Changes in milk yield in dairy cows associated with metabolic and reproductive disease and lameness

A study was undertaken of 1594 lactations occurring in 732 British Friesian, Ayrshire and Holstein crossbred cows. One thousand two-hundred of these lactations were used to consider the association between the occurrence of hypocalcaemia, ketosis, hypomagnesaemia, dystocia, retained placenta, endometritis and lameness and changes in milk yield. A statistical technique was applied which used the relationship between pairs of consecutive lactations in the same cow to assess losses in milk yield associated with disease relative to an individual's own potential. Seven hundred and seventy-two pairs of consecutive lactations from the 1200 lactations were available for this purpose.Average significant reductions of 6–7% in peak milk yield occurred in lactations in which the cow had a retained placenta or ketosis. Cows which had ketosis showed a slower decline in milk yield in later lactation and there was no overall significant difference in 305-day milk yield, However, for cows which had a retained placenta, there was no corresponding reduction in rate of decline, and 305-day milk yield was on average 7% lower. There were no significant associations between hypocalcaemia, hypomagnesaemia, dystocia or endometritis and milk yield.Cases of lameness, which occurred during a 20-week period following peak yield and were mainly associated with lesions involving the interdigital cleft and sole or white line sites of the claw, were more common in cows which had higher than average peak milk yields. Heel lesions appeared to be associated with lower than average 305-day yields, but this may have been due to variations in incidence with season.     

Culling of dairy cows. Part I. Effects of diseases on culling in Finnish Ayrshire cows.

The effects of 15 diseases on time until culling were studied in 39,727 Finnish Ayrshire cows that calved during 1993 and were followed until the next calving or culling. The diseases studied were: dystocia, milk fever, retained placenta, displacement of the abomasum, metritis, non-parturient paresis, ketosis, rumen disorders, acute mastitis, hypomagnesemia, lameness, traumatic reticuloperitonitis, anestrus, ovarian cysts, and teat injuries. Survival analysis, using the Cox proportional hazards model, was performed and diseases were modeled as time-dependent covariates. Different stages of lactation when culling can occur were also considered. Parity, calving season and herd were included as covariates in every model. Parity had a significant effect on culling, the risk of culling being four times higher for a cow in her sixth or higher parity than for a first parity cow. The effects of diseases varied according to when the diseases occurred and when culling occurred. Mastitis, teat injuries and lameness had a significant effect on culling throughout the whole lactation. Anestrus and ovarian cysts had a protective effect against culling at the time when they were diagnosed. In general, diseases affected culling decisions mostly at the time of their occurrence. The effect seemed to decrease with time from the diagnosis of the disease. However, milk fever, dystocia and metritis also had a significant effect on culling at the end of the lactation.     

Disposal and disease rates in British dairy herds between April 1998 and March 2002

Data derived over four years from 434 dairy herds in 1998/99 to 244 in 2001/02 revealed average disposal rates of 22.6 per cent per year, half of which were for poor fertility, mastitis and lameness. The quartile of herds with the lowest disposal rates sold an average of 11.5 per cent annually and the quartile with the highest rates sold 35.5 per cent. Average annual disease rates over the four years were as follows: for assisted calving 7.8 per cent, for digestive disease 1.2 per cent, for ketosis 0.5 per cent, for hypomagnesaemia 0.5 per cent, for hypocalcaemia 5.0 per cent and for injuries 0.8 per cent. The incidence of mastitis increased from 36.0 to 43.3 per cent of cows per year. The incidence of lameness decreased from 23.3 per cent in 1998/99 to 20.7 per cent in 2000/01 but increased to 21.9 per cent in 2001/02. Data received from the same 219 farms during the first three years showed no effective differences from the full set of data for each of the three years. The lowest annual incidences of mastitis and lameness on individual farms were below 7 per cent and 2.5 per cent, respectively. In general, housing cows in cubicles was associated with a greater risk of lameness, and housing them in straw yards with a greater risk of mastitis. However, some of the lowest rates of lameness were recorded in cubicle-housed cows and some of the lowest rates of mastitis were recorded in cows housed in yards. Larger herds were not associated, in general, with higher rates of mastitis.     

Disease frequencies in dairy cows in Sweden. v. mastisis

An epidemiologic study of mastisis in dairy cows in Sweden covering 137 002 calvings and subsequent lactations is presented and various risk factors identified.

Swedish Friesian breed (SLB) had a higher incidence of mastisis than Swedish Red and White breed (SRB). The incidence was higher during the first part of lactation and increased with parity until the seventh lactation in SRB and the sixth lactation in SLB.

Dystocia, retained placenta and parturient paresis increased the risk of mastisis during the first part of lactation in SRB, and retained placenta increased the risk of mastitis during the first part of lactation in SLB. No associations between these periparturient disorders and the occurrence of mastitis in the latter part of lactation could be found. The incidence of mastitis was increased among teat-tramp-positive cows, and a positive report of mastitis increased the risk of mastitis in subsequent calvings.

The influence of environmental factors on the occurrence of mastitis was demonstrated by a higher incidence during housing as opposed to pasture, and a decreased incidence in loose-housed cows when compared to tied zero-grazing cows during the later part of lactation. During the first part of lactation, no seasonal variation could be found, and loose-housed cows had only slightly decreased incidence during this part of lactation when compared to tied zero-grazing cows.

The removal rate was increased in the mastitis-positive cow population.     

乡村振兴战略背景下奶业健康管理及科研数据解析

乡村振兴战略对我国现代奶业健康发展具有重要指导意义.当前,我国奶业发展处于转型升级关键时期,奶牛重大疾病的发生严重妨碍奶业的健康发展.本文梳理了酸中毒、乳腺炎、子宫内膜炎、产后瘫痪、酮病和肢蹄病等奶牛重大疾病的发生率及其危害,分析了重大疾病的历年科研数据和研究层次.按照重大疾病的发病率估算,乳腺炎发病率最高,其后依次为...     

Disposal and disease rates in 340 British dairy herds

Data derived from 340 dairy herds, mainly in southern England, between April 1998 and March 1999, showed that the average total culling rate was 22.1 per cent, with 5.6 per cent for infertility, 3.6 per cent for mastitis, 1.7 per cent for lameness, 2.0 per cent for poor milk yield, 3.7 per cent for age and 5.5 per cent for miscellaneous reasons which included death. The average annual rate of assisted calvings was 8.7 per cent, of injury 0.9 per cent, digestive disease 1.3 per cent ketosis 0.4 per cent, hypomagnesaemia 0.7 per cent, hypocalcaemia 5.3 per cent, mastitis 36.6 per cent, and lameness 23.7 per cent. There was a significant association (P<0.001) between higher rates of mastitis in cows housed in straw yards as opposed to cubicles and also between higher rates of lameness in cows housed in cubicles as opposed to yards (P<0.015). However, there were farms with low rates of mastitis in cows kept in straw yards and low rates of lameness in cows kept in cubicles. Larger herds tended to have more problems with lameness and higher bulk milk somatic cell counts (BMSCC). There was a positive association between BMSCC and mastitis rate.     

Optimizing replacement of dairy cows: modeling the effects of diseases

We modified an existing dairy management decision model by including economically important dairy cattle diseases, and illustrated how their inclusion changed culling recommendations. Nine common diseases having treatment and veterinary costs, and affecting milk yield, fertility and survival, were considered important in the culling decision process. A sequence of stages was established during which diseases were considered significant: mastitis and lameness, any time during lactation; dystocia, milk fever and retained placenta, 0-4 days of lactation; displaced abomasum, 5-30 days; ketosis and metritis, 5-60 days; and cystic ovaries, 61-120 days. Some diseases were risk factors for others. Baseline incidences and disease effects were obtained from the literature. The effects of various disease combinations on milk yield, fertility, survival and economics were estimated. Adding diseases into the model did not increase voluntary or total culling rate. However, diseased animals were recommended for culling much more than healthy cows, regardless of parity or production level. Cows in the highest production level were not recommended for culling even if they contracted a disease. The annuity per cow decreased and herdlife increased when diseases were in the model. Higher replacement cost also increased herdlife and decreased when diseases were in the model. Higher replacement cost also increased herdlife and decreased the annuity and voluntary culling rate.     

Disease frequencies of tied zero-grazing dairy cows and of dairy cows on pasture during summer and tied during winter

Disease frequencies of Swedish Red and White Breed (SRB) and Swedish Friesian Breed (SLB) in tied herds with zero-grazing management system and in tied herds with pasture periods are presented. Incidences are compared both with respect to season and between the two systems. Figures are given for accidents and nine different diseases.In zero-grazing cows no seasonal difference could be demonstrated except for a higher risk of ketosis and tramped teat during wintertime for SRB.Cows of both breeds kept on pasture had lower risks of dystocia, ketosis, mastitis and tramped test during this period, but an increased risk of accidents and inflammation of the hoof(s). SRB cows also had higher risks of retained placenta, parturient paresis and non-inflammatory diseases of the hoof(s) during pasture period.Comparison of year-round incidence in the two management systems revealed a higher risk of retained placenta in zero-grazing cows of both breeds and higher risk or parturient paresis in zero-grazing SRB cows. The risk of accidents was decreased in zero-grazing cows of both breeds.The relative risks of tramped teat, mastitis and diseases of the hoof(s) varied depending on the herd size distribution of the control group. Increased risk of mastitis in zero-grazing cows of both breeds and of tramped teat in zero-grazing SLB cows was found when comparing with cows from a group of mainly smaller herds with pasture feeding during summer. However, comparison with cows from a group of herds with the same herd size distribution as zero-grazing cows revealed decreased risk of tramped teat, mastitis and inflammation of the hoof(s) in zero-grazing SRB cows and decreased risk of diseases of the hoof(s) in zero-grazing SLB cows.     

奶牛亚临床酮症的研究进展

酮症是高产奶牛在泌乳前期的常见病。根据有无临床症状将酮症分为临床酮症（clinical ketosis,CK）和亚临床酮症（subclinical ketosis,SCK）。酮症会导致奶牛血液或牛奶中酮体浓度增加,目前主要通过检测血液中β-羟丁酸（BHBA）浓度高低来对酮症进行诊断。CK对奶牛的影响比较明显,因此更能引起牧场主的关注。而奶牛患有SCK后不表现出临床症状,往往容易被牧场主忽视。SCK如同CK和奶牛围产期其他疾病一样是造成奶牛经济和福利损失的主要原因之一。SCK大大增加了奶牛产后相关疾病的风险,如CK、真胃移位、胎衣不下、乳房炎和子宫炎等,另外患有SCK的奶牛生产性能大幅度下降（泌乳性能降低、繁殖性能变差、淘汰率增加）,给牧场的发展带来了不可估量的损失。SCK可能在未被发现的时候就已经开始对生产性能产生影响,而且它对生产性能的影响与CK引起的影响相当,但是由于缺乏临床症状而不被牧场重视。作者在这篇综述中将着重介绍奶牛SCK的最新研究进展,这不仅有助于进一步了解奶牛酮症的发病机理及SCK对生产力的不利影响,并且可提供针对SCK的不同检测方法和可行的预测方法来帮助牧场进行早期诊断,减少因SCK造成的奶牛福利和经济损失。     

Risk factors for abomasal displacement in dairy cows.

OBJECTIVE: To determine whether various periparturient events or 305-day milk production during the previous lactation period were associated with abomasal displacement in dairy cows. DESIGN: Retrospective, case-control study. ANIMALS: 75 pairs of case and control cows from 3 university-owned and 3 commercial dairy herds. PROCEDURE: Cows with abomasal displacement were matched with control cows on the basis of herd of origin, breed, age, and calving date. Frequency of specific periparturient events during the period from 2 weeks prior to parturition to diagnosis of abomasal displacement, as well as milk production during the preceding lactation period, were compared between case and control cows. RESULTS: Multivariate analyses indicated that case cows were significantly more likely to have had retained placenta, ketosis, a stillborn calf, metritis, twins, or parturient paresis than were control cows. Dystocia, mastitis, and milk production during the previous lactation period were not associated with abomasal displacement. CLINICAL IMPLICATIONS: Results indicated that a variety of periparturient events were associated with development of abomasal displacement among dairy cows.     

Disease, production and culling in Holstein-Friesian cows I. The data

A two-and-a-half-year study was undertaken in 32 commercial dairy herds within a 50-mile radius of Guelph, Ontario, in order to provide a comprehensive evaluation of relationships amongst diseases, production parameters and risk of removal in Holstein-Friesian cows. Diseases consisted of common clinical diseases as well as two subclinical diseases (mastitis and ketosis).

The data set consisted of a total of 2875 lactation records from 2008 cows. The means and standard deviations of some of the production parameters were: age 4.9 ± 2.5 year, breed class average for milk 140 ± 26 BCM units, milk production per day of life 18.0 ± 3.8 kg and days to conception 118 ± 60 days. Lactational incidence rates of the more common diseases were: reproductive tract infections 0.182, mastitis 0.168, cystic ovaries 0.104, subclinical ketosis 0.096, retained placenta 0.086 and ketosis 0.074. The average lactation mean log somatic cell count was 179 000 cells/ml. The times postpartum to the first diagnosis of all disease conditions are presented.     

投服博威钙对奶牛产奶性能和健康状况的影响

选择2～5胎成年泌乳母牛40头,按照年龄、胎次、分娩时间相近的原则随机分为试验组与对照组,每组20头,研究博威钙对产后奶牛产奶性能和健康状况的影响。试验组奶牛产后0h及12h分别投喂1粒博威钙,对照组采用常规补钙(通过输液,每头奶牛补氯化钙25g)。结果发现,与对照组相比,试验组奶牛平均日产奶量提高了2.05kg,体细胞数降低了37.3%(P<0.05);乳尿素氮的变化不显著(P>0.05)。在产后奶牛健康状况方面,试验组奶牛的亚临床型低血钙症、临床型低血钙症、隐性乳房炎、临床型乳房炎和胎衣不下的发病率均显著低于对照组,真胃移位、酮病以及蹄病方面的发病率则无显著变化。研究表明,补饲博威钙能够改善产后奶牛的健康状况,提高奶牛产奶性能和养殖效益。     

Bovine haptoglobin response in clinically defined field conditions

In order to assess the usefulness of haptoglobin as a measure of the acute phase response in cattle, the concentration of serum haptoglobin was estimated in the non-infectious conditions of milk fever and ketosis, and in the infectious conditions of severe mastitis, acute severe metritis, retained placenta and chronic endometritis. Mean haptoglobin concentrations were normal in cattle with non-infectious conditions and chronic endometritis but significantly increased in cattle with infectious conditions.     

Disease frequencies in dairy cows in Sweden. IV. ketosis

An epidemiologic study of ketosis in dairy cows in Sweden covering approximately 125 000 calvings in 1268 herds is presented and various risk factors identified.The Swedish Red and White breed (SRB) had a higher incidence of ketosis than the Swedish Friesian breed (SLB). A positive report of parturient paresis, alone or in combination with a positive report of retained placenta increased the risk of ketosis in SRB cows. Simultaneous reports of parturient paresis and retained placenta increased the risk of ketosis in SLB cows. Tied cows of both breeds with pasture had a decreased risk during the months of pasture. The incidence of ketosis decreased with herd size, and tied zero-grazing cows had a higher incidence than loose-housed cows.Cows reported positive once for ketosis had an increased risk in subsequent calvings but no increased risk of removal during lactation.     

Associations between use of electric cow-trainers and clinical diseases, reproductive performance and culling in Swedish dairy cattle

The aims of this follow-up study were: (a) to evaluate the role of ECT technology as a risk factor for several diseases; and (b) to determine if the effects of these diseases on cows' reproductive performance and as risk factors for culling are influenced by exposure to ECTs. Diseases considered were retained placenta, metritis, ketosis, cystic ovaries, silent heat, milk fever, clinical mastitis, and foot and leg problems. We used historical and contemporary controls (with control herds selected to match the experimental herds for size and location). Data consisted of 10264 Swedish Red and White (SRB) and 5461 Swedish Friesian (SLB) lactation records in 150 herds of which 33 used cow-trainers. Logistic regression was used to estimate the effects of parity and exposure to electric cow-trainers on the risks of diseases and the effects of diseases and exposure to electric cow-trainers on risk of culling. The least-squares procedure was used to estimate the effects of diseases on reproductive performance.

The dominant effects associated with use of electric cow-trainers were an increased risk for silent heat, clinical mastitis, ketosis and culling relative to cows in herds not using cow-trainers. Diseases had negative effects on reproductive performance and the effects were larger for cows in herds using cow-trainers. In herds using electric cow-trainers, the largest increase in the interval from first service to conception (58 days) was caused by the occurrences of silent heat, cystic ovaries and the combination of two or more diseases. Retained placenta, metritis, cystic ovaries, clinical mastitis and a combination of two or more diseases increased the risk of culling about two times relative to healthy primiparous cows with the increase being greater for cows in herds using cow-trainers. Silent heat did not increase risk of culling in control groups, but was the largest risk factor for culling in the exposed group. We concluded that exposure to electric cow-trainers increased the incidence risk of silent heat, clinical mastitis, and ketosis and changed silent heat from a neutral disease with respect to culling to a major risk factor. Finally, exposure to cow-trainers increased the general negative effect of diseases on the cows' reproductive performance and risk for culling.     

Disease frequencies in dairy cows in Sweden. II. Retained placenta

An epidemiologic study of retained placenta in dairy cows in Sweden covering 140 000 calvings is presented and various risk factors identified.

Swedish Friesian Breed (SLB) had a higher incidence than Swedish Red and White Breed (SRB). The incidence showed a linear increase with age, both when analysing the entire data set and when analysing the frequencies in cows negative for risk factors shown to increase the incidence of retained placenta, e.g., twinning, parturient paresis and dystocia. Male calves increased the risk. Loose-housed cows of both breeds had a lower incidence than tied zero-grazing cows, suggesting exercise to be a sparing factor. An increased recurrence risk ratio was found in second, third and fourth calvings for SRB and in second and third calvings for SLB.

SRB cows with a positive report of retained placenta had an increased risk of removal during the lactation. In dystocia and parturient paresis negative SLB cows, retained placenta increased the risk of removal, whereas a positive report of this disease in dystocia and/or parturient paresis positive cows did not further increase the risk removal.     

A cow‐level association of ruminal pH on body condition score,serum beta‐hydroxybutyrate and postpartum disorders in Thai dairy cattle

Subacute ruminal acidosis in dairy cows occurs when ruminal pH is below about 5.5. However, the exact threshold level of ruminal pH affecting cow health is still in debate. This investigation was carried out in 505 cows within 31 farms. The postpartum disorders, including dystocia, retained placenta, anestrus, cystic ovary, metritis, clinical mastitis and lameness, were analyzed. Ruminal pH, serum beta‐hydroxy butyrate (SBHB), serum urea nitrogen and body condition score (BCS) were measured once during the 3 to 6 weeks postpartum, while BCS was determined once more at 1 week before calving. Ruminal pH was determinded by ruminocentesis technique. The ruminal pH was evaluated to study the association with BCS, SBHB and postpartum disorders using linear regression in a generalized linear mixed model with farm as a random effect. The results show that low ruminal pH was associated with dystocia, metritis and lameness. Moreover, a low ruminal pH can be found in cows with a high loss of BCS after calving and also in cows with low SBHB postpartum. These findings confirmed the feasibility of the ruminocentesis technique and the association of low ruminal pH on various postpartum disorders at the individual cow level. However, the consequences of low ruminal pH on dairy cow health still needs more exploration for a better understanding of the physiological mechanisms.     

An epidemiologic study of disease in 32 registered Holstein dairy herds in British Columbia.

Data recorded in a herd health management system were obtained from 32 registered Holstein dairy herds from British Columbia. Frequencies of disease were described, and the effect of herd, age, year, season, and the interrelationships between diseases within a lactation on the occurrence of disease were evaluated. Lactational incidence rates were computed for diseases with a short period of risk (ie, udder edema, milk fever, retained placenta, metritis, displaced abomasum, and ketosis), whereas for diseases with a longer period of risk (ie, cystic ovaries, mastitis and stable footrot), incidence densities were calculated. Overall, the disease incidence was low and showed an increase in frequency by year, which we attributed to more observing and complete recording by the owner, rather than an actual increase in disease incidence. Most diseases occurred early in lactation and their frequency increased with lactation number; the exception was udder edema, which occurred mainly during the first 2 lactations. An informal path model of disease interrelationships was made conditional on herd. Based on the results we inferred 2 independent pathways: one started by udder edema, and the other by milk fever. Udder edema was directly associated with mastitis occurrence from 0 to 30 d in lactation, metritis, and cystic ovaries. Mastitis from 0-30 d in lactation increased the risk of both mastitis from 31-150 d in lactation and cystic ovaries. Both of these increased the risk of late lactation mastitis. Milk fever was directly related with displaced abomasum, which increased the risk of footrot. In general, diseases that occurred in early lactation tended to increase the risk of other diseases later in lactation.     

Risk factors for metritis in Danish dairy cows

A retrospective longitudinal study of metritis was conducted in Denmark on data collected during 1993-1994. Data on herd size, breed, parity, and treatment of disease were obtained from the Danish Cattle Database. Management and production-facility data were collected using a questionnaire, conducted as a telephone interview in 1994. The study included 2144 herds from three regions in Denmark (102,060 cows). Herd-level variables included were: herd size, housing, flooring, grazing, calving measures, and calving supervision. Cow-level variables were: parity, breed, calving season and whether the cow had been treated by a veterinarian for dystocia or the diseases: retained placenta, reproductive disease, ketosis, milk fever, or dry cow mastitis.Marginal multivariable logistic-regression analyses were performed. The cow with highest odds of metritis was a first or greater than or equal to third parity cow, of large breed, that calved during November-April, in a zero-grazing herd. The cow had been treated for dystocia, retained placenta, and at least one other reproductive disease, but not for ketosis.