Evaluation of risk factors for development of catheter-associated jugular thrombophlebitis in horses: 50 cases (1993-1998)

OBJECTIVE: To evaluate risk factors associated with development of catheter-associated jugular thrombophlebitis in hospitalized horses. DESIGN: Retrospective case-control study. ANIMALS: 50 horses with thrombophlebitis and 100 control horses. PROCEDURE: Medical records from 1993 through 1998 were searched for horses with thrombophlebitis. Horses that were hospitalized for at least 5 days, had an i.v. catheter placed in a jugular vein (other than for solely anesthetic purposes), and had no evidence of thrombophlebitis during admission or hospitalization were chosen as controls. Signalment, history, clinicopathologic findings, primary illness, and treatment were obtained from the medical records. Data were analyzed by use of logistic regression to perform univariate and multivariate analyses. RESULTS: For a horse with endotoxemia, the odds of developing thrombophlebitis were 18 times those for a similar horse without endotoxemia. For a horse with salmonellosis, the odds of developing thrombophlebitis were 68 times those for a similar horse without salmonellosis. For a horse with hypoproteinemia, the odds of developing thrombophlebitis were almost 5 times those for a similar horse without hypoproteinemia. For a horse in the medicine section, the odds of developing thrombophlebitis were 16 times those for a similar horse in the surgery section. For a horse with large intestinal dise, the odds of developing thrombophlebitis were 4 times those for a similar horse without large intestinal disease. For a horse receiving antidiarrheal or antiulcerative medications, the odds of developing thrombophlebitis were 31 times those for a similar horse not receiving these medications. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that patient factors, including large intestinal disease, hypoproteinemia, salmonellosis, and endotoxemia, were associated with development of catheter-associated thrombophlebitis in horses.     

Complications of blind-stitch abomasopexy: 20 cases (1980-1985)

Over a 5-year period, 20 adult Holstein cows were admitted to the New York State College of Veterinary Medicine because of complications following blind-stitch percutaneous abomasopexy for correction of left-displaced abomasum. Of the 20 cows, 16 were treated surgically, 2 were treated medically, and 2 were admitted to the pathology service for necropsy. Complications associated with the blind-stitch technique included peritonitis, cellulitis, abomasal displacement or evisceration, complete forestomach obstruction, and thrombophlebitis of the subcutaneous abdominal vein. Because of the various complications associated with blind-stitch percutaneous abomasopexy, we concluded that it is not an appropriate procedure for correction of left displaced abomasum in valuable cattle, but may be used as an alternative for salvage in less valuable cows.     

Long-term jugular vein catheterization in horses

The use of soft catheter materials in large-bore veins has allowed safe long-term venous access in human patients. Similar principles were applied to groups of horses; the jugular vein was catheterized for 14 days (group 1) and for 30 days (group 2). Three catheter materials were compared, and the clinical and histologic findings indicated that the least reaction was associated with silastic, followed by polyurethane; polytetraflouroethylene caused marked reaction. Our results suggest that by using catheters made of materials (especially silastic) that are less stiff or rigid, the duration of catheterization can be increased to 14 days or longer with minimal complications.     

Gross and histopathological observations of long-term catheterized vessels in experimental sheep

Chronic indwelling central vessel catheters provide vascular access for compartmental infusion or sampling. However, complications with catheter patency during the postoperative and/or experimental period often arise. In order to identify physiological occurrences common with such complications, 10 multicatheterized sheep (61.8 +/- 7.8 kg BW), obtained from a previous nutrient flux study were used for gross and histopathological investigation. Catheters had been surgically placed in a hepatic portal vein (PVC), a hepatic vein (HVC), a distal mesenteric vein (MVC) and a mesenteric artery (MAC). In the previous study, catheters (PVC, HVC and MAC) were used to collect blood samples or infuse (MVC) p-aminohippurate. Catheters were maintained for a total of 58 days prior to necropsy. Histopathological findings indicated that catheter failures were associated with the following tissue responses: (i) thromboses with frequent focal vasculitis; (ii) euplastic tissues associated with extensive fibrosis; (iii) granulomas; (iv) neo-vascularization of the media; (v) calcification processes; and (vi) micro-abscesses. Additional studies are needed that address and incorporate improvement of catheter design and placement to minimize irritation of endothelium, improvement of catheter treatments and therapeutic regimes, and development and use of alternative anti-coagulants. A greater understanding of the mechanisms leading to failure will help researchers improve catheter performance and patency.     

高产奶牛孕检后同期发情程序选择的研究

为了研究适用于高产奶牛的同期发情程序方案,将218头膘情良好、子宫和卵巢发育正常的不同胎次荷斯坦牛随机分成两组,试验1组为106头,试验2组为112头,分别采用两种同期程序(0.5.6.8和0.7.8.9)进行处理,测定情期受胎率,用于评价两种同期程序对高产奶牛的适用性.结果表明,试验2组情期受胎率平均为41.96％,...     

Peripartum changes in plasma estrone sulfate and estradiol-17beta profiles associated with and without the retention of fetal membranes in holstein-friesian cattle

The aim of this study was to evaluate the changes in plasma concentrations of estrone sulfate (E(1)S) and estradiol-17beta (E(2)beta) during the peripartum period (from day 10 prepartum to day 1 postpartum) associated with and without retention of fetal membranes (RFM) in Holstein-Friesian cattle (n=42). Plasma samples were analyzed for E(1)S and E(2)beta by ELISA. All parturitions were spontaneous and normal. Of 38 cattle delivering singletons, 29 had no RFM (singleton-normal group) and nine had RFM for more than 12 h (singleton-RFM group). Four cows gave birth to twins, and each twin had its own fetal membrane (FM). Two twinning cows expelled both FMs normally within 12 h (twin-normal group). In the remaining 2 twinning cows (twin-RFM group), the FM was expelled normally for one twin (first), while the FM of the other (second) was retained. There were no significant differences in the E(1)S concentrations or their increments from the concentrations on the preceding day between the normal and RFM groups of singleton cows on any peripartum day. The mean plasma E(2)beta concentrations on each day from day 10 to day 3 prepartum were significantly lower (P<0.05) in the singleton-RFM group compared with the singleton-normal group; however, on days 2 and 1 prepartum, the increments in the E(2)beta concentrations from the concentrations on the preceding days were significantly higher (P<0.05) in the singleton-RFM group than in the singleton-normal group. Thus, the plasma E(1)S concentrations just before parturition may not be associated with RFM. In the cows with RFM, the lower plasma E(2)beta concentrations that were found prior to day 2 prepartum may have been associated with immature placentomes, and the rapid rise in plasma E(2) beta within 1 to 2 days prior to calving may have produced asynchrony of placental and/or fetal maturation in relation to calving, thus resulting in RFM.     

Management practices associated with udder health of first-parity dairy cows in early lactation

This study aimed at investigating associations between management routines including feeding, housing, and milking around calving, and udder health of first-parity cows in early lactation in Swedish large, high producing, low bulk-milk somatic cell count (SCC) dairy herds housed in free stalls. Seventy-two dairy herds participated and data concerning 1189 first-parity cows calving during the study period (October 2005-January 2006) was collected. Multivariable regression analysis were performed with three different outcomes; within-herd number of first-parity cows veterinary treated for clinical mastitis at days -10 to 60 after calving, within-herd number of first-parity cows with a SCC> or =200,000cells/mL at first test-day, and SCC of first-parity cows at first test-day. Cow factors significantly associated with good udder health of first-parity cows (few cases of clinical mastitis and or low SCC) were being of the Swedish Red breed, having a high milk yield at first test-day, and a milk-urea > or =5mmol/L at first test-day. Herd factors significantly associated with good udder health were having mattresses as flooring in the cubicles in the lactating cow housing, and to house the first-parity cows in tie stalls 1 month before calving. Cow factors significantly associated with poor udder health of first-parity cows were having a milk-urea <4mmol/L at first test-day. Herd factors significantly associated with poor udder health of first-parity cows were feeding first-parity cows sugar-beet pulp or corn silage, and to give silage from a different batch to pregnant heifers than to lactating cows. Moreover, to have sawdust or shavings in the calving pen, to be moved from the calving pen > or =2 days after calving, to milk first-parity cows at the calving site instead of in the parlor, and to rinse, clean or disinfect milking units before a first-parity cow was milked were also significantly associated with poor udder health of first-parity cows. The results indicate that different control measures must be taken depending on the nature of the udder health problem.     

Immune responses during the peripartum period in dairy cows with postpartum endometritis

Determining the immune responses to the development of endometritis during the peripartum period may assist in the development of more efficient reproductive management regimens for dairy herds. In this study, we compared the peripartum immune responses of dairy cows that develop endometritis by 4 weeks postpartum (n = 11) to cows that did not develop this disease (n = 19). Blood samples were collected 1 week before calving, just after or during calving, and then at weeks 1, 2, 3, and 4 postpartum. Cows that developed endometriris had significantly higher total leukocyte, neutrophil, lymphocyte, and monocyte counts than the control cows (P < 0.05) at all time points. The leukocytes from cows that developed endometritis were significantly less phagocytic than those from control cows at all sampling time points (P < 0.01). The serum TNFalpha concentrations of the control cows decreased linearly from the prepartum time point (P = 0.0029), but the endometritis cows showed a different profile (P > 0.05). As a result, the serum TNFalpha concentrations were greater in the endometritis group (P < 0.01) than in the control group during the third and fourth weeks postpartum. The greater total leukocyte numbers and neutrophil, lymphocyte and monocyte counts, and the maintenance of elevated serum TNFalpha levels in the cows with endometritis may be due to infection in the postpartum period. Furthermore, the decreased phagocytic capacity of leukocytes during the peripartum period, including at the prepartum time point, makes cows more susceptible to postpartum endometritis.     

A study of the dynamics of digital dermatitis in 742 lactating dairy cows

Digital dermatitis (DD) is a contagious disease of cattle affecting the skin of the claw. The disease presents with a range of severities and can be associated with lameness. Information about the disease dynamics of DD is scarce. Parity and lactation stage have been identified as risk factors for DD and studies have also indicated that not all cows are equal regarding their risk of recurrent disease and prospects for cure from DD. The aim of this study was to investigate host heterogeneity to DD and to identify disease patterns of DD and factors associated with the development and resolution of lesions. In three commercial dairy herds, 742 lactating cows were observed for DD lesions weekly for 11 or 12 weeks. The effects of parity, lactation stage and duration of preceding episode on the hazard of transitions between healthy and lesion states were analysed using a multilevel multistate discrete-time model. One or more DD lesions were observed in 460 cows and lesions were observed in 2426 out of 10,585 observations. In total, 1755 uncensored episodes with DD lesions were observed. Early lactation was associated with a reduced risk of developing lesions compared with mid and late lactation. Lesions that developed in late lactation had a greater likelihood of resolution compared with lesions that developed during early lactation. There was a reduced risk of lesions developing in parity 3 compared with parity 1 cows, but an increased risk of lesions developing in parity 2 compared with parity 1 cows. In the present study, the mean duration of uncensored DD episodes was 1.7 weeks indicating that the duration of the majority of DD lesions might be shorter than the 42 days reported previously. The transitions between disease states suggest that DD is a dynamic disease, and that the early stage lesions are more transient than expected from previous studies. We conclude that studies with shorter observation intervals than one week are needed to fully understand and describe the individual and group dynamics of DD.     

Preventive effect of mildly altering dietary cation-anion difference on milk fever in dairy cows

In the present study, we examined whether mildly altering dietary cation-anion difference (DCAD) contributes to the prevention of milk fever in dairy cows. Thirty multiparous cows and ten primiparous cows (heifer group) were used in this study and the multiparous cows were randomly divided into three groups of ten animals each (anion, non-anion and control groups). The cows in the anion group were given supplemental salts that slightly lowered DCAD. These salts consisted of 115 g of CaCO3, 42 g of CaHPO4, 65 g of MgSO4 x 7 H2O and 80 g of CaCl2 x 2 H2O as a daily dose for each cow, using a catheter from 21 days before the expected date of parturition until parturition. The cows in the non-anion group were given only the same Ca, Mg and ip supplement but no sulfate and chloride salts as that in the anion group. The cows in the control and heifer groups were not given any additional supplement. The incidence of hypocalcemia in the anion group decreased to approximately half of those in the non-anion and control groups, while the heifer group did not develop hypocalcemia at all. In addition, the number of days spent for the treatment of hypocalcemia and the number of drug bottles (calcium borogluconate solution) used for the treatment decreased to less than half in the anion group compared with those in the non-anion and control groups. At parturition, the serum Ca concentration in the control (6.2 +/- 1.9 mg/dl, mean +/- standard deviation) and non-anion groups (6.4 +/- 1.7 mg/dl) were significantly lower than that in the heifer group (8.3 +/- 0.4 mg/dl), and the level in the anion group was intermediate (7.3 +/- 1.3 mg/dl). The change in ionized Ca concentration was almost the same as that in serum Ca concentration, but only the concentration in the anion group tended to increase slightly from a week before parturition and was significantly higher than that in all other groups three days before parturition. Urinary pH in the anion group was maintained at a mildly acidic level (6.8-7.0) for the last two weeks before parturition, compared with those in the control (7.3-7.5) and non-anion groups (7.9-8.1), and similar to that in the heifer group (6.3-7.3). The urinary Ca excretion was the highest in the anion group among all groups during the prepartum period. There were no specific changes in the excretion of parathyroid hormone and 1,25-dihydroxyvitamin D in all groups of multiparous cows while the levels of these hormones remained low in the heifer group throughout the experimental period. The data in the present study indicates that the administration of anion salts that slightly lowered DCAD in the preparum period was effective for preventing milk fever in multiparous cows. Safe and mild metabolic acidosis induced by the anion salts could be evaluated by urinary pH (6.8-7.0), and might increase the responsiveness to Ca requirement at parturition through some complex mechanisms unrelated to the excretion of Ca-related hormones. In addition, it was clarified that primiparous cows have a high potential to respond to sudden Ca demand unrelated to hormone excretion, and their Ca metabolism was in some respects similar to that in multiparous cows fed anion salts. Therefore, manipulating mildly DCAD is expected to be an effective, safe and natural method for preventing milk fever in dairy cows.     

Efficacy of using an internal teat sealer to prevent new intramammary infections in nonlactating dairy cattle

OBJECTIVE: To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period. DESIGN: Controlled clinical trial. ANIMALS: 939 Holstein-Friesian dairy cows from 16 herds. PROCEDURES: Results of bacteriologic culture of milk samples collected 14 days prior to the end of lactation were used to assign cows to groups (group 1 = negative results for all quarters; group 2 = positive results for > or = 1 quarter). Quarters of cows in group 1 were treated with an ITS or a single intramammary dose of cloxacillin; quarters of cows in group 2 were treated with cloxacillin in conjunction with an ITS or with cloxacillin alone. Milk samples were collected at the end of lactation and within 8 days after calving. RESULTS: Regardless of whether the outcome of interest was new IMIs caused by any pathogens, major pathogens, environmental pathogens, or streptococci other than Streptococcus agalactiae, quarters in group 2 treated with both cloxacillin and an ITS were less likely to develop a new IMI than were quarters treated with cloxacillin alone. For cows in group 1, no significant difference in risk of new IMIs was found between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for dairy cattle with an IMI late in the lactation period, intramammary administration of cloxacillin at the end of lactation followed by insertion of an ITS enhanced protection against development of new IMIs, compared with use of cloxacillin alone.     

Dietary factors associated with milk somatic cell counts in dairy cows in Brittany, France

A survey (Enquête Ecopathologique Bretagne) was conducted in France for 4 years (1986–1990) in 48 commercial dairy herds (25–80 cows per herd) located in Brittany. Three groups of herd-years were made up to study peripartum dietary factors associated with milk somatic cell counts in the early lactation period (ECC). The first group included 20 herd-years with high ECC (over 400 000 cells ml⁻¹). The second group included herdyears with medium ECC (n = 20, median ECC 222 000) and the last group herd-years with low ECC (n = 20, median ECC 95 000). Herd data (components of the diet, milk yield and reproduction parameters, clinical diseases, biochemical and hematological indicators, body and dirtiness scores) were analyzed using discrimination by barycentric analysis. Two separate analysis were conducted according to study period (LG period, last 60 days of gestation; EL period, first 60 days of lactation).

The high ECC group had the following characteristics: (1) higher plasma gamma glutamyl transferase levels in the LG period; (2) higher quantities of cereal-based concentrates in the diet in the EL period; (3) shorter durations of feeding with Italian rye grass silage in the EL period. The relevance of the risk factors for high ECC are discussed with reference to dietary linolenic acid/linoleic acid ratio (through the synthesis of leukotrienes as chemotactic agents for the polymorphonuclear leukocytes), dietary energy supplies and liver fluke infestation in the herds. We speculate that nutritional factors could modulate the leukocyte activity in the milk and that supplementations with certain polyunsaturated fatty acids would be able to prevent the development of inflammation in the udder.     

Effects of long-term dietary supplementation with clinoptilolite on incidence of parturient paresis and serum concentrations of total calcium, phosphate, magnesium, potassium, and sodium in dairy cows

OBJECTIVE: To determine whether dietary supplementation with clinoptilolite affects the incidence of parturient paresis and serum concentrations of total calcium (tCa), inorganic phosphorus (PO(4) (2)), magnesium (Mg2+), potassium (K+), and sodium (Na+) in dairy cattle. ANIMALS: 52 dairy cows. Procedure-Cows were placed into 3 groups. The first 2 groups (group A [n = 17] and group B [17]) were offered a concentrate supplemented with 1.25% and 2.5% clinoptilolite, respectively. The third (group C [n = 18]) served as a control and was offered the concentrate alone. The experiment started 1 month before parturition and lasted until the beginning of the next nonlactating period. Around the time of calving, all cows were monitored for the development of parturient paresis. Blood samples were taken at the commencement of the experiment, on the day of calving, and thereafter at monthly intervals to measure serum tCa, PO(4) (2), Mg2+, K+, and Na+ concentrations. Results-The incidence of parturient paresis in group B cows was significantly lower, compared with group C cows. However, serum concentrations of tCa, P(O4) (2), Mg2+, K+, and Na+ were not significantly affected by long-term supplementation with clinoptilolite. CONCLUSIONS AND CLINICAL RELEVANCE: In the context of this experiment, clinoptilolite supplementation at 2.5% appeared to have reduced the incidence of parturient paresis in dairy cows, suggesting that its effectiveness depends on the amount incorporated in the ration of cows. Addition of clinoptilolite in the concentrate of dairy cows during the nonlactating period could be used as a cost-effective preventive treatment for parturient paresis.     

Reproductive Performance in Cows with Extended Calving Interval*

Contents The effects of increased calving intervals on reproduction were studied in two herds. In Herd 1 cows were managed for 12‐ or 15‐month calving intervals and in Herd 2 for 12‐ or 18‐month intervals. Data from the study revealed that managing cows for a longer calving interval improved the fertility. Animals with a short interval needed more hormonal treatments to be inseminated on time due to anoestrus, compared to animals with longer intervals. Once the animals were inseminated there was a tendency for a higher conception rate at first AI in the 15‐month group compared with the 12‐month group. The cows in the 15‐month group needed a lower number of AIs per serviced cow and a shorter period from the first AI to conception. Culling due to fertility problems was more frequent in the 12‐month group. A longer period of days open did not imply an increased risk for development of cystic ovaries and did not result in weaker heat symptoms over time.     

饲料营养对母牛繁殖率影响效果研究

通过对妊娠后期（后１４２ｄ）母牛、带犊哺乳母牛的不同阶段饲料营养配合试验,探讨母牛的饲养技术方案。选择条件大致相同的妊娠后期母牛３６头,随机分为试验１、２组和对照组各１２头。试验１组和试验２组根据妊娠月份及粗饲料种类不同,粗饲料日喂量各有所调整,对照组牛则采用当地的传统饲养方式。试验结果,试验１组母牛产仔成活１１头,哺乳期平均１１７ｄ,断奶成活１０头,繁殖成活率８３．３％,母牛产后开始发情时间平均     

Biomarkers for the activation of calcium metabolism in dairy cows: elevation of tartrate-resistant acid phosphatase activity by lowering dietary cation-anion difference is associated with the prevention of milk fever

In our previous study, it was demonstrated that the administration of anion salts, which slightly lower the dietary cation-anion difference (DCAD), in the prepartum period is safe and effective for preventing milk fever in multiparous cows. In the present study, several biomarkers, which might show activation of Ca metabolism, were analyzed using stored samples in the previous study to investigate the mechanism of the preventive effect on milk fever by lowering DCAD. Changes in bone-specific alkaline phosphatase activity, osteocalcin and insulin-like growth factor I concentrations in serum were almost the same among the three groups of multiparous cows with or without the oral administration of anion salts, while the levels of these serum biomarkers in the group of primiparous cows (heifer group) were much higher compared with those in the three multiparous groups throughout the experimental period. Urinary deoxypyridinoline excretion was not a useful biomarker for dairy cows because it hardly changed during the peripartum period in all groups. However, serum tartrate-resistant acid phosphatase (TRAP) activity, which is known as a biomarker of osteoclast activity, was well associated with the administration of anion salts lowering DCAD because among the three multiparous groups, only the group of multiparous cows fed the anion salts (anion group) showed an increased level, which rose to the level in the heifer group, and was markedly higher than those in the other control groups of multiparous cows. The increased activity of serum TRAP in the anion group suggested that Ca in the plasma pool was mobilized smoothly from bone-bound Ca via mature osteoclasts at parturition, which might be due to prior activation under mild acidosis induced by slightly lowering DCAD. Therefore, TRAP was the best biomarker to monitor the activation of Ca metabolism in dairy cows fed anion salts.     

Pulmonary thromboembolism in cats

Pulmonary thromboembolism (PTE) is rarely diagnosed in cats, and the clinical features of the disease are not well known. PTE was diagnosed at postmortem examination in 17 cats, a prevalence of 0.06% over a 24-year period. The age of affected cats ranged from 10 months to 18 years, although young (<4 years) and old (>10 years) cats were more commonly affected than were middle-aged cats. Males and females were equally affected. The majority of cats with PTE (n = 16) had concurrent disease, which was often severe. The most common diseases identified in association with PTE were neoplasia, anemia of unidentified cause, and pancreatitis. Cats with glomerulonephritis, encephalitis, pneumonia, heart disease, and hepatic lipidosis were also represented in this study. Most cats with PTE demonstrated dyspnea and respiratory distress before death or euthanasia, but PTE was not recognized ante mortem in any cat studied. In conclusion, PTE can affect cats of any age and is associated with a variety of systemic and inflammatory disorders. It is recommended that the same clinical criteria used to increase the suspicion of PTE in dogs should also be applied to cats.     

The scintigraphic evaluation of the pulmonary perfusion pattern of dogs hospitalised with babesiosis

The possibility of coagulopathy in Babesia canis rossi infections in the canine patient has been suggested in the literature, but minimal work has been done to evaluate the clinicopathological nature of it in further detail. Pulmonary thromboembolism (PTE) has not yet been implicated in canine babesiosis (CB), but may also be one of the causes of the sudden dyspnoea and tachypnoea that are frequently seen in complicated CB patients. The objective of this study was to prospectively evaluate the scintigraphic pulmonary perfusion pattern in hospitalised dogs with babesiosis in an attempt to ascertain whether a scintigraphic pattern consistent with clinically relevant PTE does indeed occur in these patients. The study consisted of a normal control group of 9 mature healthy Beagle dogs (group 1) and a Babesia group with 14 dogs of a variety of breeds that were naturally infected with Babesia (group 2). Pulmonary perfusion scintigraphy was performed after making thoracic radiographs and performing a blood gas analysis in both groups. The scintigraphic images were visually inspected for changes suggestive of PTE, but not a single dog in group 2 had pleural-based, wedge-shaped perfusion defects which would have resulted in a high probability for clinically relevant PTE. The scintigraphic pulmonary perfusion pattern demonstrated was not significantly different between the 2 groups (P = 1.00).     

Effects of Full-Length Kisspeptin Administration on Follicular Development in Japanese Black Beef Cows

Kisspeptin is a key molecule that stimulates gonadotropin secretion via release of gonadotropin-releasing hormone (GnRH). In the present study, our aim was to investigate whether kisspeptin has stimulatory effects on follicular development via GnRH/gonadotropin secretion in cows. Japanese Black beef cows were intravenously injected with full-length bovine kisspeptin [Kp-53 (0.2 or 2 nmol/kg)] or vehicle 5 days after they exhibited standing estrus (Day 0). In cows injected with Kp-53 at 2 nmol/kg, the follicular sizes of the first dominant follicles increased on Day 6 and thereafter. Ovulation of the first dominant follicle occurred in 1 out of 4 cows treated with Kp-53 at 2 nmol/kg. Injection of Kp-53 at 2 nmol/kg increased the concentration of plasma luteinizing hormone (LH) but not follicle-stimulating hormone, over a 4-h period following injection in all cows. The present study suggests that administration of full-length kisspeptin causes LH secretion, which is sustained for a few hours, and it is capable of stimulating follicular development and/or ovulation.     

不同全株玉米青贮饲喂量对妊娠期母牛体况、血液指标及后代犊牛的影响

试验旨在研究全株玉米青贮饲喂量及精粗饲料配比对妊娠期母牛体况、血液指标及后代犊牛的影响。选用40头体重相近、2岁、1胎的妊娠期7个月左右的西门塔尔母牛,随机分为4组,每组10头,试验期3个月。Ⅰ组每头每天饲喂全株玉米青贮14 kg、燕麦秸1 kg、精料补充料3 kg,Ⅱ组每头每天饲喂全株玉米青贮19 kg、燕麦秸1 kg、精料补充料1 kg,Ⅲ组每头每天饲喂全株玉米青贮19 kg、燕麦秸2 kg,Ⅳ组每头每天饲喂全株玉米青贮22 kg、燕麦秸1 kg。产犊后各组母牛统一更换为泌乳料,母牛带犊哺乳,6月龄断奶。结果表明:Ⅳ组的干物质摄入量低于Ⅰ组(P<0.05);Ⅲ组和Ⅳ组的氮摄入量低于其他组(P<0.01),Ⅰ组最高(P<0.01);Ⅲ组的纤维摄入量高于其他组(P<0.01);各组体况评分无差异;妊娠期7月末,Ⅳ组血液锰含量低于其他组(P<0.05);妊娠期9月末,Ⅲ组和Ⅳ组的血清尿素氮含量低于其他组(P<0.01);Ⅳ组母牛所产犊牛的胸围低于Ⅰ组和Ⅱ组(P<0.05),且有3头因生长缺陷被淘汰;6月龄时,各组犊牛体况指标无差异。综上,推荐肉牛能繁母牛妊娠后期每日提供全株玉米青贮19 kg、燕麦秸1~2 kg、精料补充料0~1 kg。