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1.
Over the past few decades, the luteolytic dose of prostaglandin F2α (PGF2α) and its analogs, used to synchronize estrus for fixed-time insemination in dairy cattle, have remained unchanged. Given the beneficial effects of PGF2α on a young corpus luteum and on multiple ovulations in a fixed-time insemination protocol, and its therapeutic abortive effects on multiple ovulations in pregnant cows, we propose the use of a double PGF2α dose or two PGF2α treatments 24 hours apart. Ultrasonography procedures serve to identify luteal structures and may therefore help to determine the best PGF2α dose to improve the fertility of high-producing dairy cows.  相似文献   

2.
Prostaglandin F2α (PGF2α) and its analogs are used to induce luteolysis in estrus synchronization programs to terminate unwanted pregnancies or to promote ovulation in certain cow subpopulations. In the past few decades, the luteolytic dose of PGF2α has remained unchanged. This review explores the clinical implications of increasing the standard dose for these applications in high-producing dairy cows. Ultrasonography may assist in selecting the most appropriate PGF2α dose and improve the results. A reference has been used for PGF2α for promoting ovulation in herds showing poor reproductive performance.  相似文献   

3.
The purpose of the present research was to compare the enzyme activity of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), α-amylase, α-manosidase, β-N-acetyloglucosaminidase, β-glucuronidase, and β-galactosidase in the cervical mucus of cows during spontaneous and induced estrus. Friesian cows (n = 106) were assigned to 4 groups: 1) no treatment; 2) progesterone releasing intervaginal device (PRID) for 12 days plus pregnant mare serum gonadotrophin (PMSG) at the removal of the PRID; 3) PGF2α2 doses 11 days apart; and 4) PRID for 7 days plus PGF2α 1 dose, 24 hours before removal of the PRID. Fourteen cows were excluded from the trial because of an inadequate quantity of cervical mucus collected or a lost PRID. The cows from the 3 induced estrus groups were artificially inseminated (AI) twice, while those with spontaneous estrus received only a single AI. Cervical mucus samples were collected from all cows 5 to 30 min before the first AI. The results are summarized as follows: 1) ALP and α-amylase activity for spontaneous estrus were similar to those for induced estrus; 2) LDH activity levels during spontaneous estrus were significantly lower (P < 0.001) than that in the P4 and P4+PGF2α induced estrus groups; and 3) glycosidases' activity was significantly lower (P < 0.001) in the spontaneous estrus group than that in the induced estrous groups. In conclusion, the activity of most enzymes in the cervical mucus of cows, in the present study, was significantly different between the spontaneous and the induced estrus groups.  相似文献   

4.
Fifteen Holstein cows were treated with two doses of 25 mg of a prostaglandin F2α (PGF2α as dinoprost tromethamine) administered intramuscularly 11 days apart. The cows were then divided into three groups and inseminated either at 72, 80 or 72 and 96 hours after the second dose of PGF2α. Thirteen cows ovulated after the second prostaglandin treatment. Eight cows were diagnosed pregnant by rectal palpation 42 days after insemination but only five calved. PGF2α induced luteolysis in cows with active corpora lutea as evidenced by the dramatic decreases in the plasma progesterone concentrations after treatment. In contrast, following PGF2α administration to cows in follicular or late luteal phase the concentrations of plasma progesterone either increased gradually or remained low for several days before increasing to maximal levels. The ovulatory rate after the two doses of PGF2α11 days apart was high. However, the pregnancy rate after this treatment was influenced by other factors including abnormal ovarian function.  相似文献   

5.
Recently, we observed that lipopolysaccharide (LPS) suppresses corpus luteum (CL) function in isolated perfused ovaries. It remained unclear if this suppression was due to increased luteal PGF2α secretion or LPS-induced apoptosis. Therefore, possible impacts of PGF2α and LPS were inhibited by a non-steroidal anti-inflammatory drug (flunixin) and an endotoxin-binding agent (polymyxin B), respectively. Bovine ovaries with a mid-cycle CL were collected immediately after slaughter and perfused for 240 min. After 50 min of equilibration, either flunixin or polymyxin B (5 μg/ml of each) were added to the perfusion medium of six ovaries, respectively. All ovaries (n = 12) were treated with E. coli LPS (0.5 μg/ml) 60 min after the onset of perfusion, and received 500 I.U. of hCG after 210 min of perfusion. Progesterone and PGF2α were measured in the effluent perfusate every 10 and 30 min, respectively. Biopsies of the CL were collected every 60 min to determine the mRNA expression of the cytokine TNFA and factors of apoptosis (CASP3, -8). Flunixin-treatment inhibited the increase of PGF2α after LPS-challenge that was observed in the polymyxin B-treated (PX-LPS) ovaries. After hCG-stimulation, progesterone secretion increased (P < 0.05) in group PX-LPS but not in the flunixin-treated (F-LPS) ovaries. Compared to initial values before LPS-challenge, luteal mRNA expression of TNFA and CASP3 was increased (P < 0.05) in group F-LPS at 120 and 180 min, respectively, and those of CASP8 was decreased (P < 0.05) in PX-LPS at 60 and 120 min after LPS-treatment. In conclusion, although flunixin managed to inhibit PGF2α, it did not suffice to successfully prevent LPS-induced apoptosis. However, endotoxin-binding polymyxin B resulted in luteal responsiveness to hCG after LPS-challenge.  相似文献   

6.
Objectives were to evaluate risk factors affecting ovulatory responses and conception rate to the Ovsynch protocol. Holstein cows, 466, were submitted to the Ovsynch protocol [day 0, GnRH‐1; day 7, prostaglandin (PG) F2α; day 9, GnRH‐2] and 103 cows were inseminated 12 h after GnRH‐2. Information on parity, days in milk at GnRH‐1, body condition, milk yield, exposure to heat stress, pre‐synchronization with PGF2α and the use of progesterone insert from GnRH‐1 to PGF2α was collected. Ovaries were scanned to determine responses to treatments. Overall, 54.7%, 10.6%, 2.2%, 81.1%, 9.0%, 91.5% and 36.9% of the cows ovulated to GnRH‐1, multiple ovulated to GnRH‐1, ovulated before GnRH‐2, ovulated to GnRH‐2, multiple ovulated to GnRH‐2, experienced corpus luteum (CL) regression and conceived, respectively. Ovulation to GnRH‐1 was greater in cows without a CL at GnRH‐1, cows with follicles >19 mm and cows not pre‐synchronized with PGF2α 14 days before GnRH‐1. Multiple ovulations to GnRH‐1 increased in cows without CL at GnRH‐1 and cows with follicles ≤19 mm at GnRH‐1. Ovulation before GnRH‐2 was greater in cows without CL at PGF2α. Ovulation to GnRH‐2 increased in cows that received a progesterone insert, cows with a CL at GnRH‐1, cows with follicles not regressing from the PGF2α to GnRH‐2, cows with larger follicles at GnRH‐2, cows that ovulated to GnRH‐1 and cows not pre‐synchronized. Multiple ovulations after GnRH‐2 increased in cows with no CL at GnRH‐1, multiparous cows and cows that multiple ovulated to GnRH‐1. Conception rate at 42 days after AI increased in cows with body condition score > 2.75 and cows that ovulated to GnRH‐2. Strategies that optimize ovulation to GnRH‐2, such as increased ovulation to GnRH‐1, should improve response to the Ovsynch protocol.  相似文献   

7.
We examined the response to exogenous prostaglandin F2α in cattle with or without palpable structures believed to be ovarian follicles. All animals had ovarian structures diagnosed by palpation as corpora lutea. The cows were placed into two groups: those with follicles which were estimated by the palpators to be ≤13 mm diameter (n=60); and cows with no palpable follicles or with follicles <13 mm diameter (n=133). Comparisons of proportion in estrus within five days, days to estrus, and milk progesterone levels failed to show significant differences between the groups.  相似文献   

8.
The occurrence of multiple metabolic and inflammatory diseases in dairy cows is higher during the periparturient period, which may be triggered by bacterial components, but not a viable bacterium. This study aimed to determine the association of endometritis and ovarian follicular cyst (OFC) with mastitis in dairy cows. Ninety-eight Holstein dairy cows were clinically examined for endometritis and OFC approximately 30–50 days after calving. Blood and milk samples were collected for the determination of milk somatic cell count (SCC); milk interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), and interleukin-8 (IL-8) concentrations; and plasma haptoglobin (Hp) and lipopolysaccharide-binding protein (LBP) concentrations. Of the 98 dairy cows included in this study, 12 were diagnosed with endometritis and 37 cows were identified as OFC-positive, whereas the remaining 49 cows were healthy (without endometritis or OFC). The average and maximum SCCs and plasma Hp and LBP concentrations were not significantly different between the healthy cows and those with endometritis or OFC. However, when the maximum SCC was classified as <300, 300–1,000, or >1,000 × 103 cells/ml, the percentage of cows with the maximum SCC <300 × 103 cells/ml was significantly lower in the endometritis and OFC-positive groups than in the healthy group. These results suggested that cows with endometritis and OFC during the postpartum period exhibit high SCC, indicating that some bacterial components can be transferred between organs.  相似文献   

9.
The aim of this study was to examine whether increased frequency of luteinizing hormone (LH) pulses influences luteal progesterone (P4) secretion by measuring progesterone concentrations at the secreted (caudal vena cava) and circulating levels (jugular vein) in lactating dairy cows. Cows received six intravenous administrations of 2.5 μg of GnRH (gonadorelin acetate, n=4) or 2 ml saline (n=3) at 1-h intervals on 12.4 ± 0.4 (mean ± SE) days after ovulation. Blood samples were collected from the caudal vena cava and jugular vein every 12 min for 12 h (6 h before and after treatment). During the 6 h after treatment, frequency of LH pulses (5.3 ± 0.3 and 3.0 ± 0.0 pulses/6 h) and mean LH concentration (0.50 ± 0.06 and 0.38 ± 0.05 ng/ml) were greater (P<0.05) in GnRH-treated cows than in saline-treated cows. Mean P4 concentration and amplitude of P4 pulses in the caudal vena cava during the 6 h after treatment were greater (P<0.05) in GnRH-treated cows than in saline-treated cows, but the frequency of P4 pulses was not different between the groups. Mean P4 concentration in the jugular vein during the 6 h after treatment was also higher (P<0.05) in GnRH-treated cows than in saline-treated cows (7.0 ± 1.3 and 5.4 ± 0.9 ng/ml). These results indicate that the increased frequency of LH pulses stimulates progesterone secretion from the functional corpus luteum and brings about higher P4 concentrations in the circulating blood in lactating dairy cows.  相似文献   

10.
The objective of our study was to compare the characteristics of the corpus luteum (CL) formed after ovulation of the dominant follicle (DF) of the first follicular wave (W1) and those of the CL formed after ovulation of the DF of the second (induced) follicular wave (W2). Non-lactating Holstein cows were used for this study. In Experiment 1, cows were treated with PGF2α and GnRH on days 6 and 8 (day 0 = day of follicular wave emergence) for W1 (n = 6) and W2 (n = 6), respectively. Dominant follicles were aspirated on day 9 to quantify the amounts of mRNA (VEGF120, VEGF164, FGF-2, StAR, P450-scc and 3β-HSD) in granulosa cells (GC). In Experiment 2, the size and blood flow area of the CL formed after ovulation of the DF in W1 (W1CL; n = 6) and W2 (W2CL; n = 6) (the day of DF ovulation in W1 and W2 was day 10) were evaluated on days 12, 15, 18 and 21. The plasma P4 concentration was measured on days 10 to 21. The amounts of VEGF164, P450-scc and 3β-HSD mRNA were higher (P < 0.05) in the DF in W1, and those of VEGF120,FGF-2 and StAR mRNA tended to be higher (P < 0.1) in the DF in W1. The size of the CL was greater in the W1CL on days 15, 18 and 21. The blood flow area of the CL was greater in the W1CL on days 12 and 15. The plasma P4 concentrations were higher in the W1CL. These results indicate that the CL formed after ovulation of the DF in W1 was greater in terms of size, blood flow and plasma P4 concentration.  相似文献   

11.
In this study, the effect of serum paraoxonase-1 (PON-1) activity on superovulation response and embryo yield was evaluated. The study material comprised 50 Holstein cows aged 3–4 years on postpartum day 90–120 with a body condition score of 3–3.25. A progesterone-based estrus synchronization protocol was initially administered to the selected donors. For this purpose, progesterone source was inserted intravaginally (day 0) and gonadotropin-releasing hormone injection was performed (day 6). Seven days after the insertion of progesterone device, follicle-stimulating hormone injections (total dose of 500 µg in decreasing doses for 4 days) were administered for superovulation. On the morning of the ninth day, prostaglandin (PG) F2α was administered, and the progesterone device was removed from the vagina in the evening on the same day. Two days after PGF2α administration, fixed-time artificial insemination was performed in the morning and in the evening. On the day of artificial insemination, blood samples were taken from the donors to determine the serum PON-1 activity. Uterine flushing was performed seven days after insemination. The results revealed that the serum PON-1 activity (mean ± SD, 562.71 ± 140.23 U/l) of the cows that responded to superovulation (donors with total corpus luteum count of ≥3 in both ovaries) was higher than those (389.91 ± 80.51 U/l) that did not (P<0.05). On the day of insemination, a positive correlation was determined between serum PON-1 activity and the counts of total corpus luteum (r=0.398), total oocyte/embryo (r=0.468), transferable embryo (r=0.453), and Code I embryos (r=0.315, P<0.05). Unlike the Code I embryos, there was no significant correlation between serum PON-1 activity and the number of Code III embryos. Moreover, no significant difference in the number of Code III embryos between the two PON-1 groups was observed. However, embryo yield and quality were found to have increased with increased PON-1 activity. Therefore, it was concluded that serum PON-1 activity may be associated with superovulation response, embryo yield and quality in donor cows.  相似文献   

12.
This study compares in two experiments the responses of lactating dairy cows to four different progesterone-based protocols for fixed-time artificial insemination (FTAI) in terms of their effects on follicular/luteal dynamics and fertility. The protocols consisted of a progesterone intravaginal device fitted for five days, along with the administration of different combinations of gonadotropin releasing hormone, equine chorionic gonadotropin and a single or double dose (24 h apart) of prostaglandin F2α. In Experiment I, the data were derived from 232 lactating cows. Binary logistic regression identified no effects of treatment on ovulation failure or multiple ovulation 10 days post artificial insemination (AI). Based on the odds ratio, the likelihood of ovulation failure was lower (by a factor of 0.1) in cows showing at least one corpus luteum (CL) upon treatment than in cows lacking a CL; repeat breeders (> 3 AI) and cows with multiple CLs at treatment showed lower (by a factor of 0.44) and higher (by a factor of 9.0) risks of multiple ovulation, respectively, than the remaining animals. In Experiment II, the data were derived from 5173 AIs. The independent variable treatment failed to affect the conception rate 28–34 days post AI, twin pregnancy or early fetal loss 58–64 days post AI. The results of this study demonstrate the efficacy of 5-day progesterone-based protocols for FTAI. All four protocols examined were able to induce ovulation in both cyclic and non-cyclic animals so that FTAI returned a similar pregnancy rate to spontaneous estrus. Our results suggest that the ovarian response and fertility resulting from each treatment are due more to the effect of ovarian structures at treatment than to the different combinations of hormones investigated.  相似文献   

13.
This study aimed to assess the impact of seasonal thermal stress on oxidative stress, immune response, and stress hormones of lactating dairy cows in subtropical regions with different levels of temperature-humidity index (THI). A total of 32 healthy lactating Holstein dairy cows experienced 4 seasons (8 cows/season). The physiological parameters were categorized into low THI (LTHI, THI = 42.97 ± 0.95) in winter, moderate THI (MTHI, THI = 61.84 ± 0.42) in spring and autumn, and high THI period (HTHI, THI = 86.09 ± 0.23) in summer. The blood samples were collected twice in each season to measure oxidative stress, inflammatory and hormonal parameters. Our results showed THI had a positive correlation with the rectal temperature (R2 = 0.821, P < 0.001) and respiratory rate (R2 = 0.816, P < 0.001). Dry matter intake, milk yield and fat percentage also significantly differed among groups (P < 0.05). Compared with the MTHI group, the LTHI group exhibited a significant increase in malondialdehyde (MDA) level (P < 0.001), and the HTHI group displayed a significant increase in levels of cortisol, interleukin (IL)-10, IL-1β and tumor necrosis factor-α (P < 0.001). Opposite changes in serum endotoxin and immunoglobulin G levels were observed with the increasing THI (P < 0.001). LTHI notably increased the triiodothyronine level, although the thyroxine level was reduced by LTHI and HTHI compared with the MTHI group. In conclusion, LTHI and HTHI conditions may induce different degrees of oxidative stress, inflammation response, and stress hormone imbalances on lactating dairy cows, therefore environmental management is necessary for the health of dairy cows in extreme weather conditions.  相似文献   

14.
Very little is known about the effects of hormonal synchronization of follicle waves and superovulation on the estrogen content of a cow’s milk. The objective of this study was to determine the effect in dairy cows of synchronization with estradiol-17β (E2) and progesterone (P4) on milk E2 concentrations and to compare these levels with those achieved during superstimulation for 4 d with porcine follicle-stimulating hormone (FSH). The milk E2 concentrations were raised significantly above pretreatment levels (P < 0.05) for 2 d after synchronization, the mean peak being 40.2 ± 18.5 (standard error) pg/mL and the pretreatment mean 1.5 ± 0.5 pg/mL. The mean peak E2 concentration during ovarian stimulation was 4.4 ± 0.7 pg/mL. The mean E2 concentration was significantly higher (P < 0.05) after synchronization than during superstimulation for the 1st milking after synchronization but not subsequent milkings. The milk estrone concentrations were above pretreatment levels for 1 d after synchronization and were not different from those observed during superstimulation.  相似文献   

15.
This study compared the responses shown by lactating dairy cows to four different P4-based protocols for AI at estrus. Cows with no estrous signs 96 h after progesterone intravaginal device (PRID) removal were subjected to fixed-time AI (FTAI), and their data were also included in the study. In Experiment I, follicular/luteal and endometrial dynamics were assessed every 12 h from the beginning of treatment until AI. The estrous response was examined in Experiment II, and fertility was assessed in both experiments. The protocols consisted of a PRID fitted for five days, along with the administration of different combinations of gonadotropin releasing hormone (GnRH), equine chorionic gonadotropin and a single or double dose (24 h apart) of prostaglandin F2α. In Experiment I (40 cows), animals receiving GnRH at the start of treatment showed a significantly higher ovulation rate during the PRID insertion period while estrus was delayed. In Experiment II (351 cows), according to the odds ratios, cows showing luteal activity at the time of treatment were less likely to show estrus than cows with no signs of luteal activity. Treatment affected the estrous response and the interval from PRID removal to estrus but did not affect conception rates 28–34 days post AI. Primiparous cows displayed a better estrous response than multiparous cows. Our findings reveal acceptable results of 5-day P4-based protocols for AI at estrus in high-producing dairy cows. Time from treatment to estrus emerged as a good guide for FTAI after a 5-day P4-based synchronization protocol.  相似文献   

16.

Background

The main objective of this study was to estimate the effect of supplementation with Saccaromyces cerevisiae (SC) (Yea-Sacc® 1026) on milk production, metabolic parameters and the resumption of ovarian activity in early lactation dairy cows.

Methods

The experiment was conducted during 2005/2006 in a commercial tied-house farm with an average of 200 milking Estonian Holstein Friesian cows. The late pregnant multiparous cows (n = 46) were randomly divided into two groups; one group received 10 g yeast culture from two weeks before to 14 weeks after calving. The groups were fed a total mixed ration with silages and concentrates. Milk recording data and blood samples for plasma metabolites were taken. Resumption of luteal activity was determined using milk progesterone (P4) measurements. Uterine bacteriology and ovarian ultrasonography (US) were performed and body condition scores (BCS) and clinical disease occurrences were recorded. For analysis, the statistical software Stata 9.2 and R were used to compute Cox proportional hazard and linear mixed models.

Results

The average milk production per cow did not differ between the groups (32.7 ± 6.4 vs 30.7 ± 5.3 kg/day in the SC and control groups respectively), but the production of milk fat (P < 0.001) and milk protein (P < 0.001) were higher in the SC group. There was no effect of treatment on BCS. The analysis of energy-related metabolites in early lactation showed no significant differences between the groups. In both groups higher levels of β-hydroxybutyrate (BHB) appeared from days 14 to 28 after parturition and the concentration of non-esterfied fatty acid (NEFA) was higher from days 1–7 post partum (PP). According to US and P4 results, all cows in both groups ovulated during the experimental period. The resumption of ovarian activity (first ovulations) and time required for elimination of bacteria from the uterus did not differ between the groups.

Conclusion

Supplementation with SC had an effect on milk protein and fat production, but did not influence the milk yield. No effects on PP metabolic status, bacterial elimination from the uterus nor the resumption of ovarian activity were found.  相似文献   

17.
The objective of this study was to determine rates of estrus and conception in lactating multiparous Holstein cows given 500 μg of cloprostenol intramuscularly after detection of the following ≥ 60 d after parturition: a solid corpus luteum (CL), a CL with a nonechodense cavity ≤ 20 mm in diameter (CLcav), a luteal cyst (cavity > 20 mm in diameter and a luteinized wall > 3 mm in diameter), or a follicular cyst (cavity > 20 mm and a luteinized wall ≤ 3 mm in diameter). The estrus rates were 335/419 (80.0%), 183/223 (82.1%), 170/182 (93.4%), and 44/87 (50.6%), respectively (P < 0.0001), and the conception rates 30 to 36 d after insemination among the estrous cows with an apparently normal mucus discharge were 130/285 (45.6%), 44/141 (31.2%), 39/79 (49.4%), and 19/30 (63.3%), respectively (P < 0.002). Compared with a solid CL, a CLcav did not affect the estrus rate but significantly reduced the conception rate (P < 0.05), and the estrus rates were significantly higher and lower in cows with a luteal or follicular cyst, respectively (P < 0.05).  相似文献   

18.
Peripheral plasma levels of 15-keto-13,14-dihydro-PGF2α, progesterone, Cortisol, LH and prolactin were studied in 6 primiparous postpartum dairy cows. The cows were followed by hormone measurements and clinical examinations from parturition until pregnancy was established. Blood was collected 3 times per day. The cervix, uterus and ovaries were examined by rectal palpation at 6–10 days intervals. The cows were observed for signs of oestrus twice daily and were additionally teased with a bull to provoke standing heat.Four cows had a normal parturition and dropped their fetal membranes shortly afterwards. (NR group). The remaining 2 retained their fetal membranes for more than 24 h following parturition (RFM group). One out of 6 cows showed standing oestrus at the first ovulation, 4 animals were in oestrus at the second ovulation and all cows showed signs of oestrus at the third ovulation. Although the length of the first luteal phase varied from 9 to 22 days a corpus luteum was in all cases palpated. The secretion of progesterone during the first luteal phase was terminated by a PGF2α release.A significant difference in 15-keto-13,14-dihydro-PGF2α levels between the 2 groups was found on days 0–4 (2.39 vs 6.87 nmol/1 at Ρ < 0.06). Postpartum prostaglandin F2α release as reflected by the level of 15-keto-13,14-dihydro-PGF2α lasted shorter in the NR group than in the RFM group (15–17 vs 21 days). Significant positive correlations between 15-keto-13,14-dihydro-PGF2α and Cortisol as well as between prolactin and Cortisol during the first 24 days postpartum were noted only in cows having normal parturition. The most pronounced daily prolactin variations occurred during the second luteal phase (NR group), when a significant difference between the times 8.00, 12.00 and 15.00 was recorded (14.7, 31.5 and 19.7 μg/l, respectively). Moreover, a partial negative correlation between log value of prolactin and arithmetical value of LH was found in these cows only during the first luteal phase after parturition.  相似文献   

19.
Intravenous administration of 2.6–3.3 µg/kg of an endotoxin from Salmonella typhimurium to goats caused a marked drop in plasma Ca levels associated with an increase of prostaglandin synthesis and release measured as peripheral plasma levels of 15-keto-13,14-dihydro-PGF2 α. This is one of the main metabolites of PGF2 α, but also PGE2 α is partly metabolised to this compound. The infusion of 10 mg of PGF2 α lowered plasma Ca levels. Ten mg of PGE2 did not change Ca concentrations significantly.  相似文献   

20.
Changes in immune factors expressed by milk somatic cells from Holstein cows with hypocalcemia after calving were investigated in this study. Fourteen multiparous Holstein cows after their 3rd or 4th calving in one farm were used. The cows were divided into 2 groups: 7 cows needing treatment due to onset of hypocalcemia (hypocalcemia group; age = 5.53 ± 0.27 years, parity = 3.14 ± 0.14) and 7 cows without health problems (control group; age = 5.88 ± 0.31 years, parity = 3.57 ± 0.26). Milk samples were collected aseptically using a cannula and mRNA of immune factors expressed by milk somatic cells were analyzed. Milk samples (50 mL) were collected from the right rear mammary gland of cows before milking at day 1 and weeks 1, 2, 4, and 8 after calving. All milk samples showed a negative reaction to the California Mastitis Test. Levels of relative interleukin (IL)-6 and cathelicidin in the hypocalcemia group were lower than those in the control group in weeks 1 to 8. A significant difference in relative IL-6 levels was found in week 4 (P < 0.05). These results suggest that levels of IL-6 expressed by milk somatic cells may be affected by hypocalcemia in dairy cows.  相似文献   

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