口服促孕散治疗前后持久黄体奶牛B超影像学的研究

为探讨促孕散治疗持久黄体的作用机理,本研究通过直肠检查结合B超直肠检查对持久黄体奶牛做出诊断后口服促孕散,应用B超每3 d对黄体直径、卵泡数量、卵巢长度、卵巢宽度、子宫角纵径和子宫颈纵径进行测量,并统计1次,与用药前进行对比。30头持久黄体奶牛口服促孕散后,治疗有效头数25头,有效率为83.3%。停药后第1天卵巢出现小卵泡和中等卵泡,停药后分别在第10和19天大卵泡数量最多,部分奶牛出现发情并排卵,与用药前卵巢相比,结果发现左、右侧卵巢长在停药后均降低,但差异不显著(P>0.05);左、右卵巢宽在停药后均降低,但差异不显著(P>0.05);子宫颈纵径和子宫角纵径均在停药后升高,但差异不显著(P>0.05)。结果表明,B超是诊断奶牛持久黄体的有效手段,中药促孕散对持久黄体奶牛卵巢和子宫形态等指标具有一定的影响,可以促进黄体的溶解。     

Effect of feeding on reproductive performance in Finnish dairy cows

The effect of 2 types of feeding on the involution of the genital tract and on the fertility was studied in 79 Finnish dairy cows on a research farm. The cows were fed twice a day with home-produced feed in accordance with the Finnish feeding standard. The cows were divided according to the type of feed into a hay-urea group and a silage group. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The time required for the complete involution of uterus and cervix was recorded. The cows in the silage group had a significantly longer time in uterine involution, a lower fertility rate at first insemination and a longer interval from calving to conception than those in the hay-urea group. The pregnancy rate in the first insemination was in the hay-urea group 91% and in the silage group 57%. The interval between calving and the first insemination was shorter in the hay-urea group than in the silage group: 71.4 +/- 10.6 and 74.0 +/- 10.3 days, respectively. The interval between calving and conception was in the hay-urea group significantly (p less than 0.01) shorter than in the silage group; 74.8 +/- 15.1 and 89.5 +/- 24.4 days, respectively.     

Associations of prepartum body condition score with occurrence of clinical endometritis and resumption of postpartum ovarian activity in dairy cattle

This study was performed to investigate the effect of periparturient body condition score on the occurrence of clinical endometritis and postpartum resumption of ovarian activity in dairy cows. Eighty-seven lactating Holstein cows, fed with a total mixed ration diet, were included into the study. Body condition scoring (using a 5-point scale with quarter-point divisions) was performed by the same investigator using the visual technique every 2 weeks, from 2 weeks before until 6 weeks after calving. Palpation of the reproductive tract and ultrasonographic assessment of ovaries for detection of corpus luteum using a rectal linear probe was also performed at 2, 4, and 6 weeks after calving. Cows with clinical endometritis had significantly lower body condition score (BCS) than normal cows at all weeks pre- and postcalving, and cows that did not ovulate until 45 days after calving had a significantly lower BCS pre- and postpartum. Cows that did not ovulate until 45 days after calving also lost more BCS from 2 weeks before to 4 weeks after calving. Besides, first ovulation after calving take occurred later in cows with clinical endometritis compared to normal cows (P?<?0.05). In conclusion, low BCS is a risk factor for postpartum endometritis and delayed cyclicity in dairy cows. BCS loss from dry-off to early lactation and occurrence of clinical endometritis can significantly affect postpartum ovarian activity.     

Acupuncture prevents the postpartum reduction in matrix metalloproteinase type‐2 immunoexpression,tissue concentration and enzyme activity in bovine caruncles

The objectives of this study were to determine the effects of acupuncture in dairy cows (Bos taurus) on caruncular matrix metalloproteinase type‐2 (MMP2) at 0, 2 and 4 hr after calving. Acupuncture (n = 6) was applied at 0 and 2 hr after calving to 6 points that relax the cervix and stimulate uterine contractions. Controls (n = 9) were kept in a stanchion for 15 min without acupuncture. All of the cows in the study delivered their placenta in <4 hr. Formalin‐fixed caruncles were paraffin‐embedded and subjected to routine immunohistochemistry to determine MMP2 expression, which was scored by a single observer. Flash frozen caruncles were homogenized, and protein concentration was determined. MMP2 concentrations were calculated using commercial bovine ELISAs. MMP2 enzyme activity was determined using zymography. The mean value for each time point for each cow was used to calculate the mean ± SEM for each treatment group. MMP2 was predominantly localized to the epithelial and subepithelial stromal cells of the caruncles in both treatment groups. MMP2 immunoexpression was lower 4 hr after calving in the control cows (p = 0.012) but not in the acupuncture treated cows indicating that acupuncture treatment maintained MMP expression. MMP2 tissue concentration was lower 2 hr after calving in the control cows (p = 0.048) but not in the acupuncture treated cows. MMP2 enzyme activity decreased from 0 to 2 hr after calving in control cows (p = 0.046) but not in acupuncture treated cows. This study provides physiologic evidence for the effects of acupuncture on the bovine reproductive tract and substantiates the use of this treatment in cases of placental retention.     

The Effect of Lactation on Post‐Partum Uterine Involution in Holstein Dairy Cows

The objective was to examine the effect of lactation on uterine involution in post‐partum dairy cows. Holstein primiparous cows were used (n = 19, mean age: 3.9 ± 0.1 years). At calving, cows were randomly assigned to one of two treatment groups, lactating (n = 11) or non‐lactating (i.e. dried off at calving, n = 8). Examination of the reproductive tract was carried out by ultrasonography twice weekly until week 7 post‐partum. Blood samples were collected twice weekly for the analysis of progesterone to indicate the resumption of cyclicity and metabolites indicative of energy status. Uterine involution was assessed in terms of size of the uterine horns, uterine body diameter and uterine fluid volume as assessed by the amount of non‐echogenic material measured by ultrasound and position of the uterus. Vaginal mucous score was taken on day 28 post‐partum for the assessment of uterine inflammation. Resumption of cyclicity (serum progesterone > 1 ng/ml) had occurred in both groups on average by day 21 post‐partum. Concentrations of non‐esterified fatty acids and beta‐hydroxybutyrate were higher, whereas concentrations of glucose, insulin and IGF‐1 were lower (p < 0.05) in lactating compared to non‐lactating cows. Lactating cows had a smaller mean uterine body diameter (p < 0.05) than non‐lactating cows from days 28 to 42 post‐partum (day 28: 20.2 ± 1.3 vs 24.9 ± 1.5 mm, respectively) and had a lower mean uterine fluid volume up to day 49 (p < 0.05). By day 49, there was no difference in uterine diameter (15.2 ± 1.8 vs 15.2 ± 1.6 mm) or uterine fluid volume (0.11 ± 0.38 vs 0.18 ± 0.46) between lactating and non‐lactating cows, respectively. Vaginal mucous score revealed no evidence of uterine inflammation in either group. In conclusion, while lactation induced significant alterations in metabolic status, it did not have a major effect on the rate of uterine involution as defined in this study.     

Longitudinal observation on reproductive and lactation performances of smallholder crossbred dairy cattle in Fitche,Oromia region,central Ethiopia

A two-year longitudinal study was conducted to assess the reproductive and lactation performances of smallholder crossbred dairy cattle in Fitche, central Ethiopia. Twenty-four smallholder dairy farms were monitored and data on reproductive, breeding, lactation and management aspects of crossbred dairy cows (n = 69) were collected and analysed. Moreover, milk samples were collected and analysed for progesterone. The overall Least-squares means for calving interval (CI), calving to conception interval (CCI) and first observed oestrus after calving were 516, 253 and 141 days, respectively. Suckling significantly prolonged these intervals. The mean first onset of luteal activity (OLA) after calving was 52 days, while 67.4% (n = 43) had a delayed (>55 days) return to cyclicity after calving. Suckling and parity number significantly (p < 0.05) influenced the OLA. The mean lactation length was 54.4 weeks. The overall daily mean milk yield for the first 43 weeks of lactation after calving was 11.7 L/day. The estimated daily milk yield increased slowly and reached peak (13.8 L/day) around the 11th week post partum and declined gradually and steadily. Suckling status, season of calving and parity number significantly influenced the estimated daily milk yield. In conclusion, the present study indicated that the smallholder crossbred dairy cows in the study area had prolonged intervals to first oestrus after calving, to conception and to the next calving, and thus their reproductive performance is unsatisfactory. Delayed first onset of luteal activity (postpartum anoestrus) contributed to these extended intervals. Further detailed investigation is suggested to examine the effects of other relevant factors on the reproductive and lactation performances of smallholder crossbred dairy cows for appropriate intervention.     

Relationships between insulin-like growth factor-I,milk yield,body condition score,and postpartum luteal activity in high-producing dairy cows

The relations between body condition score (BCS), milk yield, serum insulin-like growth factor-I (IGF-I) profile, and luteal activity were investigated in postpartum dairy cows. Seventy-one healthy high-producing multiparous Holstein cows were subjected to transrectal ultrasound scanning twice weekly from the first to the eighth week postpartum. Blood samples were collected twice weekly to measure serum progesterone (P4) and every 2 weeks to detect serum IGF-I concentrations. BCS was monitored weekly after calving. Cows with serum P4 concentrations ≥1 ng/ml on at least two consecutive samplings were considered to have commenced luteal activity. Commencement of luteal activity (C-LA) was observed earlier than 45 days postpartum in 71.8% of cows while 28.2% showed C-LA later than 45 days. Prolonged luteal phase was the most common abnormal pattern of luteal activity observed. Cows with a C-LA earlier than 45 days postpartum had higher (P ≤ 0.05) mean serum concentrations of IGF-I than those with later C-LA. In addition, cows which showed C-LA earlier than 45 days postpartum had more optimal productive indices including shorter calving to conception interval and calving to first service interval (P ≤ 0.05), and fewer services per conception (P = 0.07). C-LA was significantly later in cows that lost more than 0.5 BCS units within 3 weeks postpartum than in those that lost less than 0.5 units BCS during the same interval (P = 0.02). We conclude that high-producing dairy cows with higher postpartum serum IGF-I concentrations have earlier commencement and normal luteal activity, and better reproductive performance. Severity and duration of BCS loss adversely affect commencement of luteal activity.     

Uterine involution in Finnish dairy cows

The effect of parity on the cervical and uterine involution was studied in 79 Finnish dairy cows on a research farm. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The diameters of the cervix and uterine horns were estimated manually. The parous uterine horn was compared with the non-parous one. The results were separately analysed in primiparous cows (n = 18) and in those with the third calving (n = 61). A significant difference (p less than 0.001) between the parous and non-parous uterine horns was obtained until 21 days. Thereafter, involution still continued and equal diameters for the horns were not found until 5 weeks after parturition. A decline of the cervical diameter continued until 30 days after the delivery. The parity had no significant effect on the swiftness of uterine or cervical involution. However, in multiparous cows the cervical diameter remained larger than that in the primiparous animals still at 8 weeks postpartum.     

Subclinical endometritis in Zebu x Friesian crossbred dairy cows: its risk factors,association with subclinical mastitis and effect on reproductive performance

A study was carried out on 59 clinically healthy Zebu x Friesian crossbred cows to determine the prevalence of subclinical endometritis, associated factors and its effect on the reproductive performance. Subclinical endometritis was diagnosed by endometrial cytology using uterine lavege technique and subclinical mastitis using CMT. The clinical, management and reproductive data were obtained from a weekly follow up visit of each cow for a period of 6 months after calving. The prevalence of subclinical endometritis, with ≥5% neutrophil count, was 47.5% and 30.5% at week 4 and 8, significantly decreasing (P = 0.002) as postpartum period advanced. Body condition score at week 4 postpartum (OR = 4.5, P = 0.017) and regular cow exercise (OR = 4.8, P = 0.026) were the significant risk factors while post-calving hygiene (P = 0.06) was poorly associated. Subclinical endometritis was also directly associated with subclinical mastitis at both week 4 (OR = 4.5, P = 0.012) and 8 (OR = 3.6, P = 0.031) postpartum. The risk of first service pregnancy (OR = 5.1, P = 0.004) was higher in cows negative for subclinical endometritis at week 8 postpartum and the proportion of cows that required more than 3 services was higher in cows with uterine inflammation. Also the proportion of cows diagnosed pregnant within 180 DIM was higher in cows with normal uterus at both week 4 (OR = 10.3, P = 0.001) and week 8(OR = 21.8, P = 0.001). These results indicated that subclinical endometritis was directly associated with poor body condition and subclinical mastitis and that it had negative effect on reproductive traits of dairy cows. This association may also reflect the possibility of translocation of bacteria/bacterial products from the uterus to the udder or vic-versa or else the presence of common cause for both endometritis and mastitis.     

Lack of effects of an equine chorionic gonadotropin (eCG) administration between days 9 and 15 postpartum on reproductive performance in a Holstein dairy herd

Recently, it has been demonstrated that administration of equine chorionic gonadotropin (eCG) in the postpartum period in dairy cows can enhance follicle growth, reduce the interval from calving to first ovulation and increase plasma estradiol concentrations, and, thus, could enhance reproductive performance in a dairy herd when administered on day 6 postpartum. The aim of this study was to investigate the effects of a single dose of eCG between days 9 and 15 postpartum on parameters of reproductive performance in dairy cows. German Holstein cows (n = 1937; primiparous cows: n = 748; pluriparous cows: n = 1189) in a commercial dairy farm were randomly assigned to three experimental groups. Animals within the group eCG received a single dose of 600 IU eCG intramuscularly (i.m.) between days 9 and 15 postpartum followed by an i.m. administration of 500 μg cloprostenol after 14 days. Those of treatment group PG received cloprostenol only between days 23 and 29 postpartum. Cows of the control group remained untreated. Starting on day 49 postpartum, cows were subjected to a Presynch‐Ovsynch protocol and inseminated artificially. The impact of application time (days postpartum) of eCG on the intervals calving to first service and calving to conception was statistically not significant. Outcomes of reproductive performance (i.e. first service conception rate, proportion of pregnant cows until 100 and 150 days in milk [DIM], number of inseminations until 150 DIM, calving to first service interval and calving to conception interval) did not differ significantly between treatment group eCG and group PG compared to control group. Regarding postpartum eCG administration, significant interactions between treatment and parity, season, milk yield, and early puerperal disorders, respectively, could not be shown. In conclusion, an eCG treatment of dairy cows between days 9 and 15 postpartum to increase reproductive performance cannot be recommended under the given circumstances.     

Evaluation of the factors that affect the pregnancy rates during embryo transfer in beef heifers

The aim of this study was to evaluate the effects of the transfer side, transfer location, cervix transfer score, type and diameter of corpus luteum (CL) during embryo transfer on pregnancy rates in beef heifers. Progesterone-based synchronization and superovulation protocol were applied to Simmental cows used as donors (n = 168). Uterine flushings were performed on day 7 following artificial insemination. Obtained Code I (excellent or good) and II (fair) quality embryos were transferred to recipient beef heifers (n = 561). During embryo transfer, side of transfer (right or left), transfer location (the cranial or middle third of uterine horn), cervix transfer score (easy, moderate or difficult) and type (CLa, CLb and CLc) and diameter of CL were determined. Pregnancy rates following the transfer of Code I and II embryos were 44.66% and 33.07%, respectively (p < .05). The rates of pregnancy after transfers to the right and left uterine horn were 37% and 42.2%, respectively (p > .05). The pregnancy rates were 41.2%, 34.9% and 30.3% for cervix transfer scores as easy, moderate and difficult, respectively (p > .05). Pregnancy rates after transfer to the cranial third and middle third were 41.06% and 29.67%, respectively (p < .05). According to types of CL, pregnancy rates were 31.7%, 40.4% and 45.3% for CLa, CLb and CLc, respectively (p < .05). Moreover, it was found that as the CL diameter increased, the pregnancy rates increased. As a result, it was concluded that there was no effect of side of transfer and cervix transfer score, but embryo quality, transfer location, type and diameter of CL had significant effects on the pregnancy rate during embryo transfer in beef heifers.     

Relationships between endometrial cytology and interval to first ovulation,and pregnancy in postpartum dairy cows in a single herd

The objectives were to investigate the relationships between endometrial cytology (EC) and interval from calving to first ovulation, and pregnancy in dairy cows, and that between uterine fluid and EC. On day 25 postpartum, 39 dairy cows were grouped based on EC, as having low (⩽8%) or high (>8%) polymorphonuclear cells (PMN), and the quantity of uterine fluid was assessed by ultrasound. The interval from calving to first ovulation was shorter in low, than in high PMN cows (32 vs. 45 d). A greater proportion of cows with uterine fluid had high PMN (64% vs. 21%), and the PMN increased from 14% to 34% as the quantity of uterine fluid increased. The mean interval from calving to ovulation was longer in primiparous cows with high PMN (49 d) compared to that of primiparous and multiparous cows with low PMN (28 and 29 d, respectively). Although the conception rate to first service at 92 d postpartum was not different between PMN groups, the cumulative pregnancy at 270 d tended to be higher in low than in high PMN (80% vs. 58%) multiparous cows. Also, cows that had uterine fluid on day 25 postpartum had a shorter interval from calving to pregnancy than those with no uterine fluid (161 vs. 208 d). In conclusion, combining transrectal ultrasonography with endometrial cytology on day 25 postpartum has diagnostic value in the assessment of uterine inflammation.     

Ultrasonographic findings of the corpus luteum and the gravid uterus during heat stress in dairy cattle

The objectives of this study were to assess alterations in, echogenic appearance, size and blood flow in the corpus luteum, the placentomes and the blood flow in umbilical and uterine arteries that heat stress can cause in cooled pregnant dairy cows. Pregnant cows were allocated in two groups and the gravid uteri, along with the ipsilateral corpora lutea were examined during the winter (group W, n = 9) or the summer (group S, n = 10). The grey-scale ultrasound and colour flow imaging of the corpus luteum and placentome were performed. In addition, the umbilical and uterine artery diameters and haemodynamic parameters in the vessels were calculated. At the time of ultrasonographic examination, cortisol concentrations were higher, and progesterone levels tended to be lower in group S compared to group W. The grey-scale ultrasound evaluation of corpora lutea and placentomes was lower in group S compared to group W. The diameter of umbilical artery and the blood volume in the vessel were less in group S than in group W. We infer that heat stress affects foetal blood supply and possibly the structure of placentomes and corpora lutea, but it differently affects the blood flow characteristics in the umbilical and uterine arteries.     

Pre‐ and Post‐Partum Mild Underfeeding Influences Gene Expression in the Reproductive Tract of Cyclic Dairy Cows

Undernutrition before and after calving has a detrimental effect on the fertility of dairy cows. The effect of nutritional stress was previously reported to influence gene expression in key tissues for metabolic health and reproduction such as the liver and the genital tract early after calving, but not at breeding, that is, between 70 and 90 days post‐partum. This study investigated the effects of pre‐ and post‐partum mild underfeeding on global gene expression in the oviduct, endometrium and corpus luteum of eight multiparous Holstein cows during the early and middle phases of an induced cycle 80 days post‐partum. Four control cows received 100% of energy and protein requirements during the dry period and after calving, while four underfed received 80% of control diet. Oestrous synchronization treatment was used to induce ovulation on D80 post‐partum. Oviducts, ovaries and the anterior part of each uterine horn were recovered surgically 4, 8, 12 and 15 days after ovulation. Corpora lutea were dissected from the ovaries, and the endometrium was separated from the stroma and myometrium in each uterine horn. The oviduct segments were comprised of ampulla and isthmus. RNAs from ipsi‐ and contralateral samples were pooled on an equal weight basis. In each tissue, gene expression was assessed on a custom bovine 10K array. No differentially expressed gene (DEG) in the corpus luteum was identified between underfed and control, conversely to 293 DEGs in the oviduct vs 1 in the endometrium under a false discovery rate (FDR) < 0.10 and 1370 DEGs vs 3, respectively, under FDR < 0.15. Additionally, we used dedicated statistics (regularized canonical correlation analysis) to correlate the post‐partum patterns of six plasma metabolites and hormones related to energy metabolism measured weekly between calving and D80 with gene expression. High correlations were observed between post‐partum patterns of IGF‐1, insulin, β‐hydroxybutyrate and the expression in the oviduct of genes related to reproductive system disease, connective tissue disorders and metabolic disease. Moreover, we found special interest in the literature to retinoic acid‐related genes (e.g. FABP5/CRABP2) that might indicate abnormalities in post‐partum tissue repair mechanisms. In conclusion, this experiment highlights relationships between underfeeding and gene expression in the oviduct and endometrium after ovulation in cyclic Holstein cows. This might help to explain the effect of mild undernutrition on fertilization failure and early embryonic mortality in post‐partum dairy cows.     

Ovarian activity in beef and dairy cows with prolonged postpartum period and heifers that fail to conceive

The primary objectives of this study were to investigate incidence of abnormal ovarian cyclicity (AOC) and its type in dairy and beef cows with prolonged postpartum period (>90 days) and in heifers that fail to conceive. A total of 53 animals were included in the study: 17 Friesian crosses, 16 Braford crosses, eight Brangus crosses, and 12 local Kedah-Kelantan (KKX) crosses. These animals were initially checked for absence of pregnancy via palpation per rectum. Blood samples for progesterone analysis were obtained twice a week for 2 to 3 months following their spontaneous oestrous cycle, and all animals were rechecked for pregnancy at the end of the study. Progesterone analysis indicated that 33.9% of the total animals were having AOC: 18.9% with cessation of ovarian cyclicity, 9.4% with prolonged luteal phases (PLP), and 5.7% short luteal phases. The highest incidence was observed in Brangus crosses (62.5%), followed by Braford crosses (43.8%), and Friesian crosses (35.3%). In contrast, no AOC was observed in the local KKX breeds, and all of them were found to be pregnant at the end of the study. A significant difference (p < 0.05) in the incidence of AOC and its type was observed between Kedah-Kelantan crosses and the other breeds. Although not significant (p > 0.05), Friesian crosses showed a higher percentage incidence of AOC than beef cows (40% vs 36.4%), with major types being PLP (26.7%) in dairy and cessation of ovarian cycle (27.3%) in beef cows. Compared with beef heifers, beef cows showed a higher percentage of AOC (36.4% vs 28.6%) where again, cessation of cyclicity was the predominant abnormality. In conclusion, AOC reflected by abnormal endocrine pattern is a possible cause of reduction in fertility for dairy and beef cows beyond 90 days postpartum and heifers that fail to conceive.     

Effects of Feeding Dry Glycerol to Primiparous Holstein Dairy Cows on Follicular Development,Reproductive Performance and Metabolic Parameters Related to Fertility during the Early Post‐partum Period

This study examined the effects of dry glycerol supplementation on follicular growth, post‐partum interval to first ovulation, concentration of serum metabolites and hormones related to fertility, body condition score (BCS) and body weight (BW) in primiparous Holstein dairy cows. Sixty primiparous Holstein dairy cows were randomly assigned to two groups (control: n = 30 and glycerol supplemented: n = 30). Dry glycerol (250 g/day/cow) was fed as a top dressing to the common lactating total mixed ration (TMR) from parturition to 21 days post‐partum. Ovaries were examined four times using ultrasonography on days 13, 19, 25 and 36 post‐partum to determine ovarian follicular growth. Concentration of serum metabolites and hormones was determined weekly. Body condition score was evaluated weekly from weeks 1 to 5 after parturition, and BWs were recorded three times on days 1, 11 and 21 during the experimental period. The cows fed dry glycerol had more large follicles (p < 0.0001) and corpora lutea (CL) (p = 0.02) compared with the control cows. Days to the first ovulation (p = 0.06), days to first oestrus (p = 0.05), services per conception (p = 0.06) and days open (p = 0.004) were positively affected by dry glycerol supplementation. Serum concentration of glucose and insulin was higher in dry glycerol‐supplemented cows (p = 0.1; p = 0.06, respectively). Feeding glycerol had no effect on mean serum concentrations of β‐hydroxybutyrate, non‐esterified fatty acids and IGF‐1 during the experimental period. However, significant differences were observed at concentration of BHBA and IGF‐1 (p = 0.02 and p = 0.04, respectively) between two groups on day 21 after calving. The cows in the glycerol‐fed group had higher serum progesterone concentrations on days 33 (p = 0.007) and 36 (p = 0.004) after calving. Supplemented cows had lower body condition loss during weeks 1–5 after calving compared with the control cows (0.34 vs 0.41 BCS). In week 13 post‐partum, the proportion of cycling cows was 83.3 and 69.9% for those which received supplemented or non‐supplemented diet, respectively. These results demonstrated that feeding dry glycerol as a glucogenic supply may be useful to improve negative energy balance and reproductive efficiency in young cows which calve with high requirement of energy.     

Puncture and drainage of the subordinate follicles at timed artificial insemination prevents the risk of twin pregnancy in dairy cows

The objective of this study was to determine whether fluid drainage from the subordinate follicles by ovum pickup procedures prevents the risk of twin pregnancy without reducing the fertility of the cow. Lactating dairy cows with at least two follicles over 12 mm diameter located one on each ovary and selected from synchronized groups for fixed‐time insemination were assigned to a Control (n = 49) or Drainage (n = 49) group. The largest follicle was considered as the dominant follicle. Draining of all subordinate follicles (≥10 mm) was performed in the Drainage group. All drained follicles developed as a corpus luteum 7 days later. In the Control cows, the presence of two corpora lutea (55.1%) was lower (p = .003) than those in the Drainage cows (87.8%), whereas the incidence of twin pregnancies was 50% and 0% for the Control and Drainage groups, respectively (p < .001). Draining did not affect the pregnancy rate. These results indicate that puncture and drainage of the subordinate follicles at insemination may eliminate the risk of twin pregnancies and reduce the risk of subsequent pregnancy loss by increasing the incidence of additional corpora lutea.     

Doppler sonography of uterine blood flow at mid‐oestrus during different degree of clinical endometritis in dairy cows

The present study was aimed at analysing the mid‐oestrous uterine blood flow parameters during varying degree of endometritis in dairy cows. Degree of clinical endometritis was adjudged on the basis of visual examination of uterine discharge collected from cows at mid‐oestrus, that is mild (slightly turbid; n = 13), moderate (turbid with pus flakes; n = 14) and severe (milky; n = 13). Pulsatility and resistance indices (PI and RI), time average mean velocity (TAMEAN), time average maximum velocity (TAMAX), diameter of the artery, volume of blood flow, Doppler pulse duration (DPD) and systolic upstroke/acceleration time (AT) were measured to study the spectral waveforms at mid‐oestrus. Significantly higher (p < .01) PI and RI were found in cows diagnosed with mild degree in comparison with cows diagnosed with moderate and severe degrees of clinical endometritis. There was significantly higher (p < .01) velocity (TAMEAN and TAMAX), volume of blood flow (BFV‐TAMEAN, BFV‐TAMAX) and DPD in both the middle uterine arteries during moderate and severe degrees of clinical endometritis as compared to mild endometritis. However, significantly higher (p < .01) AT was recorded in cows diagnosed with mild degree as compared to moderate and severe degrees of clinical endometritis. Pearson's correlation analysis has shown that RI was positively correlated with PI and AT in all the groups under study (mild degree, r = .72 and .49; moderate degree, r = .54 and .38; severe degree, r = .90 and .42; p < .05). However, there found significantly negative correlation (p < .05) with other parameters in all the cows irrespective of degree of inflammation. Therefore, it may be deducted that assessment of uterine inflammation can be done with a non‐invasive technique known as Doppler sonography which can be useful in adjudging the hemodynamic changes inside uterus and future fertility of dairy cows.     

Significance of nitric oxide concentration in plasma and uterine secretes with puerperal endometritis in dairy cows

Endometritis is an inflammation of the endometrial lining of the uterus without systemic signs, which is associated with chronic postpartum infection of the uterus with pathogenic bacteria. Nitric oxide (NO) is an inflammatory mediator that among other effects causes smooth muscle relaxation and mediated cytoimmunity and inflammation toxicity. To see if the nitric oxide concentration in plasma and uterine secrets is related with postpartum endometritis, NO concentrations in plasma and uterine secrets were measured in dairy cows with puerperal endometritis (clinical endometritis (n = 60) and subclinical endometritis (n = 58)). Cows with clinical or subclinical endometritis showed higher concentrations of NO in both plasma and uterine secrets when compared with normal cows and the highest concentrations of NO in plasma and uterine secrets were found in dairy cows with clinical endometritis. Expression level of NOS2 mRNA in endometrial biopsies from cows with puerperal endometritis was also higher and the highest expression of NOS2 mRNA was found in cows with clinical endometritis. The results showed that concentrations of NO in plasma and uterine fluid are related with the degree of endometritis which may be useful to diagnose the endometritis in dairy cows.     

Incidence of subclinical endometritis and its effects on reproductive performance of crossbred dairy cows

In dairy cattle, uterine infections are not life threatening and often unavoidable; however, they reduce fertility and increase the production costs of properties. The aim of this study was to evaluate the incidence of subclinical endometritis from 32 to 70 days in milk (DIM) and its effects on the reproductive performance of crossbred dairy cows. Lactating cows (Holstein/Gir; n?=?172), with no history of retained placenta, without clinical signs of uterine infection were used. The body condition score (BCS) was evaluated on a scale from 1 to 5. Ultrasound examination was performed to evaluate uterine lining and ovarian activity, while vaginal mucus was analyzed by gloved hand. The diagnosis of subclinical endometritis was performed by endometrial cytobrush technique. The samples were collected, stained, and examined microscopically; positive cases for subclinical endometritis were considered with the presence of ≥5 % of neutrophils. Later, the cows were submitted to conventional artificial insemination or timed artificial insemination. The incidence of subclinical endometritis in the herd was 26 %, and this was not affected by the season of calving, presence of corpus luteum, DIM, and parity. Cows with a BCS ≤2.50 had a higher incidence of subclinical endometritis. The conception rate to first insemination and pregnancy rate at 150 days postpartum were not influenced by the presence of subclinical endometritis in crossbred dairy cows.