An epidemiological and genetic study on registered diseases in Finnish Ayrshire cattle. II. Reproductive disorders

The epidemiology and genetic variability of the most common reproductive diseases were examined. The data set consisted of the lactation records of 70,775 Finnish Ayrshire dairy cows. Each cow was under observation for 2 days before for 305 days after calving. Lactation incidence rates (%) were: dystocia (DYST) 0.9, retained placenta (RTPL) 4.5, metritis (METR) 2.3, anoestrus and suboe&trus (ESTR) 5.2, and ovulatory dysfunction (CYST) 7.0. These diseases formed 33 % of all first treatmetns by veterinarians during farm visits. The occurrence of DYST, RTPL and METR was lowest in parity 2. ESTR decreased and CYST increased with parity. Cows calving during the dark season (September-February) had a higher risk of ESTR, METR and CYST (odds ratios (OR) 2.2–1.1) and a lower risk of RTPL (OR 0.9) than those calving during the light season (March-August). The increase in herd milk yield was positively associated with the occurrence of reproductive disorders. The cows with a history of parturient paresis had a higher risk of contracting CYST, RTPL and METR (OR 6.6–1.8), the cows with retained placenta of contracting metritis (OR 5.1), the cows with metritis of contracting ESTR and CYST (OR 1.5–1.7), the cows with mastitis of contracting METR and ESTR (OR 2.0–1.3) and the cows with ketosis of contracting METR, ESTR and CYST (OR 2.7–1.6). Heretabilities were determined for 5 diseases and for infertility in general. Heritability estimates for parity 2 were: DYST 2 %, RTPL 3 %, METR 7 %, ESTR 12 %, CYST 12 %, and infertility in general 5 %. Heritability for calving interval was 5 % in parity 1 and 6 % in parity 2.     

Meta-analysis of the prevalence of mastitis and associated risk factors in dairy cattle in Ethiopia

Mastitis is among the most prevalent disease that contributes for the reduction of milk production in dairy herds. Although several published studies have estimated the prevalence of mastitis, variation among studies is great. The objective of the present meta-analysis was to provide a pooled estimate of the prevalence of overall, clinical, and subclinical mastitis in dairy cattle in Ethiopia. A pooled estimate was also conducted by potential risk factors. The literature search was restricted to studies published in English language from January 2002 to June 2016. Meta-analysis of 39 studies was done under random effects model using metafor package in R software. The pooled estimate of the overall prevalence of mastitis on cow-basis was found to be 47.0% (95% confidence interval [CI]?=?42.0, 52.0). The pooled prevalence with the 95% CI for clinical and subclinical mastitis was 8.3% (95% CI?=?6.5, 10.3) and 37% (95% CI?=?32.9, 40.7) respectively. There is a statistically significant and high heterogeneity of the prevalence estimates between published studies. The odds of occurrence of mastitis were higher in cows at early (odds ratio [OR]?=?1.6; 95% CI?=?1.4, 1.8) and late lactation (OR?=?1.3; 95% CI?=?1.2, 1.5) than mid lactation, in cows with 3–4 (OR?=?1.5; 95% CI?=?1.4, 1.7) and >4 parity number (OR?=?2.9; 95% CI?=?2.6, 3.4) than those with 1–2 parity number. Previous history of mastitis, floor type, milking hygiene, and udder injury had also statistically significant effect on pooled prevalence of mastitis (P?<?0.05). The present study reported that there is high prevalence of mastitis in dairy cows in Ethiopia, which could contribute to the low productivity in lactating cows. The statistically significant association of risk factors such as floor type, milking hygiene, and presence of udder injury with mastitis may suggest that dairy farmers can reduce the occurrence of the disease by improving their management practices.     

Cytological endometritis diagnosed at artificial insemination in repeat breeder dairy cows

This study aimed to (i) assess the prevalence of cytological endometritis (CYTO) diagnosed at artificial insemination (AI); (ii) evaluate the effect of CYTO on the pregnancy outcome of the same AI sample; and (iii) determine the risk factors associated with CYTO diagnosed at AI in repeat breeder (RB) dairy cows. We analysed the productive and reproductive performances of 146 RB Holstein‐Friesian cows. To obtain a CYTO sample at AI, we used the cytotape technique. Generalized mixed effect models were computed to find the risk factors associated with the pregnancy and CYTO outcome. Based on ≥1% PMN cut‐off point, the CYTO prevalence at AI in RB cows was 25.3%. The overall pregnancy at AI was 44.2%. The conception rate in CYTO‐positive (n = 37) RB cows was 29.7% versus 49.5% for CYTO‐negative (n = 109) cows. A RB cow diagnosed CYTO positive at AI had 0.47 [odds ratio (OR)] odds to become pregnant in comparison with a CYTO‐negative cow. Cows that produced more milk than their counterparts in this study had increased odds (OR = 1.01) to be CYTO positive at AI. A novel risk factor positively associated with CYTO diagnosed at AI in RB cows was the level of daily milk urea (OR = 1.11). To conclude, CYTO at the moment of AI had a significantly negative effect on the pregnancy outcome in RB dairy cows. However, as only one of fourth of RB cows is affected with CYTO at AI, it may not be considered a key element associated with the RB syndrome.     

The effect of twinning on milk yield,dystocia, calf birth weight and open days in Holstein dairy cows of Iran

Calving records of Iranian Holsteins from April 1998 to September 2006 comprising 16 herds with 104 572 calving events representing 4045 twin births were used to evaluate reported open days, calving difficulties and calf birth weight in single‐ and twin‐births and the relationship exists between twinning and milk production. A logistic regression model was constructed to analyse dystocia for single‐ and twin‐births. In addition, statistical analyses of 305‐day milk yield, open days and calf birth weight were performed using the general linear models procedure. The odds of dystocia was greater after twin births [p < 0.0001; odds ratio (OR) = 2.32]. The odds of dystocia decreased from parity 1 to parity 2 and beyond (p < 0.0001; OR = 0.44). Open days were significantly different between single (129.28 days) and twin (144.88 days) births (p < 0.05). Calf birth weights were significantly greater for singletons than twins (43.33 kg vs. 34.36 kg; p < 0.05). In addition, twin‐calved cows had greater 305‐day milk production than single‐calved cows (p < 0.05). In general, development of practical management strategies to cope with the negative effects associated with twinning on dairies is critical, especially if the trend towards increased twinning in the dairy cattle population continues.     

Low Incidence of an Altered Endometrial Epidermal Growth Factor (EGF) Profile in Repeat Breeder Holstein Heifers and Differential Effect of Parity on the EGF Profile Between Fertile Holstein (Dairy) and Japanese Black (Beef) Cattle

A high incidence (about 70%) of alteration in endometrial epidermal growth factor (EGF) profile, i.e., loss of 2 peaks on days 2–4 and 13–14, has been linked to a reduced fertility in multiparous repeat breeder Holstein cows. However, the EGF profile in Holstein heifers and other breeds (types) of cattle has not been investigated. In study 1, EGF concentrations were determined using endometrial tissues obtained by biopsy on days 3, 7 and 14 from 84 fertile Holstein heifers to obtain a normal range and 53 repeat breeder Holstein heifers to estimate incidence of alterations in the EGF profile. In repeat breeder heifers, EGF concentrations were similar to fertile controls on 3 days and five animals (9.4%) had an altered EGF profile with EGF concentrations below the normal range on days 3 and 14. In study 2, EGF concentrations on day 3 were repeatedly examined from the nulliparous period to the third postpartum period in 28 Holstein (dairy) and 47 Japanese Black (beef) cattle. The effect of parity on EGF concentrations on day 3 was different between Holstein and Japanese Black cattle. In Japanese Black cows, the EGF concentrations were consistently high throughout the study period, while in Holstein cows, the EGF concentrations decreased after the second calving. In conclusion, unlike multiparous repeat breeder Holstein cows, an altered EGF profile may not be a major cause of repeat breeding in Holstein heifers, and the peak EGF concentrations around day 3 may decrease even in fertile populations of multiparous dairy cows, but not in beef cows.     

Leptin receptor expression and its change in association with the normalization of EGF profile after seminal plasma treatment in repeat breeder dairy cows

Factors associated with high milk production levels have been linked to alterations in the endometrial epidermal growth factor (EGF) profile, a cause of reduced fertility in dairy cows. Therefore, we examined the leptin system that connects nutritional status and reproduction in dairy cattle related to reduced fertility in repeat breeder cows. Plasma leptin concentrations were measured in 18 heifers, 20 high-yielding control cows, and 26 repeat breeder cows, showing an altered EGF profile. Then, all repeat breeder cows were infused with seminal plasma (SP) into the vagina at the next estrus to normalize the EGF profile, while heifers and control cows were infused with vehicle alone. All animals were examined for EGF profiles. Eighteen repeat breeder cows, nine heifers, and nine control cows were also determined for leptin receptor (Ob-R) expression levels in the estrous cycle before and after the infusion. SP normalized the EGF profile in 53.8% of the repeat breeder cows. Leptin concentrations were similar in all groups, regardless of the treatment results for the EGF profile. In contrast, Ob-R levels in repeat breeder and control cows were similar and higher than those in heifers before SP treatment. Ob-R in repeat breeders showing a normal EGF profile after treatment decreased to an intermediate level between heifers and control cows and may provide a clue to take measures against repeat breeding in dairy cows.     

Use of postpartum vaginoscopic (visual vaginal) examination of dairy cows for the diagnosis of endometritis and the association of endrometritis with reduced reproductive performance

OBJECTIVE: To assess the association between the findings from vaginoscopic examination of postpartum dairy cows with peripartum reproductive disease and their subsequent reproductive performance, and to determine the factors that might be associated with a positive vaginoscopic examination (VV). METHODS: Cows (n=1325) from 17 seasonal calving dairy herds were enrolled if they had been calved at least 7 days and had at least one of the following conditions that placed them at risk of endometritis: retained fetal membranes (RFM), dystocia, a dead calf, hypocalcaemia, twin birth, calving induction or an observed vulval discharge (VD). Examination was undertaken 28-37 days before mating start date (MSD) within each herd. All cows were body condition scored (BCS) and were VV scored on a scale of 0 (clear) to 3 (purulent). The uterus and ovaries were assessed by rectal palpation. RESULTS: Cows with a positive VV score (1-3) were less likely to conceive to first service and had a lower pregnancy proportion than cows that had a negative VV score (score 0). Mean MSD to conception interval was longer in VV-positive cows. A positive VV score was associated with a low BCS, primiparity, intrapelvic uterus, poor uterine tone, large uterus, RFM, VD, dystocia, dead calf and twins. CONCLUSION: In the present study a positive VV score was associated with reduced reproductive performance and was more common in primiparous and low BCS cows. Of the at-risk cows, those with RFM, VD, dystocia, dead calf or twins were more likely to have a positive VV score.     

Alteration of the Endometrial EGF Profile as a Potential Mechanism Connecting the Alterations in the Ovarian Steroid Hormone Profile to Embryonic Loss in Repeat Breeders and High-producing Cows

Poor reproductive efficiency is a worldwide problem that has affected the dairy industry during the last several decades. In an attempt to explain the changes in reproductive physiology caused by high milk production, a model of elevated steroid metabolism in lactating dairy cows has been proposed. A slow increase in levels and low peak levels of estradiol (E₂) and progesterone (P₄) characterize endocrine changes in high producing cows. Similar changes have been reported in the repeat breeder cows. The abnormal changes in E₂ and P₄ concentrations of these cows may cause an improper uterine environment due to disturbed expression of growth factors and cytokines in the endometrium. This review focuses on the alteration in epidermal growth factor (EGF) profile in the endometrium during the estrous cycle. The normal cow has two peaks of EGF concentrations on days 2–4 and 13–14. Low concentrations of EGF on these days distinguished both high-producing and repeat breeder cows from normal cows. Alteration of the EGF profile could be found in 70 and 40% of the repeat breeder and high-producing cows, respectively. Treatment with a high dose of estradiol benzoate and an intravaginal progesterone-releasing device restored the normal EGF profile in about 70% of the affected cows. The cows having a normal EGF profile after treatment showed a higher pregnancy rate than the cows with the altered profile. Further studies to understand the etiology of the alteration in the EGF profile are needed to develop another treatment option and preventive management for this problem.     

Herd-level risk factors associated with fecal shedding of Shiga toxin-encoding bacteria on dairy farms in Minnesota,USA

This study aimed to identify herd-level risk factors associated with fecal shedding of Shiga toxin-encoding bacteria (STB) on dairy cattle farms in Minnesota, USA. After adjustment for farm size, risk factors included: use of total mixed ration (TMR) for lactating dairy cows [odds ratio (OR) = 3.0; 95% confidence interval (CI): 1.8 to 5.1], no use of monensin for weaned calves (OR = 4.8, 95% CI: 2.5, 9.3), and no use of decoquinate for preweaned calves (OR = 2.2, 95% CI: 1.4, 3.6). Fecal shedding of STB was more common in small herds (< 100 cows, OR = 3.6, 95% CI: 2.1, 6.2) than in large herds (≥ 100 cows). Herd management factors related to cattle feeding practices were associated with fecal shedding of STB.     

Dystocia in Friesian cows and its effects on postpartum reproductive performance and milk production

A total of 1,243 records for 585 dairy Friesian cows from 1997–2004 were used to study the factors affecting dystocia and its effects on reproductive performance and milk production. The overall incidence of dystocia was 6.9%. The percentage of dystocia decreased with increasing live body weight, age, and parity of cows (P < 0.05); however, it increased with increasing birth weight of calves (P < 0.05). The highest percentage of dystocia was detected in winter season, but the least percentage was in summer season (P < 0.05). The percentage of incidence of dystocia was significantly (P < 0.05) higher with winter feeding compared to summer ration (8.2% vs. 5.1%). The percentage of incidence of dystocia was significantly (P < 0.05) higher with twinning than single calving (15.5% vs. 6.5%), while not significantly affected by the sex of born calves. Incidence of dystocia had adverse effects on reproductive performance and milk yield. The service interval, service period, days open, and calving interval were significantly (P < 0.05) longer in cows afflicted with dystocia compared to normal cows. The conception rate was lower (P < 0.05), but the number of service per conception was higher (P < 0.05) in cows afflicted with dystocia compared to normal cows (60.5% vs. 73.0% and 3.4 vs. 2.7, respectively). Average daily milk yield was lower (P < 0.05) by 1 kg for cows with incidence of dystocia compared to normal cows.     

Effect of dystocia on subsequent reproductive performance and functional longevity in Holstein cows

The objective of this study was to evaluate the effect of dystocia on the reproductive performance and functional longevity in Iranian Holsteins. Data consisted of 1 467 064 lactation records of 581 421 Holstein cows from 3083 herds which were collected by the Animal Breeding Center of Iran from April 1987 to February 2014. Reproduction traits in this study included interval from first to second calving, days open and days from first calving to first service. The generalized linear model was used for the statistical analysis of reproductive traits. Survival analysis was performed using the Weibull proportional hazards models to analyse the impact of dystocia on functional longevity. The incidence of dystocia had an adverse effect on the reproductive performance of dairy cows. Therefore, reproductive traits deteriorated along with increase in dystocia score (p < 0.05). The culling risk was increased along with increase in the score of dystocia (p < 0.0001). The greatest culling risk was observed in primiparous cows, small herds and low‐yielding cows (p < 0.0001). Also, the lowest culling risk was found for cows calving at the youngest age (<27 months), and cows with age at first calving >33 months had the greatest risk (p < 0.0001). The results of current study indicated that dystocia had important negative effects on the reproductive performance and functional longevity in dairy cows, and it should be avoided as much as possible to provide a good perspective in the scope of economic and animal welfare issues in dairy herds.     

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

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

Effects of periparturient diseases and conditions on the reproductive performance of New Zealand dairy cows

AIM: To determine the effect of retained foetal membranes (RFM), periparturient recumbency, calf mortality, dystocia, twin births and induction of parturition on submission and pregnancy rates of pasture-fed, seasonally-calving dairy cows in New Zealand. METHODS: Data were retrospectively collected for 2652 cows from 11 herds on the occurrence of periparturient diseases and condition, calving date, age and treatment for anoestrus prior to the planned start of mating (PSM). The effects of each disease or condition on submission and pregnancy rate by 28 days after PSM, final pregnancy rate, and the proportion of cows that conceived more than 50 days after PSM were examined using separate logistic regression models. Results are expressed as odds ratios (OR). Additionally, the effect of each disease or condition on the interval from PSM to conception was examined using survival analysis. Age, herd and late calving (i.e. cows calved < or =40 days before PSM) were included as factors in the models examined. RESULTS: Induction of parturition increased the risk of RFM (OR=3.3, p<0.01). The 28-day submission rate was affected by age and herd but not by any of the periparturient conditions examined. The 28-day pregnancy rate was reduced by RFM (OR=0.04, p<0.05), induction of parturition (OR=0.67, p<0.01), assisted calving (OR=0.61, p<0.01), late calving (OR=0.55, p<0.05) and anoestrus (OR=0.27, p<0.05). The final pregnancy rate was reduced by RFM (OR=0.013, p<0.01), induction (OR=0.25, p<0.05), assisted calving (OR=0.30, p<0.005) and anoestrus (OR=0.32, p<0.05), and was increased if the cow was submitted for mating within 28 days after PSM (OR=2.72, p<0.05). Effects of recumbency and twinning were not significant in any of the models. CONCLUSIONS: Cows that had had RFM or were assisted, induced or late to calve, had significantly lower pregnancy rates or took longer to conceive than unaffected herd-mates. CLINICAL RELEVANCE: Intervention programs aimed at the examination and treatment of cows with periparturient conditions may improve the reproductive performance of New Zealand dairy herds. Investigations of poor reproductive performance of a herd should include analysis of the prevalence and effects of periparturient diseases and conditions.     

Prevalence, bacterial causes, and antimicrobial susceptibility profile of mastitis isolates from cows in large-scale dairy farms of Northern Ethiopia

The study was undertaken to determine the prevalence of bovine mastitis, isolate mastitis causing bacteria, assess the association of some risk factors, and determine the antibiotic resistance pattern of bacterial isolates in cows in large-scale dairy farms of Northern Ethiopia. A total of 305 lactating and nonlactating cows were included in the present study. The overall prevalence of clinical and subclinical mastitis was 3.6 and 33.8?%, respectively. The quarter level prevalence was 15.4?%; from which, 11.9 and 1.1?% were subclinical form and blind teat, respectively, while the remaining 2.4?% were of clinical form. Staphylococcus aureus accounted for 36?% of the isolates followed by Escherichia coli (27.3?%). Risk factors including age (p?9?years (OR?=?3.63, 95?% CI?=?1.42-9.25)), cows with four to seven calves (OR?=?3.39, 95?% CI?=?2.06-5.60), and cows in late lactation stage (OR?=?3.79, 95?% CI?=?1.64-8.75). In multivariable logistic regression analysis, age (p?=?0.005) and lactation stage (p?=?0.027) showed statistically significant association with the occurrence of mastitis. The antimicrobial susceptibility pattern showed high susceptibility of S. aureus to nalidixic acid (82.4?%) followed by chloramphenicol (58.8?%); however, these species were resistant to the rest of the antimicrobials tested. Highest resistance was observed against clindamycin and ampicillin. Coliform bacteria (E. coli and Klebsiella pneumoniae) showed resistance to most of the antimicrobials used. Detailed investigation is needed to identify the interplay of managemental and environmental risk factors to design appropriate control measures.     

产后20天应用氯前列烯醇对分娩期和产后期异常奶牛繁殖指标的影响

本试验选用276头高产中国荷斯坦牛为研究对象,其中120头初产奶牛和156头经产奶牛均表现为分娩期异常或产后期异常,如难产、胎衣不下、双胎难产、早产或子宫感染。试验牛被分为处理组与对照组。处理组在产后20d间隔811连续两次皮下注射氯前列烯醇（0.4mg/次）,对照组注射4．0mL灭菌生理盐水。然后观察其首次发情的时间、适合第一次人工授精的时间、首次授精妊娠率、150d妊娠率、产后的空怀天数、重复配种奶牛的比例和每头牛的授精次数。结果表明,产后应用前列腺素对产后首次发情的时间和产后首次人工授精的时间没有影响,但处理组奶牛首次人工授精的妊娠率明显升高,这在头胎牛更为明显;产后应用氯前列烯醇可明显减少平均授精次数、缩短产后空怀时间、增加产后150d泌乳奶牛的妊娠率、降低产犊后重复配种率。     

Risk factors for anaplasmosis in dairy cows during the peripartum

Anaplasma marginale is endemic in tropical and subtropical areas around the world. Some studies have suggested that cows during peripartum may present a transient immunosuppression state and development of clinical signs of anaplasmosis. The aim of this study was to investigate the relationship between some risk factors and the seroprevalence of A. marginale in dairy cows during peripartum in Rio de Janeiro, Brazil. The risk factors analyzed in association with the prevalence of antibodies against A. marginale in dairy cows were calving season, reproductive experience, breed standard, tick infestations, stocking density, and milk yield. The antibodies against A. marginale were tested in indirect enzyme-linked immunosorbent assays. A primary screening using a 2 × k contingency table of the exposed variables with the outcomes was performed. All variables for which p?<?0.20 were included in a fixed effects log regression. The risk factors investigated to anaplasmosis were calving (OR 2.61, IC 1.08–7.63), breed standard (OR 3.83, IC 0.08–0.28), reproductive experience (OR 33.7, IC 2.14–5.16), milk yield (OR 3.9, IC 2.24–7.03), Rhipicephalus microplus infestations (OR 10.3, IC 0.05–0.17), and stocking density (OR 22.3, IC 0.05–0.17). Low titers of antibodies against A. marginale during peripartum had been characterized as a period previous to development of clinical anaplasmosis. Thus, studies on anaplasmosis should consider each farm as an epidemiological unit, where environmental and immunological factors may influence the endemic status of the pathogen.     

Review: Cost of Reproductive Diseases and Conditions in Cattle

Based on information from USDA National Animal Health Reporting System early State pilot studies and more recent national studies, the cost of reproductive diseases and conditions was estimated for beef and dairy cattle. We estimate the total yearly cost of female infertility, abortions/stillbirths, dystocia, retained placentas, and metritis/pyometra to be $441 to $502 million for beef producers and $473 to $484 million for dairy producers with an aggregate national total of approximately $1 billion annually. This loss is over six times more costly than that resulting from respiratory diseases. Three-fourths of the cost for reproductive diseases and conditions can be attributed to female infertility and dystocia and the failure to produce a healthy calf that will survive the first 24 h of life. Aggregate national costs are roughly evenly divided between beef and dairy; per cow costs are more than three times greater for dairy cows ($52.60) than for beef cows ($14.00). Approximately equal national costs are attained because there are more than three times more beef cows than dairy cows. One factor contributing to the greater cost for dairy cows is lost milk production associated with dystocia and retained placentas. Lost milk production accounts for one-third of the costs associated with reproductive diseases and conditions in dairy cattle. We conclude from this review and our resulting estimates that focusing on developing strategies to increase the probability of conception, minimize dystocia, and produce a healthy calf that survives beyond the first 24 h of birth must continue to receive high priority in both dairy and beef cattle management and research.     

Body Condition Change Ante- and Postpartum, Health and Reproductive Performance in German Holstein Cows

The effects of body condition score (BCS) change and status ante‐ and postpartum (pp) on health and reproductive performance in 234 German Holstein cows from eight dairy farms were evaluated. BCS was determined from 6 weeks antepartum until 20 weeks pp in 2‐week intervals. Three and 5 weeks pp progesterone concentrations in blood serum were determined to detect the presence of luteal tissue as an indicator of cyclicity. The incidence of various diseases, percent cycling cows, reproductive measures and culling rate were assessed. Data were subjected to logistic regression to account for possible herd and lactation number effects. Cows with a low BCS status (<3.0) at calving and during early lactation (4–10 weeks pp) were at a higher risk of suffering from lameness (OR 2.9–9.4), not being cycling at 3 and/or 5 weeks pp (OR 2.24–3.99) and being culled (OR 2.56–2.79) than cows in better body condition (≥3.0) In addition, cows with a low BCS status at parturition were at a higher risk of developing endometritis (OR 2.95) and becoming pregnant later than 105 days pp (OR 5.92) than cows with a BCS ≥ 3.0. At 10 weeks pp, the risk of dystocia (OR 4.10) or retained placenta (OR 2.78) at the preceding calving and not being pregnant at 200 days pp (OR 2.42) was higher in cows with a BCS < 3.0 than with a BCS ≥ 3.0. Cows with no BCS loss antepartum were more likely to have an interval from calving to first artificial insemination of <80 days and <105 days open, to be cycling at 3 and 5 weeks pp and to be pregnant at 200 days pp than cows with a BCS loss of >0.25 (OR 2.44–6.67). Furthermore, cows with no BCS loss from calving to 4 weeks pp had a lower risk of suffering from displaced abomasum than cows with a slight or a severe BCS loss (OR 0.09–0.07 respectively). In conclusion, our results suggest that body condition loss during the antepartal period affected BCS status at parturition and to a certain extent during lactation which was linked to a higher incidence of reproductive disorders and lameness, a higher culling rate and lower reproductive performance.     

Effect of administration of a controlled-release monensin capsule on incidence of calving-related disorders, fertility, and milk yield in dairy cows

OBJECTIVE: To determine the effect of a controlled-release monensin capsule administered at cessation of lactation on incidence of calving-related disorders, fertility, and milk yield in dairy cows. ANIMALS: 290 dairy cows treated with monensin and 290 untreated control cows. PROCEDURE: Treated cows received a capsule that released monensin at 335 mg/d for 95 days. Incidence of calving-related disorders; daily milk yield up to 20 days postpartum; test-day milk yield, fat, protein, and mature-equivalent 305-day milk production; and body condition score at calving were determined. Reproductive variables were conception rate at first service, pregnancy rate, and calving-to-conception interval. RESULTS: Cows treated with monensin were 2.1 times as likely to develop dystocia and 0.8 times as likely to develop metritis as control cows. For milk yield, there was an interaction of treatment X time X parity. In multiparous cows, monensin significantly improved milk yield at test days 4 and 7. In addition, monensin increased body condition score at calving. CONCLUSIONS AND CLINICAL RELEVANCE: Despite increasing the likelihood of developing dystocia and metritis, administration of monensin improved the lactational performance of multiparous cows and may be a promising additive for use at the time of cessation of lactation.     

Incidence and treatment of inadequate postovulatory progesterone concentrations in repeat breeder cows

The incidence of low day 5 milk progesterone in dairy cows has been investigated and the efficacy of treating the problem assessed. The incidence of inadequate milk progesterone (empirically defined as <3ng/mL) in repeat breeder cows was 34% compared with 11.4% in first insemination cows. Treatment with an intravaginal progesterone device for 7 days starting from day 5 or 6 did not improve pregnancy rate. Treatment with 1500 iu human chorionic gonadotrophin (hCG) on day 5 gave an increase in pregnancy rate that was dependent on initial progesterone concentration and significant (P<0.05) in multiparous but not primiparous cows. While the incidence of inadequate day 5 progesterone was high in repeat breeder cows, it was responsive to hCG treatment, although only in multiparous and not primiparous animals.