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1.
Van Saun RJ 《Theriogenology》2008,70(3):508-514
The role of nutrition, especially the role of energy and protein status, on reproductive performance of production animals has been well documented. Comparatively, there is a true paucity of literature regarding nutritional mediation of reproductive performance in llamas and alpacas. Following seasonal patterns of feed availability in South America, adverse effects of nutritional deprivation on reproductive performance are well recognized, suggesting similar nutrition-reproduction interrelationships. Camelids, with their unique metabolism, may have some peculiar interrelationships between reproduction and protein and phosphorus nutrition. This presentation will review basic issues of energy and protein nutrition relative to reproductive performance in llamas and alpacas, based primarily on hypotheses and extrapolation from other species. Opportunities for research on this topic will be discussed, including preliminary data from current research.  相似文献   

2.
The effects of lactational status and reproductive status on patterns of follicle growth and regression were studied in 41 llamas. Animals were examined daily by transrectal ultrasonography for at least 30 days. The presence or absence of a corpus luteum and the diameter of the largest and second largest follicle in each ovary were recorded. Llamas were categorized as lactating (N = 16) or non-lactating (N = 25) and randomly allotted to the following groups (reproductive status): (1) unmated (anovulatory group, N = 14), (2) mated by a vasectomized male (ovulatory non-pregnant group, N = 12), (3) mated by an intact male and confirmed pregnant (pregnant group, N = 15). Ovulation occurred on the 2nd day after mating with a vasectomized or intact male in 26/27 (96%) ovulating llamas. Interval from mating to ovulation (2.0 +/- 0.1 days) and growth rate of the preovulatory follicle (0.8 +/- 0.2 mm/day) were not affected by lactational status or the type of mating (vasectomized vs intact male). Waves of follicular activity were indicated by periodic increases in the number of follicles detected and an associated emergence of a dominant follicle that grew to greater than or equal to 7 mm. There was an inverse relationship (r = -0.2; P = 0.002) between the number of follicles detected and the diameter of the largest follicle. Successive dominant follicles emerged at intervals of 19.8 +/- 0.7 days in unmated and vasectomy-mated llamas and 14.8 +/- 0.6 days in pregnant llamas (P = 0.001). Lactation was associated with an interwave interval that was shortened by 2.5 +/- 0.05 days averaged over all groups (P = 0.03). Maximum diameter of anovulatory dominant follicles ranged from 9 to 16 mm and was greater (P less than 0.05) for non-pregnant llamas (anovulatory group, 12.1 +/- 0.4 mm; ovulatory group, 11.5 +/- 0.2 mm) than for pregnant llamas (9.7 +/- 0.2 mm). In addition, lactation was associated with smaller (P less than 0.05) maximum diameter of dominant follicles averaged over all reproductive statuses (10.4 +/- 0.2 vs 11.7 +/- 0.3 mm). The corpus luteum was maintained for a mean of 10 days after ovulation in non-pregnant llamas and to the end of the observational period in pregnant llamas. The presence (ovulatory non-pregnant group) and persistence (pregnant group) of a corpus luteum was associated with a depression in the number of follicles detected and reduced prominence of dominant follicles (anovulatory group greater than ovulatory non-pregnant group greater than pregnant group).(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

3.
This study was designed to: 1) characterize the effect of ovulation-inducing factor (OIF) on pituitary LH secretion in ovariectomized (OVX) llamas; and 2) determine the effect of OIF on LH secretion in OVX llamas pretreated with estradiol-17β (E-17β) or estradiol benzoate (EB). In Experiment 1, intact and OVX llamas (n = 5 or 6 per group) were assigned to a two by two factorial design: 1) Intact llamas treated with 1 mL of phosphate buffered saline (PBS); 2) Intact llamas treated with 1 mg of purified OIF; 3) OVX llamas treated with 1 mL of PBS; or 4) OVX llamas treated with 1 mg of purified OIF. In Experiment 2, intact and OVX llamas (n = 5 or 6 per group) were randomly assigned to the following groups: 1) Intact llamas treated with 1 mg of purified OIF; 2) OVX llamas treated with 1.0 mL of PBS; 3) OVX llamas treated with 1.0 mg of purified OIF; 4) OVX llamas primed with E-17β, followed by 1.0 mg of purified OIF. Experiment 3 was similar as described for Experiment 2, except that priming was done with EB. In Experiment 1, animal category by treatment and animal category by treatment by time interactions tended (P = 0.08) to affect LH concentration. The effect of OIF on LH released was partly restored (P < 0.05), to the values observed for the intact OIF-treated females, when OVX llamas were primed with E-17β or BE (Experiments 2 and 3). We concluded that peripheral estradiol concentrations in llamas partially modulates the effect of OIF on pituitary LH secretion; however, other ovarian factor(s) could also participate in this modulatory action.  相似文献   

4.
The development of assisted reproductive technologies such as embryo transfer (ET), artificial insemination (AI) and in vitro fertilization (IVF) in South American camelids is considerably behind that of other livestock species. Poor success of the embryo transfer technique has been related to a lack of an effective superstimulatory treatment, low embryo recovery rate, and the recovery of hatched blastocysts that are not conducive to the cryopreservation process. Superstimulation has been attempted using equine chorionic gonadotropin (eCG) and follicle stimulating hormone (FSH) during the luteal, or the sexually receptive phase, sometimes given at follicular wave emergence. The rationale for inducing a luteal phase prior to or during superstimulation in camelids is not clearly understood, but it may simply reflect an empirical bias to conventional methods used in other ruminants. The number of ovulations or CL varies widely among studies, ranging from 2 to more than 15 per animal, with the number of transferable embryos ranging from 0 to 4 per animal. The control of follicular growth combined with superstimulatory protocols has resulted in a more consistent ovarian response and a greater number of follicles available for aspiration and oocyte collection. Recent studies in llamas have demonstrated that the use of ovulation inducing treatments or follicle ablation can synchronize follicular wave emergence allowing the initiation of gonadotropin treatment in the absence of a dominant follicle resulting in a more consistent ovulatory response. Few studies in alpacas have been reported, but it appears from recent field studies that the ovarian response is more variable and that there is a greater number of poor responders than in llamas. A review of superstimulation protocols that have been used in llamas and alpacas in the last 15 years is provided, including a discussion of the potential of protocols designed to initiate treatment at specific stages of follicular growth.  相似文献   

5.
In this study, the clinical progression of experimental infection of llamas ( Lama glama) with Parelaphostrongylus tenuis is described. The onset and characterization of neurologic deficits and changes in the hematology, serum biochemical, and cerebrospinal fluid (CSF) in affected llamas are compared before and after appearance of clinical signs. Sixteen apparently healthy, male llamas (median age; 12 months) were used. Five llamas were maintained as uninfected controls, and five, three, and three llamas were orally inoculated with five, ten, and 25 third-stage larvae (L3) of P. tenuis, respectively. The onset, degree, and characterization of neurologic deficits were recorded. Hematology, serum biochemistry, and CSF were analyzed before exposure (Pre) and after neurologic signs appeared (Post). Necropsy and worm recovery from the central nervous system (CNS) were also carried out to confirm infection. Exposure of llamas to 25 L3 of P. tenuis orally resulted in consistent infection and development of disease. Overall, ten of the 11 animals exposed to P. tenuis L3 developed varying degrees of neurologic signs between 45 and 82 days post-exposure (dpe). P. tenuis was recovered from the CNS of seven of the 11 exposed llamas. Neurologic signs progressed from ataxia to paresis, and eventually paralysis. In the hematologic and serum biochemical analyses, only eosinophil count was significantly elevated in the post-exposure samples in the infected groups. Protein was significantly elevated and Pandy test was positive in CSF of infected llamas. This study comprehensively describes the clinical progression of P. tenuis infection in llamas that will prove helpful in future studies to investigate the possibilities of developing antemortem diagnostic tests and new therapeutic programs.  相似文献   

6.
Pigment types in sheep, goats, and llamas   总被引:1,自引:0,他引:1  
Pigment types in various colors of fiber from sheep, goats, and llamas were assayed by a method using high performance liquid chromatography. In these three species the black/gray group is due to eumelanin, which is fully intense in all three species. Red phenotypes are due to pheomelanin and fade considerably with age in fiber from sheep and goats, but not in llamas. This phenomenon has implications on the genetic mechanisms used in generating white fiber. Brown phenotypes in sheep are due to eumelanin, in goats these phenotypes are equivocal, and they were not observed in llamas.  相似文献   

7.
Blood samples of llamas and alpacas were typed using haemolytic, electrophoretic and isoelectric focusing procedures to assay polymorphism at 13 loci. Blood group variation was assessed using six antibody specificities produced by allo- and heteroimmunizations. Two red cell factors (A and B) behave as autosomal, codominant alleles at a closed A locus. The other four factors (C, D, E and F) behave as autosomal, dominant traits. Biochemical variation was found for red cell enzymes catalase, phosphogluconate dehydrogenase, glucose phosphate isomerase and for plasma proteins transferrin and post-albumin. No variants were found for haemoglobin, phosphoglucomutase and albumin. Estimates of probability of exclusion were 0.883 for llamas and 0.681 for alpacas, which are adequate initial levels of efficacy for purposes of parentage verification. Preliminary estimate of Nei's genetic distance measure (D) suggests that llamas and alpacas are more likely related as subspecies than as separate species.  相似文献   

8.
Immunoblotting with antiserum specific to human Gc protein was used to identify Gc protein as the previously reported polymorphic plasma postalbumin (Po) of llamas and alpacas. This is the first report of Gc polymorphism in camelid species. One Gc variant appeared to be identical in llamas, alpacas, dromedaries and bactrian camels.  相似文献   

9.
Summary. Immunoblotting with antiserum specific to human Gc protein was used to identify Gc protein as the previously reported polymorphic plasma postalbumin (Po) of llamas and alpacas. This is the first report of Gc polymorphism in camelid species. One Gc variant appeared to be identical in llamas, alpacas, dromedaries and bactrian camels.  相似文献   

10.
Oocysts obtained from a guanaco and an alpaca with natural infections were identified as Eimeria macusaniensis and evaluated for host specificity and infectivity over time. In 3 separate trials conducted over 4 yr, 4 adult llamas were fed 500-5,000 sporulated oocysts obtained from guanaco feces stored under laboratory conditions for 41-84 mo. Infections with prepatent periods of 36-41 days and patent periods of 38-55 days developed in 4/4 llamas. In a fourth trial, 3 adult llamas and 1 alpaca were each fed 1,000 sporulated E. macusaniensis oocysts obtained from alpaca feces stored in the laboratory for 3 mo. Infections with prepatent periods of 33-34 days and patent periods of 14-20 days developed in 3/3 llamas. Infection in the alpaca had a prepatent period of 58 days and a patent period of 1 day. Clinical signs associated with infection, if any, were minimal and included increased fecal mucus and occasional soft feces. These results provide evidence that E. macusaniensis is a single species transmissible amongst alpacas, llamas, and guanacos and that oocysts of this species can remain infective for many years.  相似文献   

11.
Two pregnant llamas (Lama glama) infected with Toxoplasma gondii and their offspring were evaluated clinically and serologically. Llama 1 was inoculated orally with 1,000 infective occysts of the P89 strain of T. gondii at 82 days of gestation (DOG). Llama 2 became naturally infected with T. gondii between 26 and 119 DOG. Both llamas remained clinically normal and delivered healthy offspring. Sera collected from both llamas during pregnancy and from their offspring before and after colostral ingestion were evaluated for antibodies to T. gondii by the modified agglutination test (MAT), latex agglutination test (LAT), indirect hemagglutination test (IHAT), and the Sabin-Feldman dye test (DT). In llama 1, MAT antibody titers were < 1:20, 1:320, 1:1,280, 1:640, and 1:80 at 82, 97, 109, 132, and 152 DOG, respectively. The MAT titers in naturally infected llama 2 were < 1:32, 1:320-1:640, and 1:1,280 at 26, 119-200, and 346 DOG, respectively. In both llamas, antibody titers in the DT were of similar magnitude as the MAT, but titers in the LAT and IHAT were inconsistent. Antibodies to T. gondii were not detected in precolostral sera obtained from offspring of both llamas suggesting there was no fetal T. gondii infection.  相似文献   

12.
Ratto MH  Huanca W  Singh J  Adams GP 《Theriogenology》2006,66(5):1102-1106
We have recently reported the presence of an ovulation-inducing factor (OIF) in the seminal plasma of llamas and alpacas-species characterized as induced ovulators. The study was designed to test the hypothesis that the seminal plasma of bulls will induce ovulation in llamas, and to compare the ovulation-inducing effect of seminal plasma of conspecific versus hetero-specific males. The seminal plasma of alpacas, a closely related induced ovulator (Lama pacos), and cattle, a distantly related ruminant species (Bos taurus) considered to be spontaneous ovulators, were compared with that of the llama (Lama glama). Ovulation and maximum corpus luteum diameter were compared by ultrasonography among female llamas (n=19 per group) treated intramuscularly with 2 mL of phosphate buffered saline (PBS, negative control) and those treated with 2 mL of seminal plasma of bulls, alpacas, or llamas (conspecific control). The diameter of the preovulatory follicle did not differ among groups at the time of treatment. Bull seminal plasma induced ovulations in 26% (5/19) of llamas compared to 0% (0/19) in PBS group (P<0.001). The proportion of females that ovulated was lower (P<0.01) in bull seminal plasma group compared to the groups treated with alpaca or llama seminal plasma (100%). A corpus luteum was detected on Day 8 (Day 0=treatment) in all llamas in which ovulation was detected earlier (Day 2) by ultrasonography. The diameter of the CL did not differ among groups. Results document the presence of an ovulation-inducing factor in the seminal plasma of B. taurus. The interspecies effects of seminal plasma on ovulation and luteal development provide rationale for the hypothesis that OIF is conserved among both spontaneous and induced ovulating species.  相似文献   

13.
Morphology and location of the attached cumulus-oocyte complex (COC) were studied in slaughter-house ovaries in horses (49 follicles, 9 to 44 mm), cattle (68 follicles, 6 to 18 mm), and llamas (38 follicles, 3 to 14 mm). The expected point of ovulation was marked, using the ovulation fossa in mares and the center of the projecting follicular surface in cattle and llamas. A follicle was dissected from an ovary, and tissue was removed from the follicle until the COC became visible by transillumination. However, most llama follicles protruded prominently from the ovarian surface so that dissection was not required to locate the COC. The COC was more readily recognized from the external follicular surface in mares and llamas than in cattle, primarily because of a dark oocyte. Compact COC's projected into the antrum with a smooth dome-shape in horses. The COC's in cattle were also dome-shaped but were more irregular and a few contained prominent processes. The mean diameter of the isolated follicle was calculated from 3 planes, except that in llamas the follicles were spherical so that the 3 dimensions were identical. The angle between a straight line connecting the expected ovulation site and the opposite pole and a straight line from the ovulation site to the COC was defined as the COC-location angle. This angle was chosen because it is unaltered by size of a sphere (45 degrees for a COC at the equator). The mean (+/-SEM) COC-location angle differed (P < 0.01) among horses (39.9 +/- 3.3), cattle (50.0 +/- 2.5), and llamas (64.8 +/- 2.1). In mares, the locations of the COC's did not differ from equality between follicular hemispheres, but in cattle and llamas the COC's were located with greater frequency (P < 0.05) in the hemisphere containing the expected ovulation site (cattle, 65%; llamas, 91%).  相似文献   

14.
Infectious causes of reproductive loss in camelids   总被引:2,自引:0,他引:2  
Reproductive losses in camelids are due to infertility, pregnancy loss, udder diseases and neonatal mortality caused by a variety of infectious diseases. Uterine infection and abortion represent the major complaint in camelid veterinary practice. The major infectious organisms in endometritis and metritis are E. coli and Streptococcus equi subspecies zooepidemicus. Abortion rates due to infectious diseases vary from 10% to more than 70% in some areas. Leptospirosis, toxoplasmosis and chlamydiosis have been diagnosed as the major causes of abortion in llamas and alpacas. In camels, brucellosis and trypanosomiasis represent the major causes of infectious abortion in the Middle East and Africa. Mastitis is rare in South American camelids. The prevalence of subclinical udder infection in camels can reach very high proportions in dairy camels. Udder infections are primarily due to Streptococcus agalactiae and Staphylococcus aureus. Neonatal mortality is primarily due to diarrhea following failure of passive transfer and exposure to E. coli, rotavirus, coronavirus, Coccidia and Salmonella. This paper reviews the etio-pathogenesis of these causes of reproductive losses, as well as the major risk factors and strategies to prevent their occurrence.  相似文献   

15.
Intraspecific and interspecific embryo transfer in domestic South American camelids is developing into a well-established technique. Reports reveal many benefits of using reproductive biotechnologies to allow rapid propagation of alpacas and llamas of high genetic merit (e.g., high fiber quality, preserve color variation). The objective of this review is to provide up-to-date information about embryo transfer in domestic South American camelids. Specific information is provided on criteria for male selection, donor and recipient synchronization, the practice of single- vs. super-ovulation protocols, embryo recovery and transfer techniques, advances in cryopreservation of embryos, results of intra- and inter-specific transfer, and the future of the embryo transfer in domestic South American camelids.  相似文献   

16.
The secretory patterns of progesterone in relation to concentrations of 15-ketodihydro-PGF(2alpha) (PGFM) during the period of luteolysis or of maternal recognition of pregnancy were determined in the blood of llamas mated either with an intact or a vasectomized male. The ability of flunixin meglumine (FM) to postpone luteolysis in non-pregnant llamas was investigated by injecting the drug intravenously every 6 h at a dose of 2.2 mg/kg from days 6 to 12 post-copulation into a group of non-pregnant llamas. A pulsatile pattern of prostaglandin release was recorded during luteolysis in non-pregnant llamas, giving further support to the hypothesis that PGF(2alpha) is the luteolytic agent in llamas. The mean number of peaks per animal rose from 0.3 on day 7 to 3.8 on day 10 and then declined to 1.1 on day 12 with corresponding mean peak amplitude changing from 465 to 1234 and 566 pmol l(-1), respectively. In pregnant llamas, prostaglandin pulsatile release also occurred. The mean number of peaks per animal rose from 0.4 on day 7 to 0.8 on day 10 and then declined to 0.2 on day 11 and 0.6 on day 12, with corresponding mean peak amplitude changing from 494 to 676, 388 and 547 pmol l(-1), respectively. The transient decrease and subsequent recovery in progesterone concentrations was observed to occur in connection with prostaglandin release during early pregnancy. Oestradiol-17beta plasma peak concentrations attained after luteolysis were significantly higher than those recorded in early pregnant animals (around 30 pmol l(-1) and ll pmol l(-1)). Concentrations of PGFM decreased rapidly after the first administration of FM and remained low throughout the first 2 days of treatment. Thereafter, pulsatile release of prostaglandins started, and luteolysis proceeded; but a delay of 1-1.5 days in the progesterone decline was observed. Thus, it might be suggested that a higher dose and/or a more intensive injection schedule is required in llamas than in other ruminants to prevent luteolysis.  相似文献   

17.
To compare the prevalence of Eimeria macusaniensis among midwestern llamas (Lama glama), alpacas (Lama pacos), and guanacos (Lama guanicoe), feces were obtained from Lama spp. in 10 states between October 1989 and February 1996. Feces were examined by centrifugal flotation in sugar solution (specific gravity--1.28-1.30), and oocysts were quantified by a modified McMaster method. Data were compared by host species and age classifications. Typical oocysts occurred in samples from 28% of 76 herds and 10.4% of 443 animals including 12% of 301 llamas, 7% of 115 alpacas, and 7.4% of 27 guanacos. Prevalence was significantly greater (P = 0.009) in animals < 1 yr of age in comparison to older animals for llams (22.1 v.s. 8.5%) and for all Lama spp. combined (17.1 vs. 8.4%). Fecal oocyst abundance was significantly greater (P = 0.001) in llamas < 1 yr of age in comparison to older llamas (30 vs. 16 oocysts per g of feces). Fecal oocyst intensities did not differ significantly. Prevalence in both age groups of midwestern llamas was greater than previously reported for llamas in the western United States. Prevalence in midwestern alpacas < 1 yr of age was lower than reported for alpacas of similar age in South America, but oocyst intensities were similar. These results indicate that infection with E. macusaniensis is more common in Lama spp. in North America than previously recognized.  相似文献   

18.
The aim of the study was to investigate whether a moderately elevated ambient temperature (29 degrees C, 4 weeks, 24hperday) has an effect on the spermatogenesis in male llamas (Lama glama) and to monitor the recrudescence of spermatogenesis. Thirteen llamas were used. Semen parameters were monitored in four of the llamas and six animals were castrated at different times after the heat treatment. An additional three llamas were used as control animals and were castrated without any treatment. Spermatogenesis was found to be severely impaired due to the high environmental temperature. Sperm concentration declined from 97.5 million to 10 million spermatozoa/ml. Sperm motility declined from 63.1% to 15.0% and the percentage of morphologically abnormal sperm cells increased from 26.3% up to 50.5%. The changes in sperm parameters corresponded to the histological analysis of the testes. We found an increase in destroyed tubules, where no stage of the spermatogenic cycle could be established from 1.8% up to 38.2%, and a reduction of the spermatogonial proliferation rate (Ki-67 histochemistry) represented by tubules with proliferating spermatogonia from 79.5% to 45.7% directly after the heat treatment. Apoptosis (TUNEL assay) showed no significant changes during the experiment. The recrudescence of spermatogenesis within 6 weeks after the heat treatment was found to be due to an increase of mitotic proliferation of spermatogonia and not due to a decrease in the apoptotic rate. Our data indicate that in llamas the thermoregulatory ability is not sufficient enough to prevent heat caused damage to the testis at longer acting ambient temperature of 29 degrees C.  相似文献   

19.
The response of the pituitary gland and ovary to repeated copulatory periods and/or gonadotropin-releasing hormone (GnRH, i.v. 1000 micrograms) administration was determined in llamas and alpacas. Eighty adult females (41 llamas and 39 alpacas with ovulatory follicles) were divided into three general groups for each species as follows: copulation (one or two copulations at either 6- or 24-h intervals) GnRH treatment (one or two treatments at either 6- or 24-h intervals), and combined treatment (copulation followed by GnRH treatment, or GnRH followed by copulation at either 6- or 24-h intervals). An additional control (nontreated) group was composed of 4 llamas and 4 alpacas. The first copulation or treatment with GnRH provoked LH release sufficient to cause ovulation in most of the females (alpacas, 89%; llamas, 92%); urinary pregnanediol glucuronide values, used to verify ovulation, were significantly elevated 48 h after copulation and/or GnRH treatment. A second stimulus, copulation or GnRH, provoked no LH response with concentrations similar to those in nontreated controls and in females not ovulating. Llamas and alpacas thus were refractory to a second copulatory or GnRH stimulus with regard to LH release for up to 24 h following an initial ovulatory release of LH.  相似文献   

20.

Background  

Llamas (Lama glama) are induced ovulators and the process of ovulation depends on dominant follicular size. In addition, a close relationship between behavioural estrus and ovulation is not registered in llamas. Therefore, the exogenous control of follicular development with hormones aims to predict the optimal time to mate. Oestradiol-17β (E2) and its esters are currently used in domestic species, including camelids, in synchronization treatments. But, in llamas, there is no reports regarding the appropriate dosages to be used and most protocols have been designed by extrapolation from those recommended for other ruminants. The aim of the present study was to characterize plasma E2 concentrations in intact female llamas following a single intramuscular (i.m.) injection of two oestradiol esters: oestradiol benzoate (EB) and oestradiol cypionate (ECP).  相似文献   

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