Non-pregnant Cattle Research Articles

Heifer spay: A practical approach

I learned how to spay heifers in the Kimberley region of West­ern Australia. The extensive practice of beef production, lack of fences, seasonality of access to cattle, and the need for non-pregnant cattle for live export made the practice of spaying heifers commonly used.

Comparability of Pregnancy Specific Protein-B (PSPB) Concentration in Serum and Urine of Kedah-Kelantan (KK) Cattle

This study aimed to investigate the effect of serum and urine PSPB levels based on different biomarkers, such as serum and urine. Serum PSPB levels significantly increased from day 0 to day 164 (P<0.05). However, the PSPB urine concentration through the ELISA test showed higher concentration and reached the sensitivity of the ELISA test from Day 0 until Day 164 after AI. The results of urine biomarkers at Day 0, Day 42, and Day 164 were not significant (P>0.05). Serum PSPB production begins to be established after day 24 of parturition due to embryonic development. Furthermore, the urine PSPB concentration is considered an abundant protein circulating in the animal body and ready to be excreted in the urine. In this study, the ELISA test was unsuitable for detecting pregnancy. However, urine biomarkers can potentially become biomarkers by studying the range of concentrations of PSPB that can be considered pregnancy. In addition, the PSPB protein allows for more prolonged survival in the bovine body and decreases gradually from the 22nd to the 54th day after calving. The results demonstrate that PSPB can detect pregnancy early in pregnancy using biomarkers and evolution. Therefore, this study could be improved by examining PSPB levels of pregnant and non-pregnant cattle.

188 Characterization of the Vagino-Uterine Microbiota in Pregnant and Non-Pregnant Beef Cattle Using 16S Rrna Gene Sequencing and Culturing

Abstract Emerging evidence suggests that urogenital microbiome-targeted approaches may provide a novel opportunity to reduce the incidence of reproductive failures in cattle. The objectives of this study were to: 1) characterize the vaginal and uterine microbiota between beef cattle that became pregnant via artificial insemination (AI) and those that did not; 2) identify differentially abundant taxa between pregnant and non-pregnant cattle; and 3) characterize the culturable fraction of the vaginal and uterine microbiota using extensive culturing. Vaginal and uterine swab samples were collected from two cohorts of Angus-crossbred cattle: mature cows (n =100) and heifers (n = 72, vaginal swab only) at the time of AI. At 35 days post-AI, pregnancy diagnoses were made via ultrasound. A subset of vaginal and uterine swabs from cows (27 non-pregnant and 31 pregnant) and heifers (26 non-pregnant and 33 pregnant) were selected and processed for microbiota assessment using 16S rRNA gene (V3-V4) sequencing. For culturing, a subset of cryopreserved vaginal and uterine swabs (128) were plated onto three different agar types and cultured, and isolates were identified by near-full length 16S rRNA gene sequencing. Sequencing results revealed 11 taxa that were more abundant in the vaginas of heifers that failed to become pregnant via AI than heifers that did become pregnant. While there was no significant difference in vaginal microbiota community structure (P = 0.21) between pregnant and non-pregnant cows, non-pregnant cows tended to have greater microbial richness and Shannon diversity (P ≤ 0.08) compared with pregnant cows. No differentially abundant taxa were detected in the vaginas of pregnant versus non-pregnant cows. Pregnant cows had a distinct uterine microbiota community structure (R2 = 0.032, P = 0.008) but similar alpha diversity (P &amp;gt; 0.1) compared with non-pregnant cows. Twenty-eight differentially abundant taxa were observed in the uterine microbiota between pregnant and non-pregnant groups, with 11 of them more abundant in pregnant cows. Methanobrevibacter ruminantium (archaea) and Fusobacterium necrophorum were among these 11 positive pregnancy-associated taxa. Although community structure was significantly different between the vagina and uterus, 277 “core taxa” (present in ≥ 80% of all samples) were shared between the two communities. A total of 733 bacterial isolates were recovered from vaginal (512) and uterine (221) swabs under aerobic (n = 363, 83 different species) and anaerobic (n = 370, 69 species) culturing. Potential pathogenic isolates within the Trueperella, Mannheimia and Histophilus genera were most exclusively identified from vaginal swabs. Only two Lactobacillus isolates were recovered. Overall, our results indicate that pregnancy-associated taxonomic signatures are present in the bovine uterine and vaginal microbiota. Among 39 pregnancy status-associated taxa, 41% were unclassified at the genus level, suggesting that shotgun metagenomics and culturomics are needed to identify and characterize the pregnancy-associated taxa in cattle.

Interferon-Stimulated Gene Expression in Peripheral Blood Leucocytes as a Convenient Prediction Marker for Embryo Status in Embryo-Transferred Japanese Black Cows during the Peri-Implantation Period.

Pregnancy diagnosis during early gestation is important for cattle reproduction. The expression of interferon-stimulated genes (ISGs) in peripheral blood leukocytes (PBLs) was studied in embryo-transferred (ET) Japanese Black cattle. ISGs in PBLs-ISG15, MX1, MX2, and OAS1-were detected in multiple ovulation ET cattle using a real-time quantitative polymerase chain reaction, and receiver operating characteristic (ROC) curve analysis was performed. Gestational status was predicted using the average ISG levels during the normal estrous cycle (AVE) and the Youden index from the ROC curve analysis as cutoff values. The ISG15, MX1, and MX2 levels were significantly higher in pregnant cattle (n = 10) than in non-pregnant cattle (n = 23) on gestation day 21, whereas the levels of all ISGs were similar between non-pregnant and non-pregnant cattle with late embryonic death (n = 7). ISG15, MX1, and MX2 appropriately predicted the gestational status of ET cows. The statistical evaluation of the diagnostic accuracy in ET cows on day 21 of gestation presented higher values of sensitivity, specificity, accuracy, and positive predictive values of ISG15, MX1, and MX2 using the Youden index than using the AVE. Therefore, ISG15, MX1, and MX2 are excellent biomarkers of gestational status during the peri-implantation period in ET cattle.

262 Reproductive Microbiomes as Predicators of Fertility in Beef Cattle

Abstract Over the past decade, a multitude of research has sought to understand the complexity and role of the reproductive microbiome as it pertains to fertility. Previously, the reproductive microbiome was evaluated using culture-dependent methods; however, recent advancements in culture-independent, 16S rRNA gene amplicon community sequencing have vastly expanded our understanding of the reproductive tract microbiome. Early sequencing studies sought to compare the vaginal microbiome of cattle to the vaginal microbiome of healthy women, which predominantly consists of bacteria in the genus Lactobacillus and believed to be an indicator of fertility. In the vagina of beef cattle, however, there are incredibly low abundances of Lactobacillus and a greater diversity of bacterial species present. Beta-diversity, which examine differences in bacterial communities between samples, does not appear to differ in the vagina between unbred, open, or pregnant cattle. In postpartum beef cattle just prior to breeding, there are greater levels of diversity and increased bacterial species richness in the vagina compared to the uterus. Research on bacterial species within the uterus have primarily focused on pathogenic bacteria in postpartum cattle diagnosed with uterine disease. Fewer studies have investigated uterine bacterial species in presumed healthy postpartum beef cattle and the subsequent effects on fertility outcomes (e.g., pregnant vs. open at day 30). When evaluating the uterine microbiome during an industry standard estrus synchronization protocol, bacterial community abundance and diversity reduce over time regardless of resulting fertility outcomes. The greatest difference in uterine bacterial abundance between resulting pregnant and non-pregnant cattle appears to occur just prior to breeding. Numerous mechanisms could be contributing to the fluctuations in the uterine microbiome in beef cattle including circulating hormone concentrations or local immunoregulation. This presentation will focus on recent research investigating potential mechanisms that may alter the reproductive microbiome and ultimately impact fertility.

​​Impact of Trace Minerals Supplement on Reproductive Performance of Crossbred Cattle

Background: In lactating animals, the majority of factors like nutrient intake, physiological health, housing management and atmospheric conditions affect reproductive performance of the animal. In dairy animals the main factor affecting reproduction is nutrition status that too trace minerals. So to have a good return from the livestock trace minerals with balanced feeding of the animals must be done. Optimum feeding of minerals with respect to the various stages of reproductive life cycle must be done to increase the reproductive performance. Methods: Hence, present research trial was carried out at the Dairy farm of Banaras Hindu University, Dist. Varanasi (Uttar Pradesh). 24 Cross bred (Sahiwal × HF) non-cyclic, non-pregnant cattle, ranging 3 - 6 years of age were randomly selected to assess the role of trace minerals in fertility of infertile cows. Result: It is observed from the study, total 24 infertile crossbred cows were selected to induce oestrus taken for correction of anoestrosity with incorporated minerals. Total 8 out of 24 animals exhibited oestrus symptoms after the treatment. Among the animals received incorporated mineral (treatment group) 50% showed the oestrus symptoms. Among the animals under control 16.66% came into heat.

Bovine tuberculosis prevalence and risk factors in selected districts of Bangladesh.

A cross-sectional survey was conducted in selected districts of Bangladesh to estimate the prevalence of bovine tuberculosis (bTB), and to identify the risk factors for bTB. We included 1865 farmed cattle from 79 herds randomly selected from five districts. Herd and animal level data were collected using semi-structured interviews with cattle herd owners. The single intradermal comparative tuberculin test (SICTT) was used to estimate the prevalence of bTB. The risk factors were identified using mixed-effect multiple logistic regression analyses. The overall herd and animal level prevalences of bTB were estimated to be 45.6% (95% Confidence Interval [CI] = 34.3–57.2%) and 11.3 (95% CI = 9.9–12.8%), respectively, using the OIE recommended >4 mm cut-off. The true animal level prevalence of bTB was estimated to be 11.8 (95% Credible Interval = 2.1–20.3%). At the herd level, farm size, bTB history of the farm and type of husbandry were significantly associated with bTB status in univariable analysis. Similarly, age group, sex, pregnancy status and parity were significantly associated with bTB at cattle level. However, in multivariable analysis only herd size at the herd level and age group and pregnancy status at the cattle level were significant. Compared to a herd size of 1–10, the odds of bTB were 22.8 (95% CI: 5.2–100.9) and 45.6 times (95% CI: 5.0–417.7) greater in herd sizes of >20–50 and >50, respectively. The odds of bTB were 2.2 (95% CI: 1.0–4.5) and 2.5 times (95% CI: 1.1–5.4) higher in cattle aged >3–6 years and > 6 years, compared to cattle aged ≤1 year. Pregnancy increased the odds of bTB by 1.7 times (95% CI: 1.2–2.4) compared to non-pregnant cattle. Taken together, the results suggest high herd and animal level prevalence of bTB in these 5 districts, with the greatest risk of bTB in older and pregnant cattle within large herds (>20), and highlight an urgent need for continued surveillance and implementation of bTB control programs in Bangladesh.

EVALUATION OF SULFURIC ACID, BARIUM CHLORIDE, AND SEED GERMINATION ASSAY METHODS AS EARLY PREGNANCY DETECTION INSTRUMENTS IN CATTLE

This study aims to validate and re-evaluate the use of H2SO4, BaCl2, and seed germination assay (SGA) methods to detect early pregnancy in cattle. Validation was carried out in order to find out the actual test performance value, which include accuracy, sensitivity, and specificity.Validation test was done by reacting the urine of pregnant and non-pregnant cattle populations with H2SO4 solution diluted at a ratio of 1 : 4, with 1% BaCl2 solution or through germination of mung bean seeds in Petri dishes. The results of this study indicated that the H2SO4 and BaCl2 methods have poor accuracy (21.88% and 28.13%) with the sensitivity of 81.82% and 100% and specificity of 9.43% and 13.21%, respectively. Meanwhile, the SGA method had a fairly good accuracy (74.55%) with sensitivity and specificity of 45.46% and 81.82%, respectively. Based on these results, the H2SO4, BaCl2, and SGA methods are not recommended for detection of early pregnancy in the field.

Oxylipin concentrations in bovine corpora lutea during maternal recognition of pregnancy

The objective was to determine the effects of pregnancy status on oxylipin profiles and eicosanoid metabolizing enzymes and in corpora lutea (CL) or endometrial (caruncle; CAR and intercaruncle; IC) tissues. Angus crossed cattle were synchronized with the CO-Synch protocol and artificially inseminated (AI). Sixteen days after AI, cattle were euthanized, and reproductive tracts collected from 6 non-pregnant and 6 pregnant cows. Oxylipin profiles and concentrations of progesterone (P4) were obtained from CL tissues. The activity of cytochrome P450 1A (CYP1A) and UDP-glucuronosyltransferase (UGT) enzymes were determined using specific luminogenic substrates. Data were analyzed using the MIXED procedure of SAS, and the model included pregnancy status. Corpora lutea of pregnant cattle contained greater (P < 0.05) concentrations of 9,10-DiHODE, 15,16-DiHODE, and 9,10-DiHOME. These oxylipins have been observed to increase cellular proliferation and vasodilation. Activity of CYP1A in the CL and UGT in CAR and IC was not different (P > 0.05) between pregnant and non-pregnant cattle. In the CL, activity of UGT was decreased (P < 0.05) in pregnant vs. non-pregnant cattle. The decrease in CL UGT activity during pregnancy indicates alterations in local hormone metabolism, while no differences in CL weight nor amount of P4 in CL were different between pregnant and non-pregnant cattle. Moreover, the increase in specific concentrations of oxylipins in the CL may indicate a novel pathway of steroid and eicosanoid metabolism during maternal recognition of pregnancy.

Differential neutrophil gene expression in blood and milk during pre-implantation pregnancy in Karan Fries cattle

ABSTRACT The blood leucocytes, neutrophils being the first line of defense, detect the implanting embryo, which is semi-allogenic, and show changes in their gene expression. It is possible to diagnose cattle as non-pregnant around 21–24 days post insemination by progesterone (P4) assay. Concentration of progesterone level in the inseminated animals may not be an accurate method for early pregnancy diagnosis. Identification of suitable methods that allow pregnancy diagnosis around or before day 20 after artificial insemination (AI) will be of considerable value. The present study has been carried out to understand the differential gene expression of IFI16 (interferon-inducible protein 16), MX1 (Myxovirus resistance 1), OAS1 (2'-5'-Oligoadenylate Synthetase 1) and TNFα (tumor necrosis factor alpha) genes on 0, 4, 8, 12, 15, 18 and 21 days post AI, respectively, from Karan Fries cattle as a tool for early pregnancy diagnosis in neutrophil cells isolated from blood and milk. Statistical analysis between pregnant and non-pregnant animals in both blood and milk samples revealed that IFI16 gene was upregulated in the milk samples of pregnant animals on 8th day post-AI and found to be significantly different (P < 0.05) between pregnant and non-pregnant cattle and may be used as a biomarker for early pregnancy detection in cattle.

Vascular and morphological features of the corpus luteum 12 to 20 days after timed artificial insemination in dairy cattle

Our objective was to retrospectively compare pregnant versus nonpregnant cattle in terms of vascular and morphometric changes in corpora lutea between d 12 and 20 following timed artificial insemination (TAI). Crossbred (Gir × Holstein) lactating dairy cows (n = 136) and heifers (n = 111) were bred after synchronizing ovulations using an estradiol plus progesterone (P4)-based protocol. Corpus luteum (CL) characteristics (area, echotexture, blood flow) were recorded at 48-h intervals from d 12 to 20 following TAI using an ultrasound equipped with color Doppler. Blood samples were collected to determine CL function (plasma P4). Pregnancy diagnosis was performed at d 30. Quantitative assessment of colored pixels within the CL was performed using ImageJ software (National Institutes of Health, Bethesda, MD) and echotexture was quantified using custom software. Continuous variables such as luteal tissue area (LTA), CL blood flow (CLBF), adjusted CLBF (ratio LTA:CLBF), mean pixel value (MPV), pixel heterogeneity (HETER), and plasma P4 were analyzed retrospectively as repeated measures (d 12 to 20) in pregnant versus nonpregnant females using PROC MIXED (SAS Institute Inc., Cary, NC). Main effects were pregnancy status, day of cycle, and their interaction. Further analyses used only data from d 16, because this was the earliest time point of deviation between CLBF of pregnant and nonpregnant animals. We created quartiles for each variable and calculated the risk of pregnancy within quartile. Differences were determined using the chi-squared test. Plasma P4 was significantly higher in prospective pregnant versus nonpregnant cattle on d 18 and 20, whereas LTA differed only on d 20. On d 16, CLBF and adjusted CLBF diverged between pregnant and nonpregnant, followed by a progressive reduction in the latter until d 20. Mean pixel value was not affected by pregnancy status, but HETER was lower on d 20 in pregnant than in nonpregnant cattle. Likelihood of pregnancy increased from quartile (Q)1 (lowest values) to Q4 (highest) of CLBF (Q4 vs. Q1, odds ratio = 32.8, 95% confidence interval: 9.6 to 112.1) and adjusted CLBF [Q4 vs. Q1, odds ratio = 25.4, 95% confidence interval: 8.1 to 80.4), whereas a lower risk of pregnancy was observed only for animals within Q1 of plasma P4 [Q4 vs. Q1, odds ratio = 3.1, 95% confidence interval: 1.3 to 7.2). Day 16 quartiles of LTA, MPV, and HETER did not affect odds of pregnancy. In conclusion, we identified distinct CLBF patterns as early as 16 d after TAI and confirmed that CL function is lost by a reduction in blood flow, which precedes physical regression.

Determinación de Rinotraqueítis Infecciona Bovina (BHV-1) en el municipio de Toca, Boyacá

Introducción. La Rinotraqueítis Infecciosa Bovina (RIB) es una enfermedad infectocontagiosa que afecta principalmente a bovinos y bufalinos, encontrándose ampliamente distribuida a nivel mundial, siendo una de las principales causas de perdidas económica y físicas en las producciones. Objetivo. determinar la prevalencia de la Rinotraqueítis Infecciosa Bovina (BHV-1) en el municipio de Toca, Boyacá. Materiales y métodos. Se recolectaron 350 muestras de sangre Bovina, las cuales fueron procesadas en el laboratorio de la Universidad Pedagógica y Tecnológica de Colombia, mediante un kit comercial de ELISA. Resultados. La prevalencia para IBR, en el municipio de Toca, Boyacá, fue de 65,5%. No se encontró relación significativa con las variables estudiadas como abortos, distocias, no gestantes, repetición de celos, entre otras. Conclusión. La Rinotraqueítis Infecciosa Bovina es una de las principales causas de pérdidas económicas y físicas en las diversas producciones, sin embargo, no siempre es la principal causa de alteraciones reproductivas presentes en los bovinos.

Release of urinary aquaporin-2-bearing extracellular vesicles is decreased in pregnant Japanese Black cattle.

Aquaporin-2 (AQP2), a vasopressin-regulated water channel, plays an important role in renal water homeostasis. It has been reported that the level of AQP2 in human urine is altered during pregnancy. However, little is known about the level of urinary AQP2 in pregnant cattle. In this study, we examined the level of AQP2-bearing extracellular vesicles (uEV-AQP2), which account for most urinary AQP2, in both heifers and cows during the gestational and postpartum periods. The level of uEV-AQP2 was significantly decreased during gestation in comparison with the other cattle examined. Similarly, the levels of EV marker proteins in uEVs, including tumor susceptibility gene 101 (TSG101) protein and apoptosis-linked gene 2-interacting protein X (ALIX), were significantly decreased during gestation. There were significant correlations between the levels of uEV-AQP2 and uEV-TSG101, or uEV-ALIX. Immunohistochemistry data from pregnant and non-pregnant cattle supported the notion that the level of uEV-AQP2 was decreased during gestation. These data indicate that the level of uEV-AQP2 is decreased in pregnant cattle, possibly through a decrease in both the number of EVs released into the urine and renal AQP2 expression.

Investigation of Pathological Lesions and Fetal Losses in Slaughtered Cattle

In the presented study, we aimed to investigate fetal wastage and endometritis ratio in slaughterhouses. For this aim, we examined the uterus and ovarium tissues of slaughtered cattle by using macroscopic and histopathological evaluation methods to detect pregnancy and metritis ratio. Routine histopathological processing was performed for gathered tissues. All sections were stained with hematoxylin- eosin. After staining all slides were examined under the light microscopy. Out of the 140 cattle, 18 animals were found to be pregnant at different stages of pregnancy. No histopathological changes were observed in 62 uterus organs of 122 non-pregnant cattle and inflammatory uterine lesions were observed in different characters and intensities in 60 uterus organs. In result of this study, we detect the percentage of pregnant animals which are slaughtered is 12,8%. Besides, the percentage of female animals with no pathological lesions were found to be an obstacle to pregnancy is 44,2%. According to these findings, we were in the belief that these rates are a significant loss in terms of our local economy.

Major Reproductive Disorder and Performances of Small Holder Dairy Farms in and around Fitche Town, North Shoa Zone of Oromia Regional State, Central Ethiopia

A study was conducted to identify and estimate the prevalence rate of reproductive disorder and to assess the possible risk factors and reproductive performances of smallholder dairy cattle in and around Fitche town from December 2013 to June 2014. Eighty one dairy farms (average herd size=4.8) were visited and data on reproductive performance indicator, cow attributes, type of mating, body condition score and general farm management were collected. The overall mean value for Calving to Conception Interval (CCI) (n=66) and Duration After Last Calving (DALC) (n=56) for pregnant and non-pregnant cattle were 169 and 264 days respectively. The least squares mean CCI was higher (p Keywords: Smallholder Dairy Farms; Reproductive Performance; Fitche; Reproductive Disorder

Safety and efficacy of reduced dose Brucella abortus strain- 19 vaccine in non-pregnant zebu cattle (Bos indicus) heifers

In India, brucellosis a re-emerging disease, is of public health and economic concern to dairy industry. Brucella abortus strain-19 vaccine is recommended as most effective vaccine for cattle and buffaloes, however application of full dose is restricted in adults due to persistence of antibody response that interfere with serological diagnosis. In the present study 120 seronegative female cattle (60 calves and 60 young heifers each in a group) were subjected for vaccination. In each age group, 40 animals were vaccinated subcutaneously with a reduced dose of B. abortus S-19 vaccine, 10 animals with standard dose and 10 animals served as controls. Animals were observed for local or systemic reactions after vaccination as well as during study period. Blood samples were collected on day 0, 21, 60, 90 post-vaccination for antibody response and cell mediated immunity (CMI). The study revealed that the reduced dose vaccine is safe with satisfactory humoral and CMI response comparable to that of the standard dose, in both the age groups of animals when administered subcutaneously. It was concluded that the B. abortus S-19 reduced dose vaccine is safe and effective in the young and non-pregnant cattle up to the age of 30 months.

Safety and immunogenicity of a soluble native Neospora caninum tachyzoite-extract vaccine formulated with a soy lecithin/β-glucan adjuvant in pregnant cattle

The global economic impact of Neospora caninum infection in cattle herds has promoted the development of vaccines that can be safely used during pregnancy. The aim of this study was to evaluate the safety and immunogenicity of a vaccine formulated with the soluble fraction of tachyzoite's lysate and a soy-based aqueous adjuvant (sNcAg/AVEC), which was protective in the mouse model and induced strong IFN-γ responses and high avidity antibodies in non-pregnant cattle. Ten pregnant heifers were vaccinated twice during the first trimester of gestation and 8 remained unvaccinated. Anti-N. caninum immune responses were efficiently primed by vaccination, evidenced by a quick induction of IgM serum titers (7dpv) and a prompt switch to high avidity IgG shortly after infection (performed at 78 or 225 days of gestation; n=5 each); while naïve cattle elicited lower IgG titers, with a delayed kinetics. High systemic IFN-γ levels were induced after infection which did not interfere with pregnancy. No local or systemic adverse effects were recorded along the study. Calves were born in term and in good health conditions, showing that the sNcAg/AVEC vaccine was safe when applied to healthy heifers during the first trimester of gestation.

Frecuencia de presentación de gestación con relación al cuerno uterino en bovinos del trópico colombiano

El objetivo del trabajo fue determinar la frecuencia de presentación de la gestación en los cuernos uterinos derecho e izquierdo en vacas del trópico colombiano. Se diagnosticaron 1534 vacas gestantes por palpación rectal y se indicó el cuerno gestante (izquierdo o derecho). Adicionalmente, se palparon 618 vacas no gestantes cíclicas y se determinó la presencia de cuerpo lúteo (CL) o folículo (F), y se identificó el ovario (derecho o izquierdo) que contenía la estructura. En las vacas gestantes, los porcentajes de gestación derecha e izquierda fueron de 63,1 % (968/1534) y 36,9 % (566/1534) (p ≤ 0,01), y en las vacas no gestantes, el 69 % de los CL y el 68 % de los F se encontraron en el ovario derecho (p ≤ 0,01). También se inspeccionaron 300 tractos reproductivos de vacas gestantes y 300 de vacas no gestantes, pero con presencia de CL y F. En los tractos gestantes, los porcentajes de gestación derecha e izquierda fueron de 67,3 % y 32,7 % (p ≤ 0,01), y en los no gestantes, el 68 % de los CL y el 65 % de los F se encontraron en el ovario derecho (p ≤ 0,01). Se concluye que el mayor porcentaje de gestaciones en el ganado bovino del trópico colombiano se presenta en el cuerno derecho, y que la mayor presencia de CL y F se encuentra también en el ovario derecho.

The effects of fasting on some biochemical factors of liver, serum and clinical signs in cattle

BACKGROUND: Fasting is an alternative method to induce anorexia. OBJECTIVES: The biochemical factors of liver and serum and clinical signs were measured and documented in five non-lactating, non-pregnant cows following eight days of fast- ing. METHODS: Five crossbred, non-lactating, and non-pregnant cattle were used in this study. They were fasted for 8 days_ total food deprivation; however, they had free access to water. Liver biopsies were carried out one day before food deprivation (day 0) and 8 days after food deprivation by ultrasound-guided biopsy. Blood samples were taken from the jugular vein before and during fasting. The concentrations of triglyceride (TG), total lipids, glycogen, phospholipids, and total protein in liver and NEFA, BHBA, TG, total cholesterol, glucose, total lipid, APO A1, and APO B in blood serum were measured and compared. RESULTS: The results of this study showed that fasting for 8 days reduces respiratory rate by 52% and heart rate by 12.5% and has no significant effect on rectal temperature. The concentrations of the liver triglyceride (TG) and glycogen significantly increased (p=0.046) and decreased (p=0.007) on day 8, respectively. There were no significant differences in the content of liver phospholipids (p=0.83), total lipids (p=0.29), and total protein (p=0.23). The serum concentrations of NEFA and BHBA increased significantly (p=0.008) at the end of fasting period. No significant differences in the concentrations of serum TG (p=0.057), total cholesterol (p=0.93), glucose (p=0.108), total lipid (p=0.27), APO A1 (p=0.762), and APO B (p=0.92) were noticed on days 0 and 8. CONCLUSIONS: The results of the present study showed that fasting, like anorexia (as a result of diseases), induces fat mobilization from adipose tissue in response to the induced negative energy balance.

Color Doppler flow imaging for the early detection of nonpregnant cattle at 20 days after timed artificial insemination

The objective was to determine the accuracy of a pregnancy test for predicting nonpregnant cattle based on the evaluation of corpus luteum (CL) blood flow at 20d (CLBF-d20) after timed artificial insemination (TAI). Crossbred Holstein-Gir dairy heifers (n=209) and lactating cows (n=317) were synchronized for TAI using the following protocol: intravaginal implant (1.0g of progesterone) and 2mg of estradiol benzoate i.m. on d −10, implant removal and 0.526mg of sodium cloprostenol i.m. on d −2, 1mg of estradiol benzoate i.m. on d −1, and TAI on d 0. On d 20, animals underwent grayscale ultrasonography (US) to locate the CL and color flow Doppler to evaluate CLBF-d20 using a portable ultrasound equipped with a 7.5-MHz rectal transducer. Based only on a visual, subjective CLBF evaluation, the animals were classified as pregnant or not pregnant. On d 30 to 35, blinded from results of the previous diagnosis, the same operator performed a final pregnancy diagnosis using US to visualize the fetal heartbeat (gold standard; US-d30). A second evaluator also analyzed the CLBF-d20 in the same animals by watching 7-s recorded videos. Blood samples were collected from a subset of 171 females to determine, by RIA, plasma progesterone (P4) concentrations, which indicate CL function. The final pregnancy outcome (US-d30) was retrospectively compared with the CLBF-d20 diagnoses and then classified either as correct or incorrect. The number of true positive, true negative, false positive, and false negative decisions were inserted into a 2×2 decision matrix. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the CLBF-d20 test were calculated using specific equations. Binomial variables (pregnancy rate and proportions) were analyzed using Fisher’s exact test for the effect of parity and to compare between evaluators and tests (CLBF-d20 vs. plasma P4). The kappa values were calculated to quantify the agreement between CLBF-d20 and the gold standard (US-d30) and between evaluators. The performance parameters of CLBF-d20 test were as follows: sensitivity=99.0%, specificity=53.7%, positive predictive value=65.1%, negative predictive value=98.5%, and accuracy=74.8%. False negatives represented only 0.4% of the exams. No differences existed in these parameters between evaluators (no. 1 vs. no. 2) and tests (CLBF-d20 vs. plasma P4). Moreover, a high level of agreement was observed between evaluators (0.91). In conclusion, visual evaluation of CLBF-d20 represents a quick, reliable, and consistent diagnostic test that enables the early detection of nonpregnant cattle.