Duration Of Estrus Research Articles

Management of postpartum anoestrus in Vechur cows by hormonal methods

The study aimed to evaluate suitable hormonal treatment regimen for inducing oestrus in postpartum anoestrus Vechur cows and its reproductive outcome. The efficiency of Ovsynch and Ovsynch + progesterone protocols in 12 anoestrus cows was studied. Six anoestrus cows were kept as untreated control and they were observed for a period of 180 days postpartum. Both treatment protocols resulted in a complete oestrus induction response of 100 per cent. The interval from treatment to induced oestrus was significantly lower in the Ovsynch group (50.10 ± 1.44 h) than in the Ovsynch + progesterone (54.40 ± 0.48 h) group. In comparison to the control group, treatment group animals displayed a high intensity score for oestrus. The duration of oestrus in the Ovsynch group (26.41 ± 0.53 h) was significantly longer than the control (24.45 ± 0.46 h) group and the Ovsynch + progesterone group (24.13 ± 0.42 h). The overall conception rate for three consecutive AI in Ovsynch, Ovsynch + progesterone and control group were 66.67, 83.33 and 33.33 per cent, respectively. The calving to conception intervals were significantly (p<0.001) shorter in Ovsynch (118.33 ± 9.71 d) and Ovsynch + progesterone (106.67 ± 8.12 d) groups than the control (191.5 ± 5.36 d). It is concluded that hormonal treatment is effective in inducing postpartum oestrus and reducing the calving to conception interval in Vechur cows. Keywords: Ovsynch, postpartum anoestrus, progesterone, Vechur

Comparative assessment on the effect of long vis-à-vis short-term progesterone priming on reproductive attributes in silent estrus goats

Silent estrus results in spread-out kidding and extended inter-kidding interval in goats. Progesterone (P4) priming for 12-14 days could be one of the approaches for estrus induction with optimum fertility. The present work was carried to comparatively assess the duration of P4 priming on estrus and fertility in silent estrus goats. Sirohi does (n=18) with a history of anestrus and high basal P4 in paired samples were equally divided into three groups. Does in P-0 d group received 200 IU of equine chorionic gonadotropin by intramuscular route. Does in group second and third were subjected to per-vaginal P4 sponges for 7 (P-7 d) and 14 (P-14 d) days, respectively and were given 200 IU equine chorionic gonadotropin following sponge withdrawal. Estrus was monitored for 72 h at 12 h intervals using teaser buck to record estrus per cent, induction time and duration. Estrus induction was highest in P-14 d (6/6) than P-0 d and P-7 d (4/6 and 5/6), respectively. Estrus induction time was shorter in P-7 d and P-14 d than P-0 d. The estrus duration was shortest in P-14 d group. The conception and pregnancy rate did not differ significantly among the groups, though all the does in P-14 d conceived. The fertility was non-significantly higher in P-14 d (6/6) and P-7 d group (5/5) than P-0 d (3/4). It could be concluded that P4 priming for 7-14 days in silent estrus does results in improved reproductive performances.

Reproductive Response of Hair Sheep to Short or Long Duration Estrus Synchronization Protocols

Objective: Evaluate the reproductive response of hair ewes treated with estrus synchronization protocols that included a progesterone-releasing intravaginal device (CIDR) for a period of 7 or 12 days. Methodology: During the end of winter, ewes were randomly allotted to one of two estrus synchronization protocols: 1) Short-term protocol (SD), ewes (n=24) received a CIDR on Day 1 and removed on Day 7, and received 400 IU of equine chorionic gonadotropin (eCG) and 0.125 mg of cloprostenol; 2) Long-term protocol (LD), ewes (n=24) received a CIDR on Day 1, retired on Day 12 and received 400 IU eCG. Ewes showing estrous behavior were bred with a mature ram. Results: There were no differences (P>0.05) in the estrus response in both groups of ewes (100 vs 95.8% for SD and LD, respectively), the pregnancy rate (87.5 vs 87.5%), prolificacy (1.95+0.1 vs 2.2+0.1 lambs/ewe), hours between CIDR removing and the beginning of estrus (34.4+8.1 vs 34.8+9.2 h), and estrus duration (39.7+2.9 vs 39.9+4.7 h). At CIDR removal, ewes in the PL group showed a greater diameter (P<0.05) for the largest follicle in both ovaries (5.42+0.3 and 5.42+0.4 mm for the follicle in the left and right ovaries, respectively) vs PC ewes (4.25+0.1 and 4.29+0.1 mm). Limitations of study: Results observed in the follicle diameter could be due to low circulating progesterone levels in the LP group, which must be confirmed in future studies. Conclusions: The short protocol for estrus synchronization can be used in hair ewes under temperate conditions, without affecting their reproductive response.

Staging of Estrous Cycle in Rats using Vaginal Cytology and Visual Assessment

The determination of different phases of estrous cycle in lab animals is important for reproductive interventions and other experiments related to animal reproduction where rats are used as experimental models. A total 21 Wistar albino (which had completed their pubertal stage ( greater than 4 weeks) weighing approximately 100- 200 g were used in this experiment. Visual assessment was done to observe vaginal opening during different phases of the estrous cycle. This was followed by collection of vaginal discharge samples by flushing it with 0.1 ml of distilled water using micropipette. Vaginal cytology was performed in 21 rats thrice daily, along with visual assessment. The average length of estrous cycle in rats was recorded to be 4-5 days with average duration of proestrus, estrus, metestrus and diestrus of 24, 24-36, 12 and 48 hours, respectively. The average length of estrous cycle in rats was 4-5 days with recorded average duration of proestrus, estrus, metestrus and diestrus of 24, 24-36, 12 and 48 hours, respectively. Vaginal cytology can be considered as a better option compared to visual assessment for assessment of reproductive status in rats.

Impact of Estrus Response and Pregnancy Rate of Two Cows That are Injected with Prostaglandin F2α Hormone in the System Maintenance is Different to Livestock Farming

Livestock farming is an effort to breed livestock to obtain benefits or results in the form of products and income. The success of a livestock business depends on three elements commonly referred to as the production triangle, namely seeds, feed, and management. In addition, the techno-socioeconomic characteristics of livestock farmers greatly influence the development of livestock businesses and will later affect the income of livestock farmers. The aim of the research was to examine the injection of the prostaglandin F2α hormone on the estrus response and pregnancy in Ongole crossbreed and Simental crossbreed cows reared using intensive and semi-intensive rearing systems. The data obtained will be analyzed using analysis of variance (ANOVA) and if there is a real effect, continue with further testing with Duncan's Multiple Range Test. The results of research on the percentage of estrus after the first and second injection of the prostaglandin hormone can be seen in the table. The highest percentage of estrus was in the S1P2 treatment with a percentage value of 80% and the lowest percentage value was in the S2P1 and S2P2 treatments with a percentage value of 40%. The percentage of estrus after the second injection, the percentage value for all treatments increased and the percentage of estrus was highest in the S1P2 treatment with a value of 100%. The average value of onset of estrus after the second injection of the PGF2α hormone was lower than the first injection. The longest duration of estrus in the treatment after the first PGF2α hormone injection was in the S1P2 treatment with an average of 24.75 hours, while the longest duration of estrus in the treatment after the second PGF2α hormone injection was in the S2P1 treatment with an average of 25 hours. PO cattle and Simental crossbreeds injected with PGF2α gave no different estrous responses. Intensive and semi-intensive rearing systems provide no different estrous responses. Raising PO cows using a semi-intensive rearing system injected with PGF2α provides an estrous response and high pregnancy rates (60), to be one of techniques to breed cattle of PO cow and have good impact to the success of a livestock business

Reproductive Performance of Estrus Pattern in Bachaur Cows of Bihar

Background: The Bachaur is a medium sized draft purpose breed mostly present in Madhubani, Darbhanga and Sitamarhi districts of Bihar and presently the breed is at the verge of extinction. Since no data is presently available regarding the estrus pattern in these cows therefore, present study was designed to document the oestrus intensity, estrus cycle length, estrus behaviour and duration of estrus in these animals. Methods: The total of nine healthy breeding Bachaur cows aged 3 to 5 years were maintained under identical managemental conditions.The estrous cycles of nine animals was synchronized using Cloprostenol Sodium @ 500 mg I/M (Pragma®, Intas, India) in cycling Bachaur cows. Estrus was detected in the morning and evening for external signs of estrus, estrus behavior, intensity of estrus, estrus duration and estrous cycle length. Result: In the present study, mounting or mounted by other animals was observed in more than 70% and sniffing, tried to lick and Flehmen’s reaction was observed in about 66.67% of treated cows. The other parameters like bellowing, restlessness, milk yield reduction, frequent micturition and Flehmen’s reaction were recorded in 44.44%, 55.56%, 44.44%, 55.56% and 66.67%, of animals, respectively. The most appreciable physical sign of estrus recorded was intense swelling of vulva (in 88.89%) however hyperaemia of vulva, copious estrual mucous discharge, pronounced tonicity of uterus, completely dilated os cervix and presence of large palpable follicle on the ovary was observed in 44.44%, 55.56%, 66.67%, 77.78% and 66.67%, of cows respectively.

Effects of β-carotene supplementation and age on the oxidative status, production and reproductive performance of grazing ewes

Context There is some evidence that physiological stages such as breeding, pregnancy, parturition and lactation may trigger oxidative stress. It has also been observed in several species, including sheep, that age affects their vulnerability to oxidative stress. Aims This study investigated the effects of supplemental β-carotene and age on the oxidative status of grazing ewes around breeding, pregnancy, parturition and early lactation as well as on their production and reproduction performance. Methods Hundred and four ewes were divided into two broad age groups (young = 1–3 years, and old = 4–6 years). Within age groups, ewes of similar age were randomly assigned to four treatment groups (A1, A2, A3, C) by using a completely randomised block design. The young (n = 13) and old (n = 13) sheep in Groups A1, A2 and A3 were daily drenched with 100 mg, 75 mg and 50 mg β-carotene respectively. Group C was unsupplemented (Control). Supplementation lasted 28 days before oestrus synchronisation; 14 days during oestrus synchronisation (CIDR) and hand-mating; 18 days post-hand-mating; 30 days before lambing; and 15 days after lambing. All animals were grazed on Kikuyu grass (Pennisetum clandestinum). Six ewes from each group (total = 24) were sampled for blood to measure oxidative and hormonal status during the experiment. Key results Supplemental β-carotene at ≥75 mg/day may act as a pro-oxidant in ruminants under oxidatively stressed conditions such as parturition. Age did not affect the ewes’ oxidative status. The supplemental β-carotene did not affect bodyweight, oestrus parameters, corpus luteum size, conception rate and litter size. Except for a tendency of lambs from supplemented ewes to have heavier weight at 15 days old (P = 0.080), age group and supplemental β-carotene did not affect the lamb mortality rate or weight at birth or 15 days old. Older ewes showed earlier and longer duration of oestrus than did younger ewes. Conclusions Supplementation of grazing ewes with β-carotene should not be ≥75 mg/day, especially at parturition period, because it may work as a pro-oxidant. The older ewes seem to have earlier oestrus with a longer duration than do the younger ones. Implications Caution is urged when administering high doses of β-carotene to ewes during the peri-parturient period.

Assessment of Phenotypic and Reproductive Characteristics of Local Donkeys in Marathwada Region

A total of 1007 local donkeys were selected for the study of phenotypic and reproductive characters of local donkeys from different districts of the Marathwada region in Maharashtra state. Statistically non-significant differences were found in most of the phenotypic parameters. Four different body coat colour patterns i.e., grey, brown, white, and dark red brown were observed with percentage as 48.46, 21.54, 25.12 and 4.86%, respectively. Most of donkeys (96.02 %) were black muzzled with convex forehead (93.24%), white marking above muzzle (66.53%), white marking above eyes (67.72%), white marking posterior to the mandible (70.30%), dark brown lining around extremity of ear pinna (88.97 %), long white hairs at inner side of ear pinna (100%) and bearing dark strip starting from poll to switch of tail and forming cross with another dark strip at shoulder (73.48%). The mean age at puberty, age at first service, age at first oestrus, oestrus cycle duration, oestrus duration, age at first covering, age at first conception, no. of services/conception, age at first foaling, service period, foaling interval, gestation period, lifetime no. of foaling of adult female local donkeys in Marathwada region were 2.70±0.02 years, 2.79±0.02 years, 2.77±0.03 years, 6.86±0.084 days, 23.80±0.55 days, 2.96±0.01 years, 5.9±0.07 years, 1.82±0.06, 4.44± 0.01 years., 1.14±0.01 years, 2.25±0.01 years, 340.8±0.27 days and 5.98±0.07, respectively.

Methanol extract of Abrus precatorius seeds on reproduction indices, hepatorenal profiles in female albino rats

BackgroundAbrus precatorious is a member of the leguminous family with characteristic red and black seeds. The roots, leaves and seeds of this plant are used for different medicinal purpose. It principally carries flavonoids, triterpene glycosides, abrin and alkaloids. The plant had been mentioned for neuromuscular effects, neuro-protective, abortifacient, antiepileptic, anti-viral, antimalarial, antifertility, nephroprotective, immunomodulator, immunostimulatory properties, antiinflammatory activity, antidiabetic, and many others. The aim of this study was to investigate the anti-fertility activity of the methanol extract of Abrus precatorius seeds (APS) in female albino rats administered 45 and 50 mg/kg BW through oral gavage for 30 days. An Abrus precatorius seed (APS) was extracted (1:1 w/v) using methanol to obtain the crude extract. Liquid-liquid fractionation was performed on the crude methanol extract using solvents of different polarity.MethodsEighteen female rats were divided into three groups each containing six animals was used for this experiment. Group one (control), received 1 ml of saline solution, group two received 45 mg/kg and group three received 50 mg/kg body weight by oral gavage daily for a period of 30 days. At the end of the study, Body weight, Organ Weight, Estrous cycle, Hormonal Concentrations, Oxidative Stress Markers, Enzymatic Activities, Biochemical indices (Liver and Kidney panel) and Hematological parameters were also evaluated.ResultsConsequent upon the administration of A.precatorius seed methanol extract 45 and 50 mg/kg BW into the female rats resulted in changes pertaining to Body weight, Estrous cycle, Hormonal Concentrations, Antioxidant Enzymes, Serum Biochemical indices and Hematological indices significantly (p < 0.05) compared to control rats. Initial body weights are significantly (p < 0.05) indicated, whereas final weights were decreased significantly (p < 0.05). Organ weight changes i.e. Ovary, Liver and Kidney weights were found to be significantly (p < 0.05) decreased in APS administered rats compared to control. Estrous cycle study i.e. time duration of Proestrus, Estrus, Metestrus and Diestrus (in days) was significantly prolonged. Hormonal Concentrations represented by FSH, LH, Prolactin, Estradiol were significantly (p < 0.05) decreased, whereas Progesterone levels were significantly (p < 0.05) increased in APS administered female rats compared to control group of rats. All the antioxidant enzyme assayed CAT, SOD, GPx, GR and GST were found to be significantly (p < 0.05) decreased, whereas MDA concentration was found to be increased significantly (p < 0.05). Enzymatic activities and biomolecules includes Cholesterol and Ascorbic acid contents were significantly increased (p < 0.05), but G6PDH and Δ5 − 3β-HSD activities were found to be significantly (p < 0.05) decreased in APS administered group of female rats compared to control group. Biochemical indices of liver tissue presented by Bilirubin, SGPT, SGOT, Albumin and Globulin were found to be significantly (p < 0.05) increased whereas Alkaline Phosphate and Total Protein contents were found to be significantly (p < 0.05) decreased. The biochemical indices of kidney, i.e. Urea and Creatinine were significantly (p < 0.05) increased and Uric acid and Calcium contents were found to be significantly (p < 0.05) decreased in APS administered female rats compared to control group of rats. Hematological parameters including RBC, Hb, ESR and Clotting Time were found to be significantly (p < 0.05) increased but WBC levels were significantly (p < 0.05) increased in APS administered female rats compared to control group of rats.ConclusionA. Precatorius seeds have anti-fertility effect on female rats.

Comparative study of reproductive and estrus characteristics of sexed and conventional semen in crossbred cows under field conditions.

Sexed semen (SS), a reproductive biotechnology tool, can alter the sex ratio of offspring in bovines. This study elucidates a comparative analysis of estrus-related parameters influencing conception rate and pregnancy losses under field conditions between conventional and SS. In the present study, artificial insemination with (SS; n = 143) and conventional semen (CS; n = 143) was performed at spontaneous estrus, i.e., 16-18 h after the onset of estrus signs, to analyze their comparative evaluation in terms of conception rates in crossbred cows under field conditions. Different parameters such as age, parity, body condition score (BCS), estrus duration, inter-estrus interval (IEI), diameter of pre-ovulatory follicle (DPOF) at estrus, and cervical mucus properties (pH and spinnbarkeit [SBK]) were recorded for each cow. The first insemination conception rates for sexed and conventional semen were 55.24% and 63.63% whereas the overall conception rates were 49.14% and 57.37% on days 35 and 75 post-insemination, respectively, with no significant difference (p > 0.05). Conception rates between sexed and CS inseminations were statistically significant (p < 0.01), whereas factors such as age, parity, BCS, DPOF, IEI), and SBK value exhibited no substantial variance (p > 0.05) for both types of semen straw. SS straws yielded a conception rate equivalent to CS straws, with estrus duration being the key factor affecting conception under field conditions.

Effect of duration of estradiol exposure on embryo survival and endometrial gene expression in anestrous embryo recipient mares

Previous studies indicate a positive correlation between the duration of estrus prior to ovulation and likelihood of pregnancy in embryo recipient mares. However, the mechanisms by which the duration of estrus before may affect fertility remains unclear. This study aimed to determine the effect of different durations of estradiol exposure, prior to progesterone administration, on embryo viability in anestrous recipient mares, and endometrial expression of genes thought to influence embryo survival. Three groups of anestrous recipient mares treated with different duration of estradiol were used: long (LE), short (SE) and no treatment (NE). Day 8 embryos were transferred into recipient mares four days after long-acting progesterone administration and recovered 48h later to examine embryo growth and viability. The endometrial gene expression profile of selected genes was also investigated. The likelihood of recovering an embryo 48h after transfer was 46.1% (6/13), 62.5% (5/8) and 85.7% (6/7) for recipient mares from the NE, SE and LE groups, respectively (P = .09). Embryos recovered from the different groups of recipients did not, however, differ in size, morphology or the proportion of nuclei undergoing mitosis (P > .05). Abundance of mRNA for uterocalin (P19) and insulin-like growth factor 1 (IGF1) were increased in the LE compared to the NE group, while fibroblast growth factor 2 (FGF2), progesterone receptor (PGR) and insulin-like growth factor 1 receptor (IGF1R) transcript abundances were increased (P < 0.05) in the NE group compared to both SE and LE groups. In conclusion, a longer exposure of the endometrium to estradiol before progesterone tended to improve embryo survival within 48h of transfer. However, the grade, growth rate, and proportion of mitotic cells in surviving embryos did not differ among groups. If embryos are destined to fail in a suboptimal endometrial environment, they die and disappear quickly. Moreover, a more adequately estradiol-primed uterus, before the progesterone rise, seems to create a uterine environment, in terms of P19, IGF1, FGF2 and PGR gene expression, more conducive to embryo survival and further development.

Cloprostenol effect with and without male stimulation on oestrus synchronization in Peru guinea pigs.

Cloprostenol, a synthetic derivative of prostaglandin F2α, effectively triggers functional and morphological regression of the corpus luteum (luteolysis). In rural Peru, the guinea pig (Cavia porcellus) holds significance within the local economy and serves as a valuable protein source. Enhancing reproductive efficiency is crucial to achieve uniformity in weight, age, and litter size across commercial systems. Thus, our study aimed to evaluate the effect of cloprostenol with and without male stimulation on the onset, duration, and intensity of oestrus in Peru guinea pigs. A total of 128 guinea pigs (120 females and eight males) between 8 and 12 months of age, weighing between 800 and 1200 g, were distributed in cages of 15 females per treatment. Cloprostenol sodium (0 [control], 0.20, 0.25, and 0.30 mg/animal) was IM administered to the groups with and without male stimulation. Four isolated males in individual cages, different from the one used for the treatment, were considered to detect oestrus. The oestrus intensity was assessed by observing sexual behaviour signs such as restlessness, moaning, attempts to mount, pelvic elevation, loin stretching, and vulvar inflammation. The oestrus was manifested 2 days after the administration of cloprostenol sodium. At a dose of 0.30 mg/animal and with male stimulation, the earliest oestrus was observed at 46.9 h. There was a reduction in the oestrus duration (p < .05) in guinea pigs that received the three doses of cloprostenol sodium compared to the control group. The highest percentages of frank oestrus intensity (66.7%) were strongly associated with the administered doses of cloprostenol sodium (p < .01). In conclusion, the cloprostenol sodium administration was proper for rapid oestrus induction in Peru guinea pigs.

Analysis of Reproductive Performance of Female Peranakan Etawa Goats in Toari District, Kolaka Regency

The Peranakan Etawa Goat, a type of livestock highly sought after in Indonesia, particularly in the region of Southeast Sulawesi, is renowned for its ability to reproduce and adapt to the local environment. This research was conducted between April and July 2023 in the Toari District, Kolaka Regency, deliberately chosen as one of the centers of Peranakan Etawa Goat production. The population under study consisted of female Peranakan Etawa Goats owned by farmers in the villages of Ranojaya, Wonua Raya, and Rahabite. Data collection was carried out through direct interviews with respondents and secondary data collection from relevant agencies. The observed variables included the Reproductive Performance of the Peranakan Etawa Goats, such as Estrus Signs, Puberty, Mating (S/C), and Birth (litter size), which were then organized and presented in percentage form. Descriptive analysis was conducted to depict the characteristics and findings of the data. The findings indicate that the reproductive performance of Peranakan Etawa Goats in the Toari District is suboptimal, with puberty achieved at the age of 8-9 months and the duration of estrus ranging from 24-36 hours

Effect of the feeding condition and number of dominant follicles on oestrus synchronization in Swamp buffalo

The research aimed to assess how feeding conditions and the number of the dominant follicles (DF) influence oestrus synchronization in swamp buffaloes. A total of 170 swamp female buffaloes raised in semi-grazing and housekeeping were included in the study. The synchronization used CIDR method and the follicles on the day of CIDR (Controlled Internal Drug Releasing) insert and removal were tracked by sonography. The results indicated that the age of first mating, age at first calving, and caving interval showed no significant differences in the two feeding conditions. The number of follicles at CIDR insertion and removal decreased in semi-grazing, but increased in housekeeping buffaloes. The percentage of buffalo without DF, one DF, and two DFs at CIDR withdrawal did not differ statistically. The percentage of estrus was 100% in both groups. Pregnancy rates were 53.18% in semi- grazing and 52.63% in housekeeping. The onset of oestrus was similar, but the duration of oestrus was longer in the buffaloes without DF than those with one or two DFs. The percentage of pregnant buffaloes in the group without DF was significantly lower than that in the other two groups. In summary, the efficiency of oestrus synchronization did not differ between semi-grazing and housekeeping methods. Buffaloes without DF displayed longer oestrus periods and lower pregnancy rates compared to those with one or two DFs in the ovarian system.

Taurine dynamics in serum during the oestrous cycle in buffaloes.

Estrus identification is one of the common issues in buffaloes because of their short estrus duration and silent estrus problem. Hence, specific biomarkers facilitating in identifying the estrus stage would be helpful to buffalo farmers and researchers. In our previous studies, taurine, a non-protein amino acid that helps in the secretion of reproductive hormones such as GnRH, was found to be associated with postpartum anestrus in buffaloes. Therefore, the present study was conducted to explore the level of taurine in serum during different stages of the oestrous cycle in healthy cyclic buffaloes. Blood samples were collected from healthy cyclic buffaloes (n = 4), and taurine was estimated at the estrus (0th day), proestrus (-2nd day), metestrus (3rd day) and diestrus (+10th day) stages using TLC method. The days of the oestrous cycle were determined by ultrasonography and observation of behavioural signs by trained professionals. The results revealed that taurine was consistently present in the serum. However, the highest concentration of taurine was observed at the proestrus (0.20 ± 0.03 mg/mL) stage, which was greater (p < .05) than metestrus (0.10 ± 0.05 mg/mL) and diestrus (0.13 ± 0.03 mg/mL) stages, but comparable with the estrus stage. These results were also validated in the simulated population datasets of population size 6 to 10,000. Further, ROC curve analysis for the large simulated population indicated the efficiency of taurine to distinguish proestrus from metestrus and diestrus stages at a lower cutoff value of <0.1643 mg/mL with 60% sensitivity and specificity. Therefore, the present study concludes that serum taurine concentration could help in detecting proestrus stage of buffalo estrous cycle.

Interval from Oestrus to Ovulation in Dairy Cows-A Key Factor for Insemination Time: A Review.

This review describes the oestrus-to-ovulation interval, the possibility of predicting the time of ovulation, and the optimum time for insemination relative to oestrus in dairy cows. The duration of oestrus in dairy cows is approximately 8-20 h, with differences possibly related to the methods of oestrus detection and the frequency of observations. Most cows ovulate approximately 24-33 h after the onset of oestrus and 15-22 h after the end of oestrus. The interval from the preovulatory luteinising hormone (LH) surge to ovulation is approximately 4-30 h. Ovulation occurs when follicle diameter averages 18-20 mm. When it is possible to correctly determine the beginning of oestrus, artificial insemination can be performed utilizing the "a.m.-p.m. rule", and only one insemination may be applied. In cows with too long or too short oestrus-to-ovulation intervals, fertility can be compromised. One important factor that can alter the oestrus-to-ovulation interval is acute or chronic heat stress during the warm season. When there is a risk that insemination may occur too early or too late with respect to the time of ovulation, GnRH administration can be considered.

Genomic selection in dairy cattle: impact and contribution to the improvement of bovine fertility

Genomic selection has revolutionized the dairy cattle breeding industry, with ripple effects that have greatly impacted dairy herd management. Rate of genetic progress has increased markedly, especially in Holstein and Jersey breeds, for production, health, and fertility traits. Genomic testing of young bulls and heifers provides greater accuracy of selection decisions involving traditional fertility traits, such as daughter pregnancy rate, while creating the opportunity to improve novel traits, such as fetal loss. Cameras, wearable sensors, and other precision livestock farming technologies will allow selection for traits such as estrus duration and intensity that require high frequency phenotyping. At the same time, synergies between genomic testing and advanced reproductive technologies have led to rapid and widespread adoption of sexed semen, coupled with mating of females whose offspring are not needed as herd replacements to beef sires. This strategy produces added-value crossbred calves for the beef supply chain, while allowing genetically inferior mature cows that are still producing at a high level to remain in the herd for additional lactations.

102 Estradiol and follicular growth are associated with estrous behavior monitored by an accelerometer in grazing beef cows

Abstract In beef cattle, 40% of cows that display estrus do not remain pregnant after embryo transfer (ET). Estrus is a physiological behavior influenced by the concentration of sex-steroids. The use of accelerometer devices for estrus detection is a common practice in dairy operations. It remains unclear if this same artificial intelligence software can accurately measure reproductive behavior in beef females. We hypothesized that estrous variables detected by an accelerometer are associated with ovarian, hormonal, pregnancy outcome, and fertility-related variables measured in the cow. Fifty Bos indicus-influenced, cyclic, primiparous cows were fitted with an accelerometer collar (SCR Engineers, Israel) and a breeding indicator (Estrotectâ) to detect estrus after a synchronization protocol in five subsequent experimental replicates (n = 50*5 = 250). Only cows that showed estrus (d 0) remained in the study. The following variables were used from the accelerometer software: Activity Peak, Rumination Nadir, Estrus Duration, and Heat Index, calculated by proprietary algorithms. Dominant follicle (DF) diameter and plasma concentration of estradiol were measured on d -2 (day of progesterone device removal) and on d 0. On d -1 and d 4, endometrial thickness and luminal fluid accumulation were measured by ultrasonography. On d 7, two embryos were transferred/cow. Pregnancies were diagnosed on d 45 and terminated. After 30 d, a new replicate started. Cows included in at least two replicates that remained pregnant 100%, 99-50%, or less than 50% were classified as fertile, sub fertile, and infertile, respectively. Estrus display was recorded for 166 cows (66%). Estrus detection by accelerometer and Estrotect had excellent agreement rate (kappa coefficient 0.76). Cows detected in estrus only by Estrotect had 66% less pregnancy/ET than cows in estrus by both (9/21 vs. 97/145; P = 0.01). The DF diameter on d 0 was not associated with accelerometer variables. Cows with greater and moderate Activity Peak had a greater growth rate of the DF from d -2 to d 0 than lower Activity Peak cows (interaction day*Activity Peak; P = 0.06). Estradiol on d -1 was positively associated with the Activity Peak (P &amp;lt; 0.0001). Cows with lower Activity Peak had a thicker endometrium on both d -1 and d 4 (P=0.02), and greater uterine luminal fluid score on d -1 (P=0.03). Fertility status was not associated with any accelerometer variables. In conclusion, the Activity Peak is associated positively with estradiol concentration and DF growth, however no association was found with pregnancy outcome and fertility. Therefore, the main advantage of accelerometers in beef ranches is the ability to detect estrus at a similar accuracy as breeding indicators, using less labor. Future enhancements in hardware and software to allow prediction of pregnancy outcomes are expected to increase reproductive efficiency in cow-calf operations.

Temporal disposition of pelvic girdle, vagina and vulva in relation to urovagina in cycling and pregnant-postpartum cows.

Urovagina (UV) is less studied in cows. The vaginal contents, constrictor vestibule muscle activity, circulating progesterone, pelvic girdle, vagina and vulva angles were compared on Days 0 and 14 within and between UV (UV group; n = 36) and normal (N group; n = 36) cows. The oestrous duration was compared among the groups. Parameters for various UV severities were also compared. Another set of pregnant-postpartum cows (P-PP group; n = 31) underwent monthly evaluations for UV and the angles from the third month of pregnancy until the second month postpartum. The effect of age, parity and body condition score on UV severities on Day 0, and parity on angles in the P-PP group was evaluated. Different variables were correlated in different groups. The UV group was repeat breeder, exhibited prolonged oestrus and reduced progesterone on Day 14. The latter increased with UV severity on Day 0. On Day 14, severe form of UV was more prevalent. The UV severity increased with parity. In the UV group, a cranioventral pelvic girdle on Day 0 became more cranioventral on Day 14 and was correlated with the vagina moving from a caudodorsal position on Day 0 to a cranioventral position on Day 14. In the P-PP group, the pelvic girdle and vagina remained caudodorsal and UV was undetectable throughout the study. Vagina and vulva displayed a parity-by-month interaction in the P-PP group. To summarize, the UV characteristics were influenced by the oestrous cycle stage, pelvic girdle angles, and parity.

Estrous characteristics and steroid concentrations in Aceh cows (Bos indicus) after estrus synchronization using prostaglandin F2a

Abstract. Hafizuddin, Husnurrizal, Thasmi CN, Herrialfian, Salsabil NL, Siregar TN, Sutriana A. 2024. Estrous characteristics and steroid concentrations in Aceh cows (Bos indicus) after estrus synchronization using prostaglandin F2a. Biodiversitas 25: 322-328. This study aims to determine the estrous characteristics and steroid concentrations during estrus in Aceh cattle after estrus synchronization using prostaglandin F2a. This study involved 9 Aceh cows with good reproductive status, not pregnant, and has shown at least 2 regular cycles, which were divided into 3 treatment groups. The first group (GI) received a single injection treatment, the second group (G2) received a double injection treatment with an interval of 10 days, and the third group (G3) was also treatment double injection with an interval of 12 days. Symptoms and responses to estrus were reported descriptively, and the data collected on onset, intensity, and duration of estrus were analyzed using one-way analysis of variance followed by Duncan's test. The results showed that estrus symptoms were almost similar and estrus response was 100% in all three treatment groups. The onset of estrus in G1, G2, and G3 did not differ significantly (P&gt;0.05) with values of 68.00±18.33, 60.00±0.00, and 72.00±24.00 hours, respectively. The intensity of estrus in G1, G2, and G3 showed significant differences (P&lt;0.05) with scores of 3.00±0.00, 5.00±0.00 and 4.33±1.15, respectively. The duration of estrus showed no significant difference in G1, G2, and G3 (P&gt;0.05) with durations of 32.00±18.33, 72.00±0.00, and 52.00±38.57 hours, respectively. The concentrations of estradiol and progesterone obtained also showed no significant differences (P&gt;0.05) in G1, G2, and G3, with respective concentrations of 91.67±24.77, 132.00±23.15, 89.47±24.19 pg/mL and 0.98±0.59, 0.86±0.18, 1.00±0.17 ng/mL. In conclusion, estrus synchronization with PGF2a single injection and double injection in Aceh cattle was found to have 100% estrus response. However, PGF2a with double injection showed higher estrus intensity compared to single injection. In Aceh cows, the recommended protocol for estrus synchronization using PGF2a is double injection.