Cell Count In Goat Milk Research Articles

Effect of a 60-day organic selenium-supplemented diet on the decrease of somatic cell counts in goat milk.

Selenium is an important element in nutrition, showing great potential in the udder health of dairy goats and in the control of subclinical mastitis. However, there are few studies that evaluated the influence of selenium supplementation on subclinical mastitis in goats. The aim of this study was to evaluate the incidence of subclinical mastitis in dairy goats supplemented with organic selenium (Se yeast) in a semi-arid region. Sixteen Saanen × Toggenburg crossbred lactating goats were allocated randomly into two treatments: with and without addition of organic selenium (Se) to the concentrate. Milk samples were collected every 20days from each udder half to determine the somatic cell count (SSC), chloride content, pH, electrical conductivity, microbiological isolation, composition, and selenium contents. The highest serum selenium concentrations in the blood of these goats occurred at 42days of supplementation (P < 0.001). Goats which received organic selenium supplementation had higher serum selenium concentrations (P < 0.05). The milk composition variables did not differ (P > 0.05) between the tested treatments, teats, and collections. After 60days of supplementation, a difference was observed (P < 0.05) between treatments for SSC, chloride content, and pH. Addition of organic selenium to the diet of dairy goats after 60days of supplementation was promising in reducing the somatic cell count, consequently improving milk quality.

Somatic Cell Count in Goat Milk: An Indirect Quality Indicator.

A high somatic cell count (SCC) impacts dairy quality to a large extent. The goal of this work was to investigate differences in goat milk composition and technological parameters according to SCC cut-off (600, 700, 800, and 1000.103/mL). Thirty-four individual milk samples of White Shorthair goats in a similar stage of lactation were investigated. The first differences in milk quality appeared already at SCC cut-off of 600.103/mL (5.58 LSCS-linear somatic cell score), yet the most striking differences were found for SCC over 1000.103/mL (6.32 LSCS), which was expressed by lowering heat stability (126 vs. 217 s, p = 0.034), increasing protein (3.41 vs. 3.04%, p = 0.009), casein (2.80 vs. 2.44%, p = 0.034) and chloride (164 vs. 147 mg/100 mL, p = 0.004) levels, as well as non-fat dry matter (8.79 vs. 8.45%, p = 0.045). It has been shown that low levels of Staphylococcus spp. bacteria (120–1600 CFU/mL) in the mammary gland correlated with decreased lactose content (4.60 vs. 4.47 g/100 g, p = 0.022). Since our results indicate that even low SCC values may significantly affect the technological properties of goat milk, SCC should therefore be routinely screened and reported to dairy manufacturers to assure the consumer of high end-product quality.

TLR2 polymorphism (rs650082970) is associated with somatic cell count in goat milk.

Pathogens invading the mammary gland are recognized through a range of pattern recognition receptors (PRRs), residing on the plasma membrane of mammary epithelial cells. Toll-like receptor 2 (TLR2) signalling is responsible for recognition of Gram-positive bacteria, which are the most common mastitis-causing pathogens in goats. Somatic cell counts (SCC) in milk are routinely determined in goat dairy flocks and serve as an indicator of milk quality, which is highly correlated to intramammary infections. Recently, a single nucleotide polymorphism of the TLR2 was suggested to be associated with SCC in goat milk. To further test the suggested association, we genotyped 61 Slovenian Alpine goats included in the dataset. The effect of the genotype was analysed using the general linear model (GLM) procedure of SAS/STAT software. We found the TLR2 genotypes significantly (p = 0.0007) associated with milk SCC. Animals with the A/G genotype had significantly (p ≤ 0.05) lower SCC value in milk compared to the G/G genotype. Our data suggest that the A allele is the minor one and is associated with lower milk SCC. In the current study, we provide a validated PCR-RFLP based genotyping assay for the TLR2 SNP (rs650082970) and confirm its association with milk SCC. Further studies to confirm the association on a larger number of animals of different breeds and to explain functional consequences of the polymorphism in relation to SCC are encouraged.

Monitoring research of somatic cells count in goat milk in the eastern region of Ukraine

The aim of research was to analyze the contents of somatic cells (SC) in goat milk in the East of Ukraine, level of SC translocation in the process of milking, speed of SC evacuation in their secret, to conduct monitoring and ranging on the level of SC goat milk of herds in the Eastern region during 2015 seasonally. Somatic cell count was studied on a large number of animals in different zones of the East of Ukraine (1800 milk samples). Somatic cell count in goat milk of the Eastern region of Ukraine appears up to 800×10³ cells/ml at 65-71% of studied milk samples by the method of laser-running cytometry with the account of only those cells having DNA in the nucleus. While analyze of SC subpopulations in goat milk it is shown that at increase to 2 million cells/ml and more the concentration of neutrophils and lymphocytes does not change and the number of macrophages and eosinophils (р≤0,05) rises from 1,5 to 4 times accordingly. It is marked that SC contents in goat milk in the morning and evening yield of milk is different. In evening yield of milk, the somatic cell count is up to 30 % higher than in the morning one. A clear pattern of distribution of somatic cells in milk portions during milking was not detected. Average sample of yield is required to determine the somatic cell count in the milk of goats. Six of the eight goats over six months of lactation were given milk with a fairly constant somatic cell count. Low and fairly constant somatic cells content (15 to 63 × 103 cells / ml) is observed in the milk of primiparous goats.

Differential cell count of caprine milk by flow cytometry and microscopy

There is currently no consensus about the usefulness of somatic cell counts (SCC) as a key diagnostic criterion for the evaluation of caprine udder health. While traditional differential cell count by microscopic analysis may provide a more reliable basis for the detection of mastitis, this procedure is labor intensive and time consuming, due to the presence of cytoplasmic particles (CP), and thus cannot be considered for routine use. Although flow cytometric methods have been described for quick cell differentiation in cow's milk, there has been little investigation of such methods for goat somatic milk cells. The present study was therefore intended to develop a simple and quick method for differentiating caprine somatic cells by flow cytometry and to compare these results with microscopic analysis using two different staining methods. Milk samples were obtained from 25 German Brown goats and analyzed microbiologically for potentially udder-pathogenic bacteria and for SCC. In a preliminary study, somatic milk cells were incubated with specific monoclonal antibodies binding to different cell populations and simultaneously stained with the fluorescent dye SYTO ® 13. In the main experiment, it was then possible to localize the exact positions of viable and non-viable polymorphonuclear neutrophils, lymphocytes, and macrophages within SYTO ® 13 flow cytometric dot plots. The percentages of the cell populations were determined by a simple and quick incubation of cells with SYTO ® 13 and DRAQ5™ followed by flow cytometric measurement. This method allows to determine differential cell counts in goat milk rapidly and objectively.

Análise das metodologias diretas e indiretas para a contagem de células somáticas no leite de cabras hígidas

A particularidade da secreção láctea caprina, do tipo apócrina, diferente da secreção merócrina da vaca, leva a erros de interpretação durante a realização de técnicas de avaliação da celularidade do leite de fêmeas desta espécie. Portanto, o presente trabalho teve o objetivo de determinar a contagem de células somáticas pelo método indireto California Mastitis Test (CMT), e por métodos diretos, incluindo a contagem por citometria de fluxo e a contagem microscópica direta, através da coloração de verde de metil e pironina-Y, além de comparar os métodos de contagem celular. Foram analisadas 102 amostras de 51 fêmeas caprinas, das raças Saanen, Parda Alpina e Toggenburg, criadas no Estado de São Paulo. Os animais foram categorizados segundo a fase da lactação, exame físico da glândula mamária e exame do leite. As amostras foram colhidas, após a realização do exame Califórnia Mastitis Test, em duas alíquotas, uma destinada à contagem celular automática e a outra, a contagem microscópica direta, utilizando-se o corante verde de metil e pironina- Y. De acordo com os diferentes escores do CMT, observou- se 74,5% de amostras negativas, 8,8% de amostras com escore traços, 8,8% de amostras ligeiramente positivas (+), 6,8% de amostras fracamente positivas (++) e 0,9% de amostras fortemente positivas (+++). Os valores medianos das contagens de células somáticas presentes no leite de cabras, avaliadas através de contador automático e microscopia direta, e analisadas de acordo com os diferentes escores do CMT, foram, respectivamente, 181.000, 578.000, 628.000, 1.421.500 e 5.542.000 células/mL de leite e 74.991, 271.396, 71.420, 640.995 e 5.049.394 células/ mL de leite, nos escores negativo, traços, +, ++ e +++. Os valores medianos obtidos através da contagem de células somáticas pelo método automático e microscópico direto, de acordo com as fases de lactação foram de 159.500, 508.000 e 277.500 células/mL de leite, e 62.493, 89.275 e 146.411. A correlação obtida entre a contagem celular automática e microscópica direta foi de 88%. A partir dos resultados observados pode-se concluir que existe diferença na contagem celular determinada através do método automático e microscópico sendo este último o mais adequado para a determinação da celularidade no leite de cabras.

Effect of somatic cell count in goat milk on yield, sensory quality, and fatty acid profile of semisoft cheese

This study investigated the effect of somatic cell count (SCC) in goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semisoft cheese. Sixty Alpine goats without evidence of clinical mastitis were assigned to 3 groups with milk SCC level of <500,000 (low), 500,000 to 1,000,000 (medium), and 1,000,000 to 1,500,000 (high) cells/mL. Thirty kilograms of goat milk with mean SCC levels of 410,000 (low), 770,000 (medium), and 1,250,000 (high) cells/mL was obtained for the manufacture of semisoft cheese for 2 consecutive weeks in 3 lactation stages. The composition of milk was analyzed and cheese yield was recorded on d 1. Cheese samples on d 1, 60, and 120 were analyzed for total sensory scores, flavor, and body and texture by a panel of 3 expert judges and were also analyzed for FFA. Results indicated that milk composition did not change when milk SCC varied from 214,000 to 1,450,000 cells/mL. Milk with higher SCC had a lower standard plate count, whereas coliform count and psychrotrophic bacteria count were not affected. However, milk components (fat, protein, lactose, casein, and total solids) among the 3 groups were similar. As a result, no significant differences in the yield of semisoft goat cheeses were detected. However, total sensory scores and body and texture scores for cheeses made from the high SCC milk were lower than those for cheeses made from the low and medium SCC milks. The difference in milk SCC levels also resulted in diverse changes in cheese texture (hardness, springiness, and so on) and FFA profiles. Individual and total FFA increased significantly during ripening, regardless the SCC levels. It is concluded that SCC in goat milk did not affect the yield of semisoft cheese but did result in inferior sensory quality of aged cheeses.

N-acetylcysteine supplementation may affect somatic cell count in goat milk (short communication)

Abstract. The aim of this study was to estimate an influence of supplementation of exogenous N-acetylcysteine (NAC) on the somatic cell count (SCC, quantified as cells per ml) and chemical composition of goat milk. The study was carried out on 15 goats, in the last part of lactation (220-250 days). The animals were divided into 3 groups according to SCC in their milk: 1st – up to 2×106, 2nd – from 2 to 4×106 and 3rd – above 4×106. The animals were clinically healthy. They were given NAC in the amount of 12 mg/ kg of live body weight per os for 7 days, once a day, during evening milking. Milk yield, as well as fat, protein and lactose contents and SCC were studied three times: 1st – just before starting the experiment, 2nd – after 7 days of NAC application and 3rd – a week after the end of NAC application. The analysis of variance with General Linear Model (GLM) procedure of SAS® package was used. There was observed the significant decrease of SCC after one-week supplementation of NAC and stagnation of SCC after next week in all three groups. The changes of chemical composition of milk were not significant. The significant decrease of SCC may indicate improvement of health of mammary gland. The oxidation processes might be decreased and probably the increase of immune defence of organism took place. One can suggest that the supplementation of NAC may lead to improvement of goat udder health.

Relationship of somatic cell counts in goat milk to mastitis and productivity

This review covers research since the Symposium at Bella, Italy, in 1994, and as published in three major dairy research journals. It examines in particular non-pathological influences on somatic cell counts (SCCs) levels as they are unique for goat milk and different from cow milk in order to aid towards progress for establishing equitable quality standards for goat and sheep milk. Different testing equipment and procedures are of variable reliability and applicability to goat milk, unless appropriate correction factors and calibration with goat milk are used. The only reliable method for arbitration seems to be the pyronin Y-methyl green stain. Culturing goat milk samples indicated that in commercial goat herds the variation in SCC can be as much as 90% due to non-infectious factors, and a correlation with standard plate counts of bacteria may be only at r=0.44. Among pathogens found in goat udders, Staphylococcus aureus seems to cause higher levels of SCC than coagulase negative staphylococci. Prevalence of pathogenic species in different herds varies between S. aureus, S. epidermidis, and coagulase negative staphylococci. Polymorphonuclear neutrophils predominate in goat milk and at higher levels than in cow milk under non-infectious conditions. Histopathological sections of goat udders with high SCC showed absence of mastitic conditions and that healthy goat udders can have high SCC levels normally. Stage of lactation always influences SCC. In contrast to cow milk tests, a single SCC test in goat milk has little value unless stage of lactation and parity is incorporated. Curvilinear and linear regressions have been calculated for the prediction of SCC versus stage of lactation. Estrus may also elevate SCC, but definitive studies in goats are lacking. Goat milk samples before, during and after milking differ significantly in SCC. Hand milking may cause higher SCC than machine milking, but studies have been inconclusive. The few studies of effects of SCC on productivity of goat milk, cheese and yoghurt have been inconclusive so far, partly because the incidence of subclinical and clinical infections in goat udders is less than in cow udders, and any risk of antibiotic contamination is also less. Different threshold levels have been proposed for SCC, but their predictive value of udder infections has been very variable.

Relationship of somatic cell counts in goat milk to mastitis and productivity

Relationship of somatic cell counts in goat milk to mastitis and productivity

Comparative study of the effects of testing laboratory, counting method, storage and shipment on somatic cell counts in goat milk

Somatic cell counts (SCC) in goat milk from different stages of lactation were determined at four laboratories (I, II, III and IV) using the pyronin Y-methyl green (PYMG) direct microscopic method and/or Fossomatic machines calibrated with either goat or cow milk standards. The effects of sample shipment and storage on SCC of goat milk were also determined. Results of this study indicated that the PYMG microscopic method and the Fossomatic machine calibrated with goat milk standards gave comparable estimates of SCC in goat milk ( p>0.05). However, on average the Fossomatic machines ( n=3) calibrated with cow milk standards estimated SCC of goat milk to be 24.5% higher than a Fossomatic machine calibrated with goat milk standards ( p<0.05). No significant difference in SCC of goat milk existed ( p>0.05) between laboratories ( n=2) when the PYMG microscopic method was used. Shipping milk samples in an ice box (3 days) and storing in a refrigerator (3 days) did not affect SCC results ( p>0.05).

Cellular defense mechanisms in the udder and lactation of goats.

Migration of neutrophils into mammary tissue provides the first immunological line of defense against bacteria that penetrate the physical barrier of the teat canal. Evasion of neutrophil defenses provides an opportunity for invading bacteria to become established. Depletion of neutrophils results in a dramatic increase in susceptibility to intramammary infection. Numerous cytoplasmic particles are shed from the apical surface of mammary secretory cells during milk secretion in goats. Only those counting methods that are specific for deoxyribonucleic acid can distinguish cell-like particles from somatic cells and thereby give reliable estimates of somatic cell numbers in goat milk. Unlike in milk from dairy cows, the somatic cell count in goat milk is influenced by the presence of nucleated cytoplasmic particles, stage of lactation, parity, and caprine arthritis-encephalitis. Investigations indicate that a dry period is necessary for optimal milk production in dairy cows but may not be necessary in goats. However, in many other respects regulation of bovine and caprine lactation seems to be quite similar. Studies have demonstrated additive galactopoietic effects of growth hormone and frequent milking in both species and a recently isolated chemical feedback inhibitor of lactation seems effective across both species. Increasing lactational performance has the potential for decreasing milk somatic cell counts in late lactation.

Factors affecting somatic cell counts in goat milk

Many factors were found to affect cell numbers: coagulase negative staphylococci or CAEV mammary infection, but also vaccination or alimentary stress. Out of 181 halves studied, 4 (2%) were infected by Staphylococcus aureus, 41 (23%) by coagulase negative staphylococci and 136 (75%) were not infected. Somatic cell counts of 94 goats (two herds) were studied during four months (first to fifth month of lactation). The arithmetic mean cell counts for milk samples from halves infected with coagulase negative staphylococci and non-infected halves were respectively 1.04 × 10 6 and 0.52 × 10 6 cells/ml. From second lactation and more, CAEV infected halves had cell counts double those of uninfected halves ( P<0.01). About 8% of halves infected by coagulase negative staphylococci and 28% infected by CAEV had somatic cell counts lower than 0.5 × 10 6 cells/ml. Vaccination and acidosis induced an increase of cell counts in milk. A threshold of 0.8 × 10 6 cells/ml did not seem sufficiently discriminating for diagnosis of mammary infections. The weak increase of cell numbers due to CAEV infection and the susceptibility of goat udders to various stress must be taken into account before using cell count as diagnostic of mammary infections.

Interrelationships between somatic cell counts, electrical conductivity, bacteria counts, percent fat and protein in goat milk

Six French-Alpine and six Anglo-Nubian does in mid-lactation at 150–180 days of milking, were randomly selected from the University herds, and morning and afternoon milk samples from each doe were tested for interrelationships between levels of somatic cell counts (SCC), electrical conductivity (EC), standard plate counts (total bacteria counts; SPC), staphylococcus counts (STC), coliform counts (CFC), percent fat and protein in goat milk. Mean cell counts of the combined breed data for SCC, SPC, STC and CFC in goat milk were 682, 38.9, 4.03 and 0.62 × 10 3 cells per ml, respectively. Mean ECs overall for, Alpine and Nubian breeds were 4.75, 5.80, and 3.76, respectively. Average EC of Alpine milk was higher than of Nubian, whereas mean SCC of Alpine milk was lower than of Nubians. Mean EC of afternoon milk was higher than of morning milk. There were no significant correlations ( r) between levels of SCC and EC for separate or combined breed data, nor for separate or combined data of milking time. However, SCC showed significant correlation with CFC for the pooled data ( P < 0.05). The EC values had negative but highly significant ( P < 0.01) r values with % fat and protein in the milk. Results suggest that SCC and EC by current instrumentations may not be good indicators for bacterial cell counts in goat milk. Further studies are necessary to find optimal unit measures of EC instrument for caprine milk.

Bacterial Cell Counts in Goat Milk and Their Correlations with Somatic Cell Counts, Percent Fat, and Protein

Representative milk samples at morning and afternoon milking were collected periodically for 5 mo from 32 does in a Prairie View A&M University milking herd to test the concentrations of total bacterial, coliform, and staphylococcus counts and to determine the correlations among the bacterial cell counts, somatic cell counts, percent fat, and percent protein. Bacterial cell counts were assayed by microbiogical methods using different nutrient media for the three cell types. Somatic cell counts were determined by an automated fluorescent microscopic somatic cell counter. Percent fat and protein were analyzed by an automated dual beam infrared absorption analyzer. Mean counts for total bacterial, coliform, staphylococcus, and somatic cell were 2.54 × 104, .966 × 103, 3.32 × 103, and 9.08 × 105 cells/ml, respectively. The Nubian goats had higher counts in all three bacterial cell types than the Alpines, and the difference in staphylococcus counts between breeds was significant (P<.05). However, Alpine milk contained slightly higher somatic cell counts than the Nubians. None of the correlation coefficients (r) between somatic cell and bacterial cell counts was significant for the pooled data from the two breeds, but r between staphylococcus and somatic cell counts for Alpine breed was significant (P<.05). The r between somatic cell counts and percent fat or protein were significant (P<.01) for combined or separated breed data. Bacterial cell counts could not explain high somatic cell counts in the goat milk with the present testing standards of cow milk.

Differentiation and Enumeration of Somatic Cells in Goat Milk

Non-leukocytic cell-like particles commonly observed in goat milk were examined ultrastructurally and cytochemically. Transmission electron microscopy indicated that these particles were generally membrane-bound and anucleate. They contained granular material in the dilated cisternae of the endoplasmic reticulum and homogeneous electron translucent inclusions that resembled lipid. Histochemical and fluorescent staining indicated that the particles contained large amounts of protein, some lipid, but no deoxyribonucleic acid. Several methods routinely used for estimating somatic cell counts in cow milk were compared to determine which one would give accurate estimates of somatic cell counts in goat milk. No significant difference was found (P> .05) among methods which specifically measure deoxyribonucleic acid. These included Membrane Filter-DNA, direct microscopic somatic cell counts using Pyron in Y-methyl green stain, and Fossomatic cell counts. Results of the Wisconsin Mastitis Test did not differ significantly from Fossomatic cell counts. Because Coulter electronic counts and direct microscopic somatic cell counts using Levowitz-Weber stain could not differentiate between the cell-like particles and the actual leukocytes, these methods resulted in elevated cell counts that were highly variable. Results indicate that only those counting methods that are specific for deoxyribonucleic acid can distinguish cell-like particles from somatic cells, and thereby give reliable estimates of somatic cell numbers in goat milk.