Infertility In Cows Research Articles

Resilience of a beef cow-calf farming system to variations in demographic parameters1

Beef cow-calf farming systems are assumed to be resilient to biological disturbances that induce variations in herd demography; however, this hypothesis has not been fully investigated to date. Modeling is an interesting approach to study farming system resilience and to evaluate the impact of biological disturbances, taking into account interactions between system components, including biological variability and management practices. Our objective was to evaluate the resilience of beef cow-calf farming systems to variations in fertility and mortality using a modeling approach. We studied the direct effect of variations in demographic parameters on production objectives without explicitly representing the causes of the variations. We developed a stochastic model to represent the population dynamics of a beef cow-calf herd with breeding by natural service and biological processes occurring at the animal level. The model was validated by comparing observed and simulated distributions of the calving-to-calving interval, which were found to be consistent. Resistance was evaluated by the proportion of simulations where the objective in terms of number of weaned calves is reached even when there is a disturbance that persists for 10 yr. Reversibility was evaluated by the time needed to return to the predisturbance production level. Beef cow-calf farming systems did not appear to be resistant to variations in mortality and infertility rates except when increases in the infertility rates were low (0.02 for cows and 0.03 for heifers). Critical situations, consequently, may emerge with regard to farm production if management practices are not adapted. Reversibility was observed for disturbances that persist for up to 5 yr. However, the system needed 2 to 3 yr to recover its predisturbance production level and up to 4 yr after an increase in cow infertility of 0.12.

Seroprevalence of brucellosis in cattle in selected area of Bangladesh and comparison between Rose Bengal test and i-ELISA used for the screening of brucellosis

Brucellosis, a bacterial zoonoses caused by the genus Brucella is responsible for abortion and infertility in cow. Brucellosis is causing economic loss in dairy industries and prevalent worldwide including Bangladesh but limited studies are devoted to determine the prevalence and its association with reproductive factors of dairy cows in Bangladesh. Therefore, the present study was conducted to determine the seroprevalence of brucellosis in dairy cattle using screening test Rose Bengal test (RBT) and the positive sera were further confirmed by indirect- ELISA. For this purpose, a total of 400 serum samples from dairy cows with history of abortion and various reproductive disorders were collected from the Kurigram district of Bangladesh for the detection of Brucella antibody. The overall prevalence of brucellosis in dairy cattle was 2.25%. Brucellosis in cases of abortion and repeat breeding was 8.3% and 2.8%, respectively. The results shows higher prevalence of brucellosis in cases of abortion followed by repeat breeding, while there was no seropositive cases from other reproductive disorders. Age-wise sero-prevalence was found 3.0% in 2~3 years age group and 2.0% in 4~8 years age group. The prevalence of brucellosis in indigenous and cross-bred cattle was 3.6% and 1.7%, respectively. All the animals detected positive to brucellosis by RBT were not found to be positive by i-ELISA. However, the RBT might be a suitable screening test for the diagnosis of Brucella infection in field condition in Bangladesh. These data will help to develop effective disease prevention strategies.

Campylobacter as a cause of gastroenteritis in humans and animals

Campylobacter is a zoonotic microorganism in human and animal population which causes gastroenteritis; it is widespread in nature. Under the present systematics, Campylobacter (Campylobacteriaceae) family consist of 16 species and 6 subspecies. Illness can occur in various animals. It causes dysentery in swine, abortion and infertility in cows, abortions in sheep and goats, avian hepatitis in poultry, and enteritis in many species including primates and pets. Campylobacter do not produce toxins in food and it is known that Campylobacter jejuni produce endotoxin (unstable at higher temperature), enterotoxin and citotoxin. Humans can be infected if they have a direct contact with animals and contaminated food. Campylobacteriosis in humans caused by C. jejuni is also known as Campylobacter enteritis. Infective dose of less than 500 cells can cause infection. Key words: Campylobacter, gastroenteritis, humans, animals, food.

Impact of circulating concentrations of progesterone and antral age of the ovulatory follicle on fertility of high-producing lactating dairy cows

Dairy cow infertility negatively affects profit of dairy production enterprises around the world, and enhancing conception rates of dairy cows is a critical management issue to resolve. It appears that conception rates of dairy cows are attenuated due to reduced progesterone concentrations in circulation during growth of the ovulatory follicle. It is not clear how reduced progesterone influences fertility, but data presented in this brief review suggest that it can be somewhat reversed through increasing concentrations of progesterone during the growth of the ovulatory follicle before luteolysis. Ovsynch protocols may be utilised to enhance progesterone concentrations through the induction of an accessory corpus luteum (CL) following the initial gonadotropin-releasing hormone (GnRH) treatment. Cows at Day 13 of the oestrous cycle with a 7-day-old accessory CL had ~50% more progesterone at the time of prostaglandin injection of Ovsynch compared with cows with only a Day 13 CL. Ovsynch can consistently induce an accessory CL following the initial GnRH treatment if cows are on Days 6 or 7 of the oestrous cycle at the time of treatment. Pre-synchrony strategies are critical to enhance the probability that cows will be on Days 6 or 7 at first GnRH treatement of Ovsynch.

Invasion of Ureaplasma diversum in bovine spermatozoids

BackgroundUreaplasma diversum has been associated with infertility in cows. In bulls, this mollicute colonizes the prepuce and distal portion of the urethra and may infect sperm cells. The aim of this study is to analyze in vitro interaction of U. diversum isolates and ATCC strains with bovine spermatozoids. The interactions were observed by confocal microscopy and the gentamycin internalization assay.FindingsU. diversum were able to adhere to and invade spermatozoids after 30 min of infection. The gentamicin resistance assay confirmed the intracellularity and survival of U. diversum in bovine spermatozoids.ConclusionsThe intracellular nature of bovine ureaplasma identifies a new difficulty to control the reproductive of these animals.

Short communication: Expression and alternative splicing of POU1F1 pathway genes in preimplantation bovine embryos

Early embryo loss is a major contributing factor to cow infertility and that 70 to 80% of this loss occurs between d 8 and 16 postfertilization. However, little is known about the molecular mechanisms and the nature of genes involved in normal and abnormal embryonic development. Moreover, information is limited on the contributions of the genomes of dams and of embryos to the development and survival of preimplantation embryos. We hypothesized that proper gene expression level in the developing embryo is essential for embryo survival and pregnancy success. As such, the characterization of expression profiles in early embryos could lead to a better understanding of the mechanisms involved in normal and abnormal embryo development. To test this hypothesis, 2 d-8 embryo populations (degenerate embryos and blastocysts) that differed in morphology and developmental status were investigated. Expression levels of POU1F1 pathway genes were estimated in 4 sets of biological replicate pools of degenerate embryos and blastocysts. The OPN and STAT5A genes were found to be upregulated in degenerate embryos compared with blastocysts, whereas STAT5B showed similar expression levels in both embryo groups. Analysis of splice variants of OPN and STAT5A revealed expression patterns different from the total expression values of these genes. As such, measuring expression of individual transcripts should be considered in gene expression studies.

The possible role of bovine herpesvirus type-4 infection in cow infertility

Experimental and field studies have proven that the bovine herpesvirus type-4 (BHV-4) infection leads to various reproductive system problems. In this study, the role of BHV-4 infection in repeat breeding was investigated serologically. Eighty-four samples were obtained from repeat-breeding diagnosed cows in two organized dairy herds; an equal number of healthy cows were sampled from the same farms. The rest of the samples (105) were obtained from reproductively normal cows that were breeding in 18 small enterprises as a control group. The seropositivity proportion in repeat-breeding diagnosed cows was found to be significantly higher (69% (58/84)) than other cows (44% (37/84)) on the same farms. The lowest antibody positivity value for BHV-4 was detected as 24.7% (26/105) in the samples from family-type small farms. The odds ratio (OR) value was calculated as 2.834 in repeat-breeding diagnosed and healthy cows on the same farms, while 6.778 was determined in cows with and without reproductive problems on organized farms compared to small farms. As a result, the BHV-4 infection can be considered one of the reasons for repeat breeding besides other reproductive disorders.

Cytopathic effects of Tritrichomonas foetus on bovine oviduct cells

Tritrichomonas foetus is an extracellular parasite of the reproductive tract in cattle. To investigate the cytopathic effects of T. foetus in deeper parts of the reproductive tract, a bovine primary oviduct epithelial cell system (BOECs) was developed. Reproductive tracts were obtained from cows and the effect of co-incubating T. foetus with BOECs was analyzed by scanning electron, transmission electron and fluorescence microscopy. Viability tests were performed using colorimetric methods, TUNEL ( Terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling), fluorescein diacetate, propidium iodide, JC-1 and annexin-V. The results demonstrate that: (1) the in vitro oviduct epithelium is useful for interaction experiments with T. foetus; (2) T. foetus adheres to the BOECs as single separate cells, and later on the cells aggregate as large clusters; (3) the posterior region of the cell initiates the process of adhesion and forms filopodia and digitopodia; (4) T. foetus severely damages BOECs leaving imprints in the epithelial cells, wide intercellular spaces, and large lesions in the epithelium; and (5) T. foetus provokes bovine oviduct cell death by apoptosis and secondary necrosis. Our observations indicate the possibility that T. foetus can move through the reproductive tract to the oviduct and that infertility in cows can be mediated by an attack on the oviduct cells by T. foetus.

New surgical technique to correct urovagina improves the fertility of dairy cows

Several surgical techniques have been proposed for the treatment of urovagina as a major cause of infertility in cows. However, so far no technique seems to be successful in all cases. Given that an incompetent or damaged constrictor vestibuli muscle is a feature of cows with urovagina, we hypothesized that surgical correction of urovagina by cerclage of the vestibulovaginal junction under the vaginal wall cranial to the urethral opening would prevent cranial flow of urine and improve fertility. Our study was performed on 39 non-pregnant lactating Holstein-Friesian cows suffering urovagina, with a vaginal content of urine exceeding 100mL and with evident incompetence of the constrictor vestibuli muscle. Cows were randomly assigned to a Control (untreated cows, n=20) or Experimental (n=19) group. An encircling polydioxanone suture was placed in the vaginal wall at the vestibulovaginal junction to create a vestibulovaginal cerclage in the Experimental cows. Surgery was observed to resolve urovagina in 17 (89.5%) of the 19 treated cows. Pregnancy was recorded in 7/20 (35%) and 14/19 (74%) cows in the Control and Experimental groups, respectively. Using logistic regression procedures and based on the odds ratio, we determined that cows undergoing surgical correction of urovagina were 5.2 times more likely to become pregnant than untreated cows (P=0.015). Our results suggest that vestibulovaginal junction cerclage prevents the cranial flow of urine and improves the function of the constrictor vestibuli muscle in cows suffering urovagina. They also indicate that, under these conditions, urovagina correction may dramatically increase fertility.

Effects of Poor Nutrition on Reproduction of Dairy Stock on Smallholder Farms in the Tropics

The relationship between nutrition and reproduction is a topic of increasing importance. Many research reports have clearly demonstrated that energy, protein and minerals intake are the most important nutritional factors affecting reproduction and therefore milk production in dairy farms. This is particularl y evident on smallholder farms in the tropics where feed is often inadequate. On these farms, voluntary feed intake in relation to the feed required for maintenance is the most important factor determining the animal's body condition. Many of the dairy animals on smallholder farms cannot build sufficient body reserves (particularly energy and protein) due to lack of adequate feed. As a direct consequence of feed inadequacy, dairy stock on most smallholder resource-poor farms are often in poor body condition (emaciated). Conception rate and calving intervals have been shown to be highly correlated, to by weight and body condition. The study revealed that animals with low body weights showed low conception rate and long calving interval. Energy and protein have shown to maintain essential levels of blood cholesterol and improve pregnancy from 42 to 72% respectively. Correlation of reproductive hormone cycle, calf and lamb birth rates, weaning rates, lactation length and yield with plane of nutrition, have been adequately illustrated. This is evidenced by the current high incidences of dairy cow infertility on smallholder farms in Kenya. Based on the literature reviewed, the current study concluded that poor nutrition is a major contributor to the current poor reproductive performance of dairy cows on smallholder farms. Poor nutrition is also largely incriminated for predisposing animals to diseases leading to high mortality and morbidity rates on these farms. It is therefore perceived that improvement of ruminant livestock diets on smallholder farms will greatly improve reproductive performance and therefore herd productivity on smallholder farms. In the long run, this will also impact positively on the economic status of the household.

The Conference in Perspective

Coming at a time of increasing concern about the declining fertility of high-yielding cows the organisers of this conference are to be congratulated on achieving a well-balanced programme representative of the breadth and depth of the science that is now being directed to the problem of dairy cow infertility. From a starting point of uncertainty about how to deal with the problem, delegates came away very well informed scientifically and, if perhaps with varying views as to the best way forward, more aware of the multidisciplinary research and development approach now being used to investigate it. The purpose of this perspective is to capture, along with the broad issues, the relevant technical detail of the papers and discussions in a way that hopefully provides a balanced overview of the conference.

Factors associated with rectovaginal injuries in Holstein dairy cows in a herd in Tehran, Iran

Rectovaginal injuries can result in subsequent infertility in cows. In a retrospective study, records of 147 Holstein cows with evidence of rectovaginal injuries were reviewed to determine the odds ratio (OR) of these injuries and their related risk factors. The study was conducted in a large dairy (typical herd size 1420 cows) in Tehran between the years 1993 and 1996. Period prevalences were 0.4% fistula, 1.9% laceration (third degree), 5.7% pneumovagina, 1.5% urovagina and 0.8% mixed injuries. The highest risk occurred among first-calf heifers. Animals with dystocia, first-calf heifers and male calves were at higher risk for rectovaginal injuries. We concluded that (1) handling dystocia with care might have a substantial role in reducing rectovaginal injuries, (2) first-calf heifers are to be under close observation and care during calving, and (3) because rectovaginal injuries reoccur in the next calving, cows with the history of these injuries should be monitored at the next labor.

A study of the central cavity in the bovine corpus luteum.

Seven hundred and six bovine corpora lutea in various luteal stages were examined morphologically and endocrinologically to discover whether there is a relationship between the presence of a central cavity in the corpus luteum and infertility in cows. A central cavity was found in 42.1 per cent (80/190) of developing corpora lutea, 33.7 per cent (126/374) of fully developed corpora lutea, 11.1 per cent (7/63) of corpora lutea in regression and in 5.1 per cent (4/79) of corpora lutea in pregnancy. There was no significant difference between the rates of appearance of midcycle follicles in corpora lutea either with or without a central cavity. The proportion of luteal cell type 1 was higher in fully developed corpora lutea with a central cavity than without, but the reverse was found with luteal cell type 2. In fully developed corpora lutea the concentration of progesterone in the luteal tissue was significantly higher in corpora lutea with a central cavity. These results suggest that there are some differences in luteal function between corpora lutea with and without a central cavity, but that the presence of a central cavity in a corpus luteum cannot be described as a pathological condition.

Seasonal variation in semen quality of bulls and correlations with metabolic and endocrine parameters.

Sperm output and semen quality of 17 bulls sampled over 12 months showed minimal output in mid-winter and late summer and minimum quality in late summer. Monthly measurements of luteinising hormone and testosterone concentration in plasma and testosterone concentration in semen were made over 12 months. Serum non-esterified fatty acids (NEFA), albumin and total protein were also measured for the final seven months of this period. Plasma testosterone showed a strong negative correlation with sperm numbers two months hence but not in the current month. Plasma testosterone by bull and semen testosterone by month was also correlated with sperm output. Plasma luteinising hormone three months and serum total protein two months prior was positively correlated with sperm numbers ejaculated and the normality of sperm morphology, possibly by affecting the luteinising hormone dependent A0 to A1 spermatogonial division. NEFA was correlated with initial and post freezing/thawing motility in the current month, possibly by affecting membrane stability. The value of examining the bull in diagnosing infertility of cows where nutritional stress may have occurred is suggested, as is the use of albumin/total protein and NEFA measurements as a prognostic aid for time to return to normality of function of such bulls.

A clinically-diagnostic test for the detection of immunologically-conditioned infertility in cows

A clinically-diagnostic test for the detection of immunologically-conditioned infertility in cows

Pathogenicity of Campylobacter Fetus Subsp. Venerealis in Causing Infertility in Cattle

Campylobacter fetus subsp. venerealis rapidly lowered the dissolved oxygen tension of its medium on addition of components of uterine fluid. It is suggested that this organism may cause infertility in cows by restricting the supply of oxygen available to the preimplantation embryo.

Non-specific uterine infection and bovine fertility. II. Infection patterns and endometritis before and after service.

Abstract Bacteriological and histopathological studies of samples obtained from the uteri of dairy cows during the 14 days preceding first service and the 10 days immediately after the first and subsequent services did not indicate that the presence of non-specific infection or endometritis around the time of service was an important cause of infertility in cows which were free from clinically detectable uterine disease.

ARTIFICIALLY ACQUIRED INFERTILITY OF A COWS ON DAIRY FARMS IN PRIMORYE AND PRIAMURYE

The article presents data on long-term observations about the occurrence of infertility of cows on dairy farms of Primorye and Priamurya, which indicate the presence of errors in the selection of cows for insemination, which leads to unjustified losses from temporary infertility of healthy animals. The problem of selecting cows for insemination exists on dairy farms all over the world, and each farmer solves it based on his own experience, finances and traditions. Currently, a large number of methods are proposed to improve the accuracy of the definition of cows in "hunting", but as practice has shown, none of them gives 100% reliability. For 50 years of work on the biology of animal reproduction, the authors have tested many of them on dairy farms in the south of the Far East. Our experiments on large farms with free-range cattle loose housing in the Ussuriysk and Khorolsk districts of the Primorsky Territory and the Khabarovsk district of the Khabarovsk Territory confirmed the recommendations on a higher efficiency of three-time detection of cows in heat. At the "Blagodatnoye" farm in the Khabarovsk Territory, with a loose-box keeping of cows 50 cows per box, an experiment was conducted with round-the-clock observation of the animals behavior. Symptoms of sexual excitation, immobility reflex, severity of estrus were recorded continuously for 13 days. The room housed 384 cows of different ages and productivity, which came from the calving pen after calving.