上海某奶牛养殖专业合作社结核病的暴发调查

上海市某奶牛养殖专业合作社检出14头结核病阳性牛。为查明疫病发生状况,调查疫病可能的发生原因,提出针对性的防控措施,通过现场座谈、问卷调查、实地查看和档案资料查阅等方式开展了暴发调查。结果发现本次暴发调查与奶牛引进有关,历年来检测发现的结核病阳性牛和疑似牛未采取有效的隔离、淘汰处置措施,从而导致了结核病的场内循环。建议立即扑杀和无害化处理结核病阳性牛,加强环境消毒,加大结核病监测频率和力度,同时做好工作人员的结核病健康检查。     

An outbreak of sand impaction in postpartum dairy cows

Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal impaction, diagnosed by laparotomy. The pH of prepartum cows' urine was < 6.0 and of sand 8.0. Feed showed a dietary cation-anion difference < or = -110 mEq/kg. After feeding management corrections, no more cases were diagnosed.     

Hepatic lipidosis in pregnant cows on a dairy farm

Summary

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period.

After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Phosphorus supplementation of lactating dairy cattle on a Northland farm

Forty-eight Friesian or Friesian-X factory supply dairy cows were divided into two groups. Group 1 received a supplement of sodiumtripolyphosphate (TPP, 25g P, 25g Na/cow/day), and group 2 a supplement of sodium chloride (25g Na/cow/day). Supplementation began at peak lactation, when the mean serum inorganic phosphorus (Pi) of all cows was 1.13 mmol/l. After four weeks, group 2 changed from NaCl to dicalcium phosphate supplementation (25g P/cow/day). Serum Pi and yields of milk, butterfat and protein were measured before, during and after supplementation. Pasture availability was assessed and P and Ca contents in pasture and the Pi content in milk were also determined. Supplementation raised serum Pi from 1.30 mmol/l (NaCI) to 1.42 mmol/l (TPP, P<0.05) but when dicalcium phosphate replaced NaCl the difference between groups disappeared (P>0.05). P supplementation had no effect on any milk parameter. Pre-grazing pasture mass above estimated grazing height averaged 2260 kg DM and contained >or=0.39 per cent P. It is concluded that a herd mean serum Pi concentration of around 1.2-1.3 mmol/l imposes no limitation to dairy production around the period of peak lactation of grazing dairy cattle.     

Phosphorus supplementation of lactating dairy cattle on a Northland farm

Abstract

Forty-eight Friesian or Friesian-X factory supply dairy cows were divided into two groups. Group 1 received a supplement of sodiumtripolyphosphate (TPP, 25g P, 25g Na/cow/day), and group 2 a supplement of sodium chloride (25g Na/cow/day). Supplementation began at peak lactation, when the mean serum inorganic phosphorus (Pi) of all cows was 1.13 mmol/l. After four weeks, group 2 changed from NaCl to dicalcium phosphate supplementation (25g P/cow/day). Serum Pi and yields of milk, butterfat and protein were measured before, during and after supplementation. Pasture availability was assessed and P and Ca contents in pasture and the Pi content in milk were also determined. Supplementation raised serum Pi from 1.30 mmol/l (NaCI) to 1.42 mmol/l (TPP, P<0.05) but when dicalcium phosphate replaced NaCl the difference between groups disappeared (P>0.05). P supplementation had no effect on any milk parameter. Pre-grazing pasture mass above estimated grazing height averaged 2260 kg DM and contained ?0.39 per cent P. It is concluded that a herd mean serum Pi concentration of around 1.2–1.3 mmol/l imposes no limitation to dairy production around the period of peak lactation of grazing dairy cattle.     

Hepatic lipidosis in pregnant cows on a dairy farm.

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Pharmacokinetics of sulphadiazine-trimethoprim in lactating dairy cows

Five Finnish Ayrshire cows in mid or end-lactation were treated with 40 mg sulphadiazine/kg and 8 mg trimethoprim/kg using intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) routes. Elimination of sulphadiazine was not affected by the route of administration (median t1/2 4.4-5.0 h) while elimination of trimethoprim was strongly limited by slow absorption from the injection site after s.c. and i.m. administration (median for apparent t1/2 21-25 h) compared to that after i.v. administration (median t1/2 1.2 h; p < 0.05). The median bioavailability of trimethoprim was also decreased, being 37% and 55% after s.c. and i.m. administration, respectively. When i.v. administration was used, trimethoprim concentration exceeded 0.1 mg/l in milk between 0.15-8 h while sulphadiazine concentrations above 2 mg/l were maintained from 0.5-2 h to 8 h. After s.c. and i.m. administration sulphadiazine in milk behaved similar to that after i.v. administration, while trimethoprim time-concentration curves were flat and trimethoprim concentrations were around 0.1 mg/l for an extended period of time (8-12 h). Median Cmax values in milk were only 0.07 mg/l and 0.10 mg/l for s.c. and i.m. administrations, respectively. After s.c. administration, 4 out of 5 cows showed signs of pain. After i.m. administration, 2 of the cows showed clear signs of pain and one had some local tenderness at the site of injection.     

Urinary pseudouridine excretion in lactating dairy cows

Introduction   A number of systems based on metabolizable protein, such as that adopted in the UK (A gricultural and F ood R esearch C ouncil 1992) have been developed to improve the accuracy of protein rationing for ruminants. Quantification of microbial protein synthesis in the rumen is a fundamental requirement of all such systems. In the UK system, microbial protein supply is predicted from an estimate of fermentable metabolizable energy intake, using a correction for the effects of level of feeding on the energetic efficiency of microbial protein synthesis. Use of such an approach is however subject to considerable error due to large variations in the energetic efficiency of microbial protein synthesis (A gricultural R esearch C ouncil 1984). Consequently there is an urgent requirement for an on-farm diagnostic marker of microbial protein supply as a basis for adjusting diets to maximize efficiency of dietary nitrogen utilization by dairy cows (D ewhurst et al. 1996). Urinary purine derivative excretion has been proposed as a noninvasive index of microbial protein supply in ruminant animals (T opps and E lliot 1965). Use of this microbial marker is based on the assumption that purines entering the duodenum are essentially microbial in origin (M c A llan 1982), and that following metabolism, their derivatives are quantitatively recovered in the urine (C hen et al. 1990; V erbic et al. 1990). Purine metabolites excreted in ruminant urine are primarily derived from the metabolism of absorbed purines, but as a consequence of tissue adenosine triphosphate and nucleic acid turnover, a proportion of purine bases are not salvaged and re-utilized, but enter catabolic pathways, constituting an endogenous loss.     

Pharmacokinetics of sodium cephapirin in lactating dairy cows

Sodium cephapirin was administered (10 mg/kg of body weight, IM) at 8-hour intervals in 4 consecutive doses to each of 6 lactating dairy cows. Blood, normal milk, mastitic milk, urine, and endometrial tissue samples were collected serially. Mean peak cephapirin concentrations in serum were 13.3 micrograms/ml 10 minutes after the 1st injection and were 15.8 micrograms/ml 20 minutes after the 4th injection (post[initial]injection hour [PIH] 24.33). The overall elimination rate constant value was 0.66/h and plasma clearance was 760 ml/h/kg. Mean peak cephapirin concentration in normal milk was 0.11 microgram/ml at PIH 2 and mean peak cephapirin concentration in mastitic milk was 0.18 microgram/ml at PIH 4. Cephapirin was not detected in the endometrium. The highest concentration of cephapirin in urine was 452 micrograms/ml, 2 hours after the 4th dose (PIH 26).     

Fractional excretion of electrolytes in lactating dairy cows.

Samples of serum and urine were obtained simultaneously from 56 healthy lactating cows to determine ranges of fractional excretion (FE) of calcium (Ca), phosphate (PO4), magnesium (Mg), sodium (Na), potassium (K), and chloride (Cl). Samples were obtained at 3 stages of lactation: period 1 = 1 to 7 days, 2 = 83 to 112 days, and 3 = 175 to 197 days. The FE of electrolytes were significantly different among periods 1, 2, and 3 for Ca (P less than 0.001), PO4 (P less than 0.025) and Mg (P less than 0.025), but were not significantly different for Na, K, and Cl. Least squares mean FE of Ca was lowest in period 1 and not significantly different for periods 2 and 3, whereas mean FE values for PO4 and Mg were highest in period 2 and not significantly different for periods 1 and 3. The mean FE values of Na, K, and Cl did not change with stage of lactation. Age and category of milk production (high, medium, and low) did not influence the FE values of the electrolytes.     

Anaplasmosis in a Swiss dairy farm: an epidemiological outbreak investigation

In summer of 2002, a case of severe clinical bovine anaplasmosis caused great losses in a dairy farm of an animal trader in Grisons. This article outlines the general approach of an outbreak investigation considering the case of anaplasmosis as an example. The goals of such investigations are to identify and eliminate the source of a disease outbreak in order to avoid additional cases. In addition, recommendations should be developed for preventing or limiting the magnitude of similar outbreaks in the future. In the outbreak presented, the causative agents were probably brought into the dairy farm by animal trade. Due to the large herd size, a missing quarantine for new animals and the coinfection with several pathogens, this case led to a high number of fatalities. The investigations of this outbreak demonstrated the importance of an universal and consistent identification of individual animals for the reconstruction of their movements. The veterinary practitioner should be reminded to act cautiously when facing strange clinical cases and to also consider "exotic diseases" as a possible cause.     

菊芋粕对泌乳奶牛的营养价值评定

选用6头2～3胎泌乳中期健康荷斯坦奶牛,采用3×3有重复拉丁方试验设计,通过消化试验就菊芋粕对泌乳奶牛的营养价值进行评定。试验设3个日粮处理,处理1为基础日粮,处理2为菊芋粕替代15%基础日粮(干物质基础),处理3为菊芋粕替代30%基础日粮(干物质基础)。结果表明,菊芋粕风干样品中干物质、粗蛋白、粗脂肪、粗纤维、中性洗涤纤维、酸性洗涤纤维、粗灰分、钙、磷和产奶净能分别为92.43%,12.98%,0.81%,12.67%,25.93%,21.44%,3.92%,0.27%,0.20%和 5.18 MJ/kg;菊芋粕对泌乳奶牛干物质消化率、粗蛋白消化率、中性洗涤纤维消化率、酸性洗涤纤维消化率分别为61.78%,73.21%,51.65%,61.14%,消化能和产奶净能分别为10.13和5.18 MJ/kg;3个处理组试牛产奶量和乳成分无显著差异(P>0.05),表明菊芋粕是一种营养价值略低但养分消化率较高的能量饲料。     

泌乳奶牛脂肪肝早期诊断的研究

为了寻找泌乳奶牛脂肪肝早期诊断方法,本研究从某千头奶牛场随机选取了30头乳酮阳性的奶牛,其中临床酮病牛10头,亚临床酮病牛20头,测定其肝脂含量以及血中代谢指标和肝功指标。试验结果表明,脂肪肝的奶牛存在能量负平衡现象,机体呈现高游离脂肪酸血症、高酮血症,肝脂浸润越重,能量代谢障碍越严重;乳酮阳性出现时间的早晚与脂肪肝的严重程度密切相关,乳酮阳性产后出现的越早,乳酮阳性越明显,肝脂浸润越重;随肝脂浸润程度的加重,肝功多个指标会出现异常,重度的脂肪肝会引发肝功能不全。本试验证明,酮粉法可以作为早期诊断奶牛脂肪肝的初选方法,肝功指标异常可作为诊断脂肪肝的辅助方法,两者结合可作为奶牛脂肪肝的实用、有效和准确的早期诊断方法,准确率可达80%。     

Effect of carbohydrate source on ammonia utilization in lactating dairy cows

This study was conducted to investigate the effect of dextrose, starch, NDF, and a carbohydrate (CHO) mix on utilization of ruminal ammonia in dairy cows. Four ruminally and duodenally cannulated Holstein cows (BW = 788 +/- 31 kg; 217 +/- 35 d in milk) were allocated to four treatments in a 4 x 4 Latin square design trial. Cows were fed an all alfalfa diet at 12-h intervals (DMI = 22.2 +/- 0.25 kg/d). Treatments were control, white oat fiber (NDF); corn dextrose (GLU); cornstarch (STA); and a CHO mix (25% of each): apple pectin, GLU, STA, and NDF (MIX). Carbohydrates were introduced intraruminally during feeding at 20% of dietary DMI. Ruminal ammonia was labeled with (15)N. Ruminal pH was the highest for NDF followed by STA and MIX and GLU (P < 0.001). Ruminal ammonia concentration and pool size were decreased by GLU and STA compared with NDF (P < 0.001 and P = 0.03, respectively). Acetate, isobutyrate, isovalerate, and total VFA concentration in the rumen were decreased (P = 0.009 to 0.001), and butyrate was increased (P < 0.001) by GLU compared with the other CHO. Microbial N flow to the duodenum was decreased (P < 0.05) by NDF compared with the other CHO, and the flow of microbial N formed from ammonia was greater for STA compared with GLU and NDF (P = 0.04 and 0.03, respectively). Urinary N loss was decreased (P = 0.05) by GLU and STA, but overall (feces plus urine) N losses were not affected (P = 0.73) by treatment. Milk urea concentration was lowered by GLU and STA compared with NDF and MIX (P = 0.002). The proportion of bacterial N synthesized from ammonia in the rumen was greater with STA than with NDF and MIX and was least for GLU (P = 0.02). Irreversible ammonia loss and flux were lower (P = 0.09 and 0.02, respectively) for GLU than for STA and NDF. As a percentage of the dose given, cumulative secretion of (15)N ammonia in milk protein was greater for STA than for GLU or NDF (P = 0.01 and 0.001, respectively). This experiment demonstrated that provision of readily fermentable energy can decrease ammonia concentrations in the rumen through decreased ammonia production (GLU), or through enhanced uptake of ammonia for microbial protein synthesis (STA). Rapidly fermentable energy in the rumen decreased ammonia production and flux, but the overall efficiency of ammonia utilization for milk protein synthesis was only increased by enhancing ruminal microbial ammonia uptake.     

Stability of plasma metabolites and hormones in lactating dairy cows

Plasma concentration stability of glucose, free fatty acids, ketone bodies, growth hormone, insulin were determined in lactating dairy cows. Concentrations of these metabolites and hormones were measured during a 36- to 48-hour period in 3 normal, mature dairy cows in the 2nd month of lactation. Samples were taken at 30-minute intervals; also, intensive sampling (every 10 minutes) was done at varying times in relation to feeding and milking. Of the 5 components measured, glucose concentration was the most stable, easiest to assay, and most reliable for use as a diagnostic aid in assessing metabolic carbohydrate disturbances in dairy cattle.     

日粮阴阳离子差在泌乳奶牛日粮中的应用

日粮阴阳离子差（DCAD）可调控家畜体内的酸碱平衡。近年来，由于其对泌乳奶牛生产性能的影响而越来越受到研究者的重视。文章就阴阳离子差的计算，阴阳离子差对泌乳奶牛干物质采食量、泌乳量和乳成分、瘤胃参数的影响，及对DCAD在我国泌乳奶牛日粮中的应用的展望作了综合阐述。     

Behavioural signs of oestrus during pregnancy in lactating dairy cows

Abstract

Two herds of approximately 50 dairy cows were observed for oestrous behaviour for 6 weeks, 12 times a day for 30 minutes. It appeared that 3.08% of the pregnant cows showed oestrous behaviour during pregnancy (EBP) in such an intensity that they would have been considered in oestrus. With a less rigid oestrus detection threshold, 10.8% of the pregnant cows would have been considered to be in oestrus. Animals showed EBP during all months of pregnancy, but most of the behavior was observed in the middle of the gestation period.     

Effects of contrasting forage diets on phosphorus utilisation in lactating dairy cows

The effects of different forage mixtures on duodenal flow and faecal output of phosphorus (P) were measured in lactating dairy cows in two experiments. The forages comprised grass silage (GS) alone or mixtures of GS and urea-treated whole crop wheat (WCW). Replacement of GS by high levels of WCW resulted in a significant decrease in total P (TP), water-soluble P (WSP) and acid-soluble P (ASP) intakes, but increased phytate P (PP) and acid-insoluble P (AIP) intakes. Duodenal flows of all P fractions were unaffected by dietary treatments. However, the amounts of all fractions flowing to the intestine were much higher than the amounts consumed—with the exception of AIP, which was unchanged, and PP, which was considerably reduced. Diets did not significantly affect faecal outputs of TP, ASP, PP and AIP; however, faecal outputs of WSP were significantly higher on WCW than GS diets. Inclusion of WCW significantly decreased TP and WSP availabilities in the total tract but did not affect PP and AIP availabilities. A new fraction of P, which was not present in the feeds, was found in significant amounts in the intestines and proved to be soluble in dilute acid but insoluble in water. Estimated annual excretions for a herd of 100 cows ranged from 1550 to 1721 kg for total P of which 337-786 kg was WSP. The results suggest that GS based diets deposit more P in the environment. However, the potential to cause P pollution depends not only on the quantity but also on the nature of faecal P and on soil parameters.