A genetic and spatial Bayesian analysis of mastitis resistance

A nationwide health card recording system for dairy cattle was introduced in Norway in 1975 (the Norwegian Cattle Health Services). The data base holds information on mastitis occurrences on an individual cow basis. A reduction in mastitis frequency across the population is desired, and for this purpose risk factors are investigated. In this paper a Bayesian proportional hazards model is used for modelling the time to first veterinary treatment of clinical mastitis, including both genetic and environmental covariates. Sire effects were modelled as shared random components, and veterinary district was included as an environmental effect with prior spatial smoothing. A non-informative smoothing prior was assumed for the baseline hazard, and Markov chain Monte Carlo methods (MCMC) were used for inference. We propose a new measure of quality for sires, in terms of their posterior probability of being among the, say 10% best sires. The probability is an easily interpretable measure that can be directly used to rank sires. Estimating these complex probabilities is straightforward in an MCMC setting. The results indicate considerable differences between sires with regards to their daughters disease resistance. A regional effect was also discovered with the lowest risk of disease in the south-eastern parts of Norway.     

Tramped Teats – Clinical Mastitis Disease Complex in Tied Cows. Environmental Risk Factors and Interrelationships with Other Diseases

The effects of stall length, manure system, type of bedding and calving disorders on incidence rates of tramped teats, udder injuries, and clinical mastitis in Swedish Red and White tied cows, as well as interrelationships between these 3 disorders were investigated. Data used consisted of 370 herds, for a total of 45,133 cow records. Cows in herds with liquid manure system were at hihger risk of udder injuries and mastitis than in herds with solid system. Lower risk of both udder injuries and mastitis was found for cows in herds with short stall size (< 180 cm) compared to herds with stalls of 205–219 cm length. It was suggested that other factors, such as slipperiness of the stall floor and presence and type of feeding barrier, must be considered when the effect of stall characteristics on tramped teats is investigated. In farms with solid manure system cut straw or sawdust bedding increased the risk of tramped teats and mastitis relative to uncut straw. Parity and calving disorders were important risk factors for udder health and their effect was greater in herds with liquid manure system. Tramped teats and udder injuries were the most serious risk factors for clinical mastitis.     

Cumulative Risk of Bovine Mastitis Treatments in Denmark,Finland, Norway and Sweden

Data from the national dairy cow recording systems during 1997 were used to calculate lactation-specific cumulative risk of mastitis treatments and cumulative risk of removal from the herds in Denmark, Finland Norway and Sweden. Sweden had the lowest risk of recorded mastitis treatments during 305 days of lactation and Norway had the highest risk. The incidence risk of recorded mastitis treatments during 305 days of lactation in Denmark, Finland, Norway and Sweden was 0.177, 0.139, 0.215 and 0.127 for first parity cows and 0.228, 0.215, 0.358 and 0.204 for parities higher than three, respectively. The risk of a first parity cow being treated for mastitis was almost 3 times higher at calving in Norway than in Sweden. The period with the highest risk for mastitis treatments was from 2 days before calving until 14 days after calving and the highest risk for removal was from calving to 10 days after calving in all countries.The study clearly demonstrated differences in bovine mastitis treatment patterns among the Nordic countries. The most important findings were the differences in treatment risks during different lactations within each country, as well as differences in strategies with respect to the time during lactation mastitis was treated.     

Structural equation models to estimate risk of infection and tolerance to bovine mastitis

Background

One method to improve durably animal welfare is to select, as reproducers, animals with the highest ability to resist or tolerate infection. To do so, it is necessary to distinguish direct and indirect mechanisms of resistance and tolerance because selection on these traits is believed to have different epidemiological and evolutionary consequences.

Methods

We propose structural equation models with latent variables (1) to quantify the latent risk of infection and to identify, among the many potential mediators of infection, the few ones that influence it significantly and (2) to estimate direct and indirect levels of tolerance of animals infected naturally with pathogens. We applied the method to two surveys of bovine mastitis in the Walloon region of Belgium, in which we recorded herd management practices, mastitis frequency, and results of bacteriological analyses of milk samples.

Results and discussion

Structural equation models suggested that, among more than 35 surveyed herd characteristics, only nine (age, addition of urea in the rations, treatment of subclinical mastitis, presence of dirty liner, cows with hyperkeratotic teats, machine stripping, pre- and post-milking teat disinfection, and housing of milking cows in cubicles) were directly and significantly related to a latent measure of bovine mastitis, and that treatment of subclinical mastitis was involved in the pathway between post-milking teat disinfection and latent mastitis. These models also allowed the separation of direct and indirect effects of bacterial infection on milk productivity. Results suggested that infected cows were tolerant but not resistant to mastitis pathogens.

Conclusions

We revealed the advantages of structural equation models, compared to classical models, for dissecting measurements of resistance and tolerance to infectious diseases, here bovine mastitis. Using our method, we identified nine major risk factors that were directly associated with an increased risk of mastitis and suggested that cows were tolerant but not resistant to mastitis. Selection should aim at improved resistance to infection by mastitis pathogens, although further investigations are needed due to the limitations of the data used in this study.     

Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep

Genetic analysis for mastitis resistance was studied from two data sets. Firstly, risk factors for different mastitis traits, i.e. culling due to clinical or chronic mastitis and subclinical mastitis predicted from somatic cell count (SCC), were explored using data from 957 first lactation Lacaune ewes of an experimental INRA flock composed of two divergent lines for milk yield. Secondly, genetic parameters for SCC were estimated from 5 272 first lactation Lacaune ewes recorded among 38 flocks, using an animal model. In the experimental flock, the frequency of culling due to clinical mastitis (5%) was lower than that of subclinical mastitis (10%) predicted from SCC. Predicted subclinical mastitis was unfavourably associated with the milk yield level. Such an antagonism was not detected for clinical mastitis, which could result, to some extent, from its low frequency or from the limited amount of data. In practice, however, selection for mastitis resistance could be limited in a first approach to selection against subclinical mastitis using SCC. The heritability estimate of SCC was 0.15 for the lactation mean trait and varied from 0.04 to 0.12 from the first to the fifth test-day. The genetic correlation between lactation SCC and milk yield was slightly positive (0.15) but showed a strong evolution during lactation, i.e. from favourable (-0.48) to antagonistic (0.27). On a lactation basis, our results suggest that selection for mastitis resistance based on SCC is feasible. Patterns for genetic parameters within first lactation, however, require further confirmation and investigation.     

耳内镜下鼓室成形术治疗慢性化脓性中耳炎鼓膜穿孔的疗效及听力恢复的相关因素分析

摘要 目的：探讨耳内镜下鼓室成形术（TUO）治疗慢性化脓性中耳炎鼓膜穿孔的疗效,并分析影响听力恢复的相关因素。方法：回顾性分析2020年3月~2022年3月期间在邯郸市第一医院接受治疗的218例慢性化脓性中耳炎鼓膜穿孔患者的临床资料。根据手术方式的不同将患者分为A组（n=108,接受传统手术治疗）和B组（n=110,接受TUO治疗）。对比两组疗效、听力恢复情况和并发症发生率。收集B组患者的临床资料,采用多因素Logistic回归模型分析影响听力恢复的相关因素。结果：B组的临床总有效率高于A组（P<0.05）。两组术后6个月气骨导差、骨导听阈、气导听阈下降,且B组低于A组（P<0.05）。两组并发症总发生率组间对比未见差异（P>0.05）。根据听力恢复情况分为良好组（n=75）和不良组（n=35）。单因素分析结果显示,听力恢复与咽鼓管、镫骨情况、鼓室黏膜、人工听骨材料、鼓膜张肌腱、听骨链有关（P<0.05）。多因素Logistic回归模型结果显示：听骨链病变、镫骨仅剩底板、咽鼓管不通畅、人工听骨材料为生物陶瓷、无鼓膜张肌腱是听力恢复的独立危险因素（P<0.05）。结论：TUO治疗慢性化脓性中耳炎鼓膜穿孔,可提高临床治疗效果,改善听力。听骨链病变、镫骨仅剩底板、咽鼓管不通、人工听骨材料为生物陶瓷、无鼓膜张肌腱为听力恢复的危险因素。     

重症急性肾损伤患者经连续性肾脏替代治疗后肾功能恢复的影响因素

目的：通过研究重症急性肾损伤患者经连续性’肾脏替代治疗后肾功能恢复的影响因素,为重症急性肾损伤患者的诊治及预后提供科学依据。方法：选取2009年7月至2013年10月本院住院且采用CRRT治疗的284例重症急性肾损伤患者,记录患者的一般资料、APACHEII评分、血液生化指标、伴随症状及肾功能预后情况,将预后情况和各影响因素进行Logistic回归分析得出影响。肾功能恢复的影响因素。结果：284例重症急性肾损伤患者中,肾功能恢复有89例（31．33％）;肾功能恢复组的年龄、衰竭器官数、APACHEⅡ评分、动脉血二氧化碳分压、合并慢性肾脏病率及合并严重基础疾病率均低于肾功能未恢复组,而平均动脉压和血小板计数高于肾功能未恢复组（P〈0．05）,两组间合并机械通气率和合并少／无尿率无统计学差异（P〉0．05）;衰竭器官数、APAC—HEⅡ评分、合并严重基础疾病及AKl分期为CRRT治疗重症急性肾损伤患者肾功能恢复的危险因素。结论：CRRT治疗重症急性肾损伤的主要危险因素为衰竭器官数、APACHEⅡ评分、合并严重基础疾病及AKl分期。在临床治疗中,应正确评估病情,早期及时采取CRRT治疗,以提高生存率,促进肾脏功能恢复。     

Effect of timing of first clinical mastitis occurrence on lactational and reproductive performance of Holstein dairy cows

Objectives of this study were to determine the influence of timing of first clinical mastitis case occurrence on lactational and reproductive performance in high producing lactating dairy cows during the first 320 days in milk (DIM). Holstein cows, 1001, from two commercial dairy farms in California were retrospectively divided into four treatment groups according to timing of first clinical mastitis case caused by environmental pathogens: control with no recorded clinical cases of mastitis (C; n=501); first clinical mastitis prior to first postpartum AI (MG1; n=250); first clinical mastitis between first postpartum AI and pregnancy diagnosis (MG2; n=147); and first clinical mastitis after diagnosed pregnant (MG3; n=103). Clinical cases of mastitis were identified at every milking by the herd personnel based on abnormal milk or swelling of the mammary gland. A fore sample of milk was aseptically collected from every clinical case for microbiological culture. Mastitis decreased yields of milk, 3.5% fat-corrected milk, and milk components, but the effect was only observed for MG1 and MG2. Cows in the control group had lower linear somatic cell count (SCC) score throughout the lactation. Culling was increased by mastitis, and cows in the mastitis groups left the study earlier than controls. Conception rate at first postpartum AI and pregnancy rate at the end of the study were both decreased by mastitis prior to or after first AI, and MG1 and MG2 cows had extended days open. Furthermore, cows experiencing mastitis during lactation had a higher incidence of abortions. The negative effects of mastitis on reproduction were observed regardless of clinical case being caused by either Gram positive or negative bacteria. Mastitis either prior to or after first postpartum AI impairs lactation performance, increases culling, and decreases reproductive efficiency in high producing Holstein dairy cows.     

Preliminary field evidence for the association of clinical mastitis with altered interestrus intervals in dairy cattle

Clinical mastitis and reproductive records from two southern California dairy herds were used in a cross-sectional study to determine the risk of an altered interestrus interval following clinical mastitis. An altered interestrus interval was defined as cycles occurring at either less than 18 day or more than 24-day intervals. The data were stratified by herd to assess herd differences and by lactation number to assess confounding by cow parity. The predominant pathogen isolated from mastitis cases in Herd 1 was Staphylococcus aureus , whereas the predominant pathogens in Herd 2 were gram-negative isolates. Cows in Herd 1 which had coliforms cultured from mastitic milk were excluded in the analysis for comparison with Herd 2. In Herd 1, cows with clinical mastitis were less likely to have an altered interestrus interval (Relative Risk [RR]=0.9; 95% Confidence Interval [CI]=0.6,1.6) than herdmates without clinical mastitis. However, cows in Herd 2 were almost two times more likely to have an altered interestrus interval following an episode of clinical mastitis compared to herdmates without clinical mastitis (RR=1.6; 95% CI=1.3,2.0). Because herd management practices differ and could cause differences in mastitis and reproductive outcomes at the dairies, this preliminary field evidence should be followed by prospective studies of luteal function after clinical coliform mastitis.     

Mastitis in the Lactating Mink Female (Mustela vison S.) and the Development of “Greasy Kits”

“Greasy kits” is the result of a multifactorial disease complex with few known definitive aetiological factors. Mastitis has been hypothesized as a triggering factor although classical clinical signs of mastitis (rubor, tumor, dolor, calor) are rarely seen in lactating Danish mink females. In this study we sacrificed 2 groups of lactating mink females with a total of 78 mammary glands at day 19–30 after giving birth. The first group had raised normal mink kits while the other group had suffered severe attacks of greasy kits. We found no clinical or histopathological evidence of mastitis but isolated streptococci and staphylococci from 2 mammary glands in females raising greasy kits. These glands showed no clinical or histological signs of inflammation attributable to bacteria and we conclude that mastitis is not necessary for the generation of greasy kits.     

Impact of subclinical and clinical mastitis on sensitivity to pain of dairy cows

A total of 90 cows from three commercial farms were used to evaluate the relationship between subclinical mastitis and clinical mastitis and thermal nociceptive threshold. Milk strips from all udder quarters were tested for clinical mastitis with visual inspection of milk and udder alterations and for subclinical mastitis using California Mastitis Test. Milk yield was recorded, milk was sampled and further analyzed for somatic cells count (SCC). Cows were considered healthy when SCC<200 000 cells/ml and no visual alterations in milk and/or udder, with mild subclinical mastitis when SCC>200 000 cells/ml and no visual alterations in milk and/or udder, with moderate subclinical mastitis when SCC>500 000 cells/ml and no visual alterations in milk and/or udder and with clinical mastitis when visual alterations in milk and/or udder were detected. Nociceptive threshold was evaluated with the thermal threshold meter apparatus applied to the rear legs. Thermal threshold (TT) decreased when we compared healthy cows with cows presenting clinical mastitis and tended to decrease when we compare healthy cows with those with moderate subclinical mastitis. TT was lower at the ipsilateral rear leg compared with the contralateral leg to the infected mammary gland. TT linearly decreases as _log10SCC increased and it showed sharp decrease as _log10SCC exceed the value of 6.4. Increase in one unit of _log10SCC increased the odds of low thermal threshold (lower than 55.8°C). Subclinical mastitis might be a welfare issue as it tended to decrease nociceptive thermal threshold.     

Removal Risks in Swedish Friesian Dairy Cows According to Parity,Stage of Lactation,and Occurrence of Clinical Mastitis

The removal risk of Swedish Friesian dairy cows was analysed. The risk of removal increased with parity, and first parity cows were removed earlier in lactation than cows of higher parities. A positive report of clinical mastitis increased the risk of removal, both in the month of developing mastitis and during subsequent part of lactation. The consequences of different removal pattern for epidemiologic analyses of observational studies are discussed.     

非哺乳期乳腺炎的临床治疗探讨

目的:观察抗生素联合泼尼松双联药物冲击方法治疗非哺乳期急性乳腺炎的临床疗效。方法:选取本院乳腺外科2016年6月至2017年6月收治的105例非哺乳期急性乳腺炎患者作为观察对象,依照诊治顺序将其随机分为观察1组、观察2组以及对照组,每组35例患者。对照组给予口服左氧氟沙星,0.5 g/次,qd;观察1组在对照组的治疗方法中加用醋酸泼尼松片强的松20mg,qd;观察2组在对照组的治疗方法中加用醋酸泼尼松片强的松40 mg,qd,三组均以14 d为一疗程。治疗1个疗程后,评价和比较各组治疗效果、血细胞数、好转时间、痊愈时、住院时间及不良反应的发生情况。结果:治疗后,观察1组、观察2组和对照组有效率分别为82.86%、97.14%和60.00%,观察2组有效率显著高于观察1组和对照组(P0.05)。三组患者治疗后白细胞,中性粒细胞,淋巴细胞均较治疗前明显下降(P0.05),且观察2组以上指标显著低于观察1组和对照组(P0.05)。观察2组的好转时间、痊愈时间及住院时间均明显短于观察1组和对照组(P0.05),而观察1组的好转时间、痊愈时间及住院时间明显短于对照组(P0.05)。观察1组出现1例轻微胃肠道反应,1例胸闷,不良反应总发生率为5.71%(2/35);观察2组出现1例轻微胃肠道情况,不良反应总发生率为2.86%(1/35);对照组2例患者发生胸闷,1例患者出现轻微胃肠道不适,1例患者出现眩晕,不良反应发生率为11.43%(4/35),三组不良反应发生率比较差异均无统计学意义(P0.05)。结论:口服抗生素联合泼尼松治疗非哺乳期急性乳腺炎患者能提高临床疗效,且加大泼尼松口服剂量可进一步提高临床有效率,控制炎性进展,缩短痊愈时间。     

Studies on the possible role of cattle nuisance flies, especially Hydrotaea irritans, in the transmission of summer mastitis in Denmark

The summer mastitis pathogens Actinomyces pyogenes, Peptococcus indolicus, Bacteroides melaninogenicus ss. levii, Fusobacterium necrophorum and Streptococcus dysgalactiae were isolated from the polyphagous symbovine dipterans Hydrotaea irritans (Fallén) and Morellia sp. caught around dairy heifers on pasture, but not from the haematophagous species Haematobia irritans (L.), Haematobosca stimulans (Meigen), Culicoides sp. and Simulium sp. Secretions from clinical cases of summer mastitis proved to be sources of summer mastitis bacteria for more than 3 weeks despite antibiotic treatment and teat amputation. Taking into account the seasonal activity pattern of Hydrotaea irritans and its topographical distribution on grazing cattle, it appears evident that this fly may play a central role in the establishment and maintenance of the bacterial contamination with summer mastitis pathogens on the teats of healthy cattle. In the present study the survival of A.pyogenes and P.indolicus for 7 days in experimentally infected Hydrotaea irritans, as demonstrated by the recovery of these microorganisms from agar plates exposed to live infected flies, is described. However, experimental transmission of summer mastitis from sick to healthy heifers by Hydrotaea irritans proved unsuccessful.     

Effect of clinical mastitis and other diseases on reproductive performance of Holstein cows

The objective of this study was to evaluate the effect of clinical mastitis and (or) other diseases on reproductive performance in lactating Holstein cows. Cows (n=967) from a commercial dairy farm were divided into four groups retrospectively: cows with clinical mastitis and other diseases (MD, n=54), clinical mastitis only (M, n=154), other diseases only (D, n=187), and cows with no record of clinical mastitis or other diseases (H, n=572). Days in milk at first service (DIMFS), services per conception (S/C), days not pregnant (DNP), the rate at which animals became pregnant over time and the proportion of cows that remained non-pregnant during 224 days of lactation were evaluated. Groups MD and M had greater (P<0.05) DNP compared with H (155+/-15 and 140+/-5 vs. 88+/-2, respectively). Moreover, MD and M had greater (P<0.05) S/C compared with H (3.0+/-0.4 and 2.1+/-0.1 vs. 1.6+/-0.1, respectively). The rate at which animals became pregnant over time was less (P<0.05) for MD and M and tended (P=0.1) to be less for D when compared with H. In addition, proportion of cows that remained non-pregnant by 224 days of lactation was greater (P<0.05) in MD, M, and D compared with H. Cows with mastitis were also divided into three groups according to the day of occurrence of the first case of clinical mastitis: (1) clinical mastitis occurred before 56 days postpartum (MP1); (2) clinical mastitis occurred between 56 and 105 days after parturition (MP2); and (3) clinical mastitis occurred after 105 days postpartum (MP3) Regardless of the time of occurrence, DNP was greater (P<0.05) for cows with mastitis compared with H. Time of mastitis occurrence affected S/C in that cows in MP2 and MP3 had a greater S/C compared with H cows (P<0.05). Reproductive efficiency was decreased by the presence of clinical mastitis alone because a greater proportion of cows with mastitis remained non-pregnant over time. Moreover, a greater proportion of cows with mastitis or diseases remained non-pregnant by 224 postpartum. Furthermore, the negative effects on reproduction were exacerbated when cows experienced both clinical mastitis and other diseases.     

Short communication: Variance and autocorrelation of deviations in daily milk yield are related with clinical mastitis in dairy cows

Daily milk production, and fluctuations therein, can provide information on health and resilience of dairy cows. We studied variance and autocorrelation of deviations in daily milk yield in relation to the occurrence of clinical mastitis (no, early or later in lactation). Individual lactation curves were fitted to 305-d lactations of 414 dairy cows using quantile regression. Log-transformed variance (lnVar) and autocorrelation of the quantile residuals of daily milk yield (predicted – observed) were evaluated for intervals until 30 and until 305 days in milk (DIM). Cows were classified as having no mastitis (n = 249), early mastitis that first occurred before 30 DIM (n = 29); or later mastitis (n = 136). Subsequently, linear models were used to assess effects of mastitis and parity class (primiparous or multiparous) on lnVar and autocorrelations; and logistic regression analyses were performed to predict mastitis from lnVar or autocorrelation and parity. From 10 to 30 DIM, lnVar was greater for cows with early mastitis than for cows with no or late mastitis, and autocorrelation tended to be lower for cows with early mastitis than for cows with no mastitis. The lnVar and autocorrelation from 10 to 30 DIM were not predictive of late mastitis. From 10 to 305 DIM, lnVar was greater and autocorrelation was lower for both cows with early and late mastitis than for cows with no mastitis; and both were predictive of having mastitis in the 305-d lactation. Primiparous cows had lower lnVar than multiparous cows. In cows without mastitis, autocorrelation values were positively correlated with lnVar. Results confirm that increased lnVar is associated with clinical mastitis.     

Developmental origins of childhood overweight: potential public health impact

Several modifiable pre- and postnatal determinants of childhood overweight are known, but no one has examined how they influence risk of overweight in combination. We estimated the risk of overweight at age 3 years according to levels of maternal smoking during pregnancy, gestational weight gain, breastfeeding duration, and infant sleep duration. We studied 1,110 mother-child pairs in Project Viva, a prospective prebirth cohort study. The main outcome measure was child overweight (BMI for age and sex >or=95th percentile) at age 3. We ran logistic regression models with all four modifiable risk factors as well as the covariates maternal BMI and education, child race/ethnicity, and household income. From the model, we obtained the estimated probability of overweight for each of the 16 combinations of the four risk factors. During pregnancy, 9.8% of mothers smoked and 50% gained excessive weight. In infancy, 73% mother-child pairs breastfed for <12 m, and 31% of infants slept <12 h/day. Among the 3-year-old children in the cohort, 9.5% were overweight. In the prediction model, the estimated probability of overweight ranged from 0.06 among children exposed to favorable levels of all four risk factors, to 0.29 with adverse levels of all four. Healthful levels of four behaviors during early development predicted much lower probability of overweight at age 3 than adverse levels. Interventions to modify several factors during pregnancy and infancy could have substantial impact on prevention of childhood overweight.     

Differential expression of genes during mastitis in Holstein-Zebu crossbreed dairy cows

Among the potential public health problems of animal production, infectious-contagious diseases stand out. Mastitis is among the main diseases affecting dairy cattle. One of the most promising options to reduce the problems caused by this disease, besides proper sanitary and management practices, is selective breeding of resistant animals. To shed light on the immune response mechanisms involved in the resistance/susceptibility phenotype to this disease, we quantified the relative expression of the genes IL-2, IL-6, IL-8, IL-12, IFN-γ, TNF-α, TLR-2, SEMA5A, and FEZL in cells of crossbreed dairy cows, divided into two groups, one healthy and the other suffering from clinical mastitis. Total RNA was extracted from the cells in the milk from the animals in each group (with and without clinical mastitis). Gene expression was determined using the real-time PCR method. The levels of gene expression were compared, and the cows with mastitis were found to express 2.5 times more TLR-2 than those free of mastitis (P < 0.05). There were no significant differences in the expression of the other genes.     

Risk factors for postpartum ovarian cysts and their spontaneous recovery or persistence in lactating dairy cows

Cystic ovarian disease is a major cause of reproductive failure and economic loss for the dairy industry. Many cysts that develop during the early postpartum period regress spontaneously. However, it is difficult to decide at what point it would be more cost effective to treat ovarian cysts than to wait for spontaneous recovery. The objective of this study was to analyze risk factors for the development of the ovarian cystic condition during early and late postpartum, and for its persistence or recovery during the pre-service period in lactating dairy cows. Using multiple logistic regression, we analyzed data derived from 873 lactating dairy cows from a single herd. An ovarian cyst was diagnosed if it was possible to observe a single follicular structure with an antrum diameter > or = 25 mm in the absence of a corpus luteum in three sonograms performed at 7-day intervals. The cystic condition was denoted as early if the cyst was diagnosed 43-49 days postpartum, and late if detected 57-63-day postpartum. Spontaneous cyst regression before 60-day postpartum was regarded as early cystic recovery. For the early cystic group, there were no significant effects of lactation number, body condition score on prepartum Day 60, at parturition or on postpartum Day 30, or of body condition loss from parturition to 30-day postpartum. Cows calving in summer were 2.6 times more likely to develop ovarian cysts than those giving birth in winter. The risk of having a cyst was 1.9 times higher in cows with an abnormal puerperium. A 1-kg increase in milk yield raised the risk of cysts by a factor of 1.05. A 1-unit increase in body condition score (scale from 1 to 5) from prepartum Day 60 to parturition increased the risk of cyst development 8.4 times. Milk production and lactation number were negatively correlated with spontaneous early cyst recovery. A 1-kg decrease in milk production increased the probability of cyst recovery by a factor of 1.06, and a 1-unit drop in lactation number was associated with a 1.4-fold increased probability of cyst recovery. For the late cystic group, there were no significant effects of abnormal puerperium and body score data, except for a prepartum change in body score. Calving season (Odds ratio: 2.3), lactation number (Odds ratio: 1.36), increased milk production (Odds ratio: 1.05) and increased body condition score during the prepartum period (Odds ratio: 4.3) were all related to an increased risk of ovarian cysts. The probability of having a late cyst was 36.6 times greater in cows with early cysts. These findings suggest that it would be profitable to treat multiparous cows having cysts very early in the postpartum period, while treatment of primiparous cows should be delayed, at least until the end of the pre-service period, to provide the opportunity for spontaneous recovery.