Frequency of twin births among Holstein-Friesian cows in a warm dry climate

The objectives of this study were to examine 1) the effect of parity of dam and season of birth on the incidence of twins in Holstein-Friesian cattle in a warm, dry climate and 2) the sex ratio, gestation period and birth weight of calves born. Natural calvings (n = 24,843) from nine dairy farms in Saudi Arabia were evaluated over an 8-year period. The calendar year was divided into six bimonthly intervals to identify a possible seasonal effect on the number of natural twins born (twinning rate). The twinning rate increased (P < 0.05) from 1.0% (103 10,094 ) at first calving to 8.0% (1,178 14,749 ) for all the subsequent calvings. The twinning rate was similar with the second calving (P(2)) at 7.0% (417 5,929 ), the third calving (P(3)) at 7.5% (218 2,896 ), and the fourth calving (P(4)) at 7.8% (147 1,864 ). Correspondingly, cows having >/= five calves had a higher (P < 0.01) twinning rate at 9.0% (164 1,805 ) than cows with too, three or four calvings collectively at 7.3% (782 10,689 ). The seasonal effect on twinning rate was significant within all parity calvings except in primiparous females. The peak twinning rate occurred in the third season interval (May/June) at 9.3% (66 708 ) with P(2), at 13.0% (34 262 ) with P(3), at 13.8% (27 196 ) with P(4), and at 12.5% (23 184 ) with P(5) females. The male to female ratio was different (P < 0.01) for multiparous females (55:46; n = 12,305). The ratio of males to females (55:45) was also different (P < 0.01) for all twin pairs (n = 1,151), evaluated in the study. The gestation period for cows with single calves was 8.5 days longer (P < 0.05) than that of cows carrying twin calves. The birth weight of single calves was 13.1 kg greater (P < 0.05) than that of twin calves. The reason for the marked increase in the twinning rate during the warmest months may be explained by greater embryo mortality in the hot vs cool months.     

Effects of inbreeding on ovarian responses and embryo production from superovulated Mantiqueira breed cows

The objective of the present experiment was to evaluate the effects of different levels of inbreeding on ovarian response and embryo production from superovulated cows. One hundred and thirteen Mantiqueira cows (a medium-size, Bos taurus native dairy cattle breed), with inbreeding coefficients ranging from 0 to 30%, were allocated into five classes of inbreeding and subjected to superovulation treatment. At induced estrus, cows were mated with Mantiqueira bulls (with minimal inbreeding). Six to eight days after mating, the cows were slaughtered, ovarian structures counted and embryos recovered by flushing the uterine horns and oviducts. Sire, season, age, weight, parity and age at first calving of donors did not significantly affect ovarian response or embryo production and quality. There were no effects of inbreeding class on number of total corpora lutea (CL) or number of CL present in the right ovary. However, the number of CL in the left ovary was reduced (P<0.05) in cows with Class 5 (>9%) of inbreeding. The number of transferable, but not the number of non-transferable embryos or the total number of embryos from cows with Class 5 of inbreeding, was lower (P<0.05) than those of cows from Classes 0 to 4 (<9%) of inbreeding. There was a quadratic decrease in the number of transferable embryos as inbreeding coefficient increased (Y=11.077+0.34X-0.0529X(2); R(2)=0.91, P<0.01), but no significant linear or quadratic effect of inbreeding on total number of embryos or number of non-transferable embryos. In conclusion, an inbreeding coefficient>9% reduced the quality of bovine embryos at the initial stage of development.     

Effect of summer conditions and shade on the production and metabolism of Holstein dairy cows on pasture in temperate climate

For dairy cattle on pasture in temperate regions, it is largely unknown to what degree hot summer conditions impact energy metabolism, milk yield and milk composition and how effective shade is in reducing these negative effects. During the summer of 2012, a herd of Holstein cows was kept on pasture without access to shade (treatment NS). During the summers of 2011 and 2013, the herd was divided into a group with (treatment S) and a group without (treatment NS) access to shade. Shade was provided by young trees combined with shade cloths (80% reduction in solar radiation). A weather station registered the local climatic conditions on open pasture, from which we calculated daily average Heat Load Index (HLI) values. The effects of HLI and shade on rectal temperature (RT), blood plasma indicators of hyperventilation and metabolic changes due to heat stress, milk yield and milk composition were investigated. RT increased with increasing HLI, but was less for S cows than for NS cows (by 0.02°C and 0.03°C increase per unit increase of HLI, respectively). Hyperchloraemia (an increased blood plasma concentration of Cl⁻), a sign of hyperventilation, increased for NS cows but not for S cows. The plasma concentration of alkaline phosphatase, a regulator of energy metabolism in the liver, decreased with increasing HLI for NS cows only. Access to shade, thus, reduced the effect of HLI on RT, hyperchloraemia and the regulation of metabolism by the liver. As HLI increased, the plasma concentration of cholesterol decreased (indicating increased lipolysis) and the plasma concentration of creatinine increased (indicating increased protein catabolism). These effects did not differ between S and NS cows. For NS cows, after a lag-time of 2 days, the milk yield decreased with increasing HLI. For S cows, the milk yield was unaffected by HLI and its quadratic factor. The milk concentrations of lactose, protein and fat decreased as HLI increased, but only the effect on milk protein content was remediated by shade. In conclusion, access to shade tempered the negative effects of high HLI on RT, hyperchloraemia and a blood plasma indicator of changing energy metabolism (generally) as well as prevented the decrease in milk yield observed in cows without access to shade.     

The influence of thermal conditions on rectal temperature,respiration rate and pulse rate of lactating Holstein-Friesian cows in the humid tropics

The effect of minimum, maximum and mean ambient air temperatures and the temperature-humidity index (THI) of the same and the previous day on morning (a.m.) and afternoon (p.m.) rectal temperatures (RT), respiration rates (RR) and pulse rates (PR) were studied in 17 Holstein-Friesian cows over the first 125 days in the 3rd and 4th lactations. Physiological responses showed a diurnal pattern, being lower in the mornings than the afternoons: 38.6 vs 39.0° C for RT, 52.2 vs 60.7 breaths/min for RR and 58.1 vs 64.1 beats/min for PR. Correlations between RT and RR (r = – 0.043 to –0.046) and RT and PR (r = –0.178 to –0.261) were low (P> 0.05). Correlations between RR and PR (r = 0.353 to 0.365) were moderate (P<0.05). Weather variables, especially ambient temperature of the previous day, were more important and influenced physiological responses to a greater extent than other thermal factors the same day. Generally, physiological responses were influenced to a greater extent by ambient temperature than THI. Weather variables explained variations in RT (5.1–59.6%), in RR (13.0–17.8%) and in PR (22.1–25.4%). Relationships between weather variables the previous day and physiological responses were contradictory, with minimum and maximum values showing a negative relationship in contrast with a positive relationship for mean values.     

Effect of low winter temperatures on milk production of dairy cows grazed on farms in a warm temperate climate (Australia)

Two-day milk production figures for dairymen at Armidale (31° S Lat.) and Goulburn (35° S Lat.), Australia, were compared with minimum daily temperatures. Comparisons were made between production levels on days with temperatures above and below 0°C, and between days with varying intensities of cold: differences in production were minor. The infrequent, more prolonged periods of cold weather (cold being days on which the minimum temperature was below 0°C) were also associated with only very slight reductions in milk output; and the most pronounced decline in production was not attributable to low temperatures. Although short-term fluctuations in output were not related to low temperature events or low temperatures in combination with rain, thermal stress on plant growth during winter contributed to a seasonal downturn in production and below-average annual milk yields in areas with low winter temperatures.     

Comparison of the effects of eFSH and deslorelin treatment regimes on ovarian stimulation and embryo production of donor mares in early vernal transition

The objective was to compare the effects of eFSH and deslorelin treatment regimes on ovarian stimulation and embryo production of donor mares in early spring transition. Starting January 30th, mares kept under ambient light were examined by transrectal ultrasonography. When a follicle ≥25 mm was detected, mares were assigned to one of two treatment groups, using a sequential alternating treatment design. In the eFSH group, mares (n = 18) were treated twice daily with eFSH (12.5 mg im) until they achieved a follicle ≥35 mm; hCG was given 36 h later. In the deslorelin group, mares (n = 18) were treated twice daily with deslorelin (63 μg im) until a follicle ≥35 mm was detected, and then they were given hCG. Estrous mares were inseminated with fresh semen. Eight days after ovulation, embryo recovery attempts were performed. In each group, 14/18 (78%) mares ovulated following the eFSH or deslorelin treatment regimes. The mean (95% CI) interval from treatment initiation to ovulation was 8.2 d (7.3, 8.9) and 7.2 d (6.2, 8.1) in the eFSH and deslorelin groups, respectively. In the eFSH group, the number of ovulations was significantly higher (mean ± S.E.M.; 3.4 ± 0.4 vs. 1.1 ± 0.1 ovulations), and more embryos were recovered (2.6 ± 0.5 vs. 0.4 ± 0.2 embryos/recovery attempt). We concluded that eFSH and deslorelin treatment regimes were equally effective in inducing ovulation in early transitional mares, within a predictable time of treatment; however, the eFSH regime increased the number of ovulations and embryos recovered per mare.     

Dose of FSH-P as a source of variation in embryo production from superovulated cows

Various superovulation treatments were evaluated retrospectively in a commercial embryo transfer program. When it appeared that embryo production was dependent on the dose of FSH-P, a dose response curve to FSH-P was developed and embryo production compared using several treatment regimes. There was a significant effect of dose of FSH-P on embryo production in superovulated cows. At doses in excess of 28 mg, embryo production declined from 5.9 transferable embryos per collection (28 mg) to 2.7 (60 mg). Total embryos collected declined from 14.9 to 6.8 and the percent transferable from 57% to 40%. There was no advantage in using a five-day treatment over a four-day treatment regimen or in using a level over a declining dose regimen. There was a large individual variation in cow response rendering decisions on treatment changes based on single records unreliable. The percentage of zero collections increased with dose rate. Adoption of a 28-mg dose rate in commercial donors resulted in the embryo production forecast by these studies.     

Changes in plasma volume during hypohydration and rehydration in subjects from the tropics

Plasma volume (PV) at different levels of hypohydration was determined using radio-iodinated serum albumin-125 in 28 heat acclimated male volunteers in hot dry condition in a climatic chamber. The heat acclimated subjects were hypohydrated to varying degrees i.e. 1%, 2%, 3% and 4% body mass deficit by moderate work in hot conditions in a climatic chamber maintained at 45 degrees C dry bulb temperature and 30% relative humidity. A rehydration study was carried out in only those subjects who were hypohydrated to 3% and 4% body mass and they were brought back to a 2% level of hypohydration by giving a calculated amount of water. A significant decrease in PV was observed at 3% and 4% hypohydration only. The magnitude of the decrease was the same in both the groups and not related to the level of hypohydration. With partial rehydration in the 3% hypohydrated group PV was restored fully, while in the 4% hypohydrated group restoration was incomplete, indicating that at this hypohydration level some of the replenished water that entered in plasma may have moved to the intracellular compartment which may have contributed more at 4% hypohydration. It is suggested that with higher levels of thermal hypohydration significant reduction in the intracellular compartment may result in accentuated physiological strain during work in the heat.     

Biostimulatory effects of estrous cows and bulls on resumption of ovarian activity in postpartum anestrous Zebu (Bos indicus) cows in the humid tropics

Suckled postpartum Zebu (Bos indicus) cows were exposed either to estrous females alone or together with bulls to determine if this regimen would stimulate the resumption of ovarian activity. The study was carried out on 60 Zebu cows. The animals were allocated at parturition to 1 of 3 treatment groups. Group FB cows (n = 14) were exposed to progestogen treated females (approximately 3 cows per progestogen treated cow) and a bull for 42 d. Group F cows (n = 31) were exposed to progestogen treated females and after 21 d a bull was introduced and remained with the group until the end of the experiment 21 d later. Estrus was induced with Syncro Mate B treatment and the cows were in estrus when introduced into Groups FB and F. Group N cows (n = 15) were introduced to a bull 21 d after the treatments had begun in Groups FB and F, and the bull remained with these cows until the end of the study. On average, resumption of ovarian activity occurred in 57% (8/14), 19% (6/31) and 7% (1/15) of the cows in Group FB, F and N, respectively, within 21 d after the start of treatments. The difference was significant between Group FB and Groups F and N (P < 0.05). During the second part of the experiment, in which the bull was introduced to Groups F and N, an additional 32% (10/31) of the cows in Group F and 33% (5/15) in Group N resumed ovarian activity. No cows in Group FB resumed ovarian activity during this period. There were significant differences in body condition between cows that resumed ovarian activity and those that remained in anestrus (P < 0.05). We conclude that biostimulation effectively enhanced resumption of ovarian activity in anestrous suckled Zebu cows. This technique offers a potentially useful and practical way to improve reproductive efficiency in anestrous Zebu cattle in the tropics.     

Changes of phosphorous fractions under continuous corn production in a temperate clay soil

Limited efficiency of fertilizer P may be improved through an understanding of soil P fraction changes with time. This study examined sequential changes in soil organic P (Po) and inorganic P (Pi) in a Ste. Rosalie clay (Humic Gleysol; fine, mixed, frigid, Typic Humaquept) under continuous corn with and without P fertilization. Soil P was fractionated into Bicarb-Pi and Po, NaOH-1-Pi and Po, HCl-Pi, NaOH-Pi and Po, and Residue-P. In the non-P fertilized plots, soil total extractable Po declined by 14% of the initial value over five years of corn production, whereas soil Pi fractions were unchanged. The losses of soil Po were mainly from NaOH-1-Po. Added fertilizer P increased NaHCO3-Pi and NaOH-1-Pi in plots receiving 44 and 132 kg P ha^-1 yr^-1 and increased Residue-P in plots receiving 132 kg P ha^-1 yr^-1. Although NaOH-1-Po decreased slightly in the plots receiving 44 kg ha^-1 yr^-1 P fertilizer, total soil extractable Po was maintained in P fertilized plots. Mineralization of from 16 to 29 kg P ha^-1 yr^-1 Po was needed to account for soil Po losses. Bicarb-Pi and NaOH-1-Pi appeared to be most important for assessment of soil P fertility changes in long-term fertilized soils.     

Parasite loads are higher in the tropics: temperate to tropical variation in a single host-parasite system

Parasites are important selective forces upon the evolutionary ecology of their hosts. At least one hypothesis suggests that high species diversity in the tropics is associated with higher parasite abundance in tropical climates. Few studies, however, have directly assessed whether parasite abundance is higher in the tropics. To address this question, it is ideal, although seldom achievable, to compare parasite abundance in a single species that occurs over a geographical area including both temperate and tropical regions. We examined variation in blood parasite abundance in seven populations of a single lizard host species ( Eulamprus quoyii ) using a transect that spans temperate and tropical climates. Parasite prevalence (proportion of the host population infected) showed no geographical pattern. Interestingly though, parasite load was higher in lizard populations in the tropics, and was related to mean annual temperature, but not to rainfall. We speculate that in this system the relationship between latitude and parasite load is most likely due to variation in host life history over their geographic range.     

Community structure and composition in response to climate change in a temperate steppe

Climate change would have profound influences on community structure and composition, and subsequently has impacts on ecosystem functioning and feedback to climate change. A field experiment with increased temperature and precipitation was conducted to examine effects of experimental warming, increased precipitation and their interactions on community structure and composition in a temperate steppe in northern China since April 2005. Increased precipitation significantly stimulated species richness and coverage of plant community. In contrast, experimental warming markedly reduced species richness of grasses and community coverage. Species richness was positively dependent upon soil moisture (SM) across all treatments and years. Redundancy analysis (RDA) illustrated that SM dominated the response of community composition to climate change at the individual level, suggesting indirect effects of climate change on plant community composition via altering water availability. In addition, species interaction also mediated the responses of functional group coverage to increased precipitation and temperature. Our observations revealed that both abiotic (soil water availability) and biotic (interspecific interactions) factors play important roles in regulating plant community structure and composition in response to climate change in the semiarid steppe. Therefore these factors should be incorporated in model predicting terrestrial vegetation dynamics under climate change.     

Seasonal changes in milk production and fertility in high yielding dairy cows in a desert climate

The lactational performance and fertility of high yielding Friesan dairy cows in a hot desert climate were analysed for summer and winter differences. The herd is situated in the Negev desert of Israel.Contrary to all previous reports,milk yield was significantly higher in summer than in winter; furthermore fertility was not lower in the hot months. The daily range in summer temperature was from 22° to 40°C and in winter from 8° to 22°C.The results are discussed in terms of the management and feeding practice of the farm. It was suggested that the cows had been acclimatized and that their thermoneutral zone has been raised.

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Zusammenfassung Die Milchleistung und Fertilität von Hochleistungs Friesischen Milchkühen im heissen Wüstenklima wurde auf Sommer- und Winterunterschiede untersucht. Die Herde wird in der Negev Wüste in Israel gehalten. Im Gegensatz zu allen bisherigen Berichten war die Milchleistung im Sommer signifikant höher als im Winter. Die Fertilität war in den heissen Monaten nicht niedriger als in den kühlen.Der tägliche Bereich der Temperaturen war im Sommer von 22°–40°C und im Winter von 8°–22°C. Die Ergebnisse werden unter Berücksichtigung der Haltung und Fütterung diskutiert. Es wird angenommen, dass die Kühe akklimatisiert sind und die thermoneutrale Zone erhöht ist.

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Resume On a examiné les différences pouvant exister entre l'hiver et l'été dans la production laitière et la fécondité de vaches laitières sélectionnées de race frisonne placées dans un climat désertique chaud.Le troupeau se trouvait en Israël,dans le désert du Néguev. Contrairement à tous les rapports antérieurs, la production laitière fut ici plus importante en été qu'en hiver et cela de façon significative, statistiquement parlant. La fécondité ne fut pas inférieure durant la saison chaude par rapport à la saison froide. La température journalière a varié entre 22° et 40°C en été et entre 8° et 22°C en hiver. Ces résultats seront discutés en tenant compte des méthodes de stabulation et de nutrition. On admet que le bétail est acclimaté et que sa zone thermo-neutre en a été relevée.

     

Life-history strategies of Australian lizards: a comparison between the tropics and the temperate zone

Summary Previous studies have suggested that tropical and temperate-zone lizards may differ fundamentally in life histories. We tested the applicability of this idea to Australian species by comparing temperate-zone species of agamid and scincid lizards with their congeners from the seasonal tropics. Data were derived from dissection of 1,941 specimens and from published information. Clutch size and egg size were positively correlated with mean maternal body size in most lizard species from both climatic zones. Mean body size of the lizards studies did not differ between the tropics and the temperate zone, nor did egg or hatchling size. However, tropical skinks showed considerably (approximately 20%) lower clutch size and relative clutch mass than did temperate-zone skinks. This difference was partly due to the higher incidence of species with low, invariant clutch size in the tropical lizard fauna (as seen in other continents as well), but primarily due to a trend for lineages (especially genera) with relatively high fecundity to be more common in the temperate zone than in the tropics. In contrast to studies on African lizards, our data suggested that modification of clutch size between areas has not occurred within genera: congeneric species from the tropics and temperate zone did not differ in clutch size. Production of more than one clutch per annum by individual females was common in both climatic zones. Tropical lizards may differ from temperate-zone species in showing higher reproductive frequencies, more rapid growth and earlier maturation. However, most of these effects may be due to phenotypic responses to environmental conditions (especially longer annual activity season), rather than to genetically based lifehistory adaptations.     

Changes in peroxidase activity,auxin level and ethylene production during root formation by poplar shoots raised in vitro

Shoots of poplar (Populus tremula × P. tremuloïdes) were multiplied in vitro and rooted on a rooting medium in the presence of NAA. No rooting occurred in the absence of exogenous auxin. A peak of soluble peroxidase activity, which corresponded to a decrease in the free IAA level in the shoots, preceded rooting These events were considered as corresponding to the initiative phase of rooting. They are preceded by a peak in free IAA activity which might initiate the inductive phase of the rooting process. A burst of ethylene production was measured in both rooting and non-rooting shoots, but the ethylene peak from rooting shoots appeared earlier and was higher. The use of ACC indicated that the exogenous auxin might have enhanced ACC-synthetase activity.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - NAA naphthaleneacetic acid - IAA indole-3-acetic acid - 2-iP 2-isopentenyladenine - IAAsp indole-3-acetylaspartic acid - IBA indole-3-butyric acid - GC gas-chromatography     

Changes in autumn vegetation dormancy onset date and the climate controls across temperate ecosystems in China from 1982 to 2010

Vegetation phenology is a sensitive indicator of the dynamic response of terrestrial ecosystems to climate change. In this study, the spatiotemporal pattern of vegetation dormancy onset date (DOD) and its climate controls over temperate China were examined by analysing the satellite‐derived normalized difference vegetation index and concurrent climate data from 1982 to 2010. Results show that preseason (May through October) air temperature is the primary climatic control of the DOD spatial pattern across temperate China, whereas preseason cumulative precipitation is dominantly associated with the DOD spatial pattern in relatively cold regions. Temporally, the average DOD over China's temperate ecosystems has delayed by 0.13 days per year during the past three decades. However, the delay trends are not continuous throughout the 29‐year period. The DOD experienced the largest delay during the 1980s, but the delay trend slowed down or even reversed during the 1990s and 2000s. Our results also show that interannual variations in DOD are most significantly related with preseason mean temperature in most ecosystems, except for the desert ecosystem for which the variations in DOD are mainly regulated by preseason cumulative precipitation. Moreover, temperature also determines the spatial pattern of temperature sensitivity of DOD, which became significantly lower as temperature increased. On the other hand, the temperature sensitivity of DOD increases with increasing precipitation, especially in relatively dry areas (e.g. temperate grassland). This finding stresses the importance of hydrological control on the response of autumn phenology to changes in temperature, which must be accounted in current temperature‐driven phenological models.     

Association between BoLA and subclinical bovine leukemia virus infection in a herd of Holstein-Friesian cows

The role of the bovine major histocompatibility system (BoLA) in subclinical bovine leukemia virus (BLV) infection was investigated in a herd of Holstein-Friesian cows (n=240). The BoLA W8.1 allele was negatively associated with the presence of antibodies to the major BLV envelope glycoprotein, BLV-gp51 (corrected P<0.001, relative risk =0.31). These results suggest that a BoLA-linked gene(s) may influence the early spread of BLV infection. Since B cells are the primary target of BLV infection, we then determined the relationship between BoLA-A locus phenotypes and B-cell numbers in peripheral blood of seropositive and seronegative cows. There were no significant differences between BoLA-A alleles for any hematological parameter in seronegative cows. Seropositive cows with the W12.1 allele had significantly greater absolute numbers of lymphocytes per microliter and B cells per microliter than did seropositive cows with other BoLA-A phenotypes (P<0.01, respectively). The average effect associated with the W12.1 allele in BLV-infected cows was an increase of 2010 B cells per microliter of whole blood relative to BLV-infected cows with other BoLA-A phenotypes. These results demonstrate that susceptibility to the polyclonal expansion of BLV-infected B lymphocytes is associated with the W12.1 allele in Holstein-Friesian cattle. Compared with results of a previous study in a herd of Shorthorn cattle, it appears that resistance and susceptibility to subclinical progression of BLV infection are associated with different BoLA-A locus alleles in different cattle breeds.Abbreviations used in this paper AGID agar gel immunodiffusion - BLV bovine leukemia virus - BoLA bovine lymphocyte antigen - EBL enzootic bovine leukosis - HLA human leukocyte antigen - MHC major histocompatibility complex - PL persistent lymphocytosis     

FABP3, FABP4 and ANXA9 SNP genotypes in relation to breeding values for milk production traits in Polish Holstein-Friesian cows

The aim of this study is to estimate the associations between the ANXA9, FABP3, and FABP4 genotypes and the breeding value for milk production traits (yields of milk, protein, and fat, as well as protein and fat percentage) in 975 Polish Holstein-Friesian cows. The frequencies of genotypes and alleles were determined. Statistically significant relations between the ANXA9 SNP and the breeding value for fat content, as well as the FABP4 SNP and the breeding value for protein content were found. The results indicated that selection for the ANXA9 GG and FABP4 GG animals might contribute to an decreased fat content and increased protein content in milk, respectively, in Polish Holstein-Friesian cows. Although verification in the further studies is needed.     

Changes in prostaglandin production and ovarian function in gilts during endometritis induced by Escherichia coli infection

The aim of this study was to determine the prostaglandins (PGs) production and ovarian function in gilts after intrauterine infusions of 10(6) and 10(9) colony-forming units (cfu)/ml of Escherichia coli (E. coli). In Experiments 1 and 2, 30 ml of saline or 30 ml of E. coli suspension containing 10(6) or 10(9)cfu/ml, were infused once into each uterine horn in three groups of gilts on day 3 of the estrous cycle, respectively. In Experiment 1, 17 days after treatment it was revealed that inoculation of E. coli 10(9)cfu/ml induced severe acute or subacute endometritis while 10(6)cfu of E. coli evoked moderate acute endometritis or resulted in no inflammatory changes. In the gilts receiving 10(9)cfu/ml of E. coli, the concentration of 13,14-dihydro-15-keto-PGF(2)alpha in blood from the jugular vein was elevated (P<0.05-0.001) compared to concentration in the gilts inoculated with 10(6)cfu on days 8-17 after treatment. Both the E. coli-treated groups had a lower (P<0.05, P<0.01) progesterone plasma level from days 10 to 14 after administration than the control group. On day 17 of the study, infusion of E. coli 10(9)cfu/ml, in comparison to 10(6)cfu, resulted in the greater (P<0.001) content of PGE(2) in the myometrium. The content of both PGs in the endometrium as well as PGF(2alpha) in the myometrium of gilts-treated with 10(9)cfu/ml of E. coli was lower (P<0.001) than in gilts-treated with 10(6)cfu of bacteria. Newly formed corpora lutea were found in the gilts infused with 10(6), but not those infused with 10(9)cfu/ml of E. coli on day 17 after infusion. On day 8 of the study (Experiment 2), the blood from utero-ovarian vein of the gilts-treated with 10(9)cfu/ml of bacteria had a higher (P<0.05) PGF(2alpha) level and lower (P<0.001) PGE(2) level than following infusion of E. coli 10(6)cfu/ml. Also on day 8 of the study, the content of PGE(2) in the endometrium, both the PGs in the myometrium as well as cyclooxygenase-2 in the endometrium and myometrium was greater (P<0.01, P<0.001) after applying 10(9)cfu/ml than 10(6)cfu/ml of E. coli. These results indicate that intrauterine infusions of 10(6) or 10(9)cfu/ml of E. coli lead to the development of inflammatory states of different intensities which is connected with different PGF(2alpha) and PGE(2) production and function of ovaries.