Differential Somatic Cell Count Research Articles

Supraphysiological oxytocin increases the transfer of immunoglobulins and other blood components to milk during lipopolysaccharide- and lipoteichoic acid-induced mastitis in dairy cows.

Bacterial mastitis causes pathogen-dependent changes of the blood-milk barrier, and these changes can influence the differential transfer of blood components to milk. It is well known that gram-negative pathogens such as Escherichia coli can cause a greater activation of the immune system and thus a more comprehensive transfer of blood components including IgG than gram-positive pathogens such as Staphylococcus aureus. Supraphysiological doses of oxytocin (OT) have been shown to increase the permeability of the blood-milk barrier; however, the effect of OT during experimentally induced mastitis has not been investigated. Therefore, the objective of this study was to examine if intravenous administration of OT during lipopolysaccharide (LPS)- or lipoteichoic acid (LTA)-induced mastitis could influence the transfer of blood components to milk. The hypothesis was that OT could induce a greater transfer of blood components during mastitis. Twenty-seven dairy cows were injected via the teat canal with LPS, LTA, or a saline control followed by an intravenous injection of OT 2h following intramammary challenge. Milk samples were collected every half hour and analyzed for somatic cell count (SCC), IgG, lactate dehydrogenase (LDH), and serum albumin (SA). Due to the chosen dosage of LPS and LTA, there was no difference in SCC between quarters challenged with only LPS or LTA. Quarters challenged with LPS and OT had a higher SCC and a greater transfer of IgG, LDH, and SA compared with quarters challenged with only LPS. Quarters challenged with LTA and OT had a greater transfer of IgG, LDH, and SA, whereas the SCC increase did not differ from quarters only treated with LTA. In quarters treated only with OT, SCC, LDH, and SA increased, but no difference was observed in IgG concentration from untreated control quarters. In conclusion, there are pathogen-specific changes in the blood-milk barrier and OT can induce a greater transfer of blood components to milk in both LPS- and LTA-induced mastitis. Oxytocin could have implications for use as a mastitis therapy, as there was an increased transfer of IgG into the milk.

Povezanost velicine legla s proizvodnjom mlijeka, morfologijom i zdravljem vimena istocnofrizijskih ovaca

The aim of this study was to determine relationship between litter size and milk yield, udder morphology, and udder health of East Friesian ewes. For that purpose a total of 80 East Friesian ewes, from 2nd to 4th lactation, with symmetrical udders, without visible (clinical) signs of mastitis were involved in this study. Until weaning at average age of 60±5 days lambs suckled their mothers exclusively. During milking period regular milking controls (on a monthly basis) were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis were taken. Three times per lactation (1st, 3rd and 5th milking control), prior to the milking, evaluation and measuring of udder morphology traits were performed. Also, during above-mentioned test-day controls (three times per lactation) one sample of half udder milk was taken with purpose of bacterial and somatic cell counts (SCC) tests. Ewes with twin and triplet lambs had significantly (P 0.05) and depth (P>0.05). Besides that,udders of ewes with twins and triplets had higher cistern, greater teat angle and larger teat dimensions than ewes with singles, although those differences were not statistically significant. Ewes with single lamb had teats more (P<0.05) cranially oriented than ewes with twins and triplets. Significant (P<0.05) differences in somatic cell count (log10SCC) between ewes of different litter sizes were determined, regardless of the health status of mammary gland. The higher (P<0.05) prevalence of subclinical mastitis was observed in ewes with twin and triplet lambs than in ewes with singles. In 46% of mammary glands (udder halves) of sheep with twins and triplets a subclinical mastitis was established and even 65.8% of them undergone an infection of one or both halves of the udder during the milking period.

Somatic cell count and major elements in milk during lactation in buffaloes

Apparently healthy Murrah buffaloes (18) were divided equally into early, mid-and late lactation stages. The difference in somatic cell count amongst three stages of lactation were statistically highly significant. The milk somatic cell counts increased towards the end of lactation because of the higher prevalence of mastitis, normal involution of the udder and decreased milk production, which causes less dilution of the milk leucocytes. The milk Cl and Mg concentration were higher in late and lower in mid lactation. Milk Ca, P, Na, K, Fe, and Zn increased in buffaloes at advanced stage of lactation, while milk Cu remained almost same during early and mid-lactation but increased during late lactation. The Mn remained constant throughout lactation.

Single nucleotide polymorphism and haplotype effects associated with somatic cell score in German Holstein cattle.

BackgroundTo better understand the genetic determination of udder health, we performed a genome-wide association study (GWAS) on a population of 2354 German Holstein bulls for which daughter yield deviations (DYD) for somatic cell score (SCS) were available. For this study, we used genetic information of 44 576 informative single nucleotide polymorphisms (SNPs) and 11 725 inferred haplotype blocks.ResultsWhen accounting for the sub-structure of the analyzed population, 16 SNPs and 10 haplotypes in six genomic regions were significant at the Bonferroni threshold of P ≤ 1.14 × 10-6. The size of the identified regions ranged from 0.05 to 5.62 Mb. Genomic regions on chromosomes 5, 6, 18 and 19 coincided with known QTL affecting SCS, while additional genomic regions were found on chromosomes 13 and X. Of particular interest is the region on chromosome 6 between 85 and 88 Mb, where QTL for mastitis traits and significant SNPs for SCS in different Holstein populations coincide with our results. In all identified regions, except for the region on chromosome X, significant SNPs were present in significant haplotypes. The minor alleles of identified SNPs on chromosomes 18 and 19, and the major alleles of SNPs on chromosomes 6 and X were favorable for a lower SCS. Differences in somatic cell count (SCC) between alternative SNP alleles reached 14 000 cells/mL.ConclusionsThe results support the polygenic nature of the genetic determination of SCS, confirm the importance of previously reported QTL, and provide evidence for the segregation of additional QTL for SCS in Holstein cattle. The small size of the regions identified here will facilitate the search for causal genetic variations that affect gene functions.

Associations between bacterial genotype and outcome of bovine clinical Staphylococcus aureus mastitis

BackgroundStaphylococcus aureus is an important cause of clinical mastitis in dairy cows worldwide. The cure rate after antimicrobial treatment of clinical S. aureus mastitis is very variable due to both cow and bacterial factors. Studies have shown that bacterial genotype might affect short-term bacteriological and clinical cure, but the long-term outcome has been less studied. The objectives of this study were to investigate associations between bacterial genotype and long-term outcome of veterinary-treated clinical mastitis (VTCM) caused by S. aureus during a follow-up period of 120 days and to study genotype variation among Swedish S. aureus isolates. S. aureus isolates from cases of VTCM were genotyped by pulsed-field gel electrophoresis. Long-term outcome measurements used were somatic cell count (SCC), additional diagnoses of VTCM, milk yield and culling. Isolates were classified into clusters (>80% similarity) and pulsotypes (100% similarity). Clusters and pulsotypes were grouped according to occurrence. Multivariable mixed-effect linear regression models including cow and bacterial factors with possible influence on SCC or milk yield were used to calculate differences in SCC or milk yield between groups. Additional outcome measures were calculated using a test of proportions.ResultsThe isolates (n = 185) were divided into 18 clusters and 29 pulsotypes. Two pulsotypes were classified as common, and were found in 64% of the cases of VTCM. Remaining isolates were classified as less common or rare pulsotypes. The distribution was similar at cluster level. Outcome was calculated from follow-up data on 111 cows. Significantly lower SCC during the follow-up period was found in cows infected with common clusters compared to in cows infected with less common/rare clusters. The proportion of cows with SCC <200 000 cells/ml during the whole follow-up period was significantly higher in the group common clusters than in the group less common/rare clusters. Bacterial genotype did not influence the other outcome parameters.ConclusionsIn Sweden, two S. aureus pulsotypes, identified in about 64% of clinical S. aureus cases, were widespread. Cows infected with the common genotypes had significantly lower SCC during 120 days after treatment compared to cows infected with less common or rare genotypes.

Occurrence of mastitis pathogens in relation to somatic cells

There were examined 161 cows from 4 farms in total. The suspect animals were selected according to viscosity test results, clinical symptoms and somatic cell count (SCC). Milk samples were examined for the presence of pathogens and for SCC. 55 mastitis pathogens were identified. The most frequently isolated species was Enterococcus faecalis (n = 20), followed by Staphylococcus aureus (n = 6) and Streptococcus uberis (n = 5). The SCC ranged from 9 to 24 204 ths.ml−1. There was positive occurrence of bacteria genus Staphylococcus and Enterococcus at lower SCC (50 ths.ml−1) and at higher SCC numbers (&gt; 300 ths. ml−1) bacteria genus Streptococcus, Enterobacter and Escherichia coli. Differences in SCC were significant (P &lt; 0.001) in negative samples xg 131 SCC versus 491 for positive, 611 for staphylococci and 464 ths.ml−1 for other positive. SCC discrimination limit for practical likelihood of pathogen occurrence estimation in infectious sample groups was calculated. This limit for suspicion of infection is 159 for positive group, 113 for staphylococci and 174 ths.ml−1 for other positive. This could be possible to recommend the value 174 ths.ml−1 for practical use with target to apply preventive or curative measures.

Associations of risk factors with somatic cell count in bulk tank milk on organic and conventional dairy farms in the United States

In the past decade, the demand for organic agricultural products has increased rapidly in the United States and worldwide. Milk quality research is of major interest to both consumers and dairy farmers alike. However, scientific data on milk quality, herd management methods, and animal welfare on organic farms in the United States has been lacking before the research from this study. The objective of this study was to evaluate the association of bulk tank milk somatic cell count (SCC) with management characteristics on organic and conventional dairy farms in New York, Oregon, and Wisconsin. Data from similarly sized organic farms (n=192), conventional nongrazing farms (n=64), and conventional grazing farms (n=36) were collected at a single farm visit. Of the 292 farms visited, 290 bulk tank milk samples were collected. Overall, no difference in SCC was observed between the conventional and organic grazing systems. Two models were created to assess the effects of various management and herd characteristics on the logarithmic transformation of the SCC (LSCC), one using data from all herds and one using data from organic herds only. From the total herd model, more grain fed per cow per day was negatively associated with LSCC, whereas a positive bulk tank culture for Staphylococcus aureus and years that a farmer reported being in the dairy business were both positively associated with LSCC. In the organic herd model, a seasonal effect indicated that LSCC tended to increase in the summer and decrease in the winter. Grain fed per cow per day, the use of anionic salts in transition-cow diets, the use of gloves during milking, and regular use of a quarantine unit at milking were all negatively associated with LSCC. Similar to the total herd model, a Staph. aureus-positive bulk tank culture was positively associated with LSCC in the organic model. Standard plate count was also positively associated with LSCC in the organic model. Several variables that were associated with management using external resources were combined to create an external input score. In the total herd model, use of more external resources was negatively associated with LSCC. Conventional herds in the study tended to use more outside management resources than organic herds.

Nuclear magnetic resonance metabonomics reveals strong association between milk metabolites and somatic cell count in bovine milk

Somatic cell count (SCC) is associated with changes in milk composition, including changes in proteins, lipids, and milk metabolites. Somatic cell count is normally used as an indicator of mastitis infection. The compositional changes in protein and fat affect milk coagulation properties, and also the metabolite composition is thought to contribute to differential milk properties. Milk somatic cells comprise different cell types, which may contribute to differential milk metabolite fingerprints. In this study, milk from a relatively large number of individual cows, representing significant differences in SCC, were analyzed by nuclear magnetic resonance (NMR)-based metabonomics, and the milk metabolite profiles were analyzed for differences related to SCC. Global principal component analysis performed on 876 samples from 2 Danish dairy breeds and orthogonal projection of latent structures discriminant analysis performed on a smaller subset (n=70) representing high (SCC >7.2×105 cells/mL) and low (SCC <1.4×104 cells/mL) milk SCC identified latent variables, which could be attributed to milk with elevated SCC. In addition, partial least squares regression between the NMR milk metabolite profiles and SCC revealed a strong correlation. The orthogonal projection of latent structures discriminant analysis and partial least squares regressions pinpointed specific NMR spectral regions and thereby identification of milk metabolites that differed according to SCC. Relative quantification of the identified metabolites revealed that lactate, butyrate, isoleucine, acetate, and β-hydroxybutyrate were increased, whereas hippurate and fumarate were decreased in milk with high levels of somatic cells.

Short communication: Evaluation of bovine milk residues from routine milk testing programs as DNA source for genotyping

Genome-wide association studies and genomic evaluation using a dense set of genetic markers both require a large number of genotyped individuals. Collection of the respective samples contributes substantially to the cost of the approach. In dairy cattle research, the use of residues from routine milk recording would be a cost-saving alternative to obtain samples for an appropriate number of individuals with specific phenotypes in a very short time. To assess the suitability of milk recording residues, we concurrently investigated milk residues obtained after standardized milk recording procedures and blood samples from 115 cows originating from 3 farms with different milking systems by genotyping 15microsatellite markers. We found that 4% of the milk samples were possibly assigned to the wrong animal (i.e., conflicts) and that at least 27% of the milk residues were contaminated, as indicated by an extra allele not present in the blood sample. These additional alleles primarily originated from a sample with a higher somatic cell score that went through the milk sample analyzer in the milk laboratory before the target sample. Furthermore, additional allele carryover was observed across more than one sample, when the difference in somatic cell count between samples exceeded 100,000 cells/mL. Finally, in several samples, the extra allele could not be traced back to previous samples passing through the milk sample analyzer. One source of those contaminations might be sample collection on-farm due to milk traces from the previously milked cow in the hose. No correlation was found between the farm management and conflicts or contaminations. We conclude that residues from routine milk recording are not suitable for genomic evaluation or genome-wide association studies because of the high prevalence of contamination generated at several steps during the collection and processing of milk residual samples.

A HACCP-based approach to mastitis control in dairy herds. Part 2: Implementation and evaluation

Part 1 of the study described the development of a Hazard Analysis and Critical Control Point (HACCP) based programme and accompanying handbook for the control of mastitis. This paper describes the implementation and evaluation of customised HACCP-based programmes, which were developed from the handbook and assessed on six Irish dairy farms. Both quantitative and qualitative (action research) research methodologies were used to measure the success of implementation and efficacy of control of sub-clinical mastitis as measured by Somatic Cell Counts (SCC) and the degree of compliance by farmers in adopting and maintaining recommendations throughout the course of the study period. No overall differences in SCC before and during the implementation of the study were found when all six farms were considered together. Three of the six study farms experienced a significant decrease in herd milk recorded SCC during the implementation of the control programme. An essential part of the study was achieving initial agreement on recommendations as well as ongoing monitoring of compliance during the study. This pilot study shows that HACCP can be implemented on farms as a means of working towards the control of mastitis and that farmer attitude, and understanding of mastitis are crucial in terms of motivation irrespective of practical approaches used to manage mastitis.

Efficacy of conventional and extended intra-mammary treatment of persistent sub-clinical mastitis with cefquinome in lactating dairy cows

The objectives of the present study were to evaluate the efficacy of intra-mammary-administered cefquinome for the treatment of sub-clinical mastitis in lactating dairy cows and to determine if extended therapy would enhance treatment efficacy. Seventy-three Holstein dairy cows from a single farm with 150 infected quarters were enrolled in the study. Infected cows were allocated randomly to one of three treatment regimens: (1) conventional (standard) regimen: 75 mg of cefquinome administered three times at 16-h intervals (25 infected cows, 52 intra-mammary infections (IMI)), (2) extended regimen: 75 mg of cefquinome administered six times at 16-h intervals (26 infected cows, 58 IMI) and (3) negative untreated control group (22 cows, 40 IMI). Most IMI were caused by coagulase-negative staphylococci, streptococci other than Streptococcus agalactiae and coliforms. The overall bacteriological cure (BC) rates for sub-clinical IMI were 84.61%, 91.37% and 20% for the conventional, extended and the control groups, respectively, indicating a higher BC rate for the treated groups than the control group (P < 0.001). Significant differences in somatic cell count (SCC) were detected between the treated versus the control group (P < 0.001). No differences, concerning the BC rate or SCC, were observed between the extended and the conventional groups. Although fat and protein percentages increased in the treated groups, there were no significant differences in post-treatment milk production between the groups. Results of this study indicate that cefquinome therapy was effective in reducing SCC and eliminating sub-clinical IMI in lactating dairy cows, but extended therapy did not enhance treatment efficacy.

Effects of Mastitis on Buffalo Milk Quality

The objectives of this study were to compare the effectiveness of different indicators of mammary inflammation in buffalo and to evaluate the association of the indicators with buffalo milk yield, composition, and rennet coagulation properties. This study was carried out at four buffalo farms in central Italy using a total of 50 lactating buffalo. Milk from each buffalo was tested at the beginning, middle, and end of lactation. To evaluate the relationship between mastitis markers and milk components, three classes were defined for each of the following markers: total somatic cell count (TSCC), differential somatic cell count (DSCC), and bacteriological results The regression coefficient for the reference method and the alternative method of determining TSCC was 0.81, indicating that the method routinely used to analyze buffalo milk consistently underestimated actual TSCC. The milk samples positive for udder-specific bacteria also had higher TSCC values than the samples that were negative for bacteria (/ml vs. /ml). In samples that were positive for udder-specific bacteria, polymorphonuclear leukocytes (PMN) made up greater than 50% of the cells. Moreover, only 1% of the samples in the lowest TSCC class were positive for bacteria. The correlation between TSCC and PMN was stronger (0.70), and PMN values in buffalo milk increased significantly when the TSCC class changed from low (38%) to medium and high (56% and 64%). Milk yield was negatively related to TSCC. Significant changes in lactose (4.87%, 4.80% and 4.64%) and chloride content (0.650 mg/ml, 0.862 mg/ml and 0.882 mg/ml) were also observed with increasing TSCC values. Higher TSCC was associated with impaired rennet coagulation properties: the clotting time increased, while the curd firming time () and firmness decreased. We concluded that in buffalo as in dairy cows, TSCC is a valid indicator of udder inflammation; we also confirmed that a value of cells/ml should be used as the threshold value for early identification of an animal affected by subclinical mastitis. In addition to its association with significantly decreased milk yield, a TSCC value above this threshold value was associated with changes in milk composition and coagulating properties.

Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds

The share of organic dairy production in EU is increasing and this study describes the herd structure and cow performance in organic and conventional dairy production systems in Sweden. The data included records from 2 902 718 lactations, collected in organic ( n = 471) and conventional ( n = 13 976) herds between 1998 and 2005. Compared with conventional herds, the organic herds were larger and increased more rapidly in size. The replacement rate was slightly lower in organic herds and fewer Swedish Holsteins were used. The statistical analysis of cow performance in the first three lactations showed lower milk, fat and protein production in organic herds, but the increase in production from first to second lactation was larger when expressed in kg milk. Fertility was better for organically managed cows compared to conventionally managed cows, but the somatic cell count (SCC) was higher. However, at a given production level the fertility was slightly worse in organic herds while there was no difference in SCC. No interactions of importance were found between production system and breed for any trait. The results showed that organic and conventional dairy production differed regarding herd structure and cow performance. However, the differences in fertility and SCC found were to a high extent explained by the lower milk yield in organic production and no breed was found to perform better in either system.

Short Communication: Correlated Selection Responses in Somatic Cell Count from Selection Against Clinical Mastitis

Correlated selection responses in lactation mean somatic cell score (LSCS) were estimated for groups of cows selected for high protein yield and low mastitis frequency, respectively. Selection for increased milk production resulted in an unfavorable correlated response for LSCS, whereas direct selection against clinical mastitis resulted in a favorable correlated selection response. After 6 cow generations, the genetic difference between the high protein yield group and the low mastitis group was 0.3 units LSCS, equivalent to a difference in somatic cell count of approximately 15,000, assuming deviations from a population mean LSCS of 4.1.

Influence of Free-Stall Base on Tarsal Joint Lesions and Hygiene in Dairy Cows

The objective was to quantify the incidence of tarsal lesions and level of hygiene by stall bed type. Cows were scored on 100 dairies from Wisconsin, Minnesota, Indiana, Iowa, and New York in the fall and winter. Thirty-eight dairies used rubber-filled mattresses (RFM), 27 had sand beds, 29 had waterbeds, and 6 used compost packs (CPk). Stocking density, stall dimensions, bedding amount, bedding frequency, and type of bedding were recorded. One pen of early-lactation multiparous cows on each dairy was scored based on injury of the tarsal joints at the lateral and medial surfaces and tuber calcis at the dorsal, lateral, and medial surfaces. A tarsal score of 1 represented hair loss, 2 was moderate, and 3 indicated severe swelling. Differences between bed types in the percentages of cows with lesions were tested with one-way ANOVA by lesion severity and incidence, with farm as the experimental unit. Cows on sand beds or waterbeds had fewer lesion scores of 1, 2, and 3 than those on RFM. The percentages of score 1 were 54.6±4.4 (RFM), 22.5±4.7 (sand), and 29.8±4.3 (waterbed), whereas the percentages of score 2 were 14.0±1.4, 2.3±1.5, and 5.0±1.4, and of score 3 were 3.0±0.4, 0.2±0.4, and 0.4±0.4. Cows on CPk had no lesions. Hygiene scores ranged from 1 to 5, with 1 being clean and 5 soiled. The percentages of hygiene score 1 were 0 (compost), 0.4 (RFM), 0.4 (sand), and 0.4 (waterbeds); those with score 2 were 79.0, 84.0±0.01, 73.2±0.01, and 80.4±0.01; with score 3 were 20.3, 15.2±0.01, 23.8±0.01, and 18.6±0.01; with score 4 were 0.8, 0.005±0.001, 0.006±0.001, and 0.025±0.003; and with score 5 was 0 for all bed types. Cows on RFM and waterbeds had improved hygiene compared with cows on sand beds. There was no difference in somatic cell count (SCC) by bed type. The percentage of cows in fourth lactation or greater on waterbeds (19.8±1.8) was greater than those on RFM (13.3±1.6) or on sand (13.5±1.8). The percentage culled was lower for cows on waterbeds than on RFM (22.8±1.5 vs. 29.4±1.4). Score 3 tarsal lesions were correlated (r = 0.60) with SCC. The length of the sand bed was correlated with a greater percentage of mature cows. The SCC was correlated with the percentage of cows reported lame on the day of the visit (r = 0.45) and with neck rail height (r = −0.26). On dairies with RFM, severe lesions (r = 0.60), death losses (r = 0.52), and percentage of the herd reported lame on the day of the visit (r = 0.52) were all correlated with the SCC. Dairies with higher percentages of lesions had higher SCC, death losses, lameness, and culling rates. Adding bedding several times per week may reduce the incidence of lesions.

Importance of the Sampled Milk Fraction for the Prediction of Total Quarter Somatic Cell Count

This study investigated the changes in somatic cell counts (SCC) in different fractions of milk, with special emphasis on the foremilk and cisternal milk fractions. Therefore, in Experiment 1, quarter milk samples were defined as strict foremilk (F), cisternal milk (C), first 400g of alveolar milk (A1), and the remaining alveolar milk (A2). Experiment 2 included 6 foremilk fractions (F1 to F6), consisting of one hand-stripped milk jet each, and the remaining cisternal milk plus the entire alveolar milk (RM). In Experiment 1, changes during milking indicated the importance of the sampled milk fraction for measuring SCC because the decrease in the first 3 fractions (F, C, and A1) was enormous in milk with high total quarter SCC. The decline in SCC from F to C was 50% and was 80% from C to A1. Total quarter SCC presented a value of approximately 20% of SCC in F or 35% of SCC in C. Changes in milk with low or very low SCC were marginal during milking. Fractions F and C showed significant differences in SCC among different total SCC concentrations. These differences disappeared with the alveolar fractions A1 and A2. In Experiment 2, a more detailed investigation of foremilk fractions supported the findings of Experiment 1. A significant decline in the foremilk fractions even of F1 to F6 was observed in high-SCC milk at concentrations >350×103 cells/mL. Although one of these foremilk fractions presented only 0.1 to 0.2% of the total milk, the SCC was 2- to 3-fold greater than the total quarter milk SCC. Because the trait of interest (SCC) was measured directly by using the DeLaval cell counter (DCC), the quality of measurement was tested. Statistically interesting factors (repeatability, recovery rate, and potential matrix effects of milk) proved that the DCC is a useful tool for identifying the SCC of milk samples, and thus of grading udder health status. Generally, the DCC provides reliable results, but one must consider that SCC even in strict foremilk can differ dramatically from SCC in the total cisternal fraction, and thus also from SCC in the alveolar fraction.

Relationship between cellular and whey components in buffalo milk

High somatic cell count (SCC) affects milk quality and cheesemaking, resulting in a reduction in cheese yield and quality. In dairy cows, quarter milk samples with > 200,000 cells/ml are considered to have subclinical mastitis, while there is much uncertainty on the corresponding levels of SCC in buffalo milk. In this study 30 lactating water buffaloes were selected and SCC, differential somatic cell counts and several whey components were tested in quarter milk samples to assess the relationship between inflammation markers and milk quality. Overall 236 quarter milk samples were considered. To evaluate the relationship between cellular markers (SCC, polymorphonuclear leucocytes, PMN, and N-Acetyl-beta-glucosaminidase, NAGase) and other milk components, three classes were defined (low, medium and high). Analysis of milk yield showed a significant reduction in the high class of each of the three markers chosen. Overall, the highest class was characterized by significant changes in milk composition and a lower milk quality. The presence of an inflammatory status of the udder was frequent after the first trimester of lactation and in buffaloes with two or more parturitions. This study showed that significant changes in milk components can be observed when SCC are > 400,000 cells/ml, PMN are > 50% and NAGase is > 100 units. These thresholds could be suggested as levels to define udder health status in buffalo cows.

SURVEY OF MILK QUALITY ON U.S. DAIRY FARMS UTILIZING AUTOMATIC MILKING SYSTEMS

Milk quality parameters were recorded for U.S. dairy farms using automatic milking (AM) from August 2000 toJune 2003. The first farm began milking in August 2000 and additional farms were admitted to the study as they began AMoperation so that 12 AM farms were represented by June 2003. Daily records of bulk tank somatic cell count (SCC) and totalbacterial count (TBC) data were analyzed and compared to corresponding data from a cohort conventional farms in Wisconsinas well as data from European AM installations. The geometric means for all farms were 268,000 cells/mL SCC and13,300 cfu/mL TBC. There was no significant difference in SCC between AM farms and the cohort of conventional farms, buta clear and significant seasonal effect was evident for SCC for both farm types, with higher values observed during the summermonths (July, August, and September). The TBC of milk from AM farms was found to be lower than that from the cohort ofconventional farms, and there was some evidence of a seasonal effect on TBC for both types of farm. Both SCC and TBCdecreased as the amount of time that a farm utilized AM increased.

Efeito da temperatura e do tempo de armazenamento sobre a contagem de células somáticas no leite

Avaliou-se o efeito da temperatura e do tempo de armazenamento sobre a contagem de células somáticas(CCS). Amostras de leite de 21 vacas, coletadas e armazenadas às temperaturas de 5, 27, 32 e 36ºC e analisadas no 1º, 3º, 5º e 7º dia após coleta, foram classificadas em três grupos (células/ml): baixa (236.000±164.000), média (624.000±356.000) e alta CCS (1.320.000±945.000). O delineamento experimental foi o de parcelas subdivididas. As médias da CCS foram iguais (P&gt;0,05) para amostras mantidas à temperatura de 5ºC e analisadas entre o primeiro e o sétimo dias após a coleta e para aquelas mantidas às temperaturas 5, 27, 32 e 36ºC e analisadas no primeiro dia. Médias diferentes (P&lt;0,05) da CCS foram observadas para amostras mantidas a 27, 32 e 36°C a partir do 5°, 5° e 3° dias, respectivamente. Foram observados decréscimos de 57,6%, 58,5% e 27,9% nos valores iniciais da CCS nas amostras classificadas como baixa, média e alta, respectivamente. Os resultados mostram a necessidade de se encaminhar as amostras de leite para CCS sob refrigeração e de ser feita análise até sete dias após a coleta.

Effect of Prepartum Intramammary Treatment of Heifers on Somatic Cell Count, Milk Production and Mastitis Postpartum

Mastitis in heifers has been the topic of numerous studies in the past few decades. Many studies have concluded that a large percentage of heifers began their first lactation with intramammary infections (IMI), usually with coagulase-negative Staphylococcus (CNS) species. These bacteria are ubiquitous on skin and hair of heifers, and then colonize the teat canal and gland. Several studies have examined the outcome of prepartum intramammary antibiotic therapy in heifers and have shown antibiotics are successful at reducing infections.1,2 However, results have varied on the benefit of reducing these infections. Oliver et al2 found prepartum intramammary antibiotic therapy in heifers increased milk production ( + 1000 lb; 454.5 kg) and decreased somatic cell count (SCC) linear score (-0.6) significantly over untreated animals. Treatment was demonstrated to be profitable, as long as the increase in milk production is greater than 84 lb (38.1 kg).4 In the seven-state study,1 prepartum antibiotics were effective in curing IMI in heifers, but the differences in SCC and milk production between treatment and control groups were small. The goal of this study was to treat prepartum heifers with intramammary antibiotics and monitor SCC, cultures and milk production during the first part of their lactation to determine the efficacy and value of therapy.