Expression dynamics of bovine MX genes in the endometrium and placenta during early to mid pregnancy

MX belongs to a family of type I interferon (IFN)-stimulated genes, and the MX protein has antiviral activity. MX has at least two isoforms, known as MX1 and MX2, in mammals. Moreover, bovine MX1 has been found to have alternative splice variants—namely, MX1-a and MX1B. In ruminants, IFN-τ—a type I IFN—is temporarily produced from the conceptus before implantation and induces MX expression in the endometrium. However, the expression dynamics of MX after implantation are not clear. In the present study, we investigated the expression of MX1-a, MX1B and MX2 in the endometrium and placenta before and after implantation along with the expression of IFN-α, type I receptors (IFNAR1 and IFNAR2) and interferon regulatory factors (IRF3 and IRF9). Pregnant uterine samples were divided into five groups according to pregnancy days 14–18, 25–40, 50–70, 80–100, and 130–150. Tissue samples were collected from the intercaruncular endometrium (IC), caruncular endometrium (C) and fetal placenta (P). Although all the MX expressions were significantly higher in the IC and C at days 14–18, presumably caused by embryo-secreted IFN-τ stimulation, their expressions were also detectable in the IC, C and P after implantation. Furthermore, IFN-α expression was significantly higher in the IC. RT-PCR indicated IFNAR1, IFNAR2, IRF3 and IRF9 mRNA in all the tissues during pregnancy. These results suggest that all the MX genes are affected by the type I IFN pathway during pregnancy and are involved in an immune response to protect the mother and fetus.     

Sperm morphology and chromatin integrity in Swedish warmblood stallions and their relationship to pregnancy rates

Background

Artificial insemination is not as widely used in horses as in other domestic species, such as dairy cattle and pigs, partly because of the wide variation in sperm quality between stallion ejaculates and partly due to decreased fertility following the use of cooled transported spermatozoa. Furthermore, predictive tests for sperm fertilising ability are lacking. The objective of the present study was to assess sperm morphology and chromatin integrity in ejaculates obtained from 11 warmblood breeding stallions in Sweden, and to evaluate the relationship of these parameters to pregnancy rates to investigate the possibility of using these tests predictively.

Methods

Aliquots from fortyone ejaculates, obtained as part of the normal semen collection schedule at the Swedish National Stud, were used for morphological analysis by light microscopy, whereas thirtyseven were used for chromatin analysis (SCSA) by flow cytometry. The outcome of inseminations using these ejaculates was made available later in the same year.

Results

Ranges for the different parameters were as follows; normal morphology, 27–79.5%; DNA-fragmentation index (DFI), 4.8–19.0%; standard deviation of DNA fragmentation index (SD_DFI) 41.5–98.9, and mean of DNA fragmentation index (mean_DFI), 267.7–319.5. There was considerable variation among stallions, which was statistically significant for all these parameters except for mean_DFI (P < 0.001, P < 0.01, P < 0.001 and P < 0.2 respectively). There was a negative relationship between normal morphology and DFI (P < 0.05), between normal morphology and SD_DFI (P < 0.001), and between normal morphology and mean_DFI (P < 0.05). For specific defects, there was a direct relationship between the incidence of pear-shaped sperm heads and DFI (P < 0.05), and also nuclear pouches and DFI (P < 0.001), indicating that either morphological analysis or chromatin analysis was able to identify abnormalities in spermiogenesis that could compromise DNA-integrity. A positive relationship was found between normal morphology and pregnancy rate following insemination (r = 0.789; P < 0.01) and a negative relationship existed between DFI and pregnancy rate (r = -0.63; P < 0.05). Sperm motility, assessed subjectively, was not related to conception rate.

Conclusion

Either or both of the parameters, sperm morphology and sperm chromatin integrity, seem to be useful in predicting the fertilising ability of stallion ejaculates, particularly in determining cases of sub-fertility.     

Neospora caninum infection during early pregnancy in cattle: how the isolate influences infection dynamics,clinical outcome and peripheral and local immune responses

This work studies the influence of Neospora caninum intra-species diversity on abortion outcome, infection dynamics in terms of parasite dissemination and peripheral-local immune responses in pregnant cattle. Animals were intravenously inoculated at day 70 of pregnancy with 10⁷ tachyzoites of two isolates showing marked differences in virulence in vitro and in pregnant mouse models: Nc-Spain7, a high virulence isolate, and Nc-Spain8, a low-to-moderate virulence isolate. After inoculation, pregnancy was monitored, and dams were culled when foetal death was detected. Foetal mortality occurred in all infected heifers between days 24 and 49 post-infection (pi), however, it was detected sooner in Nc-Spain7-infected animals (median day = 34) than those inoculated with Nc-Spain8 (median day = 41) with a trend towards significance (P < 0.11). Similar histological lesions were observed in placentomes and in most of the foetuses from the two infected groups. However, parasites were more frequently detected in the placenta and foetuses by PCR and in the foetal brain by immunohistochemistry in Nc-Spain7-infected animals. Specific antibodies were detected starting at day 13 post-infection in all infected cattle, with higher IgG levels in Nc-Spain7-infected group. IFN-γ and IL-4 profiles also varied between infected groups in PBMC stimulation assays. Infected animals showed significant increases in their cytokine mRNA levels (IFN-γ, IL-4, IL-10, IL-12p40 and TNF-α) in the caruncle at time of foetal death. Differences between the infected groups were also observed for cytokine profiles. These results demonstrate the influence of the N. caninum isolate on foetal death outcome, infection dynamics and immune responses in cattle.     

Presence of multiple corpora lutea affects the luteolytic response to prostaglandin F2α in lactating dairy cows

Since the 1970s, luteolytic doses used for synchronizing estrus in dairy cattle have remained unchanged. This study aimed to evaluate the dose-response effect of prostaglandin F_2α (PGF_2α), which is used for synchronizing estrus, and subsequent fertility in cows with two or more corpora lutea (CL). The study population consisted of 1,683 cows with a single CL (1CL), 501 cows with multiple CL receiving a single dose of PGF_2α (2CL1), and 252 cows with multiple CL receiving a 1.5 × PGF_2α dose (2CL1.5). Cows with a single CL (n = 1,245) showed estrus significantly (P < 0.01) earlier (3.01 ± 1.23 days; mean ± SD) than cows with multiple CL (n = 287; 3.33 ± 1.69 days). Using 1CL cows as reference, the odds ratio (OR) for the estrus response in 2CL1 cows was 0.13 (P < 0.0001), whereas the ORs for estrus response and pregnancy of 2CL1.5 cows were 1.8 (P = 0.0001) and 1.7 (P = 0.001), respectively. Based on the results for only the 2CL1 cows, the OR for the estrus response was 0.7 (P = 0.01) for cows producing ≥ 45 kg of milk at treatment, compared to the remaining cows producing < 45 kg of milk. Our results showed that the presence of multiple CL reduced the estrus response to that induced by a single PGF_2α dose and milk production was inversely associated with this response, whereas an increased PGF_2α dose improved the estrus response. Therefore, an increase in the standard PGF_2α dose is recommended.     

Diazepam ameliorated myocardial ischemia-reperfusion injury via inhibition of C-C chemokine receptor type 2/tumor necrosis factor-alpha/interleukins and Bcl-2-associated X protein/caspase-3 pathways in experimental rats

Myocardial ischemia-reperfusion injury (IRI) is one of the most leading concerns for public health globally. Diazepam, a local anesthetic, has been reported for its cardioprotective potential. The present investigation aimed to evaluate the possible mechanism of action of diazepam against left anterior descending ligation-induced myocardial IRI in experimental rats. IRI was induced in healthy male rats by ligating coronary artery for 30 min and then reperfused for 60 min. The animals were pre-treated with either vehicle or diltiazem (10 mg/kg) or diazepam (1, 2.5, and 5 mg/kg) for 14 days. Compared to the IRI group, diazepam (2.5 and 5 mg/kg) markedly (P<0.05) attenuated IRI-induced alterations in cardiac function and oxido-nitrosative stress. In addition, diazepam prominently (P<0.05) improved cardiac Na⁺K⁺ATPase, Ca²⁺ATPase levels and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA expression. It also significantly (P<0.05) down-regulated cardiac mRNA expressions of cardiac troponin I (cTn-I), C-C chemokine receptor type 2 (CCR2), tumor necrosis factor-alpha (TNF-α), interleukins (IL)-1β, and IL-6. In western blot analysis, IRI-induced myocardial apoptosis was reduced by diazepam treatment reflected by a marked (P<0.05) decreased in Bcl-2-associated X protein (Bax) and Caspase-3 protein expression. Diazepam also efficiently (P<0.05) improved IRI-induced histological aberration in cardiac tissue. In conclusion, diazepam exerts cardioprotective effect by inhibiting inflammatory release (CCR2, TNF-α, and ILs), oxido-nitrosative stress, and apoptosis (Bax and Caspase-3) pathway during myocardial IRI in experimental rats.     

Number of ovulations in culled Landrace × Yorkshire gilts in the tropics associated with age,body weight and growth rate

The objective of the present study was to determine the number of ovulations in culled Landrace × Yorkshire (LY) crossbred gilts in the tropics associated with age, body weight and growth rate. The genital organs from 316 gilts were examined for gross abnormalities, and those with normal cyclic ovaries (n=155, 307 ± 4.1 days of age, 148 ± 1.6 kg body weight) were included in the analyses. Number of ovulations was defined by a count of the corpora lutea (CL) from both ovaries. On average, the number of ovulations in LY gilts was 15.9 ± 0.3 (range 4 to 27). The number of ovulations correlated with the body weight (r=0.31, P<0.001) and growth rate (r=0.20, P=0.015) of the gilts, but not with their age (P>0.05). Gilts with a body weight of 141 to 150 kg (17.0 CL, n=31) ovulated more than those with a body weight ≤130 kg (14.1 CL, P=0.014, n=23). In conclusion, both the body weight and growth rate of the gilts were significantly correlated with the number of ovulations. The maximum number of ovulations was found in gilts at a body weight of above 141 kg.     

Estrus response and fertility after a single cloprostenol treatment in dairy cows with various ovarian structures

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).     

Plasma Levels of Progesterone and Oestradiol-17 β in Reindeer (Rangifer Tarandus Tarandus) During Pregnancy

The plasma concentrations of progesterone and oestradiol-17p during pregnancy and the first 20 days after parturition were estimated in reindeer. The concentration of progesterone in the period 75–25 days prior to parturition was significantly higher than in the period 200– 75 days prior to parturition (P < 0.001). During the last 25 days before parturition the concentration decreased significantly. The concentration of oestradiol-17β was in most cases below 70 pg/ml until 50 days prior to parturition. During the last 25 days of pregnancy there was a significant increase in oestradiol-17β and the ratio progesterone/ oestradiol-17β was markedly lower than in the period 75–25 days before calving.Key words: reindeer, gestation, plasma, progesterone, oestradiol-17β     

Infusion of short chain fatty acids in the ileum improves the carcass traits,meat quality and lipid metabolism of growing pigs

Short chain fatty acids (SCFA) are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut, which are related to some physiological functions. This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits, meat quality and lipid metabolism of growing pigs. In a 28-day study, 24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments: 1) Control, 2) antibiotics (AB), 3) AB + 300 mL of SCFA1 solution (ABS1), 4) AB + 300 mL of SCFA2 solution (ABS2). The concentrations of acetate, propionate and butyrate in SCFA1 solution were respectively 61.84, 18.62 and 12.55 mmol/L, and in SCFA2 were respectively 40.08, 15.41 and 9.78 mmol/L. The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs (P < 0.05). Meanwhile, the SCFA treatments increased longissimus dorsi area (P < 0.05) and carcass weight (P = 0.058), decreased the drip loss of longissimus dorsi (P = 0.059), and reduced serum concentrations of triglyceride, total cholesterol and urea nitrogen (P < 0.05). Besides, the SCFA administration inhibited the mRNA expressions of fatty acid synthase (FAS) and acetyl-CoA carboxylase in longissimus dorsi (P < 0.05), the mRNA expression of FAS in the liver (P < 0.05), and the mRNA expression of hormone-sensitive lipase in abdominal fat (P < 0.05). Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1α in the liver (P < 0.05), the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat (P < 0.05), and the mRNA expressions of free fatty acid receptor 2, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon (P < 0.05). These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs, which was possibly due to the fact that SCFA modulated lipid metabolism.     

Ovulation of the preovulatory follicle originating from the first-wave dominant follicle leads to formation of an active corpus luteum

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.     

Dynamics of ovarian follicular development in cattle following hysterectomy and during early pregnancy

Three experiments were conducted to evaluate ovarian follicular dynamics and functional activity during pregnancy in cattle. In 11 pregnant Charolais cows of Experiment I, size of largest follicle, number of follicles and accumulated follicle size were reduced by day 27 of pregnancy on the ovary bearing the corpus luteum (CL) but not on the non-CL bearing ovary. In experiment II, local attenuation of ovarian follicular development on the CL bearing ovary of seven pregnant heifers was evident compared to the contralateral ovary without the CL. However, in four hysterectomized heifers, follicular development was sustained on both the CL- and non-CL bearing ovaries when CL maintenance was achieved without presence of the uterus or conceptus. In Experiment III, steroidogenic characteristics of the largest and second largest follicles at 17 d postestrus were evaluated for seven pregnant and six cyclic cattle. Follicle by physiological status interactions were detected for both aromatase activity of the follicle and follicular fluid concentrations of estradiol and progesterone. In cyclic cows, the largest follicle had appreciably more aromatase activity than did the second largest follicle; whereas, aromatase activity of the largest follicle from pregnant cows was less than that of cyclic cows. However, in pregnant cows the second largest follicle became the estrogen-active follicle, and this follicle occurred with a higher frequency on the ovary contralateral to the CL-bearing ovary. These changes in aromatase activity were reflected by parallel changes in estrogen concentrations of follicular fluid. The higher progesterone concentration in follicular fluid of the largest follicle in pregnant cows provided further confirmation of their atretic status. In conclusion, during early pregnancy the conceptus and/or uterus ipsilateral to the conceptus appear to secrete compounds which alter local follicular steroidogenic activity and attenuate subsequent follicular growth between 17 to 34 d of pregnancy on the CL-bearing ovary. This local mechanism acting within the ovary may contribute to the antiluteolytic effects of early pregnancy in cattle.     

Effects of different five-day progesterone-based fixed-time AI protocols on follicular/luteal dynamics and fertility in dairy cows

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 F_2α. 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.     

A field study on the usefulness of milk progesterone determination to confirm estrus and pregnancy of dairy cows in the Fraser Valley area of British Columbia

A field study was conducted to determine the usefulness of milk progesterone determination at the time of breeding to confirm estrus and at 21 days postbreeding to detect open cows. Twenty-seven dairy farmers collaborated in this study by providing milk samples on the day of breeding and 21 days later, together with pregnancy diagnosis data and information on herd reproductive management. Herd size ranged from 15 to 175 cows, the average being 65 milking cows. Six hundred and sixty-seven breeding-day samples and 472, 21-day samples were provided by the farmers. Analysis of milk samples for progesterone by a solid phase radioimmunoassay showed that only 32 (4.8%) of the services were performed when the cow was not in estrus (progesterone > 1 ng/mL). Of the 472, 21-day samples, 337 (71%) showed progesterone levels of > 1 ng/mL, while 135 (29%) showed progesterone levels of < 1 ng/mL. Subsequently, 243 (72%) of the cows with progesterone > 1 ng/mL and eight (6%) of the cows with progesterone < 1 ng/mL were diagnosed pregnant by transrectal palpation, giving a pregnancy rate of 53%. Progesterone concentration on the day of breeding was not associated with season or herd size. However, progesterone concentration at 21 days and pregnancy rate were associated with herd size. These results indicate that fertillzation failure and/or early embryonic mortality, rather than inaccurate detection of estrus, are the major reproductive problems encountered by the dairy farmers in British Columbia. Furthermore, progesterone values at 21 days were closely related to reproductive status and indicate the usefulness of milk progesterone assay for the early detection of open cows.     

Effects of administering exogenous bovine somatotropin to beef heifers during the first trimester on conceptus development as well as steroid- and eicosanoid-metabolizing enzymes

The aim of this study was to evaluate the effect of bovine somatotropin (bST) on fetal and placental development during the first third of gestation in beef heifers. Angus heifers (n = 97) were randomly assigned to either receive a 500-mg injection of bST (BST) biweekly on days 0, 15, 29, 43, and 57 of gestation or not receive bST (CTL) throughout the experiment. Body weight (BW) was assessed on days −9, −3, 0, 15, 22, 29, 43, 50, 57, 64, and 77, while blood samples were collected on days 0, 22, 50, and 64. Pregnancy status was determined via transrectal ultrasonography on days 29 and 64. A subset of pregnant heifers (BST, n = 7; CTL, n = 5) were harvested on day 84, and complete gravid reproductive tracts and liver tissue were collected for analysis. Cytochrome P450 1A (CYP1A), 2C (CYP2C), 3A (CYP3A), and uridine 5′-diphospho-glucuronosyltransferase (UGT) activities were determined. Mean change in BW and average daily gain of heifers between fixed-time artificial insemination (day 0) and day 77 did not differ between treatments (P ≥ 0.05). Mean concentrations of insulin-like growth factor 1 (IGF-1) were greater (P < 0.001) in BST (347 ± 27.7 ng/mL) compared with CTL (135 ± 32.8 ng/mL) heifers. Mean placental weight, fetal membrane weight, uterine weight, and ovarian and corpus luteum (CL) weights, as well as fetal morphometric data, did not differ (P ≥ 0.05) between treatments. However, BST heifers had greater (P = 0.03) quantities of combined fetal fluid compared with CTL (521.6 ± 22.9 vs. 429.6 ± 27.14 g, respectively). Tendencies were observed for BST heifers to have reproductive tracts with fewer placentomes (P = 0.08) and fetuses with greater umbilical diameters (P = 0.09) compared with CTL. The activity of CYP1A did not differ (P ≥ 0.05) within the maternal and fetal liver, caruncle, cotyledon, or CL tissue samples between treatments. Furthermore, CYP3A activity was only observed in maternal liver samples and was not different between treatments (P ≥ 0.05). Interestingly, CYP2C activity was greater (P = 0.01) in the liver of BST vs. CTL heifers, and UGT activity was greater (P = 0.02) in the CL from BST heifers compared with CTL. In conclusion, the administration of bST during the first third of gestation increased plasma concentrations of IGF-1, which resulted in an increase in fetal fluid, decrease in placentome number, and greater umbilical diameter, but failed to alter fetal development.     

Effects of increased ambient temperature and supplemental altrenogest before pregnancy establishment in gilts

Heat stress (HS) mitigation strategies are critically needed to combat the substantial economic effects on animal agriculture. The manifestations of seasonal infertility include delayed puberty onset, reduced conception rates, decreased litter size, and increased wean to estrus interval. To assess the effects of HS during early gestation and evaluate the benefit of supplemental altrenogest (ALT) as a mitigation strategy, 30 crossbred postpubertal gilts (157 ± 11 kg body weight) were subjected to estrous synchronization via 14 d oral administration of ALT. Artificial insemination during estrus was performed, and gilts were then placed into one of four treatment groups: HS (35 ± 1 °C for 12 h/31.60 ± 1 °C for 12 h) with (HSALT, n = 7) or without (HSCON, n = 7) 15 mg/d ALT supplementation or thermal neutral (TN; 20 ± 1 °C) conditions with (TNALT, n = 8) or without (TNCON, n = 8) 15 mg/d ALT supplementation until 12 d post-estrus (dpe). Administrating ALT occurred at 0600 hours from 3 to 12 dpe, and rectal temperatures (T_R) and respiration rates (RR) were recorded. Blood was collected via jugular venipuncture on 0, 4, 8, and 12 dpe. Gilts were euthanized humanely at 12 dpe followed by the collection of ovarian tissue, and uterine flushing for conceptus collection. In HS compared with TN gilts, RR and T_R were increased (P < 0.01) but unaffected by ALT supplementation. Feed intake was reduced (P < 0.01) by HS but unaltered by the ALT treatment. Corpora lutea (CL) weight was reduced (P < 0.01) in HSCON gilts when compared with TNCON and HSALT gilts despite progesterone concentrations in serum and luteal tissue not being affected by treatment (P ≥ 0.10). CL diameter was reduced (P ≤ 0.05) in HSALT gilts compared with other treatments. Interleukin-1β (IL1B) uterine flush concentration was not affected (P > 0.20) by environment or ALT supplementation, although moderate (P = 0.06) interaction between environment and ALT existed, as IL1B concentration in TNALT was increased (P = 0.03) compared with TNCON gilts. While environment did not affect conceptus development (P = 0.90), ALT supplementation advanced conceptus elongation (P < 0.01). Collectively, these data demonstrate that HS may affect luteal development before pregnancy establishment, and ALT increases conceptus elongation by 12 dpe.     

Enzyme activity in bovine cervical mucus during spontaneous and induced estrus

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.     

Transrectal Doppler sonography of uterine blood flow during the first two weeks after parturition in Simmenthal heifers

Transrectal Doppler sonography was used to evaluate uterine blood flow during the first two weeks after parturition in six primiparous Simmental cows. The uterine blood flow was evaluated on the day of parturition (Day 0), once daily from Days 1 to 8 and then every other day until Day 14. Blood flow was quantified by determining the diameter (D), the time-averaged maximum velocity (TAMV), the pulsatility index (PI) and the blood flow volume (BFV) of the uterine arteries ipsilateral and contralateral to the formerly pregnant uterine horn. During the first four days after calving D, TAMV and BFV declined (ipsilateral: TAMV 70%, BFV 87%, contralateral: D 47%, BFV 84%; p < 0.05), while PI increased (ipsilateral 158%, contralateral 100%; p < 0.05) distinctly. Between Days 4 and 14 only the ipsilateral D (12%) and the BFV of both arteries (ipsilateral 5%, contralateral 8%) decreased (p < 0.05). Blood flow variables were very strongly correlated with each other (r > ±0.75, p < 0.05), with negative correlations with PI and positive correlations with all other investigated factors. Overall, this study revealed characteristic changes in uterine perfusion during the first two weeks after parturition in cows that were pronounced during the first four days postpartum.