The reproductive performance of dairy cows has declined, along with an increase in their milk yield. First-service conception rates in lactating dairy cows are often lower than 50%. The precise ...detection of estrus is an important factor in the reproductive management of dairy cows for successful fertilization and pregnancy. However, estrus expression has been decreasing in modern dairy cows, affecting the detection rate of estrus. In addition to estrus, a high incidence of ovulation disorders affects the fertility of dairy cows. To address these problems, it is necessary to understand the changes in the endocrine functions that underlie estrus and ovulation disorders, and to develop effective treatment strategies. Recent studies have revealed that neurokinin B and neurokinin 3 receptor signaling play important roles in the regulation of the secretion of gonadotropin-releasing and luteinizing hormones, suggesting a potential clinical avenue for the stimulation of gonadal function. In this review, I have discussed the problems in estrus and ovulation disorders in modern dairy cows as well as the possible applications of neurokinin 3 receptor agonists in the treatment of these disorders.
This study aimed to test the hypothesis that short-term supplementation with a high-energy diet promotes embryo production following ovum pick-up (OPU) in Japanese Black cows. After a period of ...adaptation to the maintenance diet, a 200% maintenance diet was fed to the high-energy diet group (HD group, n = 6) for four weeks, and a maintenance diet was fed to the other group (MD group, n = 6). OPU-in vitro fertilization (IVF) procedures were performed on days 14, 21, and 28; follicles and oocytes were counted and morphologically graded, and cultivable oocytes were cultured for in vitro maturation,fertilization, and culture. The mean plasma insulin concentrations on days 14 and 21 were significantly higher in the HD group than in the MD group (P < 0.05). The number of follicles observed at OPU, recovered oocytes, cultivable (Grades 1 to 4) oocytes, and the rate of degenerated (Grade 6) oocytes in the HD group were significantly higher than those in the MD group (P <0.05). The proportion of cleaved oocytes was lower in the HD group than in the MD group (P <0.05); consequently, there was no significant difference in the number of blastocysts obtained between the HD and MD groups. The present findings suggest that high-energy diets can promote follicular growth in parallel with an increase in plasma concentrations of insulin, but have a detrimental effect on the quality of oocytes with the OPU-IVF procedure in Japanese Black cows.
To improve the accuracy of ultrasonographic assessment of luteal function, we investigated the relationship between ovarian ultrasonographic findings on Day 7 (Day 1 = ovulation) and plasma ...progesterone (P4) concentration, nutritional metabolic factors, and pregnancy outcome. A total of 47 spontaneous estrus events were investigated in 38 lactating Holstein cows (artificial insemination, n = 31; embryo transfer, n = 16). Transrectal ultrasonography was performed on Days 0 and 7 to measure the pre-ovulatory follicle area on Day 0 and the luteal tissue area (LTA), luteal blood flow area (LBF), relative LBF (rLBF) (= LBF/LTA), and dominant follicle area (DFA) on Day 7. Blood samples were collected on Day 7 to measure plasma P4, insulin-like growth factor-I (IGF-I), insulin, and metabolites. Plasma P4 concentration was positively correlated with LTA but was not associated with LBF or rLBF. Plasma P4 concentration was positively correlated with blood glucose and IGF-I and negatively correlated with blood urea nitrogen and free fatty acid, and no significant relationship was found between the ultrasonographic findings of the corpus luteum (CL) and these blood metabolites. Pregnant cows had smaller DFA than non-pregnant cows. In conclusion, LTA measurement can help predict plasma P4 concentration, but it was difficult to detect variations in plasma P4 concentration in relation to changes in energy status by evaluating the CL ultrasonographically. A combined assessment of CL and first-wave dominant follicle may be important in evaluating fertility.
Estrus synchronization requires multiple treatments of hormonal drugs, requiring considerable time and cost. The aim of the present study was to develop an estrus synchronization protocol using ...intravaginal administration of estradiol benzoate (EB) capsules in goats. Two types of capsules were prepared: an EB capsule that melted immediately after administration and a sustained-release (SR) EB capsule that dissolved slowly and reached a peak after 24 h. Goats with functional corpus lutea were intramuscularly treated with prostaglandin F2α (PG). At 24 h after PG administration, goats were administered 1 mg of EB solution intramuscularly (PG + 24IM; n = 6) or 1 mg of EB capsule intravaginally (PG + 24EB; n = 6). The SR EB capsule was administered intravaginally at the time of PG administration (PG + SR; n = 6). The control group (n = 6) received only PG. All groups showed estrus within 72 h after PG administration. The onset of estrus did not differ significantly between the PG + 24IM and PG + SR groups but was earlier than in the control group. Estradiol concentration in the PG + SR group peaked at 11.5 ± 6.1 h after EB and PG administration. Peak estradiol concentrations were not significantly different between the PG + 24IM and PG + SR groups (78.0 ± 25.8 and 64.0 ± 38.1 pg/ml, respectively), and were higher than the PG + 24EB and control groups (27.3 ± 8.8 and 14.6 ± 6.1 pg/ml, respectively). These results suggest that intravaginal administration of an EB capsule with a sustained-drug release base is applicable for estrus synchronization, as an alternative to intramuscular administration.
Periparturient stress can have long-term negative effects on both dairy cows and their calves and may contribute to lower productivity. The purpose of this study was to determine how periparturient ...stress is related to differences in calving difficulty and health status by measuring hair cortisol concentration in periparturient dairy cows and their calves. Calving environment (calving pen, tie stall, and group paddock), calving difficulty, calving progress, health status, and calf weight were recorded, and tail hair from 25 of the cows and their calves was collected at calving and 1 month after calving to measure hair cortisol concentration. There were no significant correlations between hair cortisol concentration and calving environment, calving difficulty, calf weight gain rate. Hair cortisol concentrations at calving were significantly higher in cows with oversized calves or twin births than in cows with normal-sized singleton calves (4.2 ± 2.2 pg/mg vs 2.1 ± 1.5 pg/mg, P<0.05). Cows with clinical disease within one month of calving had significantly higher levels of hair cortisol one month after calving compared to healthy cows (3.8 ± 1.1 pg/mg vs 2.3 ± 1.9 pg/mg, P<0.05). Calves with clinical disease within the first month after birth tended to have higher hair cortisol levels at birth than healthy calves (4.7 ± 2.4 pg/mg vs. 3.2 ± 0.9 pg/mg, P<0.1). These results suggest that calving of oversized calves and twin births and suffering clinical diseases can cause more stress for cows during the periparturient period.
The objective of this study was to examine the effectiveness of using ultrasonography for sex determination in young carp. Ultrasound images were obtained from anesthetized captive carp aged 11 to ...13 months. After sacrifice, the body length and weight, gonadal sex and weight, and gonad-somatic index were measured. Well-developed testes and ovaries filled with granulated eggs were easily distinguishable on ultrasound imaging, based on their visible characteristic morphological features. In contrast, immature, small-sized testes and ovaries lacking granulated eggs were difficult to distinguish. The mean longitudinal thickness of gonads was technically the easiest to scan for measuring gonadal size, and it correlated well with gonadal weight (
r
= 0.91) and gonad-somatic index (
r
= 0.89). Based on the area under the curve of the receiver operating characteristic curve, we determined that 6.2 mm was the cutoff value for mean longitudinal gonadal thickness at which sex could be positively determined by ultrasonography, with a sensitivity of 82.6% and specificity of 100%. Ultrasonography therefore represents an effective and non-invasive diagnostic tool for determining sex and maturity in Japanese ornamental carp.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Uterine disease reduces reproductive performance in cows.•C-reactive protein (CRP) is a systemic biomarker of inflammation.•CRP was detected in the uterine lavage fluid of cows during the puerperal ...period.•CRP measurements can be utilized as a local biomarker of uterine inflammation in cows.
Changes in the C-reactive protein (CRP) concentration, a non-specific diagnostic biomarker, in uterine lavage fluid and associations with cytological findings were examined following parturition in dairy cows. In postpartum Holstein dairy cows (n = 8), uterine lavage was performed at 3 and 6 weeks postpartum, and polymorphonuclear leukocyte (PMN) ratios to total cells (PMN:ALL) and to lymphocytes (PMN:LYM) and CRP concentrations were determined. Blood samples were collected to monitor the metabolic variables, and plasma CRP concentrations were quantified using samples collected at the same time as the uterine lavage occurred. A cytological examination was performed to determine PMN:ALL and PMN:LYM. The values for metabolic variables were within the normal range throughout the postpartum period. There was a correlation between the PMN:ALL and PMN:LYM, and both ratios were less (P < 0.05) at 6 than 3 weeks postpartum. The mean CRP concentration of the uterine lavage fluid was less at 6 (27.7 ± 9.6 ng/ml) than 3 weeks (60.8 ± 28.1 ng/ml) postpartum, whereas mean plasma CRP concentration was greater at 6 (287.4 ± 34.1 ng/ml) than 3 (254.8 ± 29.4 ng/ml) weeks postpartum. The results of the present study indicate the CRP concentration of uterine lavage fluid decreased in parallel with the frequency of PMN during uterine involution, which leads to the suggestion that uterine lavage fluid CRP concentration could be utilized as a local biomarker for evaluating uterine inflammation in cows.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•ACTH administration once daily for 7 days did not influence hair cortisol content.•More frequent and longer-term administration increased the hair cortisol content.•Hair cortisol analysis can detect ...relatively long-term changes in circulating cortisol.
Measurement of the cortisol concentration in hair has been used as an index of chronic stress in several species including humans, wildlife and domestic animals. However, how accurately the cortisol concentration in hair reflects the changes in circulating cortisol concentrations has not been well documented. The objective of the present study was to examine the effect of repeated adrenocorticotropic hormone (ACTH) administration on the reproductive function during the estrous cycle and hair cortisol concentrations in goats. In experiment 1, goats were administered ACTH (0.625 IU/10 kg of body weight, n = 6) or saline (n = 6) intramuscularly once a day for 7 days on Day 11–17 of the estrous cycle (day 0 was the day of ovulation). In experiment 2, goats were administered ACTH (0.625 IU/10 kg of body weight, n = 6) or saline (n = 6) intramuscularly twice a day on Day 11–24 of the estrous cycle. Blood samples were collected 0, 0.5, and 6 h after first administration to determine the circulating cortisol concentrations. Hair was clipped at 0, 1, and 2 months after the start of administration. In both experiments, the plasma cortisol concentration increased at 0.5 h and returned to baseline at 6 h after ACTH administration. During the experiments, estrus was observed in most animals in ACTH and saline groups (6/6 and 4/6 in experiment 1 and 5/6 and 6/6 in experiment 2, respectively) and ovulation was observed in all goats examined. However, the number of ovulatory follicles was significantly different between the ACTH and saline groups, and the maximal diameter of ovulatory follicles tended to be different (P = .07) between the ACTH and saline groups. In experiment 1, the hair cortisol concentration was not influenced by the ACTH administration throughout the sampling period. In experiment 2, the hair cortisol concentration in the ACTH group was greater at 1 month after administration than the pre-administration value, but was not significantly different at 2 months. These results suggest that repeated ACTH administration affects the development and ovulatory process of ovarian follicles and analysis of the hair cortisol concentration can be used for assessing relatively long-term changes in cortisol concentration in the circulation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Changes in the C-reactive protein (CRP) and 13,14-dihydro-15-keto-prostaglandin F2α (PGFM) concentrations of uterine lavage fluid were examined in cows given an intrauterine povidone-iodine (PI) ...infusion. The mean polymorphonuclear leukocyte (PMN) ratios (the ratio of PMN to total cells) and CRP concentration of uterine lavage fluid on the day after the treatment were significantly (P<0.05) greater in the PI infusion group (PMN: 53.0 ± 32.7%, CRP: 50.2 ± 32.3 ng/mL) than in the non-treatment control group (PMN: 7.9 ± 21.9%, CRP: 17.2 ± 5.9 ng/mL), whereas there was no significant difference in the mean PGFM concentration between the two groups. The present findings suggest that the uterine CRP level is a useful biomarker of local uterine inflammation in cows.
The objective of the present study was to develop and evaluate a sustained release vaginal progesterone (P4) capsule containing a mixture of mucoadhesive polymer and silicone fluid. Goats were ...administered a gelatin capsule containing 0.4 g of P4 mixed in silicone fluid and either a hydroxypropylmethylcellulose (HM) or polyaclil starch (PA) base. The mean plasma P4 concentrations at 2 and 12 h after administration were significantly higher in goats treated with PA capsules than in those with HM capsules. The plasma P4 concentrations in goats treated with HM capsules increased and remained above 1.0 ng/ml for 96 h after administration, whereas the plasma P4 concentrations in goats treated with PA capsules remained above 1.0 ng/ml for only 24 h after administration. In the next experiment, an HM capsule was attached to a silicone device and inserted in the vagina for 10 days. The plasma P4 concentration remained similar to that of the natural luteal phase for 9 days. These results suggest that a mixture of mucoadhesive polymer and silicone fluid has the potential to be applied clinically as a sustained release base for estrus synchronization or hormonal therapy.
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