Analysis of fertility indices of cows with extended postpartum anestrus and other reproductive disorders compared to normal cows

An analysis of computerized data on the incidence and consequences of reproductive disorders was performed on 84,818 lactations in more than 100 high producing Kibbutz dairy herds during six semiannual recording periods. The average incidence of primary reproductive disorders, which included retained placenta, abnormal lochia, endometritis, postpartum anestrus, cystic ovaries, negative pregnancy examinations and repeat breeders, was 50.4%. During all recording periods we were able to observe recurrence and repeatability of these reproductive disorders and of the fertility indices consequently seen. Cows with uterine infections diagnosed and treated before Day 20 post partum had better fertility indices than those diagnosed and treated later. The conception rate to first inseminations and the overall conception rate to all inseminations of cows with postpartum anestrus was significantly lower, while the percentage of "problem cows" (not pregnant by Day 150 post partum) was significantly higher, than in normal cows. The incidence of cystic ovaries in cows with a previous diagnosis of reproductive disorders was 2 to 3 times higher when compared to cows without such a diagnosis.     

Production, reproductive, and metabolic factors associated with chlamydial seropositivity and reproductive tract antigens in dairy herds with fertility disorders

While chlamydial infections cause abortions in cattle, its role in other reproductive disorders is uncertain. This study identified the risk factors for chlamydial infection in herds with history of subfertility. We investigated the possible effects of coinfections, different metabolic parameters, abortion, ovarian cysts, pathological vaginal discharge, length of the open period, milk yield, housing conditions and age. In cows from 34 farms with elevated reproductive disorders, 41.5% had antibodies against chlamydia, while chlamydia antigen was detected in the vagina and uterus of 46.7%. A statistical relationship between seropositivity and antigen positivity was not found. Abortion (OR = 6.6) and loose housing (OR = 2.3) were risk factors for the presence of chlamydia antibodies. Furthermore, there were significant relationships between metabolic disorders and chlamydial infections. Increased levels of beta-hydroxybutaric acid (OR = 6.8) and hypocalcaemia (OR = 6.0) often accompanied chlamydia antigen in the vagina. Increased age (OR = 1.2) and pathological vaginal discharge (OR = 2.4) were identified as risk factors for chlamydia antigen in the vagina. The largest risk factor was for the association of ovarian cysts (OR = 21.5) with uterine antigen. In conclusion, chlamydial infection in dairy herd cows is best understood as a multifactorial disease.     

Epidemiological study on factors influencing fertility indices in Israeli dairy herds

The objective of this study was to determine feeding factors connected with differences in the fertility of Israeli Kibbutz dairy herds. In an epidemiological case-control survey, data from 30, low-fertility Kibbutz dairy herds having a mean overall conception rate of 35% in multiparous cows were compared with the data from 30, high-fertility Kibbutz dairy herds having a mean overall conception rate of 48% in multiparous cows. Nutritional factors accounted for 67% of the differences between low-fertility and high-fertility herds in the overall conception rate of multiparous cows, while only 4.8% could be related to the body condition during the dry period. Among the factors which occurred more frequently in the low-fertility than in the high-fertility herds were 1) a higher average protein density and lower energy/protein ratio was fed during lactation and 2) a single feeding group was maintained for all lactating cows. 3) There were phytoestrogens in the silage or alfalfa hay, fed during lactation. 4) Faulty dry period was instituted, which was defined as the presence of at least one of the following three practices: a) the daily feed was above 3 kg of high lactation mix; b) more than 15 Mcal of net energy per day was given during the first part of the dry period; c) more than 30% of the cows were obese during the dry period. Three or more risk factors were found in one high-fertility herd and in 20 low-fertility herds. This finding emphasizes the importance of identifying and removing risk factors as a possible means for improving the reproductive performance of herds.     

Mycoflora of cervicovaginal fluids in dairy cows with or without reproductive disorders

Fungal infection of reproduction system of dairy cattle have not been received much more attention. The aim of this study was to determine the fungal infection of Holstein dairy cows with reproductive disorders or healthy. Fungal isolates of cervicovaginal fluids of 176 Holstein dairy cows were collected by using the double rod swabs for cervix and the sterilized cotton swabs for discharges of vagina. They were evaluated for fungal infections. The treatment group included 70 dairy cows with reproductive diseases, such as abortion, repeat breeder, endometritis, metritis, retention of fetal membrane, dystocia, cervicitis, and vaginitis. The control groups were included 42 healthy non-pregnant cows and 64 pregnant cows. Isolates of fungi were obtained from cervix and vagina of 27.1% and 28.6% of treatment group, 26.7% and 31.2% of pregnant cows, and 33.3% and 21.4% of healthy non-pregnant cows, respectively, indicating no significant differences. It is showed that the cervix and vagina of the treatment group have been infected by six different mycotic isolates. However, the cervix and vagina of pregnant and non-pregnant healthy cows in control group were infected with 5, 6 and 5, 4 different fungal agents, respectively. Penicillium and yeast were the most common isolated agents. Regarding to the result of this study, it is concluded that fungal infections can occur in cervicovaginal cavity of Holstein dairy cows with or without reproductive diseases.     

Comparative fertility of normal and repeat-breeding cows as embryo recipients

Morphologically normal embryos were transferred surgically into uteri of normal and repeat-breeder cows at seven days post-estrus to compare embryo survival rates in the two kinds of cows. All cows were less than ten years of age and had no abnormal genital discharges, cystic ovarian follicles, or anatomical abnormalities of the reproductive tract. Normal cows had not been inseminated after last calving. Repeat-breeders had at least four infertile services within the past six months (average of 6.2 services after calving). To test fertility of repeat-breeders at synchronized estrus, 22 anatomically-normal repeat-breeders were treated by intramuscular (i.m.) injection with prostaglandin F(2)alpha (PGF(2)alpha) on day 11 of an estrous cycle (estrus = day 0) and inseminated at induced estrus; 11 cows (50%) had a normal fetus at necropsy on day 60. Twenty-three repeat-breeders and 23 normal cows were assigned as embryo recipients and treated i.m. with PGF(2)alpha to synchronize estrus. All embryo donors were normal cows. Donors were treated with FSH and PGF(2)alpha and inseminated at estrus. On day 7 after estrus, embryos were recovered nonsurgically from donors and one embryo was transferred through a flank incision to the anterior end of the uterine horn adjacent to the corpus luteum of each recipient. Recipients that did not return to estrus were necropsied at day 60. Of 28 normal and 23 repeat-breeder recipients, 23 normal cows (82%) and 16 repeat breeders (70%) were pregnant at day 60 (P=0.235). Thus, at seven days post-estrus, the maternal environment of most of these repeat-breeders was satisfactory for maintaining pregnancy.     

Prevalence of antibodies to IBR and BVD viruses in dairy cows with reproductive disorders

We determined the prevalence of antibodies to infectious bovine rhinotracheitis virus (IBRV) and bovine viral diarrhea virus (BVDV) in sera of dairy cows on 4 different farms in the Republic of Croatia. A high percentage (60.8%) of cows had various reproductive disorders. The results showed that seroprevalence of infectious bovine rhinotracheitis (IBR) was 85.8% and that of bovine viral diarrhea (BVD) was 79.2% in tested cows. Antibodies to both viruses were found in 80.8% of cows with reproductive disorders but in only 46.8% of cows without reproductive disorders. This difference was statistically significant (P<0.01), and indicated a connection between reproductive disorders and simultaneous infections with IBR and BVD viruses in dairy cows.     

Genetic analysis of reproductive disorders in Israeli Holstein dairy cows

The heritability of common reproductive disorders was asessed in Israeli Holstein cows. Data were collected from 76,000 calvings on 102 collective farms (kibbuts) over a 36-mo period. The disorders considered were those of retained placenta, abnormal lochia, endometritis, anestrus, ovarian cysts with anestrus and ovarian cysts with nymphomania. The statistical model included fixed effects of herd-year, month of calving, duration of previous pregnancy, interaction between calving difficulty and sex of offspring, and the random effect of the sire. Herd-year effects consituted 0.68 of the explained variance of the incidence of retained placenta and approximately 0.89 of all the other disorders. Sire and calving-month effects were significant (P<0.05) for all the disorders. Heritability estimates of the disorders were 0.01 for retained placenta, abnormal lochia, and endometritis; 0.02 for anestrus; and 0.03 for all disorders. Correlations between any two disorders did not exceed 0.20. High genetic correlations were found between retained placenta and either abnormal lochia (0.90) or endometritis (0.70), while moderate genetic correlations were found among each of these and anestrus (0.30). Reproductive disorders occur as part of a complex which may be efficiently controlled by management measures. Nevertheless, breeding for resistance to reproductive disorders may also be feasible by using appropriate sires evaluated on a large number of daughters.     

Genetic and non-genetic effects on productive and reproductive traits of cows in dual-purpose herds in southeastern Mexico

Data on productive and reproductive performance of cows in dual-purpose herds were analyzed to determine the effect of some environmental and genetic factors on saleable milk yield (SMY), lactation length (LL), daily saleable milk per lactation (DMYL), calving interval (CI), and daily saleable milk per calving interval (MYCI) in dual-purpose herds in Yucatan, Mexico. Repeatabilities (re) for these traits were also estimated. Data were obtained from monthly visits to 162 herds from 1996 to 2000. The fixed factors studied were: region (central, eastern and southern), parity number (1 to 6), calving year (1996 to 2000) and calving season (dry, rainy and windy and rainy), genetic group (low- (< 0.50%), medium- (50%) and high- (> 50%) grade cows with European genes). About 2700 to 7700 cows were evaluated for each trait. All factors had significant effects (P < 0.05) on the traits except for region on CI and calving season on DMYL. The overall means for SMY, LL, DMYL, CI, and MYCI were: 1322.3 +/- 80.5 kg, 224.8 +/- 1.3 days, 5.8 +/- 0.1 kg, 555.1 +/- 16.5 days, and 3.0 +/- 0.1 kg, respectively. The re values for SMY, LL, DMYL, CI, and MYCI traits were: 0.19 +/- 0.03, 0.08 +/- 0.04, 0.16 +/- 0.04, 0.00 +/- 0.08, and 0.08 +/- 0.07, respectively. First parity cows had lower SMY, shorter LL, longer CI, and lower MYCI means than cows with more than one parity. Medium grade cows produced more SMY, DMYL and MYCI and had shorter CI than low- and high-grade cows. Therefore, under Yucatan conditions medium-grade cows should be exploited, and more attention should be given to first parity cows in order to improve the productivity in the herd. The relatively high re estimates for SMY and DMYL can be used to calculate most probable producing abilities, in order to identify which cows should be culled.     

Characteristics of the chromosome set of Holstein cows with reproductive disorders in the North-Caucasian cattle population

Increase in the degree of consanguinity of Holstein breed identified to the best-cultivated dairy breeds is one of the major ways to improve the genotypes of the dairy cattle in many countries all over the world. The widespread biotechnology and large-scale selection adoption reduced the range of the used bull sires in dairy stockbreeding, which resulted in the occurrence of different abnormalities associated with the inheritance caused by gene mutations and chromosomal disorders in the newborn calves. Since the main part of such abnormalities has a recessive inheritance pattern, they represent a hidden genetic load, which is not always expressed in a phenotype. In recent years, the cytogenetic and karyotyping approaches have become more widespread and are required for both the detailed theoretical prerequisites and the applied problem solutions to prevent losses in agricultural production. The results of the cytogenetic analysis of the North- Caucasian population of Holstein cows having problems in reproduction have been reported. The aberrant cells are detected (frequency of occurrence is 5.35%); the number of aberrations per analyzed cell (0.05/1.0) is determined; the absence of the reciprocal translocations in a karyotype in the analyzed livestock is revealed. The genealogical interrelations of ancestors of the lines of Montivik-Chifteyn no. 95679 and Reflekshn- Sovering no. 198998 bull sires with the values for stillbirth incidence among their progeny have been traced.     

A study on reproductive performance and related factors of zebu cows in pastoral herds in a semi-arid area of Tanzania

A prospective longitudinal study was carried out from September 2001 to June 2004 in three adjacent villages in a semi-arid area of Tanzania. The objectives of this study were to measure the intervals between calving and either resumption of cyclical activity or confirmation of pregnancy, to estimate calving intervals, and to investigate the effect of factors assumed to be related to postpartum reproductive performance. A total of 275 lactation periods from 177 Tanzanian Shorthorn Zebu cows managed in a traditional pastoral system in 46 households were initially included. Animals were initially screened for brucelosis and thereafter examined by palpation per rectum at 2-week intervals. Body condition score (scale 1 to 5) was assessed and girth measurement (cm) taken. Occurrence of other reproductive events such as calving, abortion, death of calf, culling and reason for culling were recorded. In a subset of 98 lactation periods from 91 cows milk samples for progesterone (P4) determination were collected twice per week from day 7 after calving to the time of confirmed pregnancy or until milk production ceased before pregnancy. The data were analysed both univariately and in multivariable Cox proportional hazard (frailty) models. The mean (+/-S.E.M.) calving interval was 500+/-13.6 days. Positive reactors in the brucellosis test were 15.6% of the tested animals. Milk P4 analysis showed the rate of abortion/late embryo loss to be 14.3%. Calf mortality rates varied between 14.6 and 17.4%. A positive relationship was found between the outcome variables likelihood of cyclical activity and likelihood of pregnancy in the Cox model, and the explanatory variables: parity and body condition score (BCS) at calving. A negative relationship was found between the outcome variables, and the explanatory variables: maximum BCS loss and calf survival/mortality. Calving in the rainy season was associated with an increased likelihood of pregnancy.     

Effect of reproductive disorders previous to conception on pregnancy attrition in dairy cows

This study was undertaken to determine whether reproductive disorders previous to conception influence pregnancy attrition in dairy cows. Reproductive disorders were registered and pregnancy diagnoses were performed as a part of a reproductive health program at 9 commercial dairy herds in northeastern Spain. Data from 3022 diagnosed pregnant lactating cows were used. Pregnancy diagnosis by palpation per rectum was performed from 33 to 70 d post insemination. Pregnancy attrition was registered when the pregnancy diagnosis was negative at the second palpation carried out between 120 and 150 d following insemination. Data analysis was performed by multiple logistic regression methods. Pregnancy attrition rates were 2.6 and 1.8 times higher in cows with previous pyometra and retained placenta, respectively, than in cows without these disorders. No effect of endometritis, ovarian cysts and repeat breeding was shown on pregnancy attrition. Our results suggest that additional efforts to reduce the risk of retained placenta and pyometra should decrease the incidence of pregnancy attrition in dairy cows.     

Causes and incidence of reproductive disorders among Zebu X taurus cross-bred cows in Andhra Pradesh

Clinical analysis of the recerds of 1396 Zebu X taurus crossbred heifers and cows of small and marginal farmers in Andhra Pradesh, examined ever a period of one year for various causes of reproductive failure, revealed that 6.01, 73.14 and 20.85 percent were of an anatomical, functional, and non-specific infectious nature, respectively. The most frequent single disorders were ovarian acyclia (58%) and endometritis (13.97%). The incidence of other conditions was: cervicitis (5.52%), genital infantilism (4.51%), anovular heats (4.15%), cystic follicular degeneration (3.65%), silent evulations (3.08%), repeat breeders (2.29%), and a lower frequency of other conditions. The indidence of disorders that led to sterility was 5.73%. Between locations, variation was observed in respect to ovarian acyclia and cystic follicular degeneration whose incidences were lower and higher than the respective averages in better managed hords.     

Gilt development and mating in commercial swine herds with varying reproductive performance

The primary objectives were to improve standard operating procedures for gilt development and mating, based on a comparison of practices among commercial Japanese herds with varying reproductive performance. Questionnaires were sent to 115 herds; the 96 herds (83.5%) responding were classified, on the basis of the upper and lower 25th percentiles of pigs weaned per mated female per year, into high-, intermediate- or low-performing herds. During gilt development, high-performing herds switched to a gilt developer diet at an earlier age than low-performing herds (P < 0.05). More high-performing herds performed first insemination “immediately,” with second insemination “6 to 12 h” after first estrus detection than low-performing herds (P < 0.05). However, there were no differences (P > 0.05) among productivity groups with regard to the use of nutritional flushing or percentage of AI used. In multilevel analyses (17,582 service records), gilts in herds using direct boar contact were 13.73 d younger at first mating than those in the herds using indirect boar contact (P < 0.05), but age was not related to feeding practices or the number of days of boar contact per week (P > 0.05). First-serviced gilts in the herds that performed first insemination “immediately” after first estrus detection had an 8.3 to 8.4% higher farrowing rate (FR) than those in herds that performed first insemination at “6 to 12 h” and “24 h” (P < 0.01). Reserviced gilts in the herds with first insemination “immediately” after first estrus detection had 7.5% higher FR than those in herds with first insemination at “6 to 12 h” (P < 0.05). Meanwhile, first-serviced and reserviced gilts in herds that restricted feed after insemination had 0.23 and 0.17 more pigs born alive (PBA) than gilts in the herds that did not restrict feed (P < 0.05). However, PBA was not related to time of insemination (P > 0.05). In conclusion, to improve gilt reproductive performance, we recommend stimulating gilt estrus by using direct boar contact, performing first insemination “immediately” after first estrus detection, and restricting feed intake after insemination.     

Microbial indices of soil fertility

AIMS: To find the new microbial parameters explaining the soil fertility from the microbial community viewpoint. METHODS AND RESULTS: Fatty acid methyl ester (FAME) analysis and terminal-restriction fragment length polymorphism (T-RFLP) analysis were carried out using 16 differently treated plots from the same field that had been kept under different fertilizer management systems since 1984. It was found that organic fertilizer application had small impact, whereas chemical fertilizer application, especially ammonium-nitrogen fertilizer, had strong impact on microbial community structures. Principal component analysis was conducted based on soil chemical and physical parameters, crop yields, FAMEs and terminal-restriction fragments (T-RFs) to provide 10 FAMEs and 10 T-RFs showing strong relation with soil fertility. CONCLUSION: We defined these 10 FAMEs and 10 T-RFs as 'keystone' biological parameters explaining soil fertility in the soil. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on the FAMEs and T-RFs related to soil fertility. Both analyses are rapid, inexpensive and reproducible means. As field assessment needs precise and rapid analysis, FAME and T-RFLP analyses and these new parameters are very useful to analyse soil fertility at biological viewpoint.     

Factors affecting reproductive performance in Ontario dairy herds

Data were collected on reproductive, health and production events in 45 dairy herds in southwestern and eastern Ontario, Canada, from July 1990 to July 1993. Mean and median days in milk at first estrus, at first service, and at conception were 85.1 and 83.9, 94.0 and 88.9, and 126.3 and 115.5 d, respectively. The mean estrus detection rate was 48.3%, with a minimum of 28.4% and a maximum of 64.2%. The mean overall conception rate was 46.7%, with a minimum of 29.8% and a maximum of 70.7%. The most commonly used used therapeutic agents were GnRH (11.5% lactational incidence risk) and PG (13.1% lactational incidence risk). Estrus management accounted for the largest portion of PG use in the herds studied (69.4%). Results of a two sample t-test indicated no significant difference in reproductive performance among herds housed in free-stall compared with those housed in tie-stall barns. Multivariate linear regression models of 3 reproductive performance measures indicated that cows with ovarian cysts and/or increased peak milk production had significantly longer calving-to-first estrus and calving-to-conception intervals as well as lower conception rates than average producing cows without cysts. Cows with metritis were found to have significantly shorter calving-to-conception intervals but no detectable difference in conception rate or calving-to-first estrus interval than their herdmates. As lactation number increased reproductive performance improved. Cows that were observed in estrus earlier conceived earlier. Animals receiving uterine infusions had significantly longer calving-to-conception intervals and lower conception rates than their herdmates. There was no detectable difference in reproductive performance for cows treated with GnRH or PG compared with the nontreated cows. An increased estrus detection rate was associated with shorter calving-to-conception intervals and lower conception rates. Based on the range of performance in the study herds, the factors with the greatest potential influence on calving-to-conception interval in the average herd were the estrus detection rate and conception rate.     

Genetic and environmental factors influencing first service conception rate and late embryonic/foetal mortality in low fertility dairy herds

The objective of this study was to identify factors affecting variation in conception rate to first artificial inseminations (AI) (CR: number of pregnant cows on D80-100/inseminated cows) and the incidence of embryonic/foetal loss (LEM) between 21 and 80 days of pregnancy (number of cows non-pregnant on D80-100/pregnant on D21) in 44 low fertility dairy herds of the west-central region of France. Reproductive status was assessed using progesterone milk concentration on D0 = Day of AI and D21-24, plasma PSPB concentration on D30-35, rectal palpation on D80-100 and observed return to oestrous. The final data set contained 1285 Prim'Holstein cows, 5.0% (64/1285) were inseminated in the luteal phase (progesterone > or = 3 ng/ml on D0), 61.3% (787/1285) were pregnant on D21-24 (progesterone < 3 ng/ml on D0 and > or = 5 ng/ml on D21-24), 15.4% lost their embryo/foetus between D21-24 and D80-100 (198/1285) and 45.8% (589/1285) were pregnant on D80-100. The incidence of late embryonic/foetal loss (LEM) was 25.2% (198/787). Multivariate logistic regression models including the random herd effect were used to analyse the relationship between AI centre, AI sire, cow's sire, parity, interval between calving and AI, milk production, milk protein content, body condition score (BCS) on D0, season of calving, season of AI, estimated genetic index on CR and LEM incidence. CR was significantly related to parity (p < 0.05), milk production after calving (p < 0.05) and estimated genetic value (p < 0.01). A significant difference in CR was observed for calving to AI interval > or = 70 days versus > or = 90 days, but the overall effect of the interval was not significant (p = 0.11). LEM incidence was affected by period of AI (p < 0.05), milk production (p < 0.05) and BCS (p < 0.05), but was not related to estimated genetic index. In conclusion, in these low fertility herds, the incidence of LEM was high and 25% of the cows lost their embryo after 21 days of pregnancy. LEM was affected by specific factors (season, BCS), which were not related to CR. The absence of a relationship between estimated genetic index and LEM in spite of its effect on CR indicates that estimated genetic merit has a greater effect on early embryonic loss or fertilisation failure than on later stages of embryo development.     

Effects of different artificial insemination techniques and sperm doses on fertility of normal mares and mares with abnormal reproductive history

The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto the uterotubal junction ipsilateral to the preovulatory follicle), storage method of semen (fresh, frozen-thawed), AI volume (0.5, 2, 12 ml), and sperm dose (50 x 10(6) or 300 x 10(6) progressively motile sperm (pms) for fresh semen and 100 or 800 x 10(6) frozen-thawed sperm with >35% post-thaw motility). The mares were inseminated once per cycle, 24 h after hCG administration when fresh semen was used, or 30 h for frozen-thawed semen. Differences in pregnancy rates between treatment groups were analyzed by Chi-squared test, and for most relevant factors (insemination technique, mare, semen, and stallion) expectation values and confidence intervals were calculated using multivariate logistic models. Neither insemination technique, volume, sperm dose, nor mare or stallion had significant effects (P > 0.05) on fertility. Type of semen, breeding mares during foal heat, and an interaction between insemination technique, semen parameters, and mares did have significant effects (P < 0.05). In problem mares, frozen semen AI yielded significantly lower pregnancy rates than fresh semen AI (16/43, 37.2% versus 25/42, 59.5%), but this was not the case in normal mares. In normal mares, hysteroscopic AI with fresh semen gave significantly (P < 0.05) better pregnancy rates than uterine body AI (27/38, 71% versus 18/38, 47.3%), whereas in problem mares this resulted in significantly lower pregnancy rates than uterine body AI (5/15, 33.3% versus 16/19, 84.2%). Our results demonstrate that for problem mares, conventional insemination into the uterine body appears to be superior to hysteroscopic insemination and in normal mares, the highest pregnancy rates can be expected by hysteroscopic insemination.