Non-cyclic Animals Research Articles

The effectiveness of intravaginal progesterone insert in Ovsynch and resynchronization protocols in cyclic and non-cyclic Holstein heifers

In the present study, it was aimed to compare of resynchronization with used progesterone (P4) releasing intravaginal device (PRID), with modified ovulation synchronization in cyclic and non-cyclic Holstein heifers. Animals were randomly divided into two groups; Group I (GI, n=87) and Group II (GII, n=88). Fixed-time artificial insemination (FTAI) following modified Ovsynch protocol with PRID insertion, was performed to all animals. In GI, used PRID was reinserted to the same animals, 15 days after the first FTAI (day 25) for 12 days. Pregnancies were detected by ultrasound in all groups on day 37. For resynchronization, prostaglandin (PG) F2α was applied to non-pregnant animals on day 37. In GI, following 48 hours from PGF2α injection, the gonadotropin-releasing hormone was administrated, and after 18 hours the second FTAI was performed. No additional treatments were applied to the non-pregnant animals found in GII, and heifers were taken to the routine service program. In both groups, the second pregnancy diagnosis was performed 27 days after inseminations by transrectal ultrasonography. Pregnancy rates (PR) following the first and overall inseminations in cyclic and non-cyclic heifers (GI and GII) were detected as 66.4% and 52.3% (P>0.05); 76.3% and 59.1% (P>0.05), respectively. In conclusion, the usage of PRID in the Ovsynch and resynchronization protocol resulted in higher PRs of non-cyclic heifers than cyclic heifers. Moreover, this study reveals that the initial P4 levels of non-cyclic animals should be used as a determinant for pregnancy success in dairy heifers.

Effect of temperature - humidity index on the onset of post- partum ovarian activity and reproductive behavior in Bos indicus cows.

The effect of climatic factors on ovarian activity and reproductive behavior (RB) was evaluated in 46 Bos indicus cows kept under grazing conditions. Temperature-humidity index (THI) was used as an indicator of stress and divided in alert, damage and emergency levels. Fat thickness (FAT) was taken during the last trimester of gestation (LTG) to approximately 90d postpartum (PP). At 30d PP animals received a progesterone (P4)-releasing device (CIDR) which was withdrawn 9d later. Ovarian activity was assessed by blood progesterone on days 21, 24, 27, 30, 49, 51, and 54 PP. Animals were divided into three groups, higher, and moderate RB and non-behavior. Sixty percent presented a THI >74 increasing dramatically from June to September up to >78. During LTG, animals lost 27% of their body reserves contrasting to PP where an increase of 2.6% (P=0.002) was observed. The percentages of cyclic and non-cyclic animals were 57 and 43%, respectively (P> 0.05). Seventy-two percent displayed RB and 28% were non-behavior (P<0.05). A negative correlation (r = -0.307; P = 0.038) between THI and RB, and a positive correlation (r = 0.427; P = 0.003) between the onset of ovarian activity and RB were observed. Differences in THI during the LTG (P<0.01) were observed between cyclic and non-cyclic animals. Non-behavior cows in the LTG had a higher THI (P <0.05). High levels of THI have a negative effect on the resumption of ovarian activity and RB in Bos indicus especially if high THI occurs during the last trimester of gestation.

Antioxidant vitamins and lipid peroxidation status in noncyclic versus cyclic ewes subjected to ram effect, before mating

This study assessed the levels of plasma vitamins A, E, and C and the lipid peroxidation status of cyclic and noncyclic ewes during pre-breeding week after a period of poor nutrition. The study was conducted on 100 crossbred fat-tailed adult ewes with body condition scores of 2.5 to 3.5, grazing on medium-to-low quality forages during summer. During 3 weeks of flushing, the ewes were fed alfalfa hay (40 %) and wheat straw (60 %) ad libitum plus 300 g of barley grain/head/day in addition to the available pasture. The ewes had been isolated for 2 months during summer and, thereafter, were kept in close proximity of the rams for 1 week before ram release. Whole blood samples were collected 7 days (day −7) and a few hours before ram release (day 1). Plasma progesterone (P4, marker of ovulation) and antioxidant vitamins and hemolysate malondialdehyde (MDA, marker of lipid peroxidation) were measured. Plasma P4 was also measured in an additional sample taken 14 days after ram release. Twenty-eight percent of ewes were noncyclic in both pre-breeding samplings (P4 ≤ 1 ng/mL). On day −7, the noncyclic ewes had higher levels of MDA (P = 0.027), but the antioxidant vitamins were not different between cyclic and noncyclic ewes (P > 0.05). On day 1, all antioxidant vitamins declined significantly in cyclic ewes, whereas they remained almost constant (P > 0.05) in noncyclic animals. At this time, MDA concentration increased in the cyclic ewes (P = 0.014). At day 14, after ram introduction, the proportion of noncyclic ewes reduced to 13 %. Oxidative stress may postpone the ewe’s cyclicity at the beginning of the breeding period but may be alleviated after a while. This may cause delayed conception and extended lambing periods. Ovarian cyclicity is capable of reducing the plasma levels of antioxidant vitamins and increases the level of lipid peroxidation.

The effect of addition of equine chorionic gonadotropin to a progesterone-based estrous synchronization protocol in buffaloes ( Bubalus bubalis) under tropical conditions

Poor estrus expression and anestrus decrease the reproductive efficiency of buffaloes. The objective of this study was to determine whether the addition of equine chorionic gonadotropin (eCG) to an estrous synchronization protocol and timed insemination could improve ovulation and pregnancy rates of anestrous buffalo cows under tropical conditions. The study population comprised 65 lactating Murrah buffalo cows which were assigned to CIDR ( n = 33) or CIDR + eCG ( n = 32) treatment groups. Cows in the CIDR group were fitted for 8 d with a controlled intravaginal drug release (CIDR) device containing 1.38 g progesterone, received GnRH (10 μg i.m.) on D 0, PGF 2α (750 μg i.m.) on D 7, and GnRH (10 μg i.m.) on D 9; whereas cows in the CIDR + eCG group received the same treatment plus eCG (500 IU, i.m.) at the time of PGF 2α treatment. All cows were inseminated 16–20 h after the second GnRH treatment. Blood samples were obtained 10 d before the start of synchronization treatment (Day –10) and at the onset of treatment (Day 0). Cows with plasma progesterone concentrations <1 ng/mL recorded in both samples (Low–Low levels of P4) were classified as non-cyclic cows. Similarly, when either one or both of the sample pair contained concentrations of serum progesterone ≥1 ng/mL (High–High, Low–High, or High–Low levels of P4), the buffaloes were classified as cyclic cows. Ovulation rate, defined as the number of buffaloes with at least one corpus luteum 10 days after insemination, was significantly higher ( P = 0.018) in the CIDR + eCG (84.4%) cows than in the CIDR cows (57.6%). Pregnancy rate was numerically lower in CIDR (27.3%) than CIDR + eCG (40.6%) cows, though differences were not significant ( P = 0.25). Pregnancy rates for CIDR + eCG cows were similar to that of cows inseminated after natural estrus (40.9%; 29/71). In the non-cyclic animals, higher ovulation rates ( P = 0.026) were recorded for the CIDR + eCG (81%) than for the CIDR cows (47.4%). Our results indicate that the addition of eCG to a progesterone-based estrous synchronization regimen substantially improves the ovulation rate in non-cyclic buffaloes. When this treatment is followed by timed AI, pregnancy rates achieved in anestrous buffaloes, whether cyclic and non-cyclic, may approach the rates observed in cows inseminated at natural estrus.

Induction of ovulation and natural oestrous cycling in the Stripe-faced Dunnart, Sminthopsis macroura

Induced ovulation allows reproduction by otherwise infertile females, and is ideal for the captive breeding of endangered species where the population is aged or breeding is unsuccessful. A predictable time of ovulation after induction has not yet been achieved in polyovular marsupials. Ovulation was induced in Sminthopsis macroura using an initial injection of 20 IU equine serum gonadotrophin (eSG; Day 0), followed on Day 4 by either 20 IU eSG (n = 25) or 0.5 mg porcine luteinizing hormone (n = 26). I.p. hormone injection was given in the morning or early evening, and reproductive status was established prior to induction. Five non-cyclic animals began to cycle naturally following induction and one gave birth to a litter. The time of ovulation after the 1st injection (7.8 +/- 0.9 days) was significantly shorter (P = 0.000) and less variable than the previous study, mimicked the timing of natural cycling, and both natural and induced animals ovulated in the early morning. In vitro oocyte movement through the oviduct, observed for the first time in a marsupial, occurred in pulses. We estimated one group of oocytes could travel the length of the oviduct in 40 min, but it was probably around 4 h. The entire ovulation time (including multiple ovulations) was estimated at 7.5 h. This study has achieved a predictable timing of ovulation after stimulation, and induced noncyclic animals to cycle naturally and give birth, providing a modified methodology for use in captive breeding programs of endangered dasyurid marsupial species with low fecundity.

Conception rate after fixed time insemination following ovsynch protocol with and without progesterone supplementation in cyclic and non-cyclic Mediterranean Italian buffaloes ( Bubalus bubalis)

The aim of this study was to test the effect of progesterone supplementation to Ovsynch protocol in cyclic and non-cyclic Mediterranean Italian buffaloes on conception rate after fixed time artificial insemination. From 169 pluriparous buffaloes, 2 groups were identified and subjected to: (1) Ovsynch protocol (OV; n = 83) and (2) Ovsynch protocol with the supplementation of progesterone from days 0 to 7 (OV + PROG.; n = 86). All cows were inseminated 16–20 h after the second GnRH administration. Within each group, non-cyclic buffaloes were identified (OV = 21 and OV + PROG. = 20). Overall conception rate was significantly higher in cyclic compared to non-cyclic buffaloes: 43.7% versus 17.0%, respectively, P = 0.001. A significant effect of progesterone supplementation on conception rate was observed in non-cyclic buffaloes (30% versus 4.7%, P = 0.04) but not in cyclic buffaloes (51.5% versus 35.7%, P = 0.077). Collectively, the presence of a large follicle (≥10 mm) detected at the beginning of the Ovsynch protocol by ultrasound significantly affected conception rate (44% versus 8%, P = 0.01). The findings of the present study suggest that (i) progesterone supplementation to the Ovsynch protocol in buffaloes increases conception rate in non-cyclic animals, (ii) the presence of a large follicle at the beginning of the Ovsynch protocol is a determining factor for a successful synchronization of ovulation and high conception rates and (iii) ultrasound monitoring can improve the overall efficiency by selectively identifying more suitable cycling animals carrying a responsive follicle at the time of first GnRH administration.

Comparison of pregnancy rates with two estrus synchronization protocols in Italian Mediterranean Buffalo cows

The aim in this study was to compare two estrus synchronization protocols in buffaloes. Animals were divided into two groups: Group A ( n=111) received 100 μg GnRH on Day 0, 375 μg PGF 2α on Day 7 and 100 μg GnRH on Day 9 (Ovsynch); Group B ( n=117) received an intravaginal drug release device (PRID ®) containing 1.55 g progesterone and a capsule with 10 mg estradiol benzoate for 10 days and were treated with a luteolytic dose of PGF 2α and 1000 IU PMSG at the time of PRID ® withdrawal. Animals were inseminated twice 18 and 42 h after the second injection of GnRH (Group A) and 60 and 84 h after PGF 2α and PMSG injections (Group B). Progesterone (P 4) concentrations in milk samples collected 12 and 2 days before treatments were used to determine cyclic and non-cyclic buffaloes, and milk P 4 concentrations 10 days after Artificial insemination (AI) were used as an index of a functional corpus luteum. Cows were palpated per rectum at 40 and 90 days after AI to determine pregnancies. All previously non-cyclic animals in Group B had elevated P 4 (>120 pg/ml milk whey) on Day 10 after AI. Accordingly, a greater ( P<0.01) relative percentage of animals with elevated P 4 10 days after AI were observed in Group B (93.2%) than in Group A (81.1%). However, there was no difference in overall pregnancy rates between the two estrus synchronization protocols (Group A, 36.0%; Group B 28.2%). When only animals with elevated P 4 on Day 10 after AI were considered, pregnancy rate was higher ( P<0.05) for animals in Group A (44.4%) than Group B (30.3%). The findings indicated that treatment with PRID ® can induce ovulation in non-cyclic buffalo cows. However, synchronization of estrus with Ovsynch resulted in a higher pregnancy rate compared with synchronization with PRID ®, particularly in cyclic buffalo.

Induced ovulation, mating success and embryonic development in the stripe-faced dunnart, Sminthopsis macroura

Induced ovulation resulting in normal embryos is rare in marsupials. In this study natural and induced ovulations were compared in mature Sminthopsis macroura (n = 122). Comparison of maturation of preovulatory oocytes by ovarian histology and examination of oocytes removed from developing follicles in 12 ovaries of 23 animals receiving 0.058 iu equine serum gonadotrophin (eSG) g(-1) with ovaries of 12 animals undergoing natural cycles showed that oocyte maturation was significantly more irregular when it was induced (P < 0.001). Postovulatory stages were examined by estimating the number of eggs ovulated from ovarian histology, and by counting oviduct and uterine contents recovered after ovulation. S. macroura receiving 0.087 iu eSG g(-1) (n = 34), administered as one (n = 17) or two (n = 17) injections, were significantly (P < 0.05) more likely to ovulate (74%), mate (80%) and have conceptuses (66%) than were animals receiving 0.058 iu eSG g(-1) (12, 53 and 0%, respectively) (n = 17), and the values were similar to those in animals (n = 36) undergoing natural cycles (100, 81 and 56%, respectively). Induced ovulation using 0.087 iu eSG g(-1) yielded significantly (P < 0.05) more oocytes per ovary (20.8 +/- 8.5; combined data) than did ovulation in animals undergoing natural cycles (13.7 +/- 3.2) (ANOVA, t test). The responses of animals induced in different phases of the oestrous cycle with 0.087 iu eSG g(-1) were not significantly different (ANOVA) with respect to the number of corpora lutea per ovary, conceptuses per animal or days to ovulation after injection. However, the proportion of females that responded after receiving 0.058 iu eSG g(-1) in the luteal phase was significantly different from that in animals treated with the same dose in the intermediate phase (P < 0.01) and in non-cyclic females treated with 0.058 iu eSG g(-1) (P < 0.02). The main benefits of the treatment were that normal embryos resulted and that 70-78% of non-cyclic animals could be induced to ovulate.

Induced ovulation, mating success and embryonic development in the stripe-faced dunnart, Sminthopsis macroura.

Induced ovulation resulting in normal embryos is rare in marsupials. In this study natural and induced ovulations were compared in mature Sminthopsis macroura (n = 122). Comparison of maturation of preovulatory oocytes by ovarian histology and examination of oocytes removed from developing follicles in 12 ovaries of 23 animals receiving 0.058 iu equine serum gonadotrophin (eSG) g(-1) with ovaries of 12 animals undergoing natural cycles showed that oocyte maturation was significantly more irregular when it was induced (P < 0.001). Postovulatory stages were examined by estimating the number of eggs ovulated from ovarian histology, and by counting oviduct and uterine contents recovered after ovulation. S. macroura receiving 0.087 iu eSG g(-1) (n = 34), administered as one (n = 17) or two (n = 17) injections, were significantly (P < 0.05) more likely to ovulate (74%), mate (80%) and have conceptuses (66%) than were animals receiving 0.058 iu eSG g(-1) (12, 53 and 0%, respectively) (n = 17), and the values were similar to those in animals (n = 36) undergoing natural cycles (100, 81 and 56%, respectively). Induced ovulation using 0.087 iu eSG g(-1) yielded significantly (P < 0.05) more oocytes per ovary (20.8 +/- 8.5; combined data) than did ovulation in animals undergoing natural cycles (13.7 +/- 3.2) (ANOVA, t test). The responses of animals induced in different phases of the oestrous cycle with 0.087 iu eSG g(-1) were not significantly different (ANOVA) with respect to the number of corpora lutea per ovary, conceptuses per animal or days to ovulation after injection. However, the proportion of females that responded after receiving 0.058 iu eSG g(-1) in the luteal phase was significantly different from that in animals treated with the same dose in the intermediate phase (P < 0.01) and in non-cyclic females treated with 0.058 iu eSG g(-1) (P < 0.02). The main benefits of the treatment were that normal embryos resulted and that 70-78% of non-cyclic animals could be induced to ovulate.

Effect of ovarian phase and follicle quality on morphology and developmental capacity of the bovine cumulus-oocyte complex.

In order to study the effect of the follicular environment on the quality and developmental competence of cumulus-oocyte complexes (COC), COC were collected from nonatretic (NA), light atretic (LA), atretic (A), and heavily atretic (HA) follicles. Cumulus-oocyte complexes were also collected from early-luteal phase ovaries (EL), from late-luteal phase ovaries (LL), from follicular phase ovaries (F), and from ovaries from non-cyclic animals (NC). Each COC was assigned to one of three quality groups based on the appearance of the cumulus investment: 1) COC-A: compact and bright, 2) COC-B: less compact and dark, and 3) COC-C: strongly expanded cumulus with dark spots. There was a high correlation between follicle quality and the distribution of the COC over the three COC qualities. The COC-A were mainly but not exclusively derived from NA follicles, COC-B were mainly derived from all classes of atretic follicles, and COC-C nearly exclusively originated from HA follicles. The developmental capacity of COC-A and COC-B, which was measured by in vitro embryo production, was consistent over the follicle qualities, except for COC-B obtained from HA follicles. They showed lower development (10.6%, P < .05) compared with COC-B from the other follicle qualities (18.9, 18.7, and 19.8%, respectively, for COC-B from NA, A, and LA follicles). The COC-B from atretic follicles produced more blastocysts (19.8%) than COC-A (12.7%, P < .05). The overall percentage of produced embryos per follicle class seemed to increase with increasing signs of atresia, except if the COC were derived from HA follicles. This increased percentage of embryos was, however, not due to a better quality of COC, but to a higher percentage of COC-B coming from these follicles. The stage of the cycle had no effect on the distribution of the COC over the three COC qualities or on the developmental capacity of COC-A or COC-B, except for COC-A from EL ovaries, which produced more (P < .05) blastocysts than COC-A from the other luteal phases (12.5% vs approximately 8%). A follow-up study was performed trying to elucidate why COC-B possess a higher developmental potency than COC-A. The answer was sought in the oocyte maturation. At several time points during maturation, oocytes were evaluated for their nuclear stage. At all time points COC-B seemed to be a few hours ahead of COC-A, and after 24 h of maturation more COC-B had reached the metaphase-2 stage. This might mean that COC-A need a longer maturation period than COC-B.

Size Dimorphism in Microtine Populations: Characteristics of Growth and Selection against Large-Sized Individuals

Wild-caught immature Clethrionomys glareolus and Microtus agrestis , 1–2 months of age, from cyclic and noncyclic populations, were reared to maximum size under constant conditions in a laboratory. Offspring from random matings were exposed to the same conditions. Maximum weights of wild animals deviated from random distributions only in cyclic populations while laboratory-bom young of both cyclic and noncyclic animals demonstrated pronounced nonrandom distributions of weight. There were clear differences between years, with the smallest animals of both wild and laboratory-bom animals being derived from declining populations. Heavy maximum weights were related to winter weight, to a high rate of growth during the winter, and, in some cases, to autumn weight and a late attainment of maximum weight. A balanced di- or polymorphy in weights at weaning obviously is common to most populations of voles, but the large-sized individuals are selected against, except under favorable conditions such as phases of cyclic increase or laboratory breeding. Large-sized and fast-growing animals may be favored in mast years with winter reproduction or at winter reproduction in increase-phases of cyclic populations.

Induction of oestrus in Saanen goats at early breeding season by intravaginal progesterone sponges (MAP) or by prostaglandin F 2α injections. Effect on different age groups

Twenty-one maiden and 29 pluriparous milking Ankara Saanen goats received either two i.m. injections of PGF 2α (n=25) or intravaginal MAP sponges (n=25) early in November at the start of the breeding season. About twice as many pluriparous goats as maiden goats exhibited estrus after either treatment (87% vs. 47%). Breeding after this induced estrus caused pregnancies in 62% of the pluriparous goats, but only in 24% of the maiden animals. Maximal concentrations of progesterone were reached 11 days after the start of the MAP treatment. Progesterone declined to basal levels two to four days after sponge withdrawal. A significant slower progesterone increase also resulting in lower maximal concentrations could be observed in maiden goats. Luteolysis was evident in all animals within 24 h after PGF 2α injection. Nine goats (six maiden and three pluriparous) did not exhibit Heat after the second injection and showed only a slow increase of progesterone. It seems that noncyclic animals are less sensitive to MAP treatment than to the first PGF 2α injection. Goats at the beginning of the breeding season may react after a premature interruption of corpus luteum function (after second PGF 2α injection) with delayed or inadequate follicular function.

Effect of cycle stage on immunoglobulin concentrations in reproductive tract secretions of the mare

The effect of cycle stage on immunoglobulin and albumin levels in serum, follicular fluid, oviductal, uterine and vaginal secretions was measured. There was no variation in serum immunoglobulin levels during the oestrous cycle, although IgM levels were elevated in cyclic mares compared to non-cyclic (immature and anoestrous) animals. Similarly, there was no cyclical variation in follicular or oviductal protein concentrations. In the uterus, IgG and IgA levels relative to total protein were higher in oestrogenic than in progestagenic secretions, while the trend in relative IgM concentrations was reversed. Albumin levels were unchanged. In mares sampled repeatedly from the uterus and vagina during a single oestrous cycle, protein levels in secretions were affected by the collection technique. However, there was variation in absolute IgG, IgA, albumin and total protein concentrations, with maxima during dioestrus and minima at oestrus. Protein concentrations were higher in vaginal than in uterine secretions, although IgA relative to total protein was higher in the uterus than the vagina.

Reproduction in Laboratory Colonies of Bank Vole, Clethrionomys glareolus, Originating from Populations with Different Degrees of Cyclicity

Reproduction in two laboratory colonies of bank vole, Clethrionomys glareolus (Schreb.), established with animals from the increase phase of a strongly cyclic population was compared with that in a colony originating from a relatively stable population. Most reproductive variables were influenced by the same factors in the cyclic and non-cyclic animals, but considerable quantitative differences were seen. The cyclic animals were heavier, had larger litters, and faster growth of young. Survival of young was much lower and the intervals between litters were longer in cyclic animals. The results are discussed in relation to reproductive differences between the original populations and in relation to a current hypothesis of evolution of different reproductive rates in populations with different degrees of cyclicity.

Reproductive capacity of rhesus monkeys following bilateral ovarian x-irradiation.

The effect of ovarian X-irradiation of the rhesus monkey upon menstrual cycle length, duration of menstrual bleeding, excretion of gonadotrophin in the urine, concentration of gonadotrophin in the pituitary gland, ovarian histology, and breeding performance was investigated. Doses below 4000 R had no significant effect upon the above criteria. By contrast, doses of 4000 to 7000 R rapidly induced amenorrhoea in most animals, but unexpectedly these animals did not excrete greater than normal amounts of gonadotrophin. The pituitary content of gonadotrophin in cyclic and non-cyclic animals was not significantly different. Some births occurred in the animals which had been X-irradiated.