Follicular Dynamics and Pregnancy Rates during Foal Heat in Colombian Paso Fino Mares Bred under Permanent Grazing.

No studies have evaluated the peripartum follicular dynamics resulting in foal heat under tropical environments. We aimed to assess retrospectively the peripartum follicular dynamics in Colombian Paso Fino mares that were inseminated at the foal heat, becoming pregnant or not. Records including follicular dynamics of pregnant mares prepartum and from foaling until foal heat ovulation were assessed in Colombian Paso Fino mares (CPF, n = 24) bred under permanent grazing in a tropical herd in Colombia. The number of ovarian follicles >10 mm before foaling and the largest follicle (F1) growth rate (mm/day) from foaling until the F1 reached the largest diameter (pre-ovulatory size) at the foal heat were assessed. Mares were inseminated at foal heat with 20 mL of semen (at least 500 million live spermatozoa) with >75% motility and 80% viability from a stallion of proven fertility. Ovulation was confirmed the day after follicles had reached the largest diameter. Quantitative data from follicular growth, the day at ovulation, from mares that became pregnant (PM) or not (NPM) at 16 days post-insemination were compared by one-way ANOVA, repeated measures ANOVA (follicle growth rate data) or Chi-square test (edema and cytology scores data). Epidemiological data, gestation length, and the number of follicles on third prepartum days did not significantly differ between PM and NPM (p > 0.05). Seventy-one percent of mares (17/24) got pregnant. Ovulatory follicles grew faster in the NPM group (n = 7), which ovulated between the seventh and ninth postpartum days, compared to PM (n = 17), which ovulated between the 11th and 13th postpartum days. Pre-ovulatory follicle diameter in PM (48.57 ± 0.8 mm) was significantly larger than in NPM (42.99 ± 1.0 mm) (p < 0.05). In addition, the PM edema score (2.93 ± 0.32 mm) on ovulation day was significantly lower (p < 0.05) than NPM (4.47 ± 0.05 mm). First postpartum ovulation occurred at 12.6 ± 0.3 and 8.5 ± 0.4 days (p < 0.05) in PM and NPM, respectively. Colombian Paso Fino mares bred under permanent grazing under tropical rainforest conditions with no foaling or postpartum complications showed a 71% gestation rate when inseminated at foal heat when ovulation occurs between the second and third postpartum week.

Ultrasonographic Screening of Dairy Cows with Normal Uterine Involution or Developing Postpartum Uterine Disease Using B-Mode, Color, and Spectral Doppler.

Uterine involution, ovarian activity, and incidence of postpartum uterine disease (PUD) were assessed in forty-eight dairy cows from calving until the 10th postpartum week. Postpartum follow-up included evaluation of uterine involution and ovarian structures by B-mode, Doppler color, and Doppler spectral ultrasound of the right uterine artery in cows with no calving or postpartum uterine problems (healthy cows). Data from cows that developed PUD (PUD cows) were compared with healthy cows matched by herd and days in milk (DIM). Data were analyzed by descriptive statistics, simple regression, one-way ANOVA, or repeated ANOVA measures, and in data analysis of healthy cows, uterine horn diameter assessed by B-mode ultrasound ranged from 22.9 ± 2.4 to 19.4 ± 1.4 mm and 19.9 ± 2.2 to 20.5 ± 2.3 mm from the fourth to the seventh postpartum week in the left and right uterine horns, respectively (P > 0.05). During the study, 15 and 7 cows had corpus luteum in the left and right ovaries, respectively. The mean time for the first postpartum CL was 30.1 ± 3.2 DIM (min 8, max 67 DIM). In data analysis of PUD cows, uterine blood flow assessed by color Doppler ranged from 7.4 ± 4.0 to 43.75 ± 10.3% in cows that developed PUD compared to 16.7 ± 11.0% in healthy cows (P > 0.05). No statistically significant changes were found in resistance index, pulsatility index, time-averaged maximum velocity, time-averaged mean velocity, or diastole/systole ratio (D/S) in cows that developed PUD compared to healthy cows (P > 0.05). Finally, no correlation was found between Doppler spectral parameters and uterine involution (P > 0.05). Our data suggest that cows receiving transition diets and exhibiting normal calving undergo a rapid macroscopic uterine involution and ovarian follicular dynamics resumption. Complete ultrasound evaluation provides valuable data for assessing uterine involution in postpartum dairy cows.

Bulls fed a high-gain diet decrease blastocyst formation after in vitro fertilization.

In brief: Paternal high-gain diet reduces blastocyst development following in vitro fertilization and embryo culture but does not affect gene expression or cellular allocation of resultant blastocysts. Abstract: Bulls used in cattle production are often overfed to induce rapid growth, early puberty, and increase sale price. While the negative consequences of undernutrition on bull sperm quality are known, it is unclear how a high-gain diet influences embryo development. We hypothesized that semen collected from bulls fed a high-gain diet would have a reduced capacity to produce blastocysts following in vitro fertilization. Eight mature bulls were stratified by body weight and fed the same diet for 67 days at either a maintenance level (0.5% body weight per day; n = 4) or a high-gain rate (1.25% body weight per day; n = 4). Semen was collected by electroejaculation at the end of the feeding regimen and subjected to sperm analysis, frozen, and used for in vitro fertilization. The high-gain diet increased body weight, average daily gain, and subcutaneous fat thickness compared to the maintenance diet. Sperm of high-gain bulls tended to have increased early necrosis and had increased post-thaw acrosome damage compared with maintenance bulls, but diet did not affect sperm motility or morphology. Semen of high-gain bulls reduced the percentage of cleaved oocytes that developed to blastocyst stage embryos. Paternal diet had no effect on the number of total or CDX2-positive cells of blastocysts, or blastocysts gene expression for markers associated with developmental capacity. Feeding bulls a high-gain diet did not affect sperm morphology or motility, but increased adiposity and reduced the ability of sperm to generate blastocyst-stage embryos.

Comparison of the immune response following subcutaneous versus intranasal modified-live virus booster vaccination against bovine respiratory disease in pre-weaning beef calves that had received primary vaccination by the intranasal route.

This study was performed to elucidate whether the route of booster vaccination affects the immune response against respiratory vaccine viruses in pre-weaning beef calves that receive primary intranasal (IN) vaccination during the first month of life. The objective was to compare the serum neutralizing antibody (SNA) titers to BHV1, BRSV, and BPI3V, cytokine mRNA expression and mucosal BHV1- and BRSV-specific IgA in nasal secretions following administration of IN or subcutaneous (SC) modified-live virus (MLV) booster vaccines 60 days after primary IN vaccination in young beef calves. Twenty-one beef calves were administered 2 mL of an IN MLV vaccine containing BHV1, BRSV, and BPI3V (Inforce3®) between one and five weeks of age. Sixty days after primary vaccination, calves were randomly assigned to one of two groups: IN-MLV (n = 11): Calves received 2 mL of the same IN MLV vaccine used for primary vaccination and 2 mL of a SC MLV vaccine containing BVDV1 & 2 (Bovi- Shield GOLD® BVD). SC-MLV (n = 10): Calves were administered 2 mL of a MLV vaccine containing, BHV1, BRSV, BPI3V, and BVDV1 & 2 (Bovi-Shield GOLD® 5). Blood and nasal secretion samples were collected on days -61 (primary vaccination), -28, -14, 0 (booster vaccination), 14, 21, 28, 42 and 60 for determination of SNA titers, cytokine gene expression analysis and nasal virus-specific IgA concentrations. Statistical analysis was performed using a repeated measures analysis through PROC GLIMMIX of SAS®. Booster vaccination by neither IN nor SC routes induced a significant increase in SNA titers against BHV1, BRSV, and BPI3V. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA titers (on day 42) and IgA concentration in nasal secretions (on days 21 and 42) compared to calves receiving IN booster vaccination. Both IN and SC booster vaccination were able to stimulate the production of BHV1-specific IgA in nasal secretions. In summary, booster vaccination of young beef calves using either SC or IN route two months after IN MLV primary vaccination resulted in comparable SNA titers, cytokine gene expression profile and virus-specific IgA concentration in nasal secretions. Only a few differences in the systemic and mucosal immune response against BHV1 and BRSV were observed. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA and secretory IgA titers compared to IN booster vaccination.

Epididymal Sperm Granuloma and Antisperm Antibodies in Donkeys.

This study aimed to describe and compare semen parameters (pre-freeze and post-freezing) and antisperm antibodies (ASA) of donkeys with epididymal sperm granuloma and healthy controls. Feral donkeys (n = 10) castrated in a concurrent study were enrolled in the present experiment. Three donkeys had unilateral granulomas, two donkeys had bilateral granulomas, whereas the remaining five had grossly normal epididymides. The granulomas were either single or multiple, firm, well-circumscribed, tan to red, and 1-5 mm in size. Upon incision, abundant, thick, tan to white-yellow fluid was recovered. Histopathology revealed epithelioid macrophages, multinucleated giant cells, and abundant sperm cell fragments with mineralized cellular debris. Each epididymis was dissected, and semen harvested for cryopreservation. Semen was assessed for sperm motility parameters, plasma membrane integrity, and mitochondrial membrane potential. All donkeys had semen cryopreserved in a standard manner. In addition, post-thaw semen from all donkeys was assessed for ASA (IgG and IgA), acrosome integrity and morphology. Post-thaw, the progressive sperm motility and the percentage of sperm with an intact plasma membrane were reduced in donkeys with sperm granuloma (P = 0.04). There was no difference in total sperm motility, morphology, or damaged acrosome across groups (P > 0.05). Three donkeys with sperm granuloma (60%) displayed increased IgG and IgA ASA. In conclusion, sperm granulomas only marginally affected sperm quality and resulted in IgG ASA binding to sperm with damaged plasma membrane. It remains to be determined if sperm granuloma and ASA affect fertility in donkeys.

Comparison of follicular development, timing of ovulation and serum progesterone, estradiol and luteinizing hormone concentrations in dairy heifers treated with 4- or 5-day CoSynch + CIDR protocols.

The use of 4-day CoSynch + Controlled internal drug release (CIDR) + timed artificial insemination (TAI) in dairy heifers has resulted in adequate pregnancy rates compared with the 5-day CoSynch + CIDR + TAI protocol. The objective of this study was to compare follicular growth, timing of ovulation and serum progesterone (P4 ), estradiol (E2 ) and luteinizing hormone (LH) concentrations in dairy heifers treated with modified 4- or 5-day CoSynch + CIDR protocols (CIDR for 4 or 5 days, PGF2 α at CIDR removal and GnRH + TAI 72 h later). Twelve cycling Holstein heifers were randomly assigned to either the 4- or 5-day Co-Synch+CIDR (n = 6/treatment) to receive an intravaginal insert CIDR® containing 1.38 g of P4 for 4 or 5 days, respectively. At CIDR removal, 25 mg of PGF2 α was injected IM; 72 h after CIDR removal, heifers received 100 µg of GnRH IM and timed artificial insemination (TAI). Follicular growth and timing of ovulation were assessed using transrectal ultrasonography. Blood samples were collected at the time of CIDR insertion and at frequent time points after CIDR removal for determination of P4 (at TAI), E2 (every 12 h) and LH (every 6 h during the first and second day and every 2 h on the third day). Heifers in the 4-day group had smaller follicles from CIDR insert removal to ovulation compared with heifers in the 5-day treatment. Five of six heifers (83.3%) in the 4-day treatment ovulated at 90-96 h post CIDR insert removal, whereas most heifers in the 5-day treatment (4/6; 66.6%) ovulated at 84-90 h post CIDR insert withdrawal. Heifers in the 5-day treatment reached greater peak LH concentration between 48 and 72 h after CIDR insert removal and lesser E2 concentration at TAI than heifers in the 4-day treatment. In conclusion, heifers in the 4-day treatment had smaller follicular diameter at 0, 30, 36, 42 and 48 h after CIDR insert removal, longer interval from CIDR insert removal to ovulation, greater E2 concentrations at TAI, and lesser peak LH concentration than heifers in the 5-day treatment. These results represent a baseline for further studies to determine if prolonging the interval to TAI by 6 h in the 4-day CoSynch+CIDR would improve pregnancy risk.

Chronic inflammatory and degenerative endometrial lesions in subfertile Criollo Limonero cattle; a B. taurus Latin-American breed threatened with extinction; A case-control study.

Criollo Limonero is a tropical Bos taurus breed for sustainable dual purpose (milk and beef) production in the South-American tropics, which is currently threatened with extinction. The objective was to perform a clinical evaluation and histopathological assessment of uterine biopsy samples of repeat breeder (RB) Criollo Limonero cattle to determine the occurrence of pathological conditions as potential causes of subfertility. Twenty-four Criollo Limonero cattle [18 cows (5-13 years old) and 6 heifers (6-7.5 years old)] that had failed to conceive after four or more services were considered for this study. Additionally, five cows with history of adequate reproductive performance were used as a control group. Animals were submitted to physical exam, vaginoscopy, and ultrasonographical evaluation of the reproductive tract. Uterine biopsy samples were collected for histopathological evaluation. Vaginoscopy revealed that 41.7% of the RB cattle had abnormal vaginal secretions, while abnormal secretions were not observed in any control cow. Ultrasonographical examination of the uterus revealed the presence of free uterine fluid in 20.8% of the RB animals, while none of the control cows had fluid in the uterine lumen. In addition, ovarian cysts were observed in 25.0% of the RB animals. Histopathological evaluation of the endometrial biopsies revealed that mononuclear leukocyte infiltration, dilated uterine glands, and periglandular fibrosis were the most prevalent lesions in the sub-fertile animals. Chronic endometritis characterized by inflammatory (mononuclear leukocyte infiltration) and degenerative (dilated glands and periglandular fibrosis) endometrial lesions, and ovarian cysts were the most frequent reproductive pathologies observed in the studied subfertile Criollo Limonero cattle, suggesting a strong association with their reduced fertility.

Comparison of 4- versus 5-day Co-Synch + controlled internal drug release (CIDR) + timed artificial insemination protocols in dairy heifers.

The objective of this study was to compare the pregnancy rate after timed artificial insemination (P/TAI) in dairy heifers treated with 4- versus 5-day Co-Synch + controlled internal drug release (CIDR) protocols. A total of 120 Holstein heifers were randomly assigned to one of two groups. The heifers received an intravaginal CIDR insert containing 1.38 g of progesterone for 4 days (Monday-Friday 4-day Co-Synch + CIDR; n = 60) or 5 days (5-day Co-Synch + CIDR; n = 60). At the time of CIDR removal, 25 mg of PGF2α was injected intramuscularly, and 72 hours after CIDR removal, the heifers received 100 µg of GnRH intramuscularly and were artificially inseminated. Artificial insemination was performed by an experienced technician, using commercial frozen-thawed semen from a single sire. Pregnancy diagnosis was performed by ultrasonography per rectum 32 days after TAI. Categorical data were analyzed using proc logistic and the chi-square test, whereas continuous variables were analyzed using the t-test of Statistical Analysis Systems. Heifers in the 4-day Co-Synch + CIDR group had an acceptable P/TAI32 (55.0%, 33 of 60), which was not different (P = 0.35) from that observed in the 5-day Co-Synch + CIDR group (63.3%, 38 of 60). Progesterone concentration at CIDR insertion or estradiol concentration at TAI did not influence the pregnancy outcomes. Interestingly, estradiol concentration at TAI was greater in the 4-day Co-Synch + CIDR group compared to the 5-day Co-Synch + CIDR group (P < 0.01). In conclusion, the Monday to Friday 4-day Co-Synch + CIDR protocol resulted in adequate P/TAI in dairy heifers, which was similar to that of the 5-day Co-Synch + CIDR protocol. This novel protocol might represent a promising hormonal treatment for TAI in dairy heifers, facilitating their reproductive management routine, while maintaining an adequate fertility.

Cryopreservation of canine spermatozoa: theoretical prediction of optimal cooling rates in the presence and absence of cryoprotective agents.

In the present study a shape independent differential scanning calorimeter (DSC) technique was used to measure the dehydration response during freezing of ejaculated canine sperm cells. Volumetric shrinkage during freezing of canine sperm cell suspensions was obtained at cooling rates of 5 and 10 degrees C/min in the presence of extracellular ice and CPAs (6 different combinations of freezing media were used, ranging from a media with no CPAs, and those with 0.5%, 3%, and 6% glycerol and with 0.5% and 3% Me(2)SO). Using previously published data, the canine sperm cell was modeled as a cylinder of length 105.7mum and a radius of 0.32mum with an osmotically inactive cell volume, V(b), of 0.6 V(o), where V(o) is the isotonic cell volume. By fitting a model of water transport to the experimentally obtained volumetric shrinkage data the best fit membrane permeability parameters (L(pg) and E(Lp)) were determined. The "combined best fit" membrane permeability parameters at 5 and 10 degrees C/min for canine sperm cells in the absence of CPAs are: L(pg)=0.52x10(-15)m(3)/Ns (0.0029mum/min-atm) and E(Lp)=64.0kJ/mol (15.3kcal/mol) (R(2)=0.99); and the corresponding parameters in the presence of CPAs ranged from L(pg)[cpa]=0.46 to 0.53x10(-15) m(3)/Ns (0.0027-0.0031mum/min-atm) and E(Lp)[cpa]=46.4-56.0kJ/mol (11.1-13.4kcal/mol). These parameters are significantly different than previously published parameters for canine and other mammalian sperm obtained at suprazero temperatures and at subzero temperatures in the absence of extracellular ice. The parameters obtained in this study also suggest that optimal rates of freezing canine sperm cells ranges from 10 to 30 degrees C/min; these theoretical cooling rates are found to be in close conformity with previously published but empirically determined optimal cooling rates.