Behavioral Signs Of Estrus Research Articles

Relationship of length of the estrous cycle to antral follicle number in crossbred beef heifers.

Length of the menstrual cycle was positively associated with antral follicle number in women. If this pattern is consistent in cattle, a value-added benefit to using automated activity monitors to determine estrous status could be the ability to predict antral follicle count (AFC). We, therefore, hypothesized that as inter-estrous interval increased ultrasonographic AFC would be greater in crossbred beef heifers. Over 3 yr, crossbred beef heifers (n = 1,394) were fitted with automated activity monitors for 81 d. From days 42 to 46, heifers were submitted for ultrasonographic examination to determine AFC. From days 60 to 81, heifers were visually observed twice daily for 45min for signs of behavioral estrus. Heifers that had a behavioral estrus that coincided with a sensor-based estrus and had a previous sensor-based estrus between 15 and 26 d earlier were used for the analysis (n = 850). A combination of regression analyses and correlation analyses were applied to understand the association between data collected by sensors and follicle number determined by ultrasonographic examination. Antral follicle count was analyzed using the GLM procedure of SAS with estrous cycle length (15 to 26 d) as a fixed effect. Estrus was more likely to initiate in the early morning hours and peak activity was greater (P < 0.0001) when estrus initiated between 0200 and 0800 hours then when estrus initiated at other times of the day. Antral follicle count did not differ due to length of the estrous cycle (P = 0.87). Thus, length of the estrous cycle obtained from three-axis accelerometers cannot be used to predict follicle number in crossbred beef heifers; however, machine learning approaches that combine multiple features could be used to integrate parameters of activity with other relevant environmental and management data to quantify AFC and improve reproductive management in beef cows.

Influence of Estrus on Dairy Cow Milk Exosomal miRNAs and Their Role in Hormone Secretion by Granulosa Cells.

Estrus is crucial for cow fertility in modern dairy farms, but almost 50% of cows do not show the behavioral signs of estrus due to silent estrus and lack of suitable and high-accuracy methods to detect estrus. MiRNA and exosomes play essential roles in reproductive function and may be developed as novel biomarkers in estrus detection. Thus, we analyzed the miRNA expression patterns in milk exosomes during estrus and the effect of milk exosomes on hormone secretion in cultured bovine granulosa cells in vitro. We found that the number of exosomes and the exosome protein concentration in estrous cow milk were significantly lower than in non-estrous cow milk. Moreover, 133 differentially expressed exosomal miRNAs were identified in estrous cow milk vs. non-estrous cow milk. Functional enrichment analyses indicated that exosomal miRNAs were involved in reproduction and hormone-synthesis-related pathways, such as cholesterol metabolism, FoxO signaling pathway, Hippo signaling pathway, mTOR signaling pathway, steroid hormone biosynthesis, Wnt signaling pathway and GnRH signaling pathway. Consistent with the enrichment signaling pathways, exosomes derived from estrous and non-estrous cow milk both could promote the secretion of estradiol and progesterone in cultured bovine granulosa cells. Furthermore, genes related to hormonal synthesis (CYP19A1, CYP11A1, HSD3B1 and RUNX2) were up-regulated after exosome treatment, while exosomes inhibited the expression of StAR. Moreover, estrous and non-estrous cow-milk-derived exosomes both could increase the expression of bcl2 and decrease the expression of p53, and did not influence the expression of caspase-3. To our knowledge, this is the first study to investigate exosomal miRNA expression patterns during dairy cow estrus and the role of exosomes in hormone secretion by bovine granulosa cells. Our findings provide a theoretical basis for further investigating milk-derived exosomes and exosomal miRNA effects on ovary function and reproduction. Moreover, bovine milk exosomes may have effects on the ovaries of human consumers of pasteurized cow milk. These differential miRNAs might provide candidate biomarkers for the diagnosis of dairy cow estrus and will assist in developing new therapeutic targets for cow infertility.

PSXII-18 Genome-Wide Association for Behavioral Anestrus in Swine

Abstract Gilts represent a significant portion of breeding females, and producer success largely depends on lifetime prolificacy and number of lifetime litters produced. Expression and precise detection of first estrus are key components for successful breeding. Failure to express behavioral signs of estrus, also known as prebreeding anestrus, affects 10-30% of gilts resulting in premature culling. Behavioral anestrus (BA), that is ovulatory cycles of the ovary without signs of estrus, is a major type of prebreeding anestrus that affects up to 5% of the gilt population at the U.S. Meat Animal Research Center. Examination of ovaries revealed that 38% of BA gilts had exhibited more than one ovulatory cycle. Identification of genomic predictors of BA could minimize prebreeding anestrus in gilts. Data collected from normal cyclic (n=2,421) and BA gilts (n=515) from a multigeneration Yorkshire-Landrace-Duroc composite population were used for a case-control genome-wide association to identify candidate genes and cell signaling pathways associated with BA in gilts. The genomic heritability for BA in the population was 0.35. Fifty-six genome-wide significant SNP were identified with proportion of phenotypic variance explained by each SNP ranging from 0.009 to 0.06. Quantitative trait loci identified for BA harbor candidate genes involved in olfaction (OR13H1) and behavioral disorders (PLCB4). Biologically this is expected because, activation of olfactory pathways by boar pheromones is important to stimulate female lordosis behavior and sexual receptivity to boar. Several candidate genes identified for BA (IGSF1, MSTN, RXRG) were previously reported for age at puberty in humans and cattle suggesting the pleiotropic nature of these genes influencing multiple estrus related traits in different species. To our knowledge this is the first large scale association analysis performed for BA in pigs and these data are an important first step to facilitate future studies to identify functional polymorphisms regulating estrus behavior in gilts.The USDA is an equal opportunity provider and employer.

HCG is more effective than the GnRH agonist buserelin for inducing the first ovulation of the breeding season in mares.

BackgroundHuman Chorionic Gonadotropin (hCG) and Gonadotropin Releasing Hormone agonists (GnRHa) are routinely used to induce ovulation in mares. However, GnRHa efficacy in transitional mares has been suggested to be low.ObjectivesThe aims of this study were as follows: (a) to compare the efficacy of hCG and GnRHa in inducing the first ovulation of the breeding season and (b) to evaluate the correlation between ovulatory response, uterine oedema and teasing score at the time of treatment during the early or late transitional phase.Study designRandomised controlled superiority trial.MethodsMares in winter anoestrus were treated with sulpiride when at least two follicles reached a diameter of 25 mm. The day after the follicle reached 35 mm in diameter, mares in oestrus were treated with GnRHa buserelin (N = 29) or hCG (N = 33) and checked daily for ovulation.ResultsMore mares (30/33, 90.1%) ovulated when the first ovulation after winter anoestrus was induced with hCG, than with GnRHa, (11/29, 38.0%) (P = .0001). Ovulation rate was lower in mares that did not show uterine oedema and full acceptance of the teaser stallion for at least three days before the treatment (32/41, 78% vs 9/21, 42.9%) P = .01.Main limitationsPlasma LH and oestrogen concentrations were not performed.ConclusionsThese results demonstrate that hCG was more effective than GnRHa for inducing ovulation in the first cycle after winter anoestrus. Uterine oedema and behavioural signs of oestrus, for at least three days before the treatment, were predictors for a positive response to ovulation induction.

Suppression of ovarian activity in a captive African Lion Panthera leo after deslorelin treatment

Abstract: With the intent to evaluate the efficiency of a contraceptive treatment for cyclic ovarian suppression in African Lionesses Panthera leo using a Gonadotrophin-Releasing Hormone (GnRH) agonist bioimplant, noninvasive fecal steroid assay associated with the observation of the behavioral estrus were employed for a period of 36 months. Five captive adult females, maintained with a vasectomized male, subcutaneously received a 9.4mg deslorelin acetate implant. The treatment initially stimulated behavioral estrus along with ovarian activity, demonstrated by an estrogen increase in two lionesses. A rise in progesterone concentration in two other animals suggested possible treatment-induced ovulation. After the initial period, deslorelin prevented ovarian activity for at least 22 months. Two females exhibited signs of behavioral estrus after 22 and 31 months. A third lioness with an increased estrogen concentration did not exhibit behavioral estrus signs or a consequent progesterone surge until 33 months after implantation, suggesting a possible resumption of ovarian activity. One female did not exhibit any behavioral estrus signs nor a rise in steroid levels after the “treatment-induced” estrus throughout the entire experiment (36 months). One lioness died after 15 months without exhibiting signs of estrus or an increased progesterone level, however, the estrogen concentration increased 12 months post-implantation, suggesting resumed ovarian activity. The study showed that long-term treatment with a GnRH agonist can be extremely effective as a contraceptive treatment in African lionesses, however, the duration of contraception may vary among individuals and may bear the risk of permanent loss of normal ovarian activity.&#x0D;

A reproductive management program aimed at increasing reinsemination of nonpregnant dairy cows at detected estrus resulted in similar reproductive performance to a program that favored timed artificial insemination

The objective of this experiment was to compare time to pregnancy and proportion of cows not pregnant 210 d after first service for cows managed for second and subsequent artificial insemination (AI) services with a reproductive management program that promoted reinsemination at detected estrus (AIE) or a program that promoted timed AI (TAI). After first service, lactating Holstein cows were blocked by parity and randomly assigned to d 32 Resynch (D32R; n = 464) or AIE Resynch (AIER; n = 512). To determine the effect of management strategies on time to pregnancy and cows not pregnant by the end of a 210 d at-risk period after first AI service, cows remained in AIER and D32R until pregnancy or herd exit. Cows in D32R received a GnRH treatment 32 ± 3 d after AI (first treatment intervention; FTI). Nonpregnancy diagnosis was conducted 7 d later by transrectal ultrasonography when nonpregnant cows with a corpus luteum (CL) ≥15 mm completed the Resynch protocol (PGF2α, 56 h later GnRH, and 16 to 18 h later TAI) and cows without a CL (NoCL cows) were enrolled in a PreG-Ovsynch protocol (GnRH, 7 d later GnRH, 7 d later PGF2α, 56 h later GnRH, and 16 to 18 h TAI) to receive TAI. For the AIER treatment, nonpregnant cows with a CL ≥15 mm observed by transrectal ultrasonography 32 ± 3 d after AI (i.e., FTI) received PGF2α to induce estrus. Cows not AIE within 7 d were enrolled in Resynch (GnRH, 7 d later PGF2α, 56 h later GnRH, and 16 to 18 h TAI). Cows in the NoCL group in AIER were enrolled in PreG-Ovsynch. Detection of estrus was performed based on visual observation of behavioral signs of estrus and tail-paint removal. Binomial data were analyzed with logistic regression and time to event data with Cox's proportional regression. After the FTI, a greater proportion of cows were AIE in AIER than D32R (36.0 vs. 11.9%) and more cows were AIE within 7 d of the FTI for AIER (25.0%) than D32R (4.8%). Overall pregnancy per AI at 68 ± 3 d after AI did not differ (AIER = 35.5% vs. D32R = 34.7%). The hazard of pregnancy up to 210 d after first AI for all cows enrolled (hazard ratio = 1.04, 95% CI 0.90 to 1.19) and for cows that received treatments only (D32R = 308, AIER = 349; hazard ratio = 1.00, 95% CI 0.85 to 1.19) did not differ. We conclude that a program aimed at increasing the proportion of cows reinseminated at detected estrus by treatment with PGF2α at 32 ± 3 d after AI may be an alternative strategy for dairy farms that prefer or need to inseminate more cows at detected estrus rather than by TAI.

Body Weight and Blood Biochemical Changes Following Nutritional Supplementation in Prepubertal Jaffrabadi Buffalo (Bubalus bubalis) Heifers

The high plan of nutrition right from an early age is believed to enhance ovarian activity and early onset of puberty in heifers. This study was therefore conducted to know the body weight, ovarian and blood biochemical changes in nutritionally supplemented and control groups of prepubertal Jaffrabadi buffalo (Bubalus bubalis) heifers. A total of 12 animals of 30 ± 2 month's age and the identical body weight of 380–410 kg from Cattle Breeding Farm, JAU, Junagadh were utilized for this study. They were randomly divided into two equal groups of 6 animals in each treatment and control groups. The heifers of the treatment group were supplemented with bypass fat (100 g), bypass protein (950 g) and chelated mineral mixture (50 g) over the routine farm feeding practices of control group, and its effect on body weight gain and blood biochemical profiles were studied at a monthly interval during 6 months of experimental period. The overall effect of nutritional supplementation on animals body weight, blood glucose and total cholesterol over the control group was statistically non-significant (p greator than 0.05) yet beneficial. The plasma total protein levels in the supplemented group increased with a duration of supplement and levels were significantly (p less than 0.05) higher over the control group. The ovarian dynamics evaluated by transrectal ultrasound during last three months of the study revealed an increasing number of growing follicles greator than 4 mm in diameters (5.00 ± 0.13 to 6.67 ± 0.40), without significant variation in diameters of largest follicles (9.14 ± 0.45 to 10.27 ± 0.85 mm) between groups or periods. However, none of the heifers exhibited behavioral signs of estrus during 6 months study, in spite of the establishment of cyclicity with the presence of developed follicles, or CLs suggesting silent ovulation, at 36 ± 2 months of age in this breed.

Fatty acid profile of milk for determining reproductive status in lactating Holstein Friesian cows

Large percentages of dairy cows do not express behavioural signs of oestrus. Faecal and urine fatty acid concentrations increase during oestrus. The objective of the present study was to determine the milk FA profile of dairy cows during the oestrous and dioestrous periods and the relationship with behavioural signs on the day of oestrus. The activity of 32 Holstein Friesian cows was measured continuously using GEA Rescounter ll pedometers (GEA Farm Technologies, Düsseldorf, Germany) and IceQubes (IceRobotics Ltd., Edinburgh, UK). Milk samples were collected on the day of oestrus and on day 14 of the subsequent oestrous cycle and analysed for FA concentration using gas chromatography (GC) and milk composition was also determined. All cows were artificially inseminated within 12 h of the onset of oestrus. On the day of oestrus, the concentration of acetic acid (P < 0.001), valeric acid (P = 0.016), caproic acid (P < 0.001) and myristoleic (P = 0.035) were greater in milk compared to day 14. On day 14 milk arachidonic acid concentration, however, was greater (P = 0.004) compared to the day of oestrus. Also, on day 14 arachidonic acid concentration was greater (P = 0.002) in non-pregnant compared to pregnant cows. In conclusion, the results of this study indicate there are changes in the concentrations of some milk FA during oestrus and dioestrus in lactating dairy cows.

Endocrine correlates of puberty in female Asian elephants (Elephas maximus) at the Pinnawala elephant orphanage, Sri Lanka

BackgroundPrevious studies have established ovarian cycle characteristics of adult Asian elephants using progestagen analyses, but little work has been done on young elephants to determine age at puberty. Demographic studies of wild Asian elephants suggest females give birth at about 12–18 years of age (conceiving at 10–16 years of age based on a 2-year gestation). However, there are a few examples of zoo elephants giving birth at only 5–6 years of age, so they would have started cycling much earlier. This study was carried out at the Pinnawela Elephant Orphanage (PEO) in Sri Lanka, where a herd of >80 captive elephants breeds successfully, resulting in a unique opportunity to monitor hormones and document initiation of ovarian cyclicity in young females, thus contributing to the normative reproductive database for this species.ResultsWe measured serum progestagens in samples collected every 10 days for 18 – 24 months from 11 females (3.5–15 years of age), and found six (5.5 – 12 years of age) already were cycling at study onset. Four females started cycling during the study at 4.5, 5.5, 7.5 and 15 years of age. There were no quantitative or qualitative differences between the first pubertal luteal phase and those of subsequent cycles. Of the 46 ovarian cycles observed, 78% were associated with clear behavioral signs of estrus (heightened bull attentiveness, and willingness of females to be mounted) during the late non-luteal period when progestagens were low. The average body weight at puberty was ~48% of that of adult female elephants at PEO.ConclusionsAsian elephants under human care, including under semi-captive conditions, may reach puberty earlier than those in the wild, perhaps due to better nutrition and reaching a body weight capable of supporting reproductive activity at a younger age. Thus, facilities with bulls need to carefully manage elephants to avoid accidental pregnancies in young females that may be too small to safely carry a pregnancy to term.

Effects of fixed time AI and AI at detected estrus on conception rate in smallholder zebu and crossbred heifers and cows subjected to double PGF2α administration.

The study was conducted to evaluate estrus response, time to the onset of estrus, and conception rate at fixed time AI and AI at detected estrus in local and crossbred heifers and cows subjected to double administration of PGF2α. One hundred twenty local (heifers, n = 27; cows, n = 33) and crossbreds (heifers, n = 21; cows, n = 39) were used for the study. About 63 and 85.7% of the local and crossbred heifers, respectively, exhibited estrus. Similarly, all crossbred cows and 90.9% of local cows showed estrus. Most heifers came to estrus between 48 and 72h while cows exhibited behavioral signs of estrus between 72 and 96h. AI at detected estrus resulted in higher conception rate than fixed time AI. Pregnancy per artificial insemination was higher in AI at detected estrus than fixed time AI. Accurate estrus detection followed by insemination are crucial factors in maximizing pregnancy, and this study has demonstrated that conception rate in smallholder heifers and cows should be inseminated following estrus detection to maximize the conception rate of the animals.

Seasonal effects on behavioral estrus signs and estrus detection efficiency in Holstein heifers

In the study, 234 Holstein heifers were observed visually during a one-year period and 1622 estrus records were used to determine seasonal effects on behavioral estrus signs and estrus detection efficiency. Estrus records were classified as standing, mounting, vaginal mucus discharging, and the other estrus signs. The rates of these estrus signs were found to be 50.6%, 22.7%, 20.7% and 6.0%, respectively and the differences were significant (P&lt;0.01). These results showed that standing behavior was the most observable estrus sign in Holstein heifers. In addition, the rates of standing behavior in each season (66.2%, 59.7%, 50.4% and 38.0% in summer, fall, spring and winter, respectively) showed that it was also more observable sign than the other signs. The rates of estrus records according to seasons were found to be 34.4%, 32.9%, 23.6% and 9.1% in winter, fall, spring and summer, respectively and the differences were also significant (P&lt;0.01). In the study, the mean overall estrus cycle length was found to be 21.15±1.85 days. The mean overall estrus detection efficiency was calculated as 57.8%. The mean detection efficiencies according to seasons were found to be 79.5%, 75.9%, 54.6% and 21.1% in winter, fall, spring and summer respectively. These results could be interpreted that estrus detection efficiency was decreased significantly with increase of temperature.

Seasonal oestrous cycle activity of captive female koalas in south-east Queensland

This study investigated the seasonality of behavioural oestrus in a captive koala population in south-east Queensland. A total of 33 sexually mature koalas were examined over a 4-year period (2009–12) to determine the possible influence of temperature, photoperiod and rainfall on the incidence of expression of behavioural oestrus without the confounding effect of lactation or limiting food resource availability. Although signs of behavioural oestrus were detected throughout the year, an obvious seasonality was apparent, with significantly fewer females displaying behavioural oestrus in late autumn and winter (May–August) than September to April (P &lt; 0.0001). While average monthly photoperiod (P &lt; 0.0001) and average monthly temperature (P &lt; 0.0001) were significantly related to oestrous behaviour, rainfall was not (P &gt; 0.05). A better understanding of the seasonality of reproductive function in the female koala will facilitate the use of reproductive management-assisted breeding technology to enable improved genetic management in captive populations.

Irregular ovarian activity, body condition and behavioural differences are associated with reproductive success in female eastern black rhinoceros (Diceros bicornis michaeli)

Ex situ populations of endangered species such as the black rhinoceros play an important role in global conservation strategies. However, the European captive population of eastern black rhinoceros is performing sub-optimally, with growth rates and genetic viability limited by low birth rates and high reproductive skew. We investigated several intrinsic differences between parous and nulliparous females that may underlie differences in reproductive success, including ovarian cyclicity, adrenal activity, behaviour and body condition. Faecal samples were collected from 39 females (17 parous, 15 nulliparous and 7 pre-reproductive) at 11 zoological institutions, every other day for between 4months and 6years. Progestagen metabolite concentration indicated that although all non-pregnant females exhibited ovarian activity, irregular cyclicity was common. Longer cycles (>40days) were more common in nulliparous females and periods of acyclicity observed more often in females that had not bred for at least 7years. Even when endocrine data indicated clear ovarian activity, overt behavioural signs of oestrus were not always apparent, particularly among nulliparous females. Faecal glucocorticoids did not differ between parous and nulliparous females, although did differ according to individual temperament. More unpredictable temperaments were associated with higher glucocorticoids, and nulliparous females tended to be rated as more unpredictable. Finally, nulliparous females had higher body condition scores than parous females. This is the first comprehensive survey of the reproductive physiology of this European captive population, and highlights a number of intrinsic differences related to parity, which may underlie differences in reproductive success among captive female black rhinoceros.

Infrared technology for estrus detection and as a predictor of time of ovulation in dairy cows in a pasture-based system

The development and application of an algorithm to assess the ability of an infrared thermography (IRT) device to predict cows in estrus and about to ovulate was investigated. Twenty cows were synchronized using a controlled internal drug release and PGF2α. Vulval and muzzle temperatures were measured every 12 hours from controlled internal drug release insertion to 32 hours after PGF2α treatment and then every 4 hours until ovulation occurred or until 128 hours after PGF2α treatment (whichever occurred first). Thermal images obtained with a FLIR T620 series infrared camera were analyzed using ThermaCAM Researcher Professional 2.9 software. Cows were also monitored for behavioral signs of estrus and color changes of an Estrotect applied to the tail head of each cow 36 hours after PGF2α treatment. Algorithms were developed by adjusting body surface temperature of individual animals for ambient temperature and humidity during each observation period, and were expressed as a deviation from the baseline temperature. Of the 20 cows enrolled in this study, 12 (60%) ovulated. An IRT estrus alert was defined using different thresholds (D = 1 °C, 1.25 °C, and 1.5 °C). Sensitivity and specificity to predict estrus depended upon the chosen threshold level. At a threshold D = 1 °C, the highest sensitivity (92%; n = 11) and the lowest specificity (29%) and positive predictive value (64%) were observed. Conversely, D = 1.5 °C resulted in sensitivity of 75%, specificity of 57%, and positive predictive value of 69%. The mean ± standard deviation intervals between onset and the end of IRT estrus alert to ovulation were 30.7 ± 8.2 and 13.3 ± 7.7 hours, respectively. Ovulation occurred 24 to 47 hours after the onset of the IRT estrus alert for eight out of the 11 ovulated cows (73%). Although the sensitivity of the IRT alert was greater than visual observation (67%) and Estrotect activation (67%), the specificity and positive predictive value were lower than these two aids (i.e., the IRT overpredicted the incidence of ovulation). Results presented indicate that IRT shows some potential as an estrus detection aid; however, further studies investigating the potential to improve the specificity and capturing data throughout entire 21-day reproductive cycles would be worthwhile.

Effects of the GnRH analogue deslorelin implants on reproduction in female domestic cats

The aim of the present study was to investigate the safety and efficacy of deslorelin, a GnRH agonist, implants in suppressing estrus behavior and matings in a controlled ambient environment in feline queens in the presence of a tomcat. Local and utero-ovarian side effects of deslorelin implants were also investigated. The queens were housed in groups and assigned to one of three treatments: group 1 received 9.5 mg deslorelin implants (N = 14), group 2 received 5 mg megestrol acetate tablets and 9.5 mg deslorelin implants (N = 7), and group 3 were given placebo implants (N = 7). All implants were placed subcutaneously cranial to the interscapular region under xylazine hydrochloride sedation. Ovarian activity was monitored by fecal estradiol (E 2) analyses. The animals were observed daily and checked individually at three-day intervals for behavioral signs of estrus. After 18.5 mo of trial, queens were ovariohysterectomized, and ovaries and uteri were weighed and evaluated histologically. E 2 levels were significantly lower in group 1 and 2 than in group 3 with an average of 128.48 ± 19.97 ng/g, 90.44 ± 7.16 ng/g and 283.26 ± 39.21 ng/g, respectively, excepting the first week of treatment. After inserting implants an initial estrus-like increase in fecal E 2 concentrations occurred in all treated queens except one female in group 2. Ovarian and uterine weights were significantly different among the groups (P < 0.01), and were lowest in groups 1 and 2. Primordial and primary follicle numbers were significantly higher in groups 1 and 2 than in group 3 (P < 0.001). Endometrial gland, antral follicle, and corpus luteum (CL) numbers were highest in group 3 (P < 0.01, 0.001, and 0.001, respectively) compared with groups 1 and 2. Deslorelin implants successfully suppressed estrus behavior and E 2 secretion in queens for 18.5 mo of the study period. Further investigations are needed to demonstrate the effects of GnRH agonists on ovarian interstitial tissue.

Reproductive behaviour of the southern-hairy nosed wombat (Lasiorhinus latifrons)

The southern hairy-nosed wombat (Lasiorhinus latifrons) is under threat as its current distribution range and population size is declining. The low reproductive rates observed for this species, both in the wild and within captivity, are a cause for concern; as such this study was designed to provide a comprehensive account of reproductive behaviour in L. latifrons. The behaviour of four groups of captive animals (each 1♂ : 2♀) was remotely monitored for 14 months using a digital video-surveillance system. Using this technology, 13 distinctive reproductive-based behaviours were identified and recorded; each behaviour was allocated to one of two categories: courtship/guarding or mating. The courtship-to-mating ritual was made up of six consecutive phases: investigation, attraction, chase, restraint, coitus and recovery. In total, 423 courtship and 49 mating bouts were observed from five (2♂ : 3♀) wombats. Courtship behaviour was observed on 116 days, with a mean bout number of 3.6 ± 0.2 per day and a mean total daily time of 29.8 ± 1.8 min. Mating was observed on 24 days, with a mean bout number of 2.1 ± 0.3 per day and a mean total daily time of 100.1 ± 9.8 min. Courtship occurred over the entire enclosure area and three distinctive courtship locomotor patterns were identified: spiral-circles, straight-lines and random. Matings occurred only in closed spaces and were always accompanied by courtship behaviour. In contrast, only 68% of all courtship days were associated with a mating event. Receptivity in the female wombats lasted for 13 h and the behavioural signs of oestrus were so subtle that only the reaction/interest of the male could be used for its detection. The covert reproductive behaviours identified for female L. latifrons closely match those previously reported for captive common wombats and may relate to this species’ need to conserve energy.

Changes in endogenous estrogens and expression of behaviors associated with estrus during the periovulatory period in Heatsynch treated Murrah buffaloes (Bubalus bubalis)

The objective of this study was (1) to establish the duration of behavioral estrus signs and timing of ovulation in Murrah buffaloes (n = 10) and (2) to determine relationship between behavioral estrus signs with change in plasma estrogen concentrations in animals treated with Heatsynch protocol. Estrus and its behavioral signs were detected at hourly intervals by visual observations per rectal examination of genitalia and bull parading four times in a day for 30 min each. Among the behavioral signs of estrus, swollen vulva was the best indicator of estrus followed by excitement and chasing by bull (90%). Among the duration of behavioral estrus signs, the first and longest duration of estrus signs was swollen vulva, which was seen up to 21.6 +/- 1.1 h after onset of estrus. The mean total duration of estrus symptoms from appearance to disappearance of all the behavioral estrus symptoms was 40.2 +/- 1.8 h. Endocrine profile during the periestrus period showed that the mean peak concentrations of total estrogen 330.9 +/- 108.3 pg/ml occurred at 9.6 +/- 1.0 h after estradiol benzoate injection. The average number of estrus symptoms observed per animal during Heatsynch treatment was 7.1. Ovulation occurred after 50.0 +/- 2.0 h after estradiol benzoate treatment and 26.7 +/- 2.0 h after end of total estrogen surge, respectively. In conclusion, our results suggest that all signs of behavioral estrus occurred after the preovulatory rise in estrogens. The first sign of estrus was swollen vulva, and this symptom persisted the longest.

Temporal changes in endogenous estrogens and expression of behaviors associated with estrus during the periovulaory period in Murrah buffaloes (Bubalus bubalis)

The objective of this study were (1) to establish the duration of behavioral estrus signs and timing of ovulation in Murrah buffaloes (n = 10) and (2) to determine relationship between behavioral estrus signs with change in plasma estrogen concentrations. Estrus and its behavioral signs were detected at hourly intervals by visual observations, per recta examination of genitalia and bull parading four times in a day for 30 minutes each. Among the behavioral signs of estrus, swollen vulva (80%) was the best indicator of estrus followed by excitement (70%). Among the duration of behavioral estrus signs the first and longest duration of estrus signs was swollen vulva which was seen upto 19.8 +/- 0.8 h after onset of estrus. The mean total duration of estrus symptoms from appearance to disappearance of all the behavioral estrus symptoms was 23.5 +/- 1.7 h. All the behavioral estrus symptoms were observed during the period of estrogen surge. Endocrine profile during the periestrus period showed that the mean peak concentrations of total estrogen 23.9 +/- 3.9 pg/ml occurred at 8.8 +/- 1.7 h after onset of estrus. The average number of estrus symptoms observed per animal during onset of spontaneous estrus was 5.7. Ovulation occurred after 37.4 +/- 1.7 h after onset of estrus and 13.4 +/- 1.0 h after end of total estrogen surge respectively. In conclusion, our results suggest that all signs of behavioral estrus occurred during the preovulatory rise in estrogens. The first sign of estrus to be observed was a swollen vulva and this symptom persisted the longest.

Estradiol increases Pet-1 and serotonin transporter mRNA in the midbrain raphe nuclei of ovariectomized rats

Previous research has shown that estradiol increases the anorexia associated with serotonin (5-HT) neurotransmission. To examine further the putative relationship between estradiol and 5-HT, we investigated whether estradiol increases the expression of Pet-1 and the 5-HT transporter ( 5-HTT), two genes implicated in the development and regulation of the 5-HT system. Ovariectomized (OVX) rats ( n = 5–6/group) were treated with 0, 2, or 10 μg estradiol benzoate (EB) in sesame oil on 2 consecutive days. Food intake and body weight were recorded 2 days later when EB-treated rats typically display signs of behavioral estrus (e.g., reduced feeding). Following the collection of behavioral data, rats were perfused, brains were removed, and coronal sections were cut through the midbrain raphe nuclei. Pet-1 and 5-HTT mRNA levels were quantified throughout the dorsal and median raphe nuclei (DRN and MRN) by conducting in situ hybridization on free-floating tissue sections using 35S-labeled cDNA probes. As expected, EB treatment decreased food intake and body weight on the day that modeled estrus. At this same time, EB treatment increased Pet-1 and 5-HTT mRNA levels within the DRN and MRN. We conclude that a physiologically relevant regimen of estradiol treatment in OVX rats increases Pet-1 and 5-HTT mRNA levels in the midbrain raphe nuclei at a time when the anorexigenic effect of estradiol is apparent. Further studies are required to determine whether the increased expression of Pet-1 and 5-HTT mRNA plays a causal role in the anorexigenic effect of estradiol.

Development and validation of a new method for visual detection of estrus in mithun ( Bos frontalis)

The objectives of this study were (1) to develop a suitable scoring scale for estrus detection based on frequency and reliability of behavioral signs of estrus in mithun ( Bos frontalis) and (2) to validate the accuracy of this method for detection of estrus in primi- and multiparous mithun cows. The study consisted of two experiments. In experiment I, all animals were observed for 30 min at 2 h intervals for at least 35 days, for signs of estrus. Estrus was further confirmed by rectal examination of the reproductive organs and quantification of plasma progesterone concentrations. Based on the frequency and reliability of a particular sign, a cumulative point scale composed of seven estrous signs that were scored with points, ranging from 3 to 100, was developed. When the sum of the scores exceeded 100 points, the animal was considered to be in estrus. This was again confirmed by rectal examination of the genitalia and quantification of plasma progesterone concentrations. Calculation of efficiency and accuracy of the developed scale showed that this scale was 100% efficient and accurate, irrespective of parity. In experiment II, the scoring scale was tested for its efficiency and accuracy for detection of estrus in primi- and multiparous mithun cows based on the behavioral observations recorded twice a day at 0630 and 1630 h for at least 35 days with each observation period lasting for 30 min. Interestingly, efficiency and accuracy of the scale for detection of estrus was 100% in this experiment. Behavioral estrus was more intense in primi- than multiparous mithun cows in both experiments. Duration of estrus was longer in primi- than multiparous animals. The results of the present investigation revealed that no individual behavioral sign of estrus can be used alone for estrus detection in mithuns; whereas the efficiency and accuracy of the scoring scale composed of seven estrous signs were 100%, even when animals were observed twice each day. In conclusion, the scoring scale that has been developed was suitable for detection of estrus in mithuns with high efficiency and accuracy. However, the scale should be validated for use by farmers to assess its practical usefulness.