奶牛产后瘫痪综合防治技术

奶牛产后瘫痪是奶牛常见营养代谢性疾病。本文阐述了本病的临床症状、发病机理,介绍了某奶牛场对该病的综合防治技术方案。     

Association between postpartum pyrexia and uterine bacterial infection in dairy cattle

The temperature of 90 dairy cattle was recorded for the first 10 days after parturition and the animals were categorised as either normal (< 39.7 degreesC) or pyrexic. Swabs were collected from the uterine lumen seven, 14, 21 and 28 days after parturition for aerobic and anaerobic culture; bacteria were identified and their growth was scored semiquantitatively. Blood samples were collected three times a week for the estimation of the concentrations of acute phase proteins. The cows' temperatures were often above the accepted normal range, but it was not a good indicator of the number of bacteria in the uterus. However, pyrexia was correlated with the presence of specific uterine pathogens (P < 0.05) and in particular with Prevotella species (P < 0.01). The pyrexic animals had a higher plasma concentration of the acute phase protein (alpha1-acid glycoprotein (P < 0.05). Although pyrexia is an indicator of postpartum inflammation, additional clinical signs are necessary to identify uterine bacterial infection.     

Energy balance and pulsatile LH secretion in early postpartum dairy cattle

The relationships between energy balance (EB), pulsatile LH secretion and circulating levels of insulin and various energy metabolites were assessed in ten lactating Holstein cows. Cows were blood sampled every 12 min via indwelling jugular catheters for 8 hr twice weekly beginning in the first week postpartum (PP) through first ovulation (1stOV). Days to negative EB nadir and days to 1stOV were highly correlated (P less than .02). LH pulse frequency (P less than .01), LH baseline (P less than .05) and mean LH (P less than .1) increased, while LH pulse amplitude tended to decrease when comparing the frequent sampling series immediately before and after the negative EB nadir. Plasma levels of non-esterified fatty acids (NEFA, r = -.40, P less than .01), insulin (r = .38, P less than .01), glucose (r = .31, P less than .01) and beta-hydroxybutyrate (r = .19, P less than .06) were correlated with EB. For within animal comparisons, NEFA was significantly correlated (r = -.44 to -.89, P less than .05) with EB in 8 of 10 cows, but no other correlations were significant. Additionally, none of the metabolites nor insulin were significant in multiple regression models for 1stOV. Therefore, it appears that pulsatile LH secretion is suppressed until the negative EB nadir is reached, at which time LH pulse frequency increases stimulating 1stOV. Since NEFA and EB are directly related, NEFA may serve as a peripheral signal of EB to the central nervous system.     

Energy metabolites in pre- and postpartum dairy cattle as predictors of reproductive disorders

This study aimed to determine values for selected energy metabolites (non-esterified fatty acid [NEFA], β-hydroxybutyrate [BHB], urea or urea:BHB ratio), together with a body condition score, associated with an increased risk of cows developing a reproductive disorder and to investigate temporal relationships between predictors and reproductive outcome. A cohort of 98 cows on one farm was monitored weekly from four weeks before to 10 weeks after calving; 89 cows provided sufficient data to calculate commencement of luteal activity (C-LA). Cows with high NEFA × urea (Nu; product of NEFA and urea) values one and three weeks after calving were twice as likely to develop cystic ovarian disease (risk ratio 2). Cows that developed endometritis had high NEFA values one (P=0.02) or four weeks (P=0.04) before calving, or low urea:BHB ratios two weeks before calving, at calving or three weeks after calving (P=0.024, P=0.031 and P=0.001, respectively). Cows that had delayed C-LA had high NEFA values one week after calving (P=0.05) or low urea:BHB ratios three or four weeks after calving (P=0.004 and P=0.003, respectively).     

Alteration of the GnRH-induced LH release by steroids in postpartum dairy cattle

The effect of elevated plasma concentrations of estradiol-17 beta (E2 beta), estrone (E1) and progesterone (P), in concentrations similar to those observed at the end of pregnancy, on the gonadotropin releasing hormone (GnRH)-induced luteinizing hormone (LH) release in postpartum dairy cows was studied. Twenty-five dairy cows in late gestation were assigned to five groups of five each to receive daily steroid treatments as follows: 1 and 2) no exogenous steroids; 3) 20 mg E2 beta and 30 mg E1; 4) 150 mg P and 5) 20 mg E2 beta + 30 mg E1 + 150 mg P. Steroids were dissolved in alcohol (vehicle) and injected sc twice daily. Cows receiving no steroids were given vehicle. Administration of steroids or vehicle began immediately after parturition (d 0) and continued for 7 d to maintain concentrations of steroids in plasma similar to prepartum concentrations. Cows in groups 2 through 5 received an injection of 100 micrograms GnRH on d 2, 8, 16, 24 and 32 postpartum, while those in group 1 received water (vehicle for GnRH) on the same days. Plasma for hormonal determinations was collected on alternate days beginning 10 d before the expected day of parturition, daily through the period of steroid treatments (d 0 to 6, postpartum) and on alternate days thereafter until d 40 postpartum. In addition, plasma was collected immediately before GnRH or water administration and at .5 h intervals thereafter for 4 h. Trends in response to treatment over days postpartum were studied by partitioning sums of squares due to linear, quadratic and cubic polynomial responses.(ABSTRACT TRUNCATED AT 250 WORDS)     

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

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

Follicular development after ovum pick-up and fertilizability of retrieved oocytes in postpartum dairy cattle

This study aimed to evaluate gonadotropin secretion and the developmental competence of follicular oocytes in dairy cattle during the early postpartum (PP) period. The number of follicles developed after transvaginal ultrasound-guided ovum pick-up (OPU) and fertilizability of retrieved oocytes were compared between cows in which the first dominant follicle (DF) ovulated (ovulated group, n=4) and did not ovulate (non-ovulated group, n=3), and between early PP (early PP group, n=2) and after the resumption of the estrous cycle (cyclic group, n=2). Follicular ablation was performed 2-4 days after the detection of DF in the second follicular wave PP. OPU was repeated 3-5 times at 3 or 4-day intervals from 3-4 days after the follicular ablation. At OPU, the follicles were enumerated and all those > or = 5 mm in diameter were aspirated. Recovered oocytes were subjected to in vitro maturation and fertilization. Both criteria were similar between ovulated and non-ovulated groups, and between early PP and cyclic groups. These results suggest that FSH/LH secretions required for follicle recruitment and subsequent follicular growth during the early PP period are similar to those after resumption of the estrous cycle. They also indicate that follicular oocytes during the early PP period have developmental competence.     

奶牛产后瘫痪的中西医治疗

产后瘫痪是奶牛分娩期的常见病、多发病,也是兽医临床难治的疾病之一。本病好发于高产或分娩胎次较多的青壮年奶牛,急症者产后1～3小时,慢者2～6天出现临床症状。一年四季均可发生,发病急,恢复慢,给奶牛生产带来很大的经济损失,而一般的西药对症治疗效果不理想。笔者通过多年的兽医临床实践,依据西医治标、中医治本的特点,采取中西医结合并辅以乳房送风的治疗方法,治疗奶牛产后瘫痪24余例,均收到良好的治疗效果。     

Nutrition and postpartum rebreeding in cattle

Body weight and condition score, although perhaps imprecise or subjective, are functional indicators of energy status and rebreeding performance after calving. Inadequate precalving and(or) postcalving energy or protein nutrition lowers pregnancy rates as well as first-service conception rates and extends postpartum intervals in suckled postpartum beef females. Normal nutritional regimens for dairy cows that are fed for maximal lactation do not exhibit long postpartum intervals or reduced fertility. Yet excessive protein intake may depress postpartum rebreeding performance, especially in older dairy cows. Feeding of ionophores, with increased ruminal propionate levels in the rumen, results in an earlier return to estrus postpartum. Underfeeding of the postpartum cow extends the period of ovarian inactivity. The underfed postpartum cow's lack of ovarian activity appears to be due to a suppression of the pulsatile release of LH from the anterior pituitary gland, which in turn is controlled by release of GnRH from the hypothalamus. Some metabolic compound(s) presumably act on the hypothalamic-pituitary-ovarian axis as the nutritional state of the animal is altered.     

Mycoplasma bovis infections in Swiss dairy cattle: a clinical investigation

Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.     

Disposition of ampicillin trihydrate in plasma,uterine tissue,lochial fluid,and milk of postpartum dairy cattle

The objective of this study was to determine the disposition of ampicillin in plasma, uterine tissue, lochial fluid, and milk of postpartum dairy cattle. Ampicillin trihydrate was administered by intramuscular (i.m.) injection at a dose of 11 mg/kg of body weight every 24 h (n = 6, total of 3 doses) or every 12 h (n = 6, total of 5 doses) for 3 days. Concentrations of ampicillin were measured in plasma, uterine tissue, lochial fluid, and milk using HPLC with ultraviolet absorption. Quantifiable ampicillin concentrations were found in plasma, milk, and lochial fluid of all cattle within 30 min, 4 h, and 4 h of administration of ampicillin trihydrate, respectively. There was no significant effect of dosing interval (every 12 vs. every 24 h) and no significant interactions between dosing interval and sampling site on the pharmacokinetic variable measured or calculated. Median peak ampicillin concentration at steady‐state was significantly higher in lochial fluid (5.27 μg/mL after q 24 h dosing) than other body fluids or tissues and significantly higher in plasma (3.11 μg/mL) compared to milk (0.49 μg/mL) or endometrial tissue (1.55 μg/mL). Ampicillin trihydrate administered once daily by the i.m. route at the label dose of 11 mg/kg of body weight achieves therapeutic concentrations in the milk, lochial fluid, and endometrial tissue of healthy postpartum dairy cattle.     

A brief review and observations on clinical ketosis in non-lactating pregnant dairy cattle

The carbohydrate and glucose metabolism is briefly discussed. A review is given of the aetiology of the different types of ketosis in ruminants with the emphasis on the cow. Clinical ketosis in non-lactating pregnant animals is highlighted in a study of 20 cases, 16 in-calf heifers and four three-year-old cows. Fourteen animals had primary clinical ketosis thought to be mainly due to underfeeding. Six animals-had secondary clinical ketosis and were suffering from accompanying primary diseases. Treatment and possible causative factors are discussed. The introduction of heifers into mobs of older cows together with the change from free grazing to being break fed seems to be a major cause of underfeeding and stress.