resistance of st. croix lambs to haemonchus contortus in experimentally and naturally acquired infections.parasitological and immunological parameters of experimental or naturally acquired infections with haemonchus contortus were compared in st. croix and dorset lambs. in experimental infections, st. croix lambs developed significantly greater levels of resistance to h. contortus, following primary exposure, as compared with dorset lambs. this resistance was influenced both by age and by prior exposure to parasites. in grazing experiments on h. contortus-infected pasture, st. croix lambs shed signi ...19921502784
leptospira serology in small ruminants on st. croix, u.s. virgin islands.a serological survey of 16 serovars of leptospira interrogans, previously reported in tropical small ruminants, was undertaken to determine the serovars involved and the prevalence of these antibodies in sheep and goats on st. croix, u. s. virgin islands (usvi). seven of eight goat herds (108 animals) had at least two seropositive animals in each herd with an individual animal seroprevalence of 26%. the 53 sheep tested (one flock only) showed a 32% seroprevalence. antibodies against seven serova ...19921626866
experimental haemonchus contortus infection in three breeds of sheep.nine- to 10-month-old florida native, st. croix and dorset/rambouillet sheep were infected with haemonchus contortus. the primary infection was terminated by anthelmintic treatment 9 weeks later and animals were then reinfected with h. contortus. dorset/rambouillet sheep showed higher fecal egg counts and decreased packed cell volumes and plasma protein levels compared with the other two breeds during the primary infection. however, no breed differences were found in total worm burdens in either ...19902399644
serological observations on the epidemiology of bluetongue virus infections in the caribbean and florida.serological surveys of cattle, sheep and goats have confirmed that infection with bluetongue virus (btv) is common in florida, puerto rico and st. croix in the usa, in the caribbean countries of jamaica, st. kitts/nevis, antigua, st. lucia, barbados, grenada, trinidad and tobago, and the bahamas, and in the south american countries of guyana and suriname. in most countries, over 50% of ruminant livestock have antibody to btv as assessed by the bluetongue immunodiffusion (btid) test. a sentinel a ...19852989905
effect of quantity and route of administration of manganese monoxide on feed intake and serum manganese in ruminants.the experiment investigated effects of high quantities of manganese and route of administration (diet versus capsule-dosed) on feed intake and blood characteristics in sheep. twenty-four florida native or florida native by st. croix crossbred wethers, 47 kg initially, were assigned randomly to eight treatments including basal diet supplemented with 0, 3000, 6000, or 9000 ppm manganese as a reagent grade manganese monoxide or basal diet plus gelatin capsules containing the equivalent of 0, 3000, ...19853989083
urea ammoniation effects on the feeding value of guineagrass (panicum maximum) hay.laboratory, digestion, and growth studies evaluated urea as a source of ammoniation for quality improvement in guineagrass (panicum maximum) hay. in a laboratory trial, 5.0-kg portions of hay were reconstituted with water to yield final forage moisture concentrations or 25 of 40% and treated with urea at 0, 4, 6, or 8% of the forage dm, with or without urease addition. main effects of forage moisture or urease addition did not influence (p > .10) cp or ndf concentration or in vitro om disappeara ...19958617681
alveolar mastocytosis and eosinophilia in lambs with naturally acquired nematode infections of protostrongylus rufescens and haemonchus contortus.specific-pathogen-free dorset and st. croix lambs were placed on pasture contaminated with haemonchus contortus third stage larvae and slugs carrying third stage larvae of protostrongylus rufescens for an entire grazing season to evaluate breed differences in acquired resistance to these nematodes. lambs were evaluated for clinical signs, clinical pathology and histopathologic lesions associated with these infections. both breeds acquired natural infections with h. contortus and lungworm when al ...19958746699
peri-parturient rise in faecal strongyle egg counts of different genotypes of sheep in north sumatra, indonesia.faecal strongyle egg counts were monitored in peri-parturient ewes and dry ewes grazing in a rubber plantation in north sumatra, indonesia. a significant rise in faecal egg counts was observed during the post-parturient period. haemonchus contortus was the dominant species in the faecal cultures of the lactating ewes. the intensity of the peri-parturient rise was affected by the genotype of the sheep, which were the local sumatra and its f1 crosses with st. croix, barbados blackbelly and java fa ...19979066065
relative resistance of dorper crossbred ewes to gastrointestinal nematode infection compared with st. croix and katahdin ewes in the southeastern united states.a study was conducted to evaluate relative resistance of dorper crossbred (do), katahdin (ka), st. croix (sc), and hampshire (ha) ewes to natural and experimental gastro-intestinal (gi) nematode infection over a 20-month period. the objective of experiment 1 was to evaluate breeds for resistance to infection acquired naturally from mixed grass pastures. in year 1 (may-december 2000) de-worming of ewes occurred during wet, hot conditions in july and during late pregnancy in december. in year 2 (j ...200212423938
effect of supplemental nutrition around lambing on hair sheep ewes and lambs during the dry and wet seasons in the u.s. virgin islands.pregnant st. croix white and barbados blackbelly hair sheep ewes were used to evaluate the effect of supplemental nutrition around the time of lambing on ewe and lamb performance during the dry and wet seasons on st. croix. beginning 14 d before expected day of lambing (d 0) and for 21 d postpartum, one group of ewes was fed a pelleted supplement in addition to grazing guinea grass pasture (feed). other ewes in the flock grazed pasture only (control). this study was conducted during the dry seas ...200312661637
performance of hair sheep composite breeds: resistance of lambs to haemonchus contortus.this study was designed to evaluate breed differences in resistance to haemonchus contortus in lambs. a total of 181 ewe lambs representing crossbred dorsets (do) and dorpers (dp; out of 1/2-dorset, 1/4-rambouillet, 1/4-finnsheep ewes) and straight-bred katahdins (kt) were evaluated over 3 yr. an additional 144 do, dp, kt, and barbados blackbelly x st. croix (hh) wethers were evaluated over 2 yr. lambs were weaned at 60 to 90 d of age. after deworming at about 4 mo of age, ewe lambs received app ...200414974560
administration of 6-methoxybenzoxazolinone (mboa) does not augment ovulatory responses in st. croix white ewes superovulated with pmsg.the objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (mboa), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with pmsg on superovulatory responses in the cycling ewe. in experiment i, st. croix white ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hcg (750 iu) at 1 day after sponge removal (day 0). ewes were assigned to one of six treatments administered on day -1: cont ...200616154300
effects of aerosolized feedyard dust that contains natural endotoxins on adult determine the clinical, clinicopathologic, and histologic effects of aerosolized feedyard dust that contains natural endotoxins on adult sheep.200216206776
prevalence of anthelmintic resistance on sheep and goat farms in the southeastern united determine prevalence of anthelmintic resistance on sheep and goat farms in the southeastern united states.200819072608
effect of breed-type on performance and carcass traits of intensively managed hair sheep.the objectives of this study were to evaluate growth performance and carcass characteristics of intensively managed purebred and crossbred hair sheep, and determine the value of the dorper breed as a terminal sire on st.croix and st. croix-cross dams. animals used were dorper×st. croix (ds), and dorper×romanov×st. croix (dx), katahdin (ka), st. croix (sc), and 3/4 st. croix-1 4 romanov (sx) wether lambs. from birth to weaning, daily gains (adg) were greater (p<0.01) for ds and ka lambs than sc ...200322062382
investigation of the booroola (fecb) and inverdale (fecx(i)) mutations in 21 prolific breeds and strains of sheep sampled in 13 countries.twenty-one of the world's prolific sheep breeds and strains were tested for the presence of the fecb mutation of bmpr1b and the fecx(i) mutation of bmp15. the breeds studied were romanov (2 strains), finn (2 strains), east friesian, teeswater, blueface leicester, hu, han, d'man, chios, mountain sheep (three breeds), german whiteheaded mutton, lleyn, loa, galician, barbados blackbelly (pure and crossbred) and st. croix. the fecb mutation was found in two breeds, hu and han from china, but not in ...200615982834
identification of a novel ovine prp polymorphism and scrapie-resistant genotypes for st. croix white and a related composite breed.susceptibility to scrapie is primarily controlled by polymorphisms in the ovine prion protein gene (prnp). here, we report a novel ovine exon three prnp polymorphism (snp g346c; p116), its association with the ovine arq allele (p116a136r154q171), and two new genotypes (parq/arr; parq/arq) for the st. croix white (scw) breed and a related composite (cmp) breed developed for meat production. the (p116) polymorphism occurs between the n-terminal cleavage site and the hydrophobic region of the ovine ...200314970684
plasma lh, fsh, testosterone, and age at puberty in ram lambs actively immunized against an inhibin alpha-subunit immunization against inhibin has been shown to advance puberty and increase ovulation rate in ewe lambs; but in ram lambs, effects on puberty and sperm production are equivocal. the objective of the present study was to determine whether active immunization against an inhibin alpha-subunit peptide advances the onset of puberty in ram lambs. st. croix hair sheep ram lambs were assigned to inhibin-immunized (n = 7) and control (n = 8) treatment groups. lambs in the inhibin-immunized group w ...200312935870
resistance to ivermectin and the effect of topical eprinomectin on faecal egg counts in st croix white hair sheep. 200212241097
the effect of ram exposure on uterine involution and luteal function during the postpartum period of hair sheep ewes in the croix white hair sheep ewes lambing in july (n = 20) or november (n = 26) were used to evaluate the effect of ram exposure on uterine involution and postpartum luteal function. ewes were exposed to an epididymectomized ram (exposed) beginning on d 7 after lambing (d 0) or kept isolated from rams (control) through d 63. the width of each uterine horn was measured using transrectal ultrasonography at 3.5-d intervals beginning within 3 d after lambing. jugular blood samples were also collected ...19989928614
comparison of different regimens of electrical stimulation applied to nonmobilized and newly mobilized latissimus dorsi muscle.we investigated the possibility of preventing further aggravation of muscle ischemia and necrosis in newly mobilized, unconditioned latissimus dorsi muscle (ldm) by utilizing short increments of stimulation with intervening rest periods. adult st. croix sheep (n = 12) weighing 30 +/- 8 kg were used in this study. fatigue tests (30 min) using different stimulation regimens before and after ldm mobilization were performed on all animals; the length of time to return to baseline levels was also mea ...19979635273
evaluation of sexual behavior of hair sheep rams in a tropical environment.we evaluated sexual behavior of st. croix white (sc; n = 5) and barbados blackbelly hair (bb; n = 4) rams under two environmental conditions in the tropics. sexually naive rams were individually exposed for 15 min to a restrained, ovariectomized ewe, three times during a 3-wk period in june, in a pen with shade (shade; 33.1+/-.3 degrees c) or without shade (sun; 38.3+/-.3 degrees c). rectal temperature (rt) of rams was measured before and after each test. sexual behaviors were recorded by observ ...19989535328
a comparison of two methods of oestrous synchronisation of hair sheep in the tropics.two trials were conducted to evaluate the efficacy of oestrous synchronisation procedures in st. croix white, barbados blackbelly hair and florida native wool ewes. in trial 1 (conducted in june), 27 ewes were treated with controlled internal drug release (cidr) devices for 12 days (cidr1) and 29 untreated ewes served as controls (cont). the cidr devices were removed on the same day that intact rams equipped with marking harnesses were placed with the ewes. time to oestrus after ram introduction ...19979233509
hair sheep genetic resources and their contribution to diversified small ruminant production in the united states.two caribbean hair sheep breeds, the st. croix (sc) and barbados blackbelly (bb), are found in the united states, and the sc has led to the development of the katahdin (k), a synthetic breed of hair sheep. these breeds have mature ewe bw ranging from 32 to 54 kg (for bb and sc) and from 55 to 73 kg (k). hair sheep and hair sheep crosses have lower rectal temperatures and respiration rates than wool breeds and a lower dmi and water intake. there are indications of increased resistance to internal ...19979078477
resistance of indonesian thin tail sheep against fasciola gigantica and f. hepatica.high resistance of indonesian thin tail (itt) sheep against fasciola gigantica has been confirmed. naive itt sheep had only 17% of the number of mature parasites collected from control st. croix sheep. in contrast, the level of resistance of itt sheep against f. hepatica was the same as that of the low resistance merino breed after both primary and secondary infections. it is suggested that resistance of itt sheep against f. gigantica was manifested in two phases. the major phase appeared to be ...19979066053
acquired resistance of merino sheep against fasciola gigantica.merino sheep acquired resistance against fasciola gigantica, which is contrary to previous observations of infections with f. hepatica in that breed. the acquired resistance was manifest against young adult parasites. st. croix sheep had previously been shown to have more resistance than european sheep against f. hepatica after primary infection; however, in f. gigantica infections in the present study there was no difference between the resistance levels of the breeds. antigenic analysis of the ...19968897512
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, an ...19968778106
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 pro ...19938440650
serological evidence for the presence of brucella antibodies in sheep and goats on saint croix, u.s. virgin islands.a serological survey for brucella antibodies in sheep and goats was completed on saint croix, united states virgin islands (usvi). seroprevalence (at suspect or reactor titer levels) for b. melitensis antibodies was 11.3% for sheep and 2.5% for goats. this is the first report, of which we are aware, of b. melitensis antibodies in sheep or goats in the caribbean islands.19938134658
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 ...19957673054
ewe productivity and subsequent preweaning lamb performance in st. croix sheep bred at different times during the year.seasonality of breeding was evaluated in 165 purebred st. croix ewes over a period of 3 yr at a latitude of 35 degrees 6' n. ewes were divided into six groups for breeding starting in august of 1989 and a group was exposed to rams every 2 mo throughout the experiment. lambing percentage was lowest for spring breeding (p < .01), which resulted in lower numbers born and weaned per ewe exposed (p < .01) and lower litter birth and weaning weights per ewe exposed (p < .01). except as compared with la ...19957665356
heterologous resistance to fasciola hepatica conferred upon rats by passive transfer of serum from different breeds of sheep.two experiments compared the protection against oral challenge with 20 metacercariae of fasciola hepatica conferred on rats by intraperitoneal injection of serum from three breeds of sheep infected with f. hepatica (barbados blackbelly, st. croix, florida native). experiment 1 used serum from sheep 5-6 months of age following two infections of 250 metacercariae each, while experiment 2 utilized serum collected from the same sheep at 10-11 months of age following either a primary (first exposure) ...19863564329
effect of season and lactation on postpartum fertility of polypay, dorset, st. croix and targhee ewes.the objective of this study was to compare rebreeding activities of spring- vs fall-lambing polypay, dorset, st. croix and targhee ewes that either suckled their lambs for 40 d or had lambs weaned at birth. seasonal effects of male fertility were reduced by utilizing an excess number of fertile rams in the spring. plasma concentrations of progesterone were monitored to assess days to the first normal ovulation, days to conception and estrous vs anestrous activity. breed, season and lactation aff ...19892737977
effects of increasing crude protein level on nitrogen retention and intestinal supply of amino acids in lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw.the effects of increasing dietary cp level on n retention (exp. 1) and intestinal supply of amino acids (aa; exp. 2) were studied in lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw (ahpws). soybean meal (sbm) was substituted for corn to increase cp level in both experiments. in exp. 1, an incomplete design for the two-way elimination of error was used to allot 24 ram lambs (mean bw = 25 kg) within breed to six cp levels (6, 8, 10, 12, 14, and 16% of dm). neutral detergent ...19911667010
environmental factors and interval from the introduction of rams to estrus in postpartum saint croix sheep.the objective of this study was to determine whether season and total rainfall during the breeding season, sheep parity, and/or litter size affect the interval from the introduction of rams to estrus (ire) in hair saint croix sheep in northeastern mexico. an analysis was made of 874 services performed during 9 years, introducing the rams into the sheep flock after an isolation period of 60 days during the postpartum period. estrus was recorded twice daily during 35 days. year and season influenc ...201121225458
nitrogen retention by lambs fed oscillating dietary protein concentrations.nitrogen excreted by beef cattle can be retained in manure or lost by volatilization to the atmosphere or by runoff and percolation into surface or ground water. increasing the retention of dietary n should decrease environmental losses. to this end, the effects of oscillating concentrations of dietary cp on nutrient retention were determined using lambs fed a 90% concentrate diet. ten st. croix lambs (average bw = 27 kg) were used in two 5x5 latin square experiments. dietary treatments were as ...199910064047
evidence for a major gene determining the resistance of indonesian thin tail sheep against fasciola gigantica.the genetic basis of the high resistance of indonesian thin tail (itt) sheep against fasciola gigantica has been studied by measuring the resistance levels of itt sheep, st. croix sheep and their f2 and f3 crossbreds. all of the sheep were bred and reared in the same environment. approximately half of the f2 and f3 crossbreds were as resistant as the itt parental breed, one-quarter had the low resistance of the st. croix parental breed and the rest had an intermediate level of resistance. it is ...19979106952
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