- 13 d of age) and assigned to a 2 x 2 factorial arrangement of moderate (MDE) or high dietary energy (HDE) and injections of vehicle (VEH) or 250 mg of bovine somatotropin (bST) every 14 d. Heifer calves in Trial 2 (n = 28; 123 +/- 20 d of age) and Trial 3 (n = 100; 134 +/- 22 d of age) nursed their dams while grazing pasture and received no creep feed (MDE) or ad libitum access to creep feed (HDE) and received VEH or bST as in Trial 1. Treatments were administered for 112 d and heifers within trial were managed alike after that time. There were no dietary treatment x bST treatment interactions for any of the variables analyzed (P > .05). Dietary energy did not affect daily gain in Trial 1; however, heifers receiving HDE in Trials 2 and 3 had greater weight, hip height growth, and fat thickness (P < .01) by the end of the treatment period. Treatment with bST increased gain in Trials 1 and 2 (P < .01) but did not affect growth in Trial 3. There were trends in all trials for HDE to reduce age at puberty (P < .15), but there were no consistent effects of bST on reproductive measures. Mammary gland composition and milk production were unaffected by treatment in Trial 1. In Trial 2, HDE decreased subsequent milk production, calf weaning weight, and mammary dry fat free tissue and DNA (P < .05). Treatment with bST in Trial 3 tended (P = .08) to result in greater milk production and increased calf weaning weights (P < .05). We conclude that bST treatment may enhance growth with no effect on reproduction. Treatment with bST did not overcome deleterious effects of HDE on milk production but may play an important role in mammogenesis.

Effects of prenatal androgenization, melengestrol acetate, and Synovex-H on feedlot performance, carcass, and sensory traits of once-calved heifers.

Three studies were designed using a 2 x 2 factorial arrangement of treatments within each experiment to evaluate the effects of various management techniques on growth and carcass traits of once-calved heifers. In Exp. 1, 33 yearling (16 control [C] and 17 prenatally androgenized [PA]) and 39 once-calved (20 C and 19 PA) nonpregnant heifers were used to evaluate the effects of age and PA. Once-calved heifers were approximately 31 kg heavier (P < .03) on-test, initially consumed 11% more (P < .01) DM, and gained 11% faster (P < .08), but had similar (P = .44) gain to feed ratios (.138 vs. .131) as yearlings. Growth performance was not affected by PA. The yearling and once-calved heifers were then slaughtered at approximately 707 and 1,080 d of age, respectively. Despite maturity differences (P < .01), marbling scores (P = .26) and percentage of choice carcasses (P = .27) were similar. However, on the basis of newly accepted grading changes, percentage of once-calved heifer carcasses grading choice decreased from 57.3 to 34.4%. Organoleptic properties did not differ. Experiments 2 and 3 were then conducted to evaluate effects of commercially available products (melengestrol acetate [MGA] and Synovex-H) on feedlot characteristics of heifers following weaning of their first calf. In Exp. 2, 48 once-calved Simmental-based heifers were fed during the summer to a constant compositional fat thickness of .8 cm. Experiment 3 was conducted in the late fall and early winter, during which 52 moderately sized heifers were fed for 116 d postweaning and slaughtered. Performance of heifers in Exp. 2 was not affected by MGA. However, heifers fed MGA in Exp. 3 gained 9% faster (P < .05) than controls. In Exp. 2, Synovex-H tended to improve ADG (P < .09) and feed efficiency (P < .07), but did not affect performance in Exp. 3. Most carcass traits were not affected by either treatment. Nonpregnant, once-calved heifers seem to have a large capacity for efficient weight gain as compared with yearling heifers. However, hormonal compounds, such as testosterone propionate provided pre- or postnatally (Synovex-H), and MGA do not appear to provide the consistent, positive responses often seen with younger, more typical feedlot heifers.

Risk factors for perinatal and postnatal mortality in lambs.

Factors associated with preweaning mortality in lambs were identified by developing risk profiles with logistic regressions for perinatal and postnatal mortality. Compared with heavy lambs, lambs of low birth weight had almost twice the risk of perinatal mortality (odds ratio [OR] = 1.9) and lambs of average weight had a slightly lower risk (OR = 0.7). Two of four lambing location categories affected perinatal mortality, with lambs born at unmonitored areas at greatest risk (OR = 2.7). Multiple births increased the risk of perinatal mortality (OR = 1.5), especially among Targhee lambs (OR = 4.0). Breed variations in perinatal mortality were significant in Suffolk lambs (OR = 1.9) and Booroola Rambouillet lambs (OR = 2.1). Lambs born weak had an increased risk of postnatal mortality while strong lambs had a decreased risk (OR = 3.7 and 0.6, respectively) if the dam had an adequate milk supply. Poor milk supply increased the risk of postnatal mortality for lambs of average vigour (OR = 3.3), but did not change the risk for weak or strong lambs. Male lambs castrated at 30 days of age were at less risk of postnatal mortality (OR = 0.3) than females. There were slight increases in the risk of postnatal mortality for intact males (OR = 1.3), low birth weight lambs (OR = 1.6), and lambs born in sheds (OR = 1.3). Suffolk lambs (OR = 1.8) and Targhee lambs (OR = 1.6) had a higher risk of postweaning mortality.

Effects of prenatal androgenization and postnatal steroid treatment on growth hormone, insulin-like growth factor I and II, insulin, thyroxine, and triidothyronine concentrations in beef heifers.

A 2 x 3 factorial arrangement of treatments was used to elucidate the mechanism(s) by which prenatal androgenization improves postnatal rate and efficiency of growth and composition of gain in beef heifers. Fifteen control (C) and 15 prenatally androgenized (PA) Angus x Simmental heifers (prenatal treatment, Pretrt) received no (N), estrogen (E), or estrogen and testosterone (ET) implants postnatally (postnatal treatment, Posttrt) to evaluate whether the postpubertal growth response after prenatal androgenization could be induced in prepubertal heifers. Blood was collected from the heifers at 6 +/- 1, 9 +/- 1, and 12 +/- 1 mo of age and analyzed from serum concentrations of growth hormone (GH), IGF-I, IGF-II, insulin, thyroxine (T4), and triiodothyronine (T3). Season of the year had a greater effect on hormone concentrations than either Pretrt or Posttrt, and there were no Pretrt x Posttrt interactions. Prenatal treatment, PA, had no effect on GH; however, Posttrt E and ET increased (P < .001) GH concentrations. Prenatal treatment, PA, increased (P < .05) IGF-I concentrations, and there was a nonsignificant increase (P = .11) in IGF-I concentrations with Posttrt E and ET. Concentrations of IGF-II were unaffected by Pretrt PA; however, they were lower (P < .01) in the Posttrt E and ET groups. Insulin, T4, T3, BW, and ADG were not affected by Pretrt and Posttrt. Concentrations of GH and IGF-I were increased in heifers that received Pretrt PA and(or) Posttrt E and ET in a manner to support improved growth performance; however, BW and ADG were similar. In prepubertal beef heifers, factors in addition to increased GH and IGF-I seem to be necessary for improved growth performance.

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: wool production and fleece quality.

The objective of this study was to compare weight and quality of fleeces of different F1 ewe types produced from breeds with a broad range of fleece types. Weights of 629 fleeces produced during 1988 through 1991 from F1 ewes that were daughters of Suffolk and Targhee dams and Finnsheep, Combo-6, Booroola Merino, St. Croix, and Barbados sires were recorded. Staple length was measured on the mid-side of each ewe present in 1991. Fleeces shorn in 1991 were sent to a wool marketing organization, and staple length, wool grade, and clean fleece yield were subjectively estimated (n = 220). Mid-side fleece samples were collected from no more than two randomly selected ewes from each subclass (breed of dam-breed of sire-age of ewe) in 1991 (n = 78) and sent to a wool laboratory where fiber diameter, yield, and percentage of colored, med, and kemp fibers were objectively determined. Ewes from Targhee dams produced fleeces with greater weight, greater fiber length, smaller fiber diameter, lower yield, and fewer colored fibers than ewes from Suffolk dams (all differences significant, P < .01). Booroola Merino-sired ewes produced heavier (P < .01) fleeces than did Finnsheep- and Combo-6-sired ewes (4.13 and 3.09 kg, respectively), and in turn, Finnsheep- and Combo-6-sired ewes produced heavier (P < .01) fleeces than did ewes sired by hair breed rams (3.09 and 1.70 kg, respectively). Among hair breed-sired ewes, St. Croixsired ewes produced heavier (P < .01) fleeces than did Barbados-sired ewes (1.88 and 1.52 kg, respectively). Fleeces produced by Booroola Merino-sired ewes had smaller (P < .01) fiber diameter than all sire breed groups except Combo-6-sired ewes, and fleeces produced by St. Croix-sired ewes had greater (P < .01) fiber diameter than all other sire breed groups. Lab scoured yield was greater (P < .01) for fleeces from ewes from hair breed than for fleeces from ewes from wool breed sires (74.2 vs 66.1%). Proportions of undesirable fibers (med, kemp, and colored) were 20 to 600 times greater (P < .01) in fleeces of ewes from hair breed sires than in fleeces of ewes from wool breed sires. In general, F1 ewes from Booroola Merino sires produced the heaviest, highest quality fleeces, and ewes from the hair breed sires of St. Croix and Barbados produced the lightest, lowest quality fleeces. Ewes from Finnsheep and Combo-6 sires produced fleeces that were more similar to the fleeces of ewes from Booroola Merino sires than to the fleeces of ewes from the hair breed sires.

Parturition and periparturient reproductive and metabolic hormone concentrations in prenatally androgenized beef heifers.

Primiparous Angus x Simmental heifers (n = 43) in a single-calf heifer (SCH) system (i.e., heifers are bred, calved, and placed in drylot pens with their calves at side and fed to slaughter weights) were studied to evaluate the effects of prenatal androgenization on parturition and on periparturient reproductive and metabolic hormone concentrations. Seven prenatally androgenized (PA) and seven control (C) heifers were used for blood collection to characterize parturient and lactation endocrine profiles; all heifers were used for blood collection to characterize postpartum ovarian cyclicity. Serum concentrations of progesterone, estradiol, testosterone, 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and prolactin from 10 d before to 3 d after parturition were similar for PA and C heifers. Calf birth weights (34.7 +/- .9 kg) and calving ease scores (1.34 +/- .14) were similar between treatments. Postpartum ovarian cyclicity was similar; only 6 of 22 PA (27.3%) and 3 of 21 C (14.3%) heifers were cyclic by 70 d postpartum, based on weekly serum progesterone concentrations. Serum concentrations of insulin, triiodothyronine (T3), and prolactin at 35, 70, and 105 d of lactation were similar for PA and C heifers; thyroxine (T4) concentrations were similar at 35 and 70 d but greater (P < .01) at 105 d of lactation in PA heifers than in C heifers. Although mean serum concentrations of insulin, T3, and T4 were similar between treatments, prolactin concentrations were greater (P < .05) in C than in PA lactating heifers. We conclude that PA heifers are similar to C heifers with respect to parturition and to periparturient reproductive and metabolic hormone concentrations. Therefore, management requirements of PA primiparous beef heifers seem to be similar to those of C primiparous beef heifers, and PA heifers can be used successfully in a SCH system.

Effect of norgestomet treatment after insemination on the calving rate of postpartum suckled beef cows.

Two experiments were conducted on postpartum suckled beef cows synchronized with Syncro-Mate B and artificially inseminated approximately 48 h after implant removal. In Exp. 1, cows (> or = 42 d postpartum at the timed AI) were randomly assigned to treated (n = 101) and control (n = 85) groups on d 12 after the timed AI. Treated cows received norgestomet/silicone implants that were left in situ for 9 d. Norgestomet treatment had no effect (P > .25) on the calving rates from the initial timed AI or from the return estrus. Nonpregnant norgestomet-treated cows returned to estrus in a more (P < .05) synchronized manner than the nonpregnant control cows. In Exp. 2, early postpartum cows (< 42 d postpartum at the first AI; n = 30) were included and all 118 cows (88 cows were > or = 42 d postpartum) received norgestomet/silicone implants as in Exp. 1. Of the 30 early postpartum cows, eight (19 to 41 d postpartum at the time of the first AI; mean = 29.3 d) calved to the first AI and nine calved to the second synchronized estrus. The calving dates at the next calving season for these 17 cows (57% of the cows in this group) was advanced an average of 46 d (319-d calving interval). The calving rates for the two timed insemination periods were similar (P > .25) for early and later (> or = 42 d postpartum) postpartum cows. Treatment with norgestomet implants on d 12 through 21 had no detrimental effects on established or subsequent pregnancy, synchronized the return estrus of nonpregnant cows, and was efficacious in establishing pregnancy early postpartum.

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: lamb production of F1 adult ewes.

Two- and three-year-old F1 crossbred ewes produced from Suffolk and Targhee dams and sires of the prolific wool breeds of Finnsheep, Combo-6, and Booroola Merino and the hair breeds of St. Croix and Barbados were pasture-mated to Dorset rams over a 4-yr period at the Dixon Springs Agricultural Center in Southern Illinois. Booroola Merino sires were homozygous for the FecB allele for high number of ovulations. The effects of age of ewe, sex of lamb (where appropriate), breed of dam, and breed of sire on condition score, breeding weight, ovulation rate, breeding to lambing interval, fertility, prolificacy, lamb survival, weaning weight, and ewe productivity were estimated. All traits were analyzed using mixed-model methodology. Crossbred ewes from Suffolk dams had a higher (P < .01) condition score, heavier (P < .01) breeding weight, higher (P < .01) ovulation rate, shorter (P < .01) breeding to lambing interval, greater (P < .01) prolificacy, heavier (P < .01) lambs at weaning, and greater (P < .05) ewe productivity than crossbred ewes from Targhee dams. Ewes from hair-breed sires had lighter (P < .01) breeding weight, lower (P < .05) ovulation rate, shorter (P < .05) breeding to lambing interval, higher (P < .05) fertility, higher (P < .05) lamb survival, lower (P < .10) lamb weaning weight, and higher (P < .05) ewe productivity than ewes sired by the prolific wool-breed rams. The breed of sire x breed of dam interaction was a significant source of variation for breeding weight, fertility, lamb survival, and ewe productivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of prenatal androgenization on performance, lactation, carcass, and sensory traits of heifers in a single-calf heifer system.

Twenty-four prenatally androgenized (PA) heifers, born to testosterone propionate-implanted cows, and 27 control (C) heifers, born to nonimplanted cows, were bred, calved, and placed in drylot pens, with calf at side, to assess the effects of PA on feedlot growth and lactational performance of heifers used in a single-calf heifer (SCH) system. Lactating heifers were fed an 85% concentrate diet, calves weaned at 117 d postpartum, and heifers slaughtered at a constant compositional end point of 1.1 cm of s.c. fat. Preweaning, PA heifers gained 22.5% faster (P < .01) and were 17.3% more efficient (P < .01) than controls. Prenatal androgenization of the heifer, however, did not affect calf growth performance. All calves gained more than 1.4 kg/d and had an average weaning weight of 159 kg at 117 d of age. Combining heifer-calf weights, PA and C pairs gained 2.88 and 2.53 kg/d, respectively. Correcting for DMI of calves, PA improved (P < .01) efficiency of beef production 10.8%. Four percent fat-corrected milk yield of PA and C heifers averaged 7.96 and 7.60 kg/d, respectively, and the percentage of milk protein and fat did not differ. Accounting for average BW, milk production, and DMI, PA and C lactating heifers should have gained 1.27 kg/d; however, gains were 137 and 127% of those predicted, respectively. Overall, pre- and postweaning, PA heifers required 10 fewer (P < .04) days on feed, gained 23% faster (P < .01), and were 16% more efficient (P < .02) than C heifers. At slaughter, PA and C heifers averaged 853 and 865 d of age, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

A fetus with an abnormal chromosome 7 and possible hydrolethalus syndrome.

A fetus with multiple abnormalities phenotypically similar to hydrolethalus syndrome, but also with broad thumbs, was found to have a de novo interstitial deletion of the terminal segment of the long arm of chromosome 7 and a small rearrangement within the proximal half of the p arm of the same chromosome. Terminal deletions of chromosome 7q fall into two broad phenotypic groups, neither of which resembles this fetus, but the digital anomalies are attributed to the 7p rearrangement disrupting the Greig syndrome gene.

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: lamb production of F1 ewe lambs.

The effects of year, sex of lamb, breed of dam, and breed of sire were estimated for age at puberty, breeding to lambing interval, breeding weight, ovulation rate, and ewe productivity (weight of lamb weaned per ewe exposed) and its component traits in F1 ewe lambs produced from Suffolk and Targhee ewes mated to rams of three wool breeds (Finnsheep, Combo-6, and Booroole Merino) and two hair breeds (St. Croix and Barbados). Ewe lambs were pasture-mated to Dorset rams when they were 8 to 10 mo of age. A total of 334 F1 ewe lambs, born in the late winters of 1986 through 1989, were exposed Year of birth was an important source of variation for age at puberty (P < .05), breding weight (P < .01), fertility (P < .05), prolificacy (P < .10), lamb survival (P < .10), lamb weaning weight (P < .05), and ewe productivity (P < .01). Ram lambs born to the F1 ewe lambs had lower (P < .10) survival rates to weaning but were heavier (P < .01) at weaning than contemporary ewe lambs. The F1 ewe lambs from Suffolk dams reached puberty earlier (P < .01), were heavier (P < .01) at breeding, and had higher (P < .01) ovulation rates and greater (P < .01) prolificacy than ewe lambs from Targhee dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: effect of breed of service sire on lamb production of Suffolk and Targhee ewes.

The effects of year, age of ewe, sex of lamb, breed of ewe, and breed of service ram on fertility, prolificacy, lamb survival, lamb weaning weight, and ewe productivity of Suffolk and Targhee ewes mated to Finnsheep, Combo-6, Booroola Merino, St. Croix, and Barbados rams were estimated. Matings were in four consecutive years using three rams per breed of service ram each year, with a total of 758 ewe-year observations. There was a significant effect of year on fertility, prolificacy, and ewe productivity. Two- and three-year-old ewes had lowest (P < .05) fertility rates, whereas 3-, 4-, and 5(+)-yr-old ewes had higher (P < .01) prolificacy and ewe productivity than 2-yr-old ewes. Ram lambs were .9 kg heavier (P < .01) at weaning than were ewe lambs. Suffolk ewes gave birth to .13 more (P < .05) lambs per ewe lambing, and their lambs were 1.4 kg heavier (P < .01) than lambs from Targhee ewes. Ewes mated to St. Croix and Barbados rams had higher (P < .10) fertility rates than ewes mated to Finnsheep rams. Lambs sired by Barbados, Finnsheep, and St. Croix rams had higher (P < .05) survival rates to weaning than lambs sired by Booroola Merino rams. The heaviest (P < .01) lambs at weaning were those sired by Finnsheep and Combo-6 rams. Ewes mated to hair-breed rams had greater (P < .05) performance for the fitness traits of fertility and lamb survival but lower (P < .01) lamb weaning weights than ewes mated to wool-breed rams.(ABSTRACT TRUNCATED AT 250 WORDS)