The association between lameness and fertility in dairy cows

One thousand, four hundred and ninety-one lactations in 770 Friesian, Holstein and Ayrshire crossbred cows have been used to study the associations between lameness and fertility. Lameness was associated with a longer interval between calving and first service and a longer interval between calving and conception. The largest increases in these intervals, of 17 and 30 days, respectively, occurred in cows with either sole or white line lesions occurring between 36 and 70 days after calving. The conception rate during the 63 days before a diagnosis of lameness was made was lower (31 per cent) than at other times (40 per cent).     

The association between indicators of inflammation and liver variables during the transition period in high-yielding dairy cows: an observational study

During the transition period, cows are confronted with infectious and inflammatory challenges leading to an acute phase response (APR) marked by increased hepatic synthesis of positive acute phase reactants (+AP) and a decrease in negative acute phase reactants (-AP). The aim of this study was to quantify the APR in 21 high-yielding dairy cows studied from 9 days before until 42 days after calving, and to assess the association between the APR, disease incidence and indicators of liver function. Repeated blood samples were analyzed for -AP (retinol, albumin, cholesterol), +AP (haptoglobin, caeruloplasmin), paraoxonase, and liver-associated variables (aspartate aminotransferase, γ-glutamyl transferase, bilirubin). All cows displayed postpartum decreases in -AP and paraoxonase, and increases in +AP and liver variables. When retrospectively categorized, cows presenting a stronger -AP decline displayed higher +AP and liver variables, and a higher disease incidence compared to cows with a milder decline. Altogether, typical changes in -AP and +AP identify the transition period as a time of increased inflammatory load. Group differences in liver variables suggest that a more severe APR may be associated with altered liver function. However, no causal relationship can be proven based on this observational dataset, and results should be interpreted cautiously.     

Associations between health disorders of French dairy cows and early and late culling within the lactation

Data from an observational study, carried out during a 4.5 year period (1986–1990), were used to quantify the effects of health disorders on the risk of culling. The study population consisted of 47 commercial Holstein dairy herds from western France, comprising 4123 cows.

Logistic regression was used to assess the relationships between health disorders and early and late culling. Fourteen main health disorders with clinical signs and one subclinical disease were studied: abortion, periparturient accident, calving provided with assistance, digestive disorders, ketosis, locomotor disorders, mastitis, metritis, milk fever, cystic ovaries, respiratory disorders, retained placenta, teat injuries, non-traumatic udder disorders and status with respect to milk somatic cell count. Adjustments were made for year, month of calving, parity, breeding value for milk, best of the two first milk production records and reproductive performance. The possible effects of interactions among variables were also studied. The herd effect was taken into account using random effect models.

Non-traumatic udder disorders, teat injuries, milk fever and the occurrence of both ketosis and assistance at calving were significantly associated with an increased risk of being early culled (odds ratios (OR) ranging from 1.6 to 10.3). Early and late abortion, late metritis, poor peproductive performance, retained placenta, non-traumatic udder disorders within 45 days post-partum and mastitis occurring in the first 3 months of the lactation were positively associated with a late culling (OR ranging from 1.2 to 6.6). Cows with lower breeding value for milk and higher parities were high risk groups for culling. A lower level of milk production and occurrence of both reproductive disorders and poor reproductive performance were risk factors for late culling.     

奶牛子宫内膜上皮细胞和间质细胞的组织块培养及鉴定

奶牛子宫内膜细胞是研究奶牛子宫内膜生理和病理机制的重要体外模型,国外关于奶牛子宫内膜细胞的分离和培养的研究很多[1-3],而国内尚未见相关报道.本研究选用荷斯坦奶牛的健康子宫内膜,应用组织块培养法培养并分离间质细胞和上皮细胞.为从细胞和分子水平进一步研究奶牛子宫内膜提供必要的条件.     

The association between first DHI milk-test parameters and subsequent displaced abomasum diagnosis in dairy cows

First Dairy Herd Improvement Corporation (DHI) test milk that was sampled prior to displaced abomasum (DA) diagnosis was used to examine the association between milk yield (kg), fat (%), protein (%), or fat/protein ratio and DA in dairy cows. 27 DA cases were matched to 3 controls per case by herd and calving date. Logistic regression was used to examine the effect of each milk parameter on the odds of DA, adjusting for lactation number and days in milk (DIM) at test. Higher odds of DA diagnosis was found with lower milk yield, higher milk fat percentage, lower milk protein percentage and higher fat/protein ratio. We conclude that milk yield, fat percentage, protein percentage and fat/protein ratio may be used to detect cows at risk for DA. Our findings also indicate that cows diagnosed with DA were energy deficient prior to DA diagnosis.     

Differences between Brahman and Holstein cows in heat-shock induced alterations of protein synthesis and secretion by oviducts and uterine endometrium

Our objectives were to test differences in protein synthesis and secretion by cultured oviducts and endometrium from Brahman and Holstein cows and the response of those tissues to in vitro heat shock. Explants of oviductal tissue obtained at estrus from Holstein (n = 5) and Brahman (n = 6) cows were cultured at a homeothermic (39 degrees C) or heat shock (43 degrees C) temperature. At 6 h, cultures were pulse-chase labeled (2 h, L[4,5-3H]leucine; 2 h, L-leucine). Endometrial explants were cultured similarly except that pulse labeling was performed for the first 0 to 15, 0 to 30, 30 to 60 and 60 to 90 min following onset of heat shock. A temperature of 43 degrees C increased secretion of nondialyzable 3H-labeled macromolecules by both oviducts of Brahmans but depressed secretion by the oviduct ipsilateral to the side of ovulation of Holsteins. For both breeds, 43 degrees C decreased incorporation of [3H]leucine into trichloroacetic acid (TCA)-precipitable radioactivity in oviducts from the ipsilateral side. Secretion of 3H-labeled macromolecules by pulse-labeled endometrial explants increased at 43 degrees C. Heat shock caused an immediate increase in TCA-precipitable radioactivity in tissue during pulse labeling for Holstein tissues. Incorporation was decreased at 43 degrees C in tissue from Brahmans in the first 30 min and increased thereafter. Incorporation of [3H]thymidine by endometrial explants from Brahmans was increased at 43 degrees C, whereas it was suppressed at 43 degrees C in explants from Holstein cows. Heat shock proteins of 72,000 and 90,000 molecular weight were present in endometrial tissues. A major secretory product of endometrium had a molecular weight of 57,500 for Brahmans and a lower molecular weight (55,600) for Holsteins.     

A comparison of performance of the Ovsynch treatment program between cycling and non-cycling cows within seasonally-calving dairy herds

OBJECTIVE: To compare performance of the Ovsynch program on reproductive performance between cycling and non cycling cows in seasonally-calving herds. PROCEDURE: An Ovsynch mating program (100 mg Gonadorelin on day 1 and day 9, 500 mg of Cloprostenol on day 7 with fixed time artificial insemination on day 10) was administered to 3,559 cows from 14 herds in Australia and New Zealand. Cycling status before planned start of mating was determined. All cows were treated and artificial insemination continued for at least 25 days after fixed time artificial insemination. Pregnancy testing was performed 75 to 100 days after fixed time artificial insemination. Multivariable modelling examined the impact of the Ovsynch program and other risk factors upon reproductive performance. RESULTS: Thirty percent of cows were classified as no visible oestrous (NVO). Odds of being NVO increased significantly for cows that were young, recently calved, and in low body condition. The fixed time artificial insemination conception rate was 35.7% and 33.2%, 21-day pregnancy rate was 54.5% and 48.4% and 42-day pregnancy rate was 69.7% and 62.6% for cycling and NVO cows respectively. Odds of pregnancy increased significantly for cows calved more than 40 days by planned start of mating, in greater body condition, and cycling, and there was a significant interaction between body condition and cycling status in both models. The return-to-service rates by 24-days were 67.6% and 55.9% and by the end of the AI period were 86.9% and 81.5% for cycling and NVO cows respectively. Odds of return to service increased significantly for cows in greater condition score in both models. Odds of return were increased for cycling cows in the 24-day multivariable model. CONCLUSION: The Ovsynch program may provide a useful treatment option for NVO cows within seasonally-calving pasture-based dairy herds.     

Evaluation of association between polymorphism within the thyroglobulin gene and milk production traits in dairy cattle

In dairy cattle, many studies have reported quantitative trait loci (QTL) on the centromeric end of chromosome 14 that affect milk production traits. One of the candidate genes in this QTL region – thyroglobulin (TG) – was previously found to be significantly associated with marbling in beef cattle. Thus, based on QTL studies in dairy cattle and because of possible effects of this gene on fat metabolism, we investigated the association of TG with milk yield and composition in Holstein dairy cattle. A total of 1279 bulls from the Cooperative Dairy DNA Repository Holstein population were genotyped for a single nucleotide polymorphism in TG used previously in beef cattle studies. Analysis of 29 sire families showed no significant association between TG variants and milk production traits. Within‐sire family analysis suggests that TG is neither the responsible gene nor a genetic marker in association with milk production traits.     

奶牛子宫内膜上皮细胞和间质细胞的分离、培养及鉴定

为了分离培养奶牛子宫内膜上皮细胞和间质细胞,给建立奶牛子宫内膜体外模型提供条件,研究采用胰蛋白酶和胶原酶消化法分离细胞,随后传代培养纯化细胞,并通过光镜观察和免疫细胞化学染色对其进行鉴别.结果表明:0.3%胰蛋白酶消化组织块1 h后可得到上皮细胞,纯度＞80%;上皮细胞呈多边型,核大而圆,具有细胞角蛋白免疫反应性.用0.1%胶原酶Ⅱ继续消化2 h,可得到间质细胞,纯度＞90%;间质细胞贴壁后可见梭形和多角形两种形态,免疫细胞化学染色显示这两种细胞均具有波形蛋白免疫反应性,而细胞角蛋白无免疫反应性,提示它们为来源于内膜基质的基质细胞,说明采用酶消化法能够成功地培养奶牛子宫内膜间质细胞和上皮细胞.     

Relationship between milk urea concentration and the fertility of dairy cows

The relationship between milk urea concentration and the fertility of dairy cows was examined in two studies. The first examined the relationship between bulk milk urea concentration and overall herd fertility, using data collected from 250 herds in the UK. There was no relationship either between bulk milk urea concentration and fertility, or between changes in bulk milk urea concentration and fertility. The second study compared the relationship between the milk urea concentration five days after service, and the fertility of individual cows on 11 UK dairy farms. There was no significant difference between the milk urea concentration of the cows that became pregnant and those that did not.     

Effect of norgestomet treatment on plasminogen activator activity in the cervical mucus and the endometrium in dairy cows

The aim of this study was to determine the effect of norgestomet treatment, in the absence or the presence of a functional corpus luteum (CL), on plasminogen activators activity (PAA) in the cervical mucus and the endometrium in dairy cows. Eleven days after oestrus (Day 0 = oestrus), 38 cows were randomly assigned to one untreated control group (n = 9) and three treatment groups (S(1), S(2) and S(3)). Animals of S(1) group (n = 9) received an implantation of norgestomet on the outer surface of the ear for 8 days, simultaneous injection of oestradiol valerate 5 mg and norgestomet 3 mg, i.m., and on Day 19 an injection of ECG 500 IU, i.m. Animals of S(2) group (n = 11) received the treatment of S(1) group, plus an administration of PGF(2)alpha on Day 10 for the regression of CL. Animals of S(3) group received the treatment of S(2) group, plus two additional norgestomet implants inserted on Day 16 for 36 h. Both types of plasminogen activators [the tissue-type (t-PA) and the urokinase-type (u-PA)] were detected in the cervical mucus and the endometrium of the cows. Plasminogen activators activity in the cervical mucus was higher in control group than in S(1), S(2) and S(3) groups (P < 0.001). In contrast, endometrial PAA did not differ among groups (P > 0.05). Oestradiol-17beta concentrations on Day 21 were higher in S(2) group than in control group (P < 0.01) and S(3) group (P < 0.05). Progesterone concentrations did not differ among groups (P > 0.05). Oestradiol-17beta concentrations could positively affect cervical mucus PAA in control group (P < 0.1), but not in other groups (P > 0.05). These findings suggest that control of estrous cycle by norgestomet administration, in dairy cows, exerts a suppressive effect on plasminogen activators synthesis and/or secretion in the cervical mucus, regardless of the absence or the presence of the CL. On the contrary, endometrial PAA is not affected by norgestomet treatment.     

The relationship between production and infertility in dairy cows

Extract

Each year increasing numbers of livestock are transported by land, rail, sea and air, vet documented observation of the behaviour of stock during transit has seldom been recorded. The trans-shipment of weaner calves between the North and South Islands of New Zealand provided an opportunity to gather information on conditions of travel and general adaptation to a journey of 1600 kilometres by road and air.     

An association between the level of oxidative stress and the concentrations of NEFA and BHBA in the plasma of ketotic dairy cows

The aim of this study was to evaluate the oxidative status in ketotic cows. We observed changes in the oxidative status and correlations between the oxidative and metabolic status in non‐ketotic (n = 10), subclinical ketotic (n = 10) and ketotic cows (n = 10). Plasma samples were analysed by standard biochemical techniques and ELISA to determine traditional metabolic parameters: triglyceride (TG), phosphonium (P), calcium (Ca), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), immune globulin (Ig), total cholesterol (TC), high‐density lipoprotein (HDL), very low‐density lipoprotein (VLDL) and lactate dehydrogenase (LDH); energy metabolism indices: glucose, β‐hydroxybutyrate (BHBA) and non‐esterified fatty acids (NEFA); and indices of oxidative status: malondialdehyde (MDA), hydrogen peroxide (H₂O₂), vitamin C, vitamin E, superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), catalase (CAT), xanthine oxidase (XOD) and total antioxidant capacity (TAOC). The results of this study showed that plasma glucose levels were lower in ketotic and subclinical ketotic cows than in non‐ketotic cows; however, the plasma NEFA and BHBA concentrations were higher. In addition, significant decreases in TC, HDL and VLDL and significant increases in AST, ALT and LDH were observed in the plasma of the ketotic cows. The ketotic cows showed decreased plasma SOD, CAT, vitamin C and vitamin E, inhibited hydroxyl radical capacity and increased plasma H₂O₂ and MDA. There were positive correlations between the plasma NEFA and ALT, AST, LDH and MDA and negative correlations between the plasma NEFA and TC, HDL, VLDL, SOD, vitamin C, vitamin E, 1542280 uric acid and inhibited hydroxyl radical capacity. In addition, there were positive correlations between BHBA concentrations and ALT, AST and LDH and negative correlations between plasma BHBA concentrations and TC, HDL, VLDL, vitamin E and inhibited hydroxyl radical capacity. Overall, ketotic dairy cows experience oxidative stress, which is presumably associated with hyperketonemia and higher NEFA.     

Neospora caninum seropositivity and association with abortions in dairy cows in Mexico

The seroprevalence of Neospora caninum infection was estimated from a sample of 813 cattle from 20 dairy herds in five regions in Mexico. The true prevalence of infection was estimated to be 42% (95% CI: 39, 46). Seropositivity was associated with abortion (odds ratio (OR)=2.0) and was higher among cows raised on-farm (41%), than among replacement cattle purchased outside the farm (28%). The ORs relating abortion to seropositivity in individual herds ranged from 1.3 to 10. Overall, 26% of the abortions were attributed to N. caninum.     

Possibilities for further research of chronic wasting in dairy cows

In this study, we reviewed the research that has been conducted in relationship with the problem of 'chronic wasting' in dairy cows in the Netherlands as was experienced during 1998 and 1999. Emphasis was drawn towards three aspects of this 'chronic wasting'; the definition, the magnitude, and the possible cause or causes. It appeared that a clear, objective definition of 'chronic wasting' in cows, and of farms with a problem of 'chronic wasting' cows is still lacking. Furthermore, the incidence (of the problem) was restricted to approximately 150 dairy farms at most. Currently, no farms with 'chronic wasting' cows are known. Combined with the uncertainty in the definition, this will hamper future research. Many of the studies were related to the hypothesis that the vaccination with the BHV1 marker vaccine had caused 'chronic wasting' in the cows. None of the results, however, substantiated this hypothesis. Other possible causes have hardly been investigated and further research would be needed to evaluate the role of nutrition, infectious agents, and genetics. However, due to the waning of the phenomenon, the availability of data and controls will be limiting.     

Relationship between the first ovulation within three weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cows

The aim of this study was to investigate the relationship between the first ovulation within 3 weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cattle in Hokkaido, Japan. In Experiment 1, 110 cows (44 primiparous and 66 multiparous) were used to determine the effects of the first ovulation within 3 weeks postpartum on subsequent ovarian cycles. Milk samples were collected twice weekly from 7 to 100 days postpartum. The first ovulation was identified by an increase in milk progesterone (P4) to more than 1 ng/ml within 3 weeks postpartum. The numbers of cows showing ovulation and anovulation within 3 weeks postpartum were 31 (70.5%) and 13 (29.5%) in the primiparous cows and 35 (53.0%) and 31 (47.0%) in the multiparous cows, respectively. The patterns of ovarian resumption after calving were classified into two types (normal ovarian cycles and abnormal ovarian cycles) on the basis of milk P4 concentrations. Initiation of normal ovarian function in cows ovulated within 3 weeks postpartum occurred earlier than in anovulated cows regardless of the number of calvings (primiparous, 27.8 days vs. 44.4 days; multiparous, 30.6 days vs. 55.7 days; P<0.01). Out of the multiparous cows that ovulated within 3 weeks postpartum, initiation of normal ovarian function followed by a normal luteal phase was earlier than when it was followed by an abnormal luteal phase (25.5 days vs. 40.4 days; P<0.05). Milk P4 concentrations after the first ovulation were lower than those after the second ovulation in both the primiparous and multiparous cows (P<0.05). In Experiment 2, 22 multiparous cows were used to determine the effects of the first ovulation within 3 weeks postpartum on subsequent fertility. Blood samples were collected once a week from 0 to 3 weeks postpartum. The interval from parturition to first service in ovulated cows was shorter than in anovulated cows (68.4 days vs. 94.8 days; P<0.05). The conception rate by 100 days after calving tended to be higher in ovulated cows than in anovulated cows (50.0% vs. 16.7%, P=0.09). In conclusion, our data strongly suggests that ovulation within 3 weeks postpartum is a crucial phenomenon for subsequent resumption of ovarian function and conception, and thus it can be used as an index of subsequent reproductive performance.     

泌乳奶牛铜缺乏与机体氧化应激的关系

为了探讨泌乳奶牛Cu缺乏与氧化应激的关系,在某集约化牛场根据血浆铜水平,将泌乳奶牛分为铜缺乏组和铜正常组。对两组牛的抗氧化指标(CP、SOD、T-AOC、GSH-Px)和血浆Cu含量进行分析。结果显示:Cu缺乏组的CP水平显著低于Cu正常组,T-AOC水平显著高于Cu正常组。SOD、GSH-Px水平和正常组无显著差异;皮尔逊相关性分析显示,血浆CP与Cu缺乏呈极显著的正相关;T-AOC与Cu缺乏呈极显著的负相关,SOD、GSH-Px与Cu缺乏无相关性;ROC分析结果显示,CP可作为泌乳奶牛铜缺乏的预警指标,临界值为13.7 U/L。结论:泌乳奶牛血浆中CP、T-AOC与铜缺乏密切相关,CP可作为泌乳奶牛Cu缺乏风险的预警指标。