Cria alpaca body weight and perinatal survival in relation to age of the dam.

The present study with alpacas determined effect of dam's age on body weight and survival of cria during the first week of life. Pregnant dams (n=424) and their crias were used in the study. Cria body weight (kg) was determined at time of placenta expulsion. Placenta weight and larger width were measured immediately after expulsion. Crias were monitored for the first week and a necropsy was performed if death occurred. Data were analyzed using analysis of variance. The body weight of crias at birth, the weight, and the largest width of placenta increased with age of the dam (P<0.05), reaching a peak at 9 years and then declined progressively. Placental efficiency also increased with the dam's age, and showed a bimodal shape, peaking at 6- and 11-year-old dams (P<0.05). Altogether, 398 crias survived and 26 died; of those 6 died of starvation, 5 of hypothermia, 4 were stillborn and the rest from other miscellaneous causes. More crias died from 2-year-old dams than from dams of any other age (P<0.05). In addition, dead crias had lesser body weights (6.4kg) than those of crias that survived (7.8kg, P<0.05). The weight and width of the placenta was similar for live and dead crias.

Ejaculatory process and related semen characteristics.

South American camelids are dribble ejaculators, and urethral contractions occur throughout copulation, which may last 25 min. The urethral contractions and their association with semen characteristics during copulation were determined in llamas and alpacas. A transrectal probe was held in the rectum of the male while copulating an artificial vagina, which was accessed underneath the dummy through a hole. The semen-collecting tube was changed every 5 min. Semen characteristics, color, volume, consistency, motility, concentration, and percentage of live sperm were determined at 5-min intervals. Urethral contractions were evenly distributed during copulation: 40 in alpacas and 63 in llamas (p < .05), with a general range of 11 to 132. Semen color was milky in 63%, and translucent in 36.5% for alpacas; and creamy (9.9%), milky (47%), and translucent (42%) for llamas. The mean volume of ejaculate was 0.3, 0.4, 0.6, 0.7, 0.6, 0.8, 0.3, and 3.0 mL for 5, 10, 15, 20, 25, and 30 min, respectively. Semen consistency was variable: viscous (65%) and semiviscous (34%) in alpacas; and viscous (57%) and semiviscous (42%) in llamas. Spermatic motility varied between 60 and 80% for the llama, and 40 and 80% for the alpaca. Spermatic concentration varied between 60 and 188 x 10(3)/mm3 in llamas, and 30 and 170 x 10(3)/mm3 in alpacas. Percentage of live sperm varied the least: 81 to 90% in llamas and 65 to 90% in alpacas. The ejaculate of llamas and alpacas is not fractionated, urethral contractions are evenly distributed, during copulation, and semen characteristics are present throughout the copulatory period.

Cortisol concentrations in the perinatal and weaning periods of alpacas.

Cortisol concentrations were determined during the perinatal and weaning periods in alpacas. Fifty males and 50 females were chosen at random (25 at each period) for blood collection on day of parturition, 3 and 5 days after birth. For the weaning period, blood samples were collected 2 days before, on the day of weaning (0), and at days 3 and 5 after weaning. Cortisol was determined using an ELISA protocol validated for the alpaca. There was no difference (P>0.05) in cortisol concentrations in both periods, perinatal and weaning between male and female crias. Cortisol was elevated at day of parturition (125.8 ng/ml) and then decreased to 27.2 ng/ml at 3 days after birth (P<0.05). Conversely, cortisol was 32.5 ng/ml 2 days before weaning and then increased at day 3 to 64.7 ng/ml (P<0.05), but then decreased to 29.4 ng/ml at day 5 after weaning. Cortisol is elevated in new-born alpacas and then decreases at the third and fifth after birth. Concentrations of cortisol are also increased after weaning and then decreased 5 days after weaning.

Growth of the conceptus in alpacas.

OBJECTIVE: To determine growth of the alpaca conceptus during early gestation, using ultrasonography. ANIMALS: 40 pregnant alpacas (20 multiparous, 20 nulliparous). PROCEDURE: Transrectal ultrasonography with a 5-MHz probe was performed 3 times weekly from days 7 through 45 after copulation (day of copulation = day 0). Blood samples were collected for progesterone assay on days of ultrasonography. RESULTS: Forty embryonic vesicles and embryos were identified and measured. Embryonic vesicles were first detected on day 12 after copulation and appeared spherical. Cumulative percentage of embryonic vesicles detected was 50, 82.5, and 100% on days 12, 14, and 16, respectively. Embryos were first detected by day 22 and heartbeats by day 24. Similarly, cumulative percentage of embryos detected was 17.5, 82.5 and 100% for 22, 24, and 26 days after copulation, respectively. Embryonic vesicles occupied both uterine horns beginning on day 19. A positive correlation existed between length and width of embryonic vesicles. Size of embryonic vesicles and embryos and progesterone concentrations did not differ between multiparous and nulliparous females. Five sets of twins were detected from days 21 through 33 after copulation, but the conceptus identified in the right uterine horn became nondetectable between days 28 and 33. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography was useful in detecting the earliest appearance of alpaca embryonic vesicles and determining the changes in growth from days 12 through 45 after copulation. Embryos were first detected by day 22. Transrectal ultrasonography was not harmful to animals and did not provoke embryonic death in this study.

Reproductive aspects and storage of semen in camelidae.

The characteristics of male and female reproductive tracts and reproductive physiology in camelids are described. An account is given on methods of collection, characteristics and storage of semen, and fertility after artificial insemination (AI) with fresh, liquid-stored and frozen-thawed lamoid and camel semen.

Degelification of alpaca semen and the effect of dilution rates on artificial insemination outcome.

Degelification of highly viscous alpaca semen was attempted using two enzymes: trypsin and collagenase. Dilution effect on artificial insemination was determined in alpacas. Semen from 4 male alpacas was collected, degelified, diluted, and inseminated into 80 female alpacas. Degelification was achieved adding trypsin and collagenase enzymes to fresh semen samples. Semen was diluted with egg-yolk glucose citrate to give concentrations of 4, 8, and 12 million spermatozoa/mL. Females were induced to ovulate with human chorionic gonadotropin and then inseminated deep into the uterine horns. Analysis of variance was used to determine differences in the effect of trypsin and collagenase on sperm acrosome and on motility and live spermatozoa. The chi-square test was used to determine differences in pregnancy of artificially inseminated females. Semen was degelified with different concentrations of trypsin and collagenase. There were differences (p < .05) in the pregnancy rate of female alpacas inseminated with 4 million (53.3%), 8 million (66.7%), and 12 million sperm/mL (61.5%). Alpaca semen may be degelified using trypsin and/or collagenase. It seems that 8 million sperm/mL is adequate for artificial insemination in alpacas.

Effect of repeated collection on semen characteristics of alpacas.

Semen characteristics of alpacas were studied after repeated collections. Twelve adult males were divided into three groups of four each for semen collection once, twice, or three times every other day. The duration of copulation; volume of ejaculate; pH; motility; sperm concentration (number of sperm/milliliter semen); total number of sperm per ejaculate; and percentages of live, normal, and abnormal spermatozoa were analyzed by regression analysis. Semen color and consistency were analyzed by the chi-square test. Between the first, second, and third ejaculations, there were differences (p < 0.05) in sperm concentration; percentages of normal spermatozoa and abnormal spermatozoa; sperm with abnormal heads and abnormal tails; and consistency (viscous, viscous, and semi-viscous). There were no differences (p > 0.05) in ejaculated volume, percentage of live spermatozoa, pH, percentage of cytoplasmic droplets, and duration of copulation. Some males from which semen was collected on the three-mating schedule ejaculated only seminal plasma during the second and third copulation starting on Day 10 of the study. There were differences between males (p < 0.05) for most of the characteristics studied. In sum, frequency of mating affected some semen characteristics that may be important determinants of the fertility of male alpacas.

Endocrine changes during early pregnancy in the alpaca.

Plasma concentrations of progesterone, 15-keto-13, 14-dihydroprostaglandin F2 alpha and oestradiol-17 beta were monitored during early pregnancy in five alpacas. Heparinized blood samples were obtained every 15 min during a 4 h period (0800 to 1200 h) from day 8 to day 13 postmating. Mean plasma concentrations of oestradiol-17 beta decreased close to the detection limit of the assay from day 8 until days 10-11, whereupon they increased again until day 13. A rapid decline in progesterone concentrations occurred after day 8 postmating. All progesterone values registered after day 10 were significantly lower than those registered on day 8. After day 9 postmating, prostaglandin metabolite peaks were detected in all animals, indicating a temporal relationship between the progesterone decline and PGF2 alpha pulsatile release. The number of peaks detected during the 4-h period, monitored on each of the 5 days (day 9 to day 13), ranged from two to four in different animals. The analysis of the prostaglandin secretory pattern in pregnant alpacas suggests that PGF2 alpha peaks might occur at a frequency similar to that observed in nonpregnant animals but with a lower magnitude.

Fertility of the male alpaca: effect of daily consecutive breeding.

The fertility of the male alpaca under different frequencies of daily consecutive matings was evaluated. Fifteen adult male Huacaya alpacas were divided randomly into three groups of five each to breed lactating female alpacas. The schedule of daily matings was two, four and six consecutive breeding per group and for nine consecutive days. Ovulation was determined by progesterone at seven days after breeding. Pregnancy was determined by ultrasonography at 15 and 30 days after breeding. Two hundred and eighty females were bred with some males not fulfilling their schedule of breeding. There were differences (P < 0.05) in the fertility rate of males breeding two and four times daily (76%) in contrast to 59% for males breeding six times. There were also differences (P < 0.05) in the fertility of individual males. Length of copulation was affected (P < 0.05) by schedule of matings, day of breeding and male. Ovulation was independent of length of copulation. Overall, it seems the fertility of the male alpaca is affected significantly when consecutive matings are over four times a day and for nine consecutive days.

Collection of semen and artificial insemination of alpacas.

Semen collection and artificial insemination have not yet been fully developed in the alpaca. Thus, we collected semen from 7 males using a modified artificial vagina placed inside a dummy. Forty adult female alpacas, previously induced to ovulate with hCG, were artificially inseminated with fresh undiluted semen by laparoscopy or by cervix. The Chisquare test was used to determine differences in the fertility rate of the 2 insemination methods. The mean duration of copulation, semen volume, sperm concentration and the percentages of live spermatozoa and normal spermatozoa were 21.6 min, 1.9 ml. 147,500/mm(3), 69.6% and 75.9%, respectively. There were 6.7% abnormal heads, 12.3% abnormal tails and 3.8% cytoplasmic droplets. The consistency of semen was viscous and formed a coagulum. The pH was 7.2, and the semen was milky white in color. The duration of copulation was comparable to natural copulation, and semen characteristics reflected those of the natural ejaculate. The percentage of pregnancy was 68%, with no differences due to method of semen deposition (laparoscopy, 67%; cervix, 73%).

Induction of parturition in alpacas and subsequent survival of neonates.

OBJECTIVE: To evaluate use of fluprostenol, dexamethasone, and oxytocin for induction of parturition in alpacas, and to determine viability of the newborn crias. DESIGN: Prospective, randomized, controlled trial. ANIMALS: 36 pregnant alpacas within 10 days of parturition. PROCEDURE: Animals were randomly assigned to treatment groups. Plasma progesterone and plasma and urine estrone sulfate concentrations were measured for 5 days after treatment. Clinical signs of the neonates were determined. RESULTS: Time between treatment and parturition was significantly shorter for animals that received fluprostenol than for animals in any other group. The highest dose of dexamethasone (0.5 mg) caused fetal death. None of the other treatments induced early parturition. Time between birth and first suckling, body weight, rectal temperature, pulse rate, and respiratory rate at birth and serum IgG concentration 24 hours after birth were not different between crias born after fluprostenol treatment and crias born to control alpacas. CLINICAL IMPLICATIONS: Fluprostenol was effective at inducing parturition in these alpacas, but dexamethasone and oxytocin were not. Crias born after fluprostenol treatment were similar to crias born to control alpacas.

Hormonal indicators of pregnancy in llamas and alpacas.

OBJECTIVE: To determine concentrations of estrone sulfate in serum, estrone sulfate in urine, relaxin in serum, and progesterone in serum in pregnant llamas and alpacas and to assess the potential of these hormones as pregnancy indicators. DESIGN: Prospective study. ANIMALS: 19 parous pregnant camelids (8 llamas and 11 alpacas). PROCEDURE: Estrone sulfate concentrations (in serum and in urine) and progesterone concentrations (in serum) were determined by enzyme immunoassay. Relaxin concentrations (in serum) were measured by radioimmunoassay. Serum and urine samples were collected daily for the first 30 days after breeding and, thereafter, once weekly until parturition. RESULTS: Estrone sulfate concentrations (in serum and in urine) peaked twice during pregnancy. The first took place 21 days after breeding and the second during the last month of pregnancy. Relaxin concentrations increased at 3 months of gestation to > 20 ng/mL, decreased at 5 months to 5 ng/mL, then increased from 8 months of pregnancy until parturition. Progesterone concentrations were detectable 4 days after breeding and were maintained > 2 ng/mL throughout pregnancy. CLINICAL IMPLICATIONS: The first increase in estrone sulfate concentration over basal values may indicate early interaction between mother and embryo, whereas the second increase may reflect fetal viability. Use of estrone sulfate concentration to diagnose pregnancy in llamas and alpacas is highly dependent on time of sampling. Relaxin concentration in serum is a superior indicator of pregnancy after the second month in the Ilama and alpaca because its existence is suggestive of interaction between mother and fetus, and concentrations are greater than basal values for a long period of pregnancy. Progesterone is not a direct product of the embryo or fetus and only indirectly confirms a diagnosis of pregnancy.

Resumption of ovarian follicular activity and uterine involution in the postpartum llama.

Resumption of ovarian follicle activity and uterine involution was studied in the post partum llama. Thirty-nine adult multiparous llamas were monitored by ultrasonography and analysis of urinary estrone sulfate for 30 d post partum at the La Raya Research Station in Peru. Uterine involution was measured in terms of reduction of length and diameter of both uterine horns. Correlation analysis was used to relate follicle size and concentration of estrone sulfate. Analysis of variance was used to determine rate of uterine involution relative to days post partum. The left ovary was palpated and scanned by Day 3 post partum in contrast to Day 1 post partum for the right ovary. Ovulatory size follicles, 7 mm, were present by Day 7.4 post partum (range 4 to 14 d). Follicle growth was detected as early as Day 4 post partum with follicle size being less during the first follicle wave (7.4 mm) compared to the second and third waves (9 to 10 mm). Concentrations of urinary estrone sulfate were positively related (P<0.05) to follicular size, but to a lesser degree during the first follicle wave (19.4 ng/mg Cr), than to the second wave (25.4 ng/mg Cr). Uterine involution, as measured by diameter, was different between the left (gravid) and right (nongravid) uterine horn (P<0.05) for the 17 d post partum, and was also different from that of control females for the 21 d post partum. Uterine involution was complete in 63% of females by Day 21 post partum.

The postpartum llama: fertility after parturition.

Fertility was evaluated at various times during the postpartum period in the llama. Fifty-six parous female llamas chosen at random were bred at 10, 20, and 30 days postpartum with six intact males. Half of the females copulated only once and the other half twice within an interval of 24 h. Ovarian activity was monitored by ultrasonography and analysis of urinary estrone sulfate and pregnanediol glucuronide (PdG). At the time of copulation, all females had developed ovulatory-size follicles. Ovulation was confirmed by the presence of a CL at 8 days after breeding and PdG concentrations > 1 ng/mg creatinine (Cr). Conception was defined as PdG concentrations > 1 ng/mg Cr at 15 days after breeding and the presence of a CL. Pregnancy was defined as the presence of a CL, PdG concentrations > 1 ng/mg Cr and an embryonic vesicle 20 days postbreeding. There were no significant differences in the proportion of females ovulating after breeding at different times postpartum; however, conception and pregnancy were significantly greater in females bred at Day 20 or 30. Ovarian follicle size was significantly larger at 30 days (9.1 mm) than at 10 and 20 days (7.9 and 8.8 mm, respectively) of breeding, with no difference in concentrations of estrone sulfate. The proportion of females conceiving as a result of breeding at 10 days postpartum (6 out of 10) was significantly less than for females bred at 20 (13 out of 15) or 30 days (16 out of 18).(ABSTRACT TRUNCATED AT 250 WORDS)

Reproductive physiology of the male camelid.

The physiology of reproduction with emphasis on endocrinology of llamas and alpacas is addressed. Information regarding male anatomy, puberty, testicular function, semen description, and sexual behavior is also included.

Reproductive endocrinology of llamas and alpacas.

The physiology of reproduction with emphasis in endocrinology of llamas and alpacas is addressed. Basic concepts of ovarian follicular dynamics, endocrine events associated with induction of ovulation, corpus luteum formation, pregnancy, parturition, postpartum interval, puberty, and sexual behavior on the female are reviewed. Pathologic conditions of the reproductive process are also reviewed.

Ovarian and endocrine patterns associated with reproductive abnormalities in llamas and alpacas.

Ovarian activity was characterized in llamas and alpacas with hypoplastic ovaries, cystic follicles, or ovulatory failure. Ovarian follicular activity was determined by transrectal ultrasonography and urinary estrone sulfate analysis; pituitary response was determined by measurement of plasma concentrations of luteinizing hormone. Llamas and alpacas with hypoplastic ovaries had follicles < or = 6 mm (minimal ovulatory size, 7 mm). Cystic follicles, defined as > 12 mm, were maintained for a mean of 9 days. Follicular activity in the ovary contralateral to the cystic follicle tended to be suppressed while the cystic follicle was present. Ovarian response to copulation in females with cystic follicles varied according to the stage of the cystic follicle. Animals with ovulatory failure did not release adequate luteinizing hormone after copulation, even though they had mature and normal follicles (8 to 12 mm). The cystic follicle syndrome appears to be temporary, whereas the syndromes involving hypoplastic ovaries and ovulatory failure may permanently affect fertility.

Pituitary response to repeated copulation and/or gonadotropin-releasing hormone administration in llamas and alpacas.

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.

In situ observation of the ovaries of llamas and alpacas by use of a laparoscopic technique.

A laparoscopic technique was used to observe in situ the ovaries of llamas and alpacas. Use of this technique results in minimal surgical stress and allows repetitive observation of various reproductive stages in the same animal. Ovarian follicular activity before and after breeding, time of ovulation, corpus luteum formation and regression, early embryo death, failure of ovulation, and the early events of pregnancy can be assessed quickly and safely. For 1,291 laparoscopies performed, postsurgical disturbance was not observed, and animals were released from the clinic 1 hour after laparoscopy.

Evaluation of intra-abdominal vasectomy in llamas and alpacas.

A method of intra-abdominal vasectomy (deferentectomy), using a laparoscopic technique in llamas and alpacas, was evaluated. Food was withheld from 14 animals for 24 hours before sedation and laparoscopy. The ductus deferens was located close to the bladder, and a 2- to 3-cm section of ductus deferens was resected with the aid of a pair of hook scissors. The procedure was completed in 5 to 8 minutes, and animals did not have any adverse effects. Forty-five days after vasectomy, animals were used for detecting sexually receptive females or inducing ovulation during reproductive physiologic studies. The procedure did not impair libido and had no effect on male sexual behavior for many years. The technique is simpler, safer, and faster than the traditional external approach.