Surface alterations in the bovine pelvic peritoneum following rectal examination of reproductive organs: a scanning electron microscopy study

The aim of the present study was to evaluate possible injury provoked by an intensive reproductive programme based on rectal palpation in the cow. Alterations to the mesothelial surface of the peritoneum and to the oviductal mucosa were explored by scanning electron microscopy (SEM). Nine multiparous Friesian cows were selected from each of two commercial dairy herds. Cows in herd 1 were maintained on a weekly reproductive health programme, while those in herd 2 were not subjected to gynaecological exploration. Surface features of the mesothelial cells of the reproductive tract and adjacent ligaments, and the oviductal mucosa were explored by SEM observation of tissue specimens from each animal. Six cows in the intensive reproductive programme showed microscopic alterations of the peritoneal surface. Strands were observed in the oviducts and adjacent ligaments in five of these cows. These strands, composed of filaments covered with mesothelial cells, were probably adhesions. Cells with abundant vacuoles on their surface were detected in the mesothelium corresponding to three animals, two of which also showed microscopic strands. No peritoneal surface alterations were observed in the cows from herd 2. No oviductal mucosal modifications were detected in either group. These findings suggest that intensive reproductive programmes based on rectal palpation may increase the risk of peritoneal surface alterations in the cow, but effects on reproductive physiology are unlikely.     

Intraperitoneal insemination and retrograde sperm transport in dairy cows

To examine the efficiency of retrograde sperm transport following intraperitoneal insemination, live and dead spermatozoa were used at different concentrations, and sperm recovery from cervical mucus (0.5 ml) 2, 6, 12 and 24 h following insemination was evaluated. Forty lactating Friesian cows, in their second to fourth lactation period, were used in this experiment. Thirty-six cows received intraperitoneally either live or dead spermatozoa. Each group of six cows received one of three total sperm numbers of 30, 45 and 90 million. Four cows were inseminated with 90 million spermatozoa into the uterus and served as a control group. All cows were inseminated towards the end of oestrus. After intrauterine insemination sperm recovery declined, but motile and/or immotile spermatozoa were recovered from all cows at any time. In cows inseminated intraperitoneally, sperm was recovered from the cervix at 6-24 h when 90 million were inseminated. A greater number of spermatozoa was recovered after dead rather than after live sperm inseminations. Only immotile, intact or broken spermatozoa and tail-less heads were recovered after intraperitioneal insemination using either live or dead spermatozoa. No sperm was recovered for 30 and 45 million inseminations. Our results show that, following intraperitoneal insemination, there is passive sperm transport from the peritoneal cavity to the genital tract close to the time of ovulation, and suggest a higher sperm retention in the genital tract when live as opposed to dead spermatozoa are used.     

Mesotheliomas and proliferative lesions of the testicular mesothelium produced in Fischer, Sprague-Dawley and Buffalo rats by methyl(acetoxymethyl)nitrosamine (DMN-OAc).

A single intraperitoneal dose of methyl(acetoxymethyl)nitrosamine (13 mg/kg body weight) given to 78 5-week-old male rats induced 25 mesotheliomas; two mesotheliomas were found in 67 control rats. All mesotheliomas arose from the peritesticular mesothelium and had a typical microscopic appearance of branching papillary fronds with a collagenous core covered by one or many layers of plump tumor cells. Cytoplasm of tumor cells contained material that reacted positively to a colloidal iron stain and was labile to hyaluronidase. In addition to frank mesotheliomas, 16 lesions, which we called atypical mesothelial proliferations, were found. These consisted of a single focus of plump mesothelial cells overlying an area of thick stroma. Often these foci included short, non-branched papillary projections above the surface of adjacent normal mesothelium. Twelve of the 16 lesions occurred in methyl(acetoxymethyl)nitrosamine-treated rats.     

Laser Micro-dissection and Quantitative RT-PCR as a Tool for Cell Identification

The mechanisms of embryo-maternal communication during the first days of embryonic life are largely unknown. Using the bovine as a model, the aims of our study were to morphologically characterize the interaction between the pre-implantation embryo and the epithelium of the maternal ampulla, isthmus and uterotubal junction by light and scanning electron microscopy. For this purpose, oviducts were removed from cows revealing a functional corpus luteum on day 3 after insemination. These were compared to oviducts removed on day 3 (metestrus) of the estrous cycle. Three days after insemination, the majority of the epithelial cells in the ampulla were secretory cells distinctly protruding into the oviductal lumen. Contrary the ampulla of cows on day 3 of the cycle predominantly revealed ciliated cells in the oviductal epithelium. As shown by Periodic Acid Schiff reaction (PAS) with and without amylase digestion, the secretory cells of the ampulla synthesized merely glycoproteins during metestrus, but large amounts of glycogen during pregnancy. In the isthmus no morphological differences were seen between pregnant and cyclic cows. The most conspicuous finding during pregnancy was seen in the uterotubal junction: Vital cumulus cells embedded in between epithelial cells had developed short cytoplasmic processes intensely contacting the epithelial uterine cells. The embryos obtained ex vivo were regularly covered with a thick layer of homogenous extracellular matrix. Contrary embryos produced in vitro – both with and without coculture with oviductal cells –revealed a clearly visible zona pellucida with spongy appearance and numerous pores. Our results imply that already during the first days of life there is intense interaction of the pre-implantation embryo and the maternal genital tract part of which may be mediated by cumulus cells.     

Embryo‐maternal Communication during the First Days of Embryonic Life

The mechanisms of embryo‐maternal communication during the first days of embryonic life are largely unknown. Using the bovine as a model, the aims of our study were to morphologically characterize the interaction between the pre‐implantation embryo and the epithelium of the maternal ampulla, isthmus and uterotubal junction by light and scanning electron microscopy. For this purpose, oviducts were removed from cows revealing a functional corpus luteum on day 3 after insemination. These were compared to oviducts removed on day 3 (metestrus) of the estrous cycle. Three days after insemination, the majority of the epithelial cells in the ampulla were secretory cells distinctly protruding into the oviductal lumen. Contrary the ampulla of cows on day 3 of the cycle predominantly revealed ciliated cells in the oviductal epithelium. As shown by Periodic Acid Schiff reaction (PAS) with and without amylase digestion, the secretory cells of the ampulla synthesized merely glycoproteins during metestrus, but large amounts of glycogen during pregnancy. In the isthmus no morphological differences were seen between pregnant and cyclic cows. The most conspicuous finding during pregnancy was seen in the uterotubal junction: Vital cumulus cells embedded in between epithelial cells had developed short cytoplasmic processes intensely contacting the epithelial uterine cells. The embryos obtained ex vivo were regularly covered with a thick layer of homogenous extracellular matrix. Contrary embryos produced in vitro– both with and without coculture with oviductal cells –revealed a clearly visible zona pellucida with spongy appearance and numerous pores. Our results imply that already during the first days of life there is intense interaction of the pre‐implantation embryo and the maternal genital tract part of which may be mediated by cumulus cells.     

An ultrastructural study of malignant mesotheliomas in two cows

Malignant mesotheliomas of two Holstein cows were examined by light and electron microscopy. These tumours were derived from peritoneal surfaces and were of biphasic type composed of mesothelial lining cells and submesothelial mesenchymal cells. Ultrastructurally, the neoplastic mesothelial cells were characterized by intermediate filaments, microvilli, desmosomes, tight junctions and basal laminae. The neoplastic submesothelial cells were closely associated with collagen filaments and some cells had several resemblance to the neoplastic mesothelial cells. The ultrastructural features of the mesotheliomas are discussed in comparison with those of adenocarcinomas and fibroblastic neoplasms. In one case of malignant granulosa cell tumour involved the left ovary and its morphology was apparently different from that of the mesothelioma. Multiple primary tumours are uncommon in cattle.     

Pre-mating injection of an analogue of gonadotrophin-releasing hormone (GnRH) and pregnancy rates to first insemination

Two hundred and ninety two dairy cows received a subcutaneous injection of a 2.5 ml solution containing 10 microg GnRH-analogue (Receptal, Hoechst A.G.) 0-6 hours before insemination, while 284 cows acting as controls were injected with 2.5 ml of sterile pyrogen-free water at the same time. The two groups, the treated and the control, were formed by matching (pairing) each oestrous cow with another on the basis of interval from calving to first mating, condition score, and age on the day of first mating after calving. The cows were in 3 factory supply dairy herds, which were visited daily during the first 3 weeks of the mating season. All the cows presented for mating each day were inseminated by the same technician using 0.5 ml of ambient-temperature semen containing 2 million spermatozoa per insemination. The semen used on any particular day originated from one ejaculate of one bull (same batch number). The cows were manually examined for pregnancy 2 to 3 months after their first insemination. A similar response was seen in all three herds irrespective of the interval from calving to mating. First mating pregnancy rates were 9.3% higher in the Receptal-treated cows than in the control group (P = 0.025). It is suggested that Receptal may have a beneficial effect on the pregnancy rate of cows that have recently ovulated as well as on those having delayed ovulation.     

Influence of Boar Seminal Plasma on the Distribution of Spermatozoa in the Genital Tract of Gilts

The main purpose of the present study was to investigate whether boar seminal plasma affects the transport of spermatozoa in the genital tract of oestrous pigs or not, with special reference to the sperm transport into the oviducts. Altogether 17 gilts were used in three experiments.Experiment I. In nine gilts one uterine horn was injected surgically with 10¹⁰ spermatozoa suspended in seminal plasma and the other uterine horn with 10¹⁰ spermatozoa suspended in TESNaK-glucose buffer solution. The sperm deposition was performed under general anaesthesia. The gilts were slaughtered 1–2 or 4–6 h after insemination. The genital tract was removed and the numbers of spermatozoa determined in oviducts and in uterine horns.Experiment II. The insemination doses were prepared exactly as in Experiment I. Approx. 24 h before insemination Polyvinylchloride cannulas were inserted into the uterine lumen of the horns, drawn via the midventral incision at linea alba subcutaneously to cutaneous incisions ventral to the vulva opening. One cannula was placed in each uterine horn. At standing heat the insemination doses were slowly injected through the cannulas. The gilts were slaughtered 1 h after insemination and the numbers of spermatozoa within the genital tract were counted.Experiment III. In three gilts under general anaesthesia the uterine horns were ligated 10 cm from the uterotubal junction. The semen doses (containing 2 × 10⁹ spermatozoa), prepared as in Experiment I, were deposited into the uterine horns anterior to the ligatures through a cannula. The gilts were slaughtered 1 h after insemination, and the numbers of spermatozoa within the oviducts and ligated part of the uterine horns were counted.In all three experiments more spermatozoa were, on average, recovered in the oviducts connected to uterine horns inseminated with spermatozoa suspended in seminal plasma. In Experiments I andII this was the case for 10 of 14 gilts and in Experiment III for all the three gilts. It is therefore suggested that boar seminal plasma pro¬motes sperm transport into the oviduct of oestrous pigs. The back¬ground mechanism for this is discussed.     

Mesothelial cells of peritoneal fluid

Cells in the peritoneal fluid from 159 horses were examined in Giemsa stained preparations using light microscopy. Normal mesothelial cells showed an oval nucleus with finely reticular chromatin and pale blue cytoplasm. Activated mesothelial cells occurred in fluids derived from mesothelium under acute or subacute, non-septic stimulus and were remarkable for their pleomorphism and intense basophilia which may mimic neoplasia. Transformed mesothelial cells seen in chronic inflammatory fluids were sometimes phagocytic and showed conspicuous cytoplasmic vacuolation.     

Cloned cows with short telomeres deliver healthy offspring with normal-length telomeres

Dolly, the first mammal cloned from a somatic cell, had shorter telomeres than age-matched controls and died at an early age because of disease. To investigate longevity and lifetime performance in cloned animals, we produced cloned cows with short telomeres using oviductal epithelial cells as donor cells. At 5 years of age, despite the presence of short telomeres, all cloned cows delivered multiple healthy offspring following artificial insemination with conventionally processed spermatozoa from noncloned bulls, and their milk production was comparable to that of donor cows. Moreover, this study revealed that the offspring had normal-length telomeres in their leukocytes and major organs. Thus, cloned animals have normal functional germ lines, and therefore germ line function can completely restore telomere lengths in clone gametes by telomerase activity, resulting in healthy offspring with normal-length telomeres.     

Scanning electron microscopic study of the functional anatomy of the porcine oviductal mucosa

A three-dimensional model has not been clearly established for the porcine oviductal mucosa. The oviducts of 12 cyclic sows were examined by Scanning Electron Microscopy to study the structure and nature of the mucosal arrangement of the oviduct. Epithelial cyclic changes were also studied. The oviductal infundibulum is an asymmetric funnel-shaped structure surrounding the ostium, in which a wide and a narrow side can be distinguished. The mucosa is more complex in the narrow side, showing numerous and tortuous longitudinal primary folds, while the mucosa becomes simpler in the wide side. Around the ostium abdominale wide secondary folds form cul-de-sacs, with their opening pointing in ovarian direction. Areas between folds throughout the lumen of the oviduct show a high-degree of complexity. Inter-fold spaces are occupied by a system of irregular grooves and pockets, with the presence of basal crypts in the caudal oviduct. Marked variations were observed in the oviductal epithelium depending on the oviductal segment, basal or apical areas of the folds, and phase of the oestrous cycle. Cyclical changes were observed in the infundibulum and ampulla, so that prominent and numerous ciliated cells lined apical areas of the folds in the follicular phase; whereas secretary cells were predominant throughout all areas of epithelial surface in the luteal phase. The oestrous cycle phase appeared do not affect the epithelial population cells of the caudal segments of the oviduct: ciliated and secretory cells uniformly lined apical and basal areas of the folds. The topography of the oviduct provides a complex system of regulation, which may influence not only the passage of cells, but also movement of fluid within the oviductal canal.     

ARTIFICIAL INSEMINATION OF BEEF CATTLE

A system for the artificial insemination fo beef cattle was described. The system involved preparation of the cattle and facilities, visual oestrous detection twice a day, drafting each morning and insemination of oestrous cows twice a day. The AI program was evaluated during the course of the program and at pregnancy test 35 to 90 days after the end of the insemination period. The insemination period was from 25 to 60 days depending on efficiency, with programs from 25 to 35 days being favoured. Results for 12218 first inseminations (65.9%) and 2222 second inseminations (57.8%) in 56 AI programs compared favourably with results in dairy AI. Pregnancy rates in lactating cows (70.5%) were significantly higher than in nonlactating cows and heifers (66.1%). Overall efficiency of well-managed AI programs were represented by 63% of cows put into a program becoming pregnant in a 29-day insemination period. Seventy-two per cent of the cows put into the program were inseminated yielding an 88% pregnancy rate. The efficiency of visual oestrous detection was 95% but this estimate did not include false positives. Efficiency of AI programs were effected by management, nutrition, infection, inseminators, facilities and the origin and type of cattle put into a program. Environmental factors such as handling, stress and thunderstorms did not effect efficiency except via a nutritional effect.     

Intraperitoneal Insemination in Mammals: A Review

This review focuses on factors associated with the development of intraperitoneal insemination in mammals. Findings to date indicate that fertility improves as the sperm cell concentration rises, but that the optimal sperm number differs in each species. Sperm washing before intraperitoneal insemination favours fertility. Peritoneal fluid shows a variable effect on spermatozoa, depending on the hormonal status of the female. The optimal time for insemination appears to be just prior to ovulation. The technique may be performed either through the abdominal or the vaginal wall. Verification of sperm deposition in the proximity of the ovaries improves fertility rates. Although associated with some risk of infection and an immune reaction against spermatozoa, the intraperitoneal technique rarely gives rise to severe anaphylactic shock, peritonitis, adhesion formation and the production of anti‐sperm antibodies and these complications may be prevented by adequate sperm pretreatment and antibiotic therapy. The success of intraperitoneal insemination in humans, with results comparable with those of intrauterine insemination in the treatment of infertility, suggest the potential use of this technique in domestic mammals, especially in those in which intrauterine insemination poses practical difficulties. Some of the methods applied in human intraperitoneal insemination, such as confirming the position of the needle in the peritoneal cavity, and sperm pre‐treatments might also improve results in domestic species. Conversely, the use of the animal model should help to develop some aspects of this technique in humans.     

A pheromonal function for the perineal skin glands in the cow

Two cows with synchronised oestrous cycles were housed with a Friesian bull. During the midcycle period of the cows, one cow was given an intradermal injection of adrenaline in the perineal region. This caused local sweat gland discharge. The other cow was treated with water. The number and types of bull-to-cow behaviours were recorded before, during and after the day of treatment. This was repeated at three-weekly intervals for a total of four times. On the day of treatment the bull directed a greater proportion of olfactory behaviours towards the adrenaline-treated cow than the other cow (P less than 0.05). There was no difference between the cows before or after the day of treatment. The above experiments were repeated with a Hereford bull who showed the same response as the Friesian for the first two but not the last two experiments. The increased proportion of bull olfactory behaviours elicited by an increased perineal skin gland discharge, adds support to our hypothesis that the perineal skin glands are the source of an oestrous pheromone in the cow.     

精子生育相关性抗原对奶牛妊娠率影响研究

为研究精子生育相关性抗原对奶牛妊娠率的影响,测试了16头种公牛精子的生育相关性抗原,进行人工授精,比较奶牛的妊娠情况.结果显示:测试的16头种公牛精子生育相关性抗原,其中13头呈阳性,3头阴性,阴性率为18.75%.在用FAA阳性精液进行人工授精的520头奶牛中,有433头奶牛怀孕,妊娠率为83.26%.而FAA阴性授精的80头奶牛中,只有52头奶牛怀孕,妊娠率为65.0%(P<0.01).因此,奶牛人工授精FAA阳性精子妊娠率比FAA阴性精子高18个百分点,大大提高了奶牛的妊娠率.     

Oestrus during pregnancy in the cow

Forty-three oestruses were observed in 35 pregnant cows in one beef suckler herd and 17 dairy herds; at each oestrus the pregnant cow stood willingly to be mounted by another cow or bull. Such oestruses were observed at all stages of pregnancy, although more often between 121 and 240 days, occurred more than once per pregnancy and were also seen in successive pregnancies. On one farm where the dairy cows were observed for four 30 minute periods daily, oestrus was recorded in 5.7 per cent of pregnant cows. The behavioural signs associated with oestrus during pregnancy were indistinguishable from those of true oestrus in non-pregnant animals and although its duration was shorter (mean 5.6 hours), its intensity was comparable to that of the true oestrus. Pregnant cows showing oestrus were usually seen interacting with other oestrous cows in the sexually active group. Pregnant cows showing oestrus had a higher mean condition score (3.9 +/- 0.64) than control pregnant cows (3.0 +/- 0.36). Physiological changes in the genital tract normally associated with true oestrus were not observed in pregnant cows showing oestrus. There was no ovulation or metoestrous bleeding. The characteristics of cervical mucus, including ferning patterns, were similar to those of pregnant cows at the same stage of pregnancy. Hormonal changes associated with oestrus in non-pregnant cows were not observed in the pregnant cows exhibiting oestrus. Seven of nine pregnant cows at oestrus stood willingly to be mounted by a bull. On seven occasions, bulls exposed only to cervical mucus from pregnant cows showing oestrus did not display flehmen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Oestrus synchronisation with a prostaglandin analogue: I. Systems in lactating dairy cattle

Three trials were completed to compare different regimes for the use of an analogue of prostaglandin F₂ alpha(“Estrumate”: ICI) in the breeding management of herds of lactating dairy cows with seasonally concentrated calving patterns. The first regime involved two injections of ‘Estrumate’ 11 days apart, followed by insemination, either at 72h and 96h after the second injection, or at the first observed oestrus. Every cow had calved at least 40 days before the first injection. The second regime involved a single ‘Estrumate’ injection given to every cow not inseminated during the first seven days of the breeding programme. Treated cows were inseminated when observed in oestrus within 48h of injection, or at 72h and again at 96h. The third regime utilised the technique of tail-painting during the pre-mating period to identify groups of cycling cows which were subsequently givena single injection of “Estrumate” and inseminated 72h lateror at a subsequent behavioural oestrus.

All regimes significantly altered the conception pattern from that obtained in untreated herd-mates. The variable incidence of post-partum anoestrus, genuine short oestrous cycles and the degree of precision in oestrus synchronisation in lactating dairy cows resulted in many animals being unnecessarily injected and/or inseminated. The third regime overcame most of these problems and could have application in many largeherds. The identification of cycling animals and insemination at detected oestrus are important components of programmes using prostaglandins for the purpose of oestrus synchronisation in lactating cows in seasonal dairy herds.     

Postpartum reproductive function in Finnish Ayrshire and Friesian cows after three subsequent parturitions

The postpartum reproduction functions of 84 Finnish Ayrshire and Friesian cows were studied on an experimental farm. The cows were divided according to type of feed into 2 groups of equal size: a hay-urea group and a silage group. The duration of the study was 3 years. Eighty-four cows were followed during their first postpartum period, 63 during 2 and 57 during 3 consecutive post partum periods.The cows were examined clinically by rectal palpation, and milk samples for progesterone assay were taken 3 times a week between calving and first insemination. External signs of heat were checked 3 times a day by the herdsmen.Intervals from calving to completed uterine and cervical involution, appearance of first palpable follicle, onset of first luteal function and onset of regular ovarian function were recorded. Intervals from calving to the first observed heat and to pregnancy were measured and the rate of successful pregnancies at the first insemination was calculated.Least squares methods were used for evaluation of the effect of individual cow, breed, parity/year and type of feed on postpartum reproductive function.The cows in the herd seemed to have equal reproductive functions which were influenced by the conditions during each year/parity rather than by the breed or type of feed.Individual cow effect was significant for the rapidity of uterine involution. Breed had no significant effect on any of the parameters studied.The effect of type of feed alone was not significant for any parameter, but when studying the intervals from calving to uterine involution and initiation of luteal function differences between the feed groups were noted within parity/year.The percentage of cows showing heat before the first dioestrus (luteal phase) increased with parity/year, and the first dioestrus was shorter than the second. The percentage of cows showing postoestrous bleeding increased with number of oestrous cycles post partum.     

Toxic elements in the sex organs of the cow and their relationship to fertility

The content of heavy metals (Cd, Hg, Pb, Cr, Cu and Zn) has been determined by atomic absorption spectrophotometry in parts of genital organs of cows with and without reproductive disorders, in blood, in placenta, in colostrum, and in the calf blood. The samples were collected in an industrially polluted area and in a relatively non-polluted area. It has been proven in the group of 99 cows that the biological quality of the oestrous cervical mucus is also influenced by toxic elements. The best conception rate after the artificial insemination (80.0%) has been found in cows with the cervical mucus without spermiotoxic properties. The genital organs of 49 cows culled because of reproductive disorders were examined. No significant differences in the content of heavy metals have been found in the separate parts of genital organs. There were also no differences between the cows with and without reproductive disorders. Toxic elements in blood have been found in cows after parturition and in newborn calves both in the polluted and the non-polluted areas. However, significant differences (p less than 0.01) were determined only in the content of Cd and Zn. The average content of all determined toxic elements in the samples of placenta in pluriparous and primiparous cows from the polluted and non-polluted areas was approximately at the same level. The content of Zn was 4.3 times higher than the hygienic standard in the colostrum of cows from the polluted area. The content of Zn exceeded the hygienic standard also in the non-polluted area, and the content of Cd and Hg was close to the hygienic standard there.     

Improved knowledge about conception rates influences the decision to stop insemination in dairy cows

The conception rate in dairy cows is dependent on a number of cow factors such as days in milk and insemination number. Unfortunately, some of these factors were not accounted for in optimal insemination and replacement decision models. By using wrong estimates of the conception rate, the calculated optimal insemination and replacement policy might differ from the real optimal insemination and replacement policy. The objective of this study was to evaluate different sets of conception rates with an increasing level of accuracy to determine the insemination policy. An existing dynamic program for optimal insemination and replacement was used to compare three different scenarios in the estimation of conception rates, based on the reproductive performance of Dutch dairy cattle: (i) constant conception rate throughout lactation, (ii) conception rate dependent on parity and months in milk, and (iii) conception rate dependent on parity, months in milk and insemination number. The time step of the model was 30.4 days (1 month). The discounted future cash flow of culling a cow at each time step (replace a heifer immediately) was compared with keeping that cow under optimal future decisions. The difference between immediate culling and optimal decisions is defined as the retention pay-off. The insemination value was calculated as the difference between the future cash flow between immediate insemination of a cow and waiting one time-step. The results show that the difference in the insemination values and the optimal time to stop insemination depend on parity, lactation stage and the relative milk yield. In older cows with equal milk yields and at the same months in milk, the insemination value was lower than in younger cows. Within a parity, the insemination value was higher for cows with a higher milk yield. On individual cow level, using more accurate conception rate as input in the optimal insemination and replacement model might reduce miscalculation of the economic consequences for at least of €20-€38 per cow per year. Basing insemination decisions on less accurate input of the probabilities of conception, however, did not have an economic consequence at the herd level. In conclusion, using the appropriate conception rate as input in the optimal insemination and replacement model would increase the precise decision for the optimal time to stop insemination and hence improve the reproductive management efficacy.