奶山羊乳房温度与体内外温度、泌乳性能的相关性研究

[目的] 随着奶山羊养殖行业的发展,规模化、集约化程度不断提高,如何能更便捷地对奶山羊的健康状况和生产性能进行有效评判,是提高奶山羊养殖效率的重要措施。[方法] 本试验通过测定奶山羊体内外温度、产奶量以及乳成分,分析乳房温度与体内外温度以及与泌乳性能之间的相关性。[结果] 发现乳房温度与舍温、额温有明显的相关性（P<0.01）,但与眼温和肛温之间没有显著相关性;此外,乳脂、非乳脂固形物与乳房温度之间也存在显著的相关性（P<0.01）。[结论] 乳房温度是一个很好的评价指标,可适宜地用于监测奶山羊健康状况和生产性能。     

Prevalence of subclinical udder infections and individual somatic cell counts in three dairy goat herds during a full lactation

For dairy goats, both the determination of the somatic cell counts (SCC) and the interpretation of these values may be a problem. Several investigations have shown that SCC for goat's milk, even from not infected mammary halves, are often higher than for cows milk. In the three herds examined about 40% of mammary halves and 30% of the goats were infected. However large differences between the three herds could be observed. In most cases, infections were caused by coagulase negative staphylococci (CNS) or corynebacteria. The SCC of individual milk samples from goats without any udder infection hardly differed from those of goats with at least one udder half infected with CNS. In 20% and 30% of the cases the SCC was higher than 750'000 cells/ml, respectively. The relation between California Mastitis Test (CMT) reactions and udder infections was not very close. Over 20% of mammary halves infected with CNS showed negative CMT reactions. On the other hand, 25% of samples from mammary halves without a proven infection reacted positively. The large differences in individual cell counts on herd and animal level indicate that production and breeding systems might be important reasons for the higher SCC. As a consequence, the most common methods for or the control of udder health and udder infections (SCC, California Mastitis Test) are of limited value for goats. Since there was only a weak relation between milk quality properties and SCC, any arguments for the introduction of legal limits below 1 million cells per ml can hardly be found.     

Direct and indirect measurement of somatic cell count as indicator of intramammary infection in dairy goats

Background

Mastitis is the most important and costly disease in dairy goat production. Subclinical mastitis is common in goats and is mainly caused by contagious bacteria. Several methods to diagnose subclinical mastitis are available. In this study indirect measurement of somatic cell count (SCC) by California Mastitis Test (CMT) and direct measurement of SCC using a portable deLaval cell counter (DCC) are evaluated. Swedish goat farmers would primarily benefit from diagnostic methods that can be used at the farm. The purpose of the study was to evaluate SCC measured by CMT and DCC as possible markers for intramammary infection (IMI) in goats without clinical symptoms of mastitis. Moreover to see how well indirect measurement of SCC (CMT) corresponded to direct measurement of SCC (DCC).

Method

Udder half milk samples were collected once from dairy goats (n = 111), in five different farms in Northern and Central Sweden. Only clinically healthy animals were included in the study. All goats were in mid to late lactation at sampling. Milk samples were analyzed for SCC by CMT and DCC at the farm, and for bacterial growth at the laboratory.

Results

Intramammary infection, defined as growth of udder pathogens, was found in 39 (18%) of the milk samples. No growth was found in 180 (81%) samples while 3 (1%) samples were contaminated. The most frequently isolated bacterial species was coagulase negative staphylococci (CNS) (72% of all isolates), followed by Staphylococcus aureus (23% of all isolates). Somatic cell count measured by DCC was strongly (p = 0.000) associated with bacterial growth. There was also a very strong association between CMT and bacterial growth. CMT 1 was associated with freedom of IMI while CMT ≥2 was associated with IMI. Indirect measurement of SCC by CMT was well correlated with SCC measured by DCC.

Conclusions

According to the results, SCC measured with CMT or DCC can predict udder infection in goats, and CMT can be used as a predictor of the SCC.     

Increase of lactoferrin concentration in mastitic goat milk

Lactoferrin concentration (LFC) in normal and mastitic milk of dairy goats were examined. LFC in bulk milk collected from 70 dairy goat farms and individual milk samples from 10 goats with mastitis were measured by enzyme-linked immunosorbent assay (ELISA) and their reaction time in methylene blue reduction test (MBRT) monitored. Bulk milk samples were categorized into three grades, such as high, normal and low, based on the reaction time in MBRT. The mean LFC in milk that was considered high quality (167 microg/ml) was significantly lower than that of those graded as normal (218 microg/ml) and low quality (304 microg/ml), while mean LFC in mastitic milk was 587 microg/m l. The correlation coefficient between milk LFC and MBRT time was found to be -0.7. Three goats were inoculated with Staphylococcus aureus into one of their udder halves. The mean milk LFC was found to be significantly higher (1500 microg/ml) than the control (30 microg/ml). These findings suggest that milk LFC may be useful as an index for intramammary infection in goats.     

Microbiological quality of goat's milk obtained under different production systems

In order to determine the safety of milk produced by smallholder dairy goat farms, a farm-based research study was conducted on commercial dairy goat farms to compare the microbiological quality of milk produced using 3 different types of dairy goat production systems (intensive, semi-intensive and extensive). A survey of dairy goat farms in and around Pretoria carried out by means of a questionnaire revealed that most of the smallholder dairy goat farms surveyed used an extensive type of production system. The method of milking varied with the type of production system, i.e. machine milking; bucket system machine milking and hand-milking, respectively. Udder half milk samples (n=270) were analysed, of which 31.1% were infected with bacteria. The lowest intra-mammary infection was found amongst goats in the herd under the extensive system (13.3%), compared with 43.3% and 36.7% infection rates under the intensive and semi-intensive production systems, respectively. Staphylococcus intermedius (coagulase positive), Staphylococcus epidermidis and Staphylococcus simulans (both coagulase negative), were the most common cause of intramammary infection with a prevalence of 85.7% of the infected udder halves. The remaining 14.3% of the infection was due to Staphylococcus aureus. Bacteriology of bulk milk samples on the other hand, showed that raw milk obtained by the bucket system milking machine had the lowest total bacterial count (16,450 colony forming units (CFU)/ml) compared to that by pipeline milking machine (36,300 CFU/ml) or hand-milking (48,000 CFU/ml). No significant relationship was found between the somatic cell counts (SCC) and presence of bacterial infection in goat milk In comparison with the herds under the other 2 production systems, it was shown that dairy goat farming under the extensive production system, where hand-milking was used, can be adequate for the production of safe raw goat milk.     

Correlations among the somatic cell count of individual bulk milk, result of the California Mastitis Test and bacteriological status of the udder in dairy cows

In a survey of about 3000 dairy cows producing low somatic cell count (SCC) milk and kept on a large-scale dairy farm, California Mastitis Test (CMT) positivity was found in 2714 udder quarters of 1491 cows. Pathogenic microorganisms were isolated from 57.6% of these 2714 udder quarters during bacteriological examination. The commonest pathogens were coagulase-negative staphylococci (CNS, 41%) and Staphylococcus aureus (32.5%); however, udder infections caused by environmental streptococci (12.8%) and coliform bacteria (6.8%) were also common. All pathogens resulted in a significant increase of the SCC in individual bulk milk (IBM) samples. In the case of CNS, this SCC elevation in IBM was significantly lower than in the case of infection by the other pathogens. In spite of this, because of the high number of udder infections caused by CNS, the adverse effect exerted by CNS on dairy herds is considered to be substantial. It was found that 54.6% of all CMT-positive cows produced IBM of an SCC below 400 thousand per ml. The milk produced by 41% of the 315 cows excreting S. aureus also had an SCC below 400 thousand per ml. This poses a serious risk of infection to the healthy herdmates. At the same time, 11% of the infected cows produced IBM with an SCC below 100 thousand per ml. On the basis of these findings, only the regular analysis of SCC of IBM can be a reliable indicator of chronic intramammary infection. As the SCC of milk produced by CMT-positive cows (and especially of those excreting pathogens) tended to increase with advancing lactation, the authors suggest that an efficient drying-off therapy should be used to restore udder health and, whenever justified, culling of cows cannot be avoided either.     

Physical examination and palpation findings of mammary glands and indications of udder health in goat milk]

In dairy goats there is less evidence for relationships between udder form traits, results of physical udder examinations and mastitis indicators in the milk than in dairy cows. In 413 goats (predominantly Weisse Deutsche Edelziege and Bunte Deutsche Edelziege) from five herds (free from C.A.E.) repeated investigations of 2537 udder halves and fore milk samples were carried out in order to compare udder traits with findings in the milk. Less than 20% positive bacteriological findings and a low incidence of clinical mastitis testified a good clinical udder health status of the herds. Small teat-floor distances, loose hanging of the udders and bottle-shaped teats, findings which tended to become more frequent as lactation and lactation numbers progressed, indurative alterations of the mammary tissues and the teats tended to be connected with higher milk cell counts (> 1 million/microliter), more polymorphonuclear milk cells (> 40%), higher electrical milk conductivity (> 6.8 mS/cm) and lower milk lactose content (< 4.6%). A similar effect had a bad state of foot trimming. It is proposed to include the studied udder traits into herd health programs and breeding schemes for goats.     

The influence of intramammary antibiotic treatment, presence of bacteria, stage of lactation and parity in dairy goats as measured by the California Milk Cell Test and somatic cell counts

The California Milk Cell Test (CMCT) and somatic cell counts (SCC) on their own were not reliable methods in the identification of subclinical mastitis in the dairy goats studied and should be accompanied by microbiological tests. However, CMCT and SCC were indicators of irritation of the udder parenchyma. In healthy goats Spectrazol Milking Cow (Schering-Plough AH) caused the least and Curaclox LC (Norbrook (ARK AH)) the most irritation of parenchyma after intramammary treatment. The effects of Rilexine 200 LC (Logos Agvet (Virbac)) were intermediate. There was a highly significant difference (P < 0.001) in the mean log SCC between treated and control groups for goats treated with Curaclox LC and Rilexine 200 LC but no significant difference was present in the mean log SCC of treatment and control groups for goats treated with Spectrazol Milking Cow at the 07:00 and at 19:00 samplings. The CMCT was an indicator of the level of SCC in goat milk. The CMCT was more useful in confirming the absence of infection, rather than in diagnosing mastitis.     

关中奶山羊乳房炎病理模型的建立

为建立关中奶山羊乳房炎模型,用分离的乳房炎病原菌,按照大肠埃希菌3×103 cfu/mL、金黄色葡萄球菌3×102 cfu/mL剂量,分别对关中奶山羊进行乳头管灌注.在不同时间点,观察测定产奶量、精神状况、食欲、乳汁外观、乳房性状、体温、体细胞数(LMT法)等指标,并进行病理学检查和病原菌分离鉴定.结果显示,攻菌后奶山...     

Effects of short period frequent milking on milk yield and udder health in Turkish Saanen goats

The major purpose of this study was to investigate whether increasing milking frequency for a short period (21 days) increases milk yield and milk components and improves udder health throughout lactation in Turkish Saanen goats. Two groups were formed (control, n = 14, treatment, n = 14); balanced by parity, bodyweight and birth type to make them homogenous. Feeding and management practices were the same for both groups. The treatment group was milked four times a day (4×) for 21 days after weaning whereas the control group was milked twice a day (2×). All the animals were milked twice daily thereafter. The pyronin methyl green stain method was used to estimate the somatic cell count (SCC), which is an indication of udder health. This method provided a count that excluded RNA and background noise while including cells with DNA. Repeated measures analyses indicated that overall differences between the 2× and 4× groups were significant for the morning, evening and total test day milk yields, in that values for the 4× group were increased 14.7, 8.8 and 12.1%, respectively. Differences between the groups for SCC were not significant. The results of this study indicate that increasing milking frequency to 4×, even for a short time (21 days), increases overall milk yield throughout lactation in dairy goats.     

A comparison of somatic cell count between organic and conventional dairy cow herds in West Germany stressing dry period related changes

Mastitis is one of the major threats to animal health and thus to productivity in all dairy farming systems. Previous studies of organic dairy herds have indicated better udder health in organic herds, as compared to conventional herds but opposite results have also been reported. In view of the great implications that the dry period (DP) has on udder health, we aimed to compare milk performance data between organic and conventional dairy herds by specifically addressing the relation of somatic cell counts in milk (SCC) before and after the DP. On 68 farms (35 organic, 33 conventional) in Western Germany individual cow and herd production data were recorded next to data on SCC (herd, individual) between June 2002 and June 2004. For data analysis, SCC values > 150,000 cells/mL were defined as indicative for disorders of udder health.     

Evaluation of the California mastitis test (CMT) reaction in goat milk and its interpretation

For evaluation of different factors regarding CMT results 65 goats were used. Age, milking hygiene and technique of the animals were recorded and the CMT results were evaluated in relation to those parameters. Correlations between CMT results and age as well milking hygiene and -technique respectively were found. Furtheron the CMT was evaluated as indicator for mastitis diagnosis. Therefore clinical examination of the udder, bacteriological examination of milk samples (aseptically collected) and the determination of the somatic cell count were carried out. The results showed that CMT is not specific for infected udder halves. As important udder pathogens staphylococci were found, S. aureus and CNS at the same level. This investigation has shown that CMT can be used as additional diagnostic tool concerning goat mastitis, but it should not be overestimated because of different factors which influence the cell count. For the control of udder health additional diagnostic measures are of utmost necessity.     

The effect of estrus synchronization treatment on somatic cell count of transitional-anestrus local-Damascus cross breed goats’ milk

An experiment was conducted to examine the effect of estrus synchronization protocols and steroid hormones concentrations on somatic cell count (SCC) of transitional-anestrus local-Damascus cross goats’ milk. Fifty-six goats (2–4-year old) were randomly assigned to three groups: fluorogestone acetate (FGA, n = 19), FGA-Prostaglandin (FGA-PGF, n = 19) and control (n = 18) groups. Intravaginal sponge containing 40 mg FGA was inserted for 13 days and an injection of 600 IU equine chorionic gonadotropin (eCG) was administered for goats of FGA and FGA-PGF groups at the time of sponge removal (day 0). In addition, goats of FGA-PGF group were injected with 10 mg dinoprost tromethamine () on day 0. Five fertile local-Damascus cross bucks were turned-in with all goats on day 0. Blood and milk samples were collected from all goats on days -13 (beginning of experiment), -6, 0, 1, 2, 7, 13 and 20 (end of the experiment). Four-year old and second-parity goats had significantly higher (p < 0.05) SCC of both udder halves than 2- and 3-year old and first-parity goats, respectively. There was a significant effect (p < 0.05) for treatment and number of kids born in the last kidding season on SCC of both udder halves. Neither estradiol nor progesterone concentrations were correlated with SCC in goats in this experiment. The SCC of both udder halves and left udder halves in goats of the control and FGA groups, respectively, increased significantly (p < 0.05) after sponge removal and buck introduction when compared with day 0, with no differences in the FGA-PGF group. This increase in SCC of the control and FGA groups coincided with peak estrus behavior. However, SCC was far below the upper limit of the current standard for normal milk. In conclusion, induction of estrus with progestagen based programs and buck introduction may cause temporary significant increase in SCC. However, the SCC values during this period of temporary increase were still in the range of acceptable values for normal milk. With the current standards for SCC of 1,000,000/ml as legal limit for abnormal milk control programs in goats, estrus synchronization programs and the estrus status should not be considered when bulk-tank milk SCC is being investigated.     

世界及我国奶山羊产业发展现状及趋势分析

近年来,世界山羊养殖数量持续增长,据联合国粮农组织(FAO)统计显示,2018年全球山羊养殖数量已超10.4亿只,其中奶山羊养殖数量超2.16亿只,约有90%以上的奶山羊和山羊奶产自亚洲和非洲。欧洲的奶山羊存栏和产奶量均在亚洲和非洲之后,但其单产水平远高于其他各大洲,在世界奶山羊每只平均年产奶量100 kg以上的国家中,前十位均为欧洲国家。我国奶山羊产业发展迅速,2018年我国奶山羊实际存栏约518万只,年产羊奶量约100万t,约占全国鲜奶产量的3.3%。本文对全球及我国奶山羊产业进行了纵向和横向比较,客观分析我国奶山羊产业的地位、发展现状以及未来发展趋势,旨在为我国奶山羊产业的发展提供参考。     

Study of intramammary infections in dairy goats from mountainous regions in Italy

Extract

The manufacture of dairy products from the milk of small ruminants presents an opportunity to improve the economics of farming in remote areas such as the mountainous regions in northern Italy. Mastitis, particularly subclinical and chronic, is the most persistent and widespread problem affecting milk quality. Currently, there is a lack of information concerning the most common causal agents of mastitis in dairy goat herds in Italy. This study was undertaken to determine the aetiology and prevalence of intramammary infections (IMI), and to measure somatic cell counts (SCC) of dairy goats in mountainous regions of northern Italy.     

Assessment of welfare on 24 commercial UK dairy goat farms based on direct observations

The preliminary findings from an investigation into the health and welfare of goats on commercial dairy goat farms in the UK are described. An assessment protocol involving direct observations of the goats was developed in order to assess their welfare. Twenty-four dairy goat farms in England and Wales were visited and assessed during the period autumn 2004 to summer 2005. The main welfare issues identified were lameness and claw overgrowth, udder and teat lesions, skin lesions and pruritus.     

一个高体细胞数牧场奶牛隐性乳腺炎病原菌的调查

对安徽某规模牧场随机采集的314份奶样进行细菌分离鉴定、牛奶体细胞计数(SCC),并对分离比例较高的凝固酶阴性葡萄球菌(CNS)进行亚种鉴定及药敏试验。结果显示120个低体细胞数奶样(SCC25×104/mL)的细菌检出率只有8.3%,分离细菌为CNS;而194个高体细胞数奶样(SCC≥25×104/mL)细菌检出率高达72.2%,分离出的细菌主要为金黄色葡萄球菌、CNS、大肠杆菌、停乳链球菌等。其中CNS感染比例最高、为28.8%,主要包括松鼠葡萄球菌、表皮葡萄球菌、人型葡萄球菌等。乳腺内细菌感染可引起患病乳区SCC显著升高(P0.05),松鼠葡萄球菌和表皮葡萄球菌感染也可引起SCC显著升高(P0.05),不同亚种的CNS对临床常用抗菌药物青霉素、庆大霉素、红霉素有较高的耐药率,分别为71.2%、53.8%和82.7%。     

Diagnosis of paratuberculosis by fecal culture and ELISA on milk and serum samples in two types of Chilean dairy goat herds.

Fecal culture has been the primary method used to diagnose paratuberculosis in goats. It is laborious, slow, and expensive. Validation of enzyme-linked immunosorbent assays (ELISAs) on milk samples could make paratuberculosis testing more widely available for goat farmers. The aim of this study was to determine the accuracy of serum and milk ELISAs for paratuberculosis, relative to fecal culture, in Chilean dairy goats. Eight dairy goat herds were selected. Feces, blood, and milk samples were collected from all female goats >2 years old. Fecal samples were cultured using Herrold egg yolk medium with mycobactin J and antibiotics. Serum and milk samples were tested using a commercial ELISA kit for Mycobacterium avium subsp. paratuberculosis antibody detection. A total of 383 goats were tested by ELISA and fecal culture. The sensitivity of ELISA on serum and milk relative to fecal culture was 74.3% (95% CI: 59.8-88.8) and 60% (95% CI: 43.8-76.2), respectively. The corresponding values for ELISA specificity based on the percentage of non- M. avium subsp. paratuberculosis-infected goats testing ELISA-negative were 98.6% (95% CI: 96.6-100) and 99.3% (95% CI: 97.9-100) on serum and milk, respectively. Proportions of positive results for serum and fecal samples were significantly different, whereas the proportions of positive results for milk and fecal samples were not significantly different. The milk ELISA had a moderate level of agreement with fecal culture results (Kappa = 0.57). The paratuberculosis ELISA on goat milk samples may be a cost-effective, accurate alternative to fecal culture.     

Relationships between infection with caprine arthritis encephalitis virus, intramammary bacterial infection and somatic cell counts in dairy goats.

Somatic cell counts, the bacteriological condition of the milk and antibodies against caprine arthritis encephalitis virus (CAEV) were measured monthly throughout lactation in 121 lactating goats of the Murcia-Granada breed in four commercial dairy goat herds. The prevalence of bacterial intramammary infection was 5.6 per cent and the prevalence of CAEV infection was 20.6 per cent. An analysis of variance revealed a significant effect of herd, intramammary infection and the interaction between intramammary infection and CAEV on the somatic cell count. In udder halves free of intramammary infection, the somatic cell counts were significantly lower in seronegative goats than in seropositive goats (P<0.05), but the difference was not significant in udder halves persistently infected by bacteria. There was a significant increase in somatic cell counts due to bacterial intramammary infection (P<0.01) in the seronegative goats, but this effect was not present in the seropositive animals.     

Management of Goat Reproduction and Insemination for Genetic Improvement in France

Reproductive seasonality observed in all breeds of goats originating from temperate latitudes and in some breeds from subtropical latitudes can now be controlled by artificial changes in photoperiod. Short days stimulate sexual activity, while long days inhibit it. This knowledge has allowed the development of photoperiodic treatments to control sexual activity in goats, for both the buck and doe. In the French intensive milk production system, goat AI plays an important role to control reproduction and, in conjunction with progeny testing, to improve milk production. Most dairy goats are inseminated out of the breeding season with deep frozen semen, after induction of oestrus and ovulation by hormonal treatments. This protocol provides a kidding rate of approximately 65%. New breeding strategies have been developed, based on the buck effect associated with AI, to reduce the use of hormones. With the development of insemination with frozen semen, a classical selection programme was set up, including planned mating, progeny testing and the diffusion of proved sires by inseminations in herds. Functional traits have become important for efficient breeding schemes in the dairy goat industries. Based on knowledge gained over the past decade, the emphasis in selective breeding has been placed on functional traits related to udder morphology and health. New windows have been opened based on new molecular tools, allowing the detection and mapping of genes of economic importance.