Effect of progesterone from induced corpus luteum on the characteristics of a dominant follicle in dromedary camels (Camelus dromedarius)

Possibility of early pregnancy detection in alpacas (Vicugna pacos) based on fecal steroid hormone concentrations

Early pregnancy detection in alpacas, whose breeding season is limited to the rainy season and has a long gestation period, is important for reproductive management. Conventional detection methods such as ultrasonography cannot be used to detect pregnancy before 30 days after mating. In this study, we examined the feasibility of using fecal steroid hormones as an early detection method in pregnant and non-pregnant alpacas. Fecal and blood samples were collected from pregnant and non-pregnant alpacas after mating. Progesterone (P4) and estradiol 17-β were extracted and quantified from blood and fecal samples. A positive correlation exists between the steroid hormones in serum and feces, indicating that serum steroid hormone concentrations can be estimated from fecal steroid hormones. Within 10 days after mating, both pregnant and non-pregnant alpacas had fecal P4 concentrations greater than 1.0 ng/mg dry matter (DM), but by 15 days after mating, fecal P4 concentrations decreased to the pre-mating concentration in non-pregnant alpacas. From 15 days after mating, non-pregnant alpacas had a low fecal P4 concentration (< 1 ng/mg DM), whereas a high fecal P4 concentration indicated the possibility of pregnancy, suggesting that this test is clinically beneficial as a supportive test for pregnancy detection.

Effect of advancing the breeding season on reproductive performance of dromedary camels

This study examines the effect of advancing the breeding season on the reproductive performance of dromedary camels under an intensive management system. Using a synchronization protocol, timed natural mating in female camels was carried out either in September (2 months ahead of the natural breeding season, n = 182) or December (peak breeding season, n = 115). The ovarian responses (size of the dominant follicle at the time of mating and ovulation), pregnancy rate, and pregnancy losses were evaluated using ultrasonography. Blood samples were collected after mating to assess progesterone concentrations by RIA. The libido of male camels (n = 13) was evaluated objectively. Results showed that the percentage of female camels with an optimal sized follicle (11-17 mm) for breeding at the time of mating was lower in September compared to December (81.9 vs 91.3%, P = 0.03). The libido of male camels was lower in September than in December (P <0.001). The ovulation rate (86.3 vs 93.9%, P = 0.04), size of the ovulated follicle (12.7 ± 0.1 vs 13.7 ± 0.2 mm, P <0.001), pregnancy rates on Day 14 (47.8 vs 72.2%, P <0.001) and Day 90 (38.5 vs 60.9%, P <0.001) after mating was lower in September compared to December. However, pregnancy loss was not affected between months (15.7 vs 19.5%, P = 0.3). Among pregnant camels, the progesterone concentrations on Days 6, 8, 10, 12 and 14 after mating were lower in September as compared to December (P <0.001). In non-pregnant camels, the progesterone concentrations on Days 6, 8 and 10 after mating were also lower in September as compared to December (P <0.001). In conclusion, advancing the breeding season by two months, significantly affects the reproductive performance of dromedary camels, yet, acceptable pregnancy rates can be achieved.

Effect of Silage Diet (Sweet Sorghum vs. Whole-Crop Corn) and Breed on Growth Performance, Carcass Traits, and Meat Quality of Lambs

Diet and breed directly affect ruminant carcass traits and meat quality. Therefore, this research aimed to evaluate the effect of silage diet and breed on growth performance, carcass traits, and meat quality of lambs. A total of 28, 3-4 months old female lambs consisting of 14 Dorper lambs (DP) and 14 Thin-tailed Han lambs (TH) were allocated in a 2 × 2 factorial design and offered two experimental diets (sweet sorghum silage: SS; whole-crop corn silage: WS) for 90 days. Lambs fed the WS diet had a higher growth performance (p < 0.01), intramuscular fat content (p < 0.05), and bright meat color (p < 0.01) than lambs fed the SS diet. The lambs fed the SS diet showed a higher polyunsaturated fatty acid (PUFA) content than the lambs fed the WS diet (p < 0.01); there was no significant difference in growth performance and carcass characteristics between DP and TH lambs (p > 0.05). The meat of the DP lambs showed lower values of initial pH, shear force, lightness (L*), redness (a*), and saturated fatty acid (SFA) content (p < 0.05). The lamb breed influenced fewer variables of growth performance and carcass characteristics compared to the diet. The lambs fed the SS diet had higher nutritional quality meat than lambs fed the WS diet.

Monitoring and controlling follicular activity in camelids

This paper reviews that state of our knowledge concerning follicular wave dynamics, monitoring and manipulation. All camelids have overlapping follicular waves in absence of ovulation which is induced by a seminal plasma factor (βNGF). The interval between follicular waves varies. The size of the ovulatory follicle varies between 11 and 25 mm in camels and between in 6 and 13 mm in South American Camelids. The interval between induction of ovulation and next ovulatory follicle is 15 ± 1 day for all camelids. Follicular activity is best monitored by transrectal ultrasonography. Progesterone therapy for 7-15 days seems to suppress follicular dominance but does not completely inhibit follicular recruitment. Combination of estradiol and progesterone seems to provide better control of follicular activity. Both methods have provided variable results in the synchronization of follicular waves. Combination of induction of ovulation with GnRH and luteolysis at predetermined times shows some promise in synchronization of follicular dominance. These synchronization protocols require further investigation in order to provide practical approaches for fixed-time breeding. Ovarian superstimulation with FSH and eCG alone or in combination is somewhat successful. The best results are obtained when treatment is initiated at the emergence of a new follicular wave after induction of ovulation or following treatment with progesterone for 7-14 days. However, response remains extremely variable particularly in terms of ovulation rate and number of recovered embryos. Sources of this variability need to be studied including the effects of season, nutrition, doses and frequency of administration of gonadotropin.

Effects of varying doses of β-nerve growth factor on the timing of ovulation, plasma progesterone concentration and corpus luteum size in female alpacas (Vicugna pacos)

Ovulation in camelids is induced by the seminal plasma protein ovulation-inducing factor (OIF), recently identified as β-nerve growth factor (β-NGF). The present study measured the total protein concentration in alpaca seminal plasma using a bicinchoninic acid (BCA) protein quantification assay and found it to be 22.2 ± 2.0 mg mL–1. To measure the effects of varying doses of β-NGF on the incidence and timing of ovulation, corpus luteum (CL) size and plasma progesterone concentration, 24 female alpacas were synchronised and treated with either: (1) 1 mL 0.9% saline (n = 5); (2) 4 µg buserelin (n = 5); (3) 1 mg β-NGF protein (n = 5); (4) 0.1 mg β-NGF (n = 5); or (5) 0.01 mg β-NGF (n = 4). Females were examined by transrectal ultrasonography at 1–2-h intervals between 20 and 45 h after treatment or until ovulation occurred, as well as on Day 8 to observe the size of the CL, at which time blood was collected to measure plasma progesterone concentrations. Ovulation was detected in 0/5, 5/5, 5/5, 3/5 and 0/4 female alpacas treated with saline, buserelin, 1, 0.1 and 0.01 mg β-NGF, respectively. Mean ovulation interval (P = 0.76), CL diameter (P = 0.96) and plasma progesterone concentration (P = 0.96) did not differ between treatments. Mean ovulation interval overall was 26.2 ± 1.0 h. In conclusion, buserelin and 1 mg β-NGF are equally effective at inducing ovulation in female alpacas, but at doses ≤0.1 mg, β-NGF is not a reliable method for the induction of ovulation.