- Aim: To evaluate two extenders and two cryoprotectant agents (CPA) for alpaca semen cryopreservation. Methods: Semen samples were obtained from four adult alpacas (Lamapacos) and frozen using extender I (TRIS, citrate, egg yolk and glucose) or extender II (skim milk, egg yolk and fructose), each containing either glycerol (G) or ethylene glycol (EG) as CPA. Consequently, four groups were formed: 1) extender I‐G; 2) extender I‐EG; 3) extender II‐G; and 4) extender II‐EG. Semen was diluted in a two‐step process: for cooling to 5 °C (extenders without CPA), and for freezing (extenders with CPA). Viability and acrosome integrity were assessed using trypan blue and Giemsa stains. Results: When compared, the motility after thawing was higher (P < 0.05) in groups II‐EG (20.0 %± 6.7 %) and II‐G (15.3 %± 4.1 %) than that in groups I‐G (4.0 %± 1.1 %) and I‐EG (1.0 %± 1.4 %). Viable spermatozoa with intact acrosomes in groups II‐EG (18.7 %± 2.9 %) and II‐G (12.7 %± 5.9 %) were higher than that in groups I‐G (5.7 %± 1.5 %) and I‐EG (4.0 %±1.0 %). Conclusion: The skim milk‐ and egg yolk‐based extenders containing ethylene glycol or glycerol to freeze alpaca semen seems to promote the survival of more sperm cells with intact acrosomes than the other extenders. more »
- Objective—To evaluate the effects of exogenous insulin on clearance of exogenous glucose in alpacas. Animals—7 adult castrated male alpacas. Procedure—Prior to each of 2 trials, food was withheld for 8 hours. Glucose (0.5 g/kg of body weight) was then administered by rapid IV infusion. During 1 of the trials, regular insulin (0.2 U/kg, IV) was also administered 15 minutes later. Blood was collected immediately before (0 minutes) and 15, 20, 25, 30, 45, 60, 90, 120, 180, and 240 minutes after glucose administration. Plasma concentrations of glucose and lactate were determined, and glucose fractional turnover rate and plasma half-life were calculated. Results—Insulin treatment caused a significant increase in fractional turnover rate of glucose and plasma lactate concentration. Plasma glucose concentrations were less in insulin-treated alpacas from 30 minutes after glucose administration (15 minutes after insulin administration) until the conclusion of each trial, compared with nontreated alpacas. In addition, plasma glucose concentration in insulin-treated alpacas returned to baseline values 1 hour sooner than in the nontreated group. Conclusion and Clinical Relevance—Glucose uptake in alpacas improves after insulin treatment, suggesting that administration of exogenous insulin will increase the therapeutic and decrease the pathologic effects of exogenous glucose administered to hypoglycemic alpacas. However, alpacas and other New World camelids should be monitored carefully during treatment with glucose or insulin, because these species appear to be partially insulin resistant. more »
- 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 more »
- Little is known about the inheritance and influence of the fleece color gene Melanocortin 1 Receptor (MC1R). Melanocortin 1 Receptor (MC1R) is a well-known gene responsible for red versus black fleece pigmentation and is hypothesized to be a candidate gene for variation in alpaca coloration patterns. Inheritance of red versus black pigmentation in the context of genetic mutation is well understood in many domesticated mammals. We characterized the MC1R gene in a population of multi-colored alpacas in order to better understand its effect on coat color in the alpaca. Our characterization of the alpaca MC1R gene revealed 11 mutations. Of these one is a 4 bp deletion, four are silent mutations and six are single nucleotide polymorphisms (SNPs) that alter the amino acid sequence (T28V, M87V, S126G, T128I, S196F, R301C). No mutation correlated completely with fleece color in alpacas at the MC1R locus. This may be due to the epistatic relationship of MC1R with other coat color genes especially agouti signaling protein (ASIP). more »
- Sources of variation in fibre diameter attributes of Australian alpacas and implications for fleece evaluation and animal selection were investigated using data collected in the years 1994–97, from 6 properties in southern Australia. Data were analysed using REML (multiple regression analysis) to determine the effect on mean fibre diameter (MFD) and coefficient of variation of MFD (CV(FD)) of age, origin (property), sex (entire male, female), breed (Huacaya, Suri), liveweight, fibre colour, individual, and interactions of these effects. The mean (n = 100) age (range) was 4.2 years (0.1–11.9), liveweight 72.0 kg (12.0–134 kg), MFD 29.1 μm (17.7–46.6 μm), CV(FD) 24.33% (15.0–36.7%). A number of variables affected MFD and CV(FD). MFD increased to 7.5 years of age, and correlations between MFD at 1.5 and 2 years of age with the MFD at older ages were much higher than correlations at younger ages. Fibre diameter 'blowout' (increase with age) was positively correlated with the actual MFD at ages 2 years and older. There were important effects of farm, and these effects differed with year and shearing age. Suris were coarser than Huacayas with the effect reducing with increased liveweight; there was no effect of sex. Fleeces of light shade were 1 μm finer than dark fleeces. CV(FD) declined rapidly between birth and 2 years of age, reaching a minimum at about 4 years of age and then increasing; however, CV(FD) measurements on young animals were very poor predictors of CV(FD) at older ages, and the response of CV(FD) to age differed with farm and year. Suris had a higher CV(FD) than Huacayas on most properties, and MFD, liveweight, and sex did not affect CV(FD). Fleeces of dark shade had higher CV(FD) than fleeces of light shade in 2 of the years. It is concluded that there are large opportunities to improve the MFD and CV(FD) of alpaca fibre through selection and breeding. The potential benefit is greatest from reducing the MFD and CV(FD) of fibre from older alpacas, through reducing the between-animal variation in MFD and CV(FD). Sampling alpacas at ages more »