https://doi.org/10.3168/jds.2024-24751

Abstract

The CellCheck Dry Cow Consult (DCC) was developed by the CellCheck Technical Working Group to enable farmers to engage with their nominated vet to develop farm-specific selective dry cow therapy (SDCT) plans, where appropriate. This study evaluated the effect of the DCC on farmer decision-making around dry cow therapy, and the udder health impact of implementing SDCT, in study herds over the 2019 and 2020 dry periods. The DCC was a 3-hour consult, delivered and funded as part of the Targeted Advisory Service on Animal Health (TASAH). Herds that completed a DCC were invited to register for a Dry Cow Review the following year. The combined dataset for analysis across both years comprised of 439 herds and 25,357 cows. Available herd size ranged from 25 to 800. The median SCC of cows dried off with teat sealant only was 47,000 cells/ml prior to drying off in 2019 and 48,000 cells/ml at first milk recording in 2020, and 43,000 cells/ml prior to drying off in 2020 and 39,000 cells/ml at first milking recording in 2021. Following both the 2019 and 2020 dry periods, cows tended to converge towards a similar median SCC early in the following lactation, irrespective of prior dry cow treatment strategy. The uptake of SDCT was greater in Review herds, with 21% of cows receiving teat sealant only in 2020, compared to 16.3% of cows in herds participating in a Consult for the first time in 2020. At an individual cow level, in both years dry period new infection rate (NIR) was approximately 2.7% higher for cows treated with teat sealant only, than for those treated with both dry cow antibiotic tubes and teat sealant, and 1.2% higher than cows treated with antibiotic only. Regardless of treatment, there was a significant association between increasing parity and the risk of a dry period new infection. Increasing herd size had a statistically significant effect on the risk of dry period new infection rates. At a herd level, there was no statistically significant increase in NIR when SDCT was used compared to herds where blanket dry cow therapy was used. While not without risk, SDCT can be successfully implemented in Irish herds; however, constant attention to hygiene and management is essential. Though there are challenges to face, facilitating continued farmer education and engagement with professional guidance will be important.

Keywords: Dairy cows; selective dry cow therapy; antimicrobial resistance.

https://doi.org/10.3390/ani14060900

Abstract

The transformation of milk into cheese largely depends on the technological properties of the raw material, with breed being a crucial factor that influences both the composition and coagulation properties of the milk used for cheesemaking. This study uses canonical correlation analysis to explore the relationships between physicochemical traits and coagulation properties in milk from various Spanish breeds, aiming to identify both common and breed-specific patterns that impact the milk technological aptitude. A total of 832 milk samples from Manchega, Assaf, Merino de Grazalema, and Merino de Los Pedroches breeds were analyzed. The milk characteristics investigated included pH, composition (fat, protein, lactose, total solids) and coagulation properties (curd firmness – A60, rennet clotting time – RCT, curd firming time – k20, and individual laboratory curd yield – ILCY). The results reveal a shared correlation structure across breeds and unique covariation patterns in some breeds that deviate from the general trend. While Assaf and Merino de Los Pedroches follow the common correlation pattern, Manchega and Merino de Grazalema exhibit distinct patterns. This research underscores the need for in-depth study and suggests that the dairy industry could benefit from shifting from the traditional focus on maximizing fat and protein for higher curd yields to considering other traits for selective breeding.

Keywords: sheep milk; coagulation; breed; canonical correlation; Manchega; Assaf; Merino.

https://doi.org/10.3390/foods13060886

Abstract

This study conducted a seasonal analysis of bulk tank milk from 77 sheep farms, to establish relationships between the concentration of major microbial groups and milk coagulation properties. The investigated milk traits included composition (pH, fat, casein, lactose), coagulation properties (curd firmness -A60-, rennet clotting time -RCT-, curd firming time -k20-, curd yield -CY-), and somatic cell score (SCS). The main microbial groups analyzed were total mesophilic bacteria (SPC), thermodurics (THERMO), psychrotrophs (PSYCHRO), Pseudomonas spp. (PSEUDO), lactic acid bacteria (LAB), catalase-negative gram-positive cocci (GPCNC), Escherichia coli (ECOLI), coliforms other than Escherichia coli (COLI), coagulase-positive staphylococci (CPS), coagulase-negative staphylococci (CNS), and spores of lactate-fermenting Clostridium (BAB). Mixed linear models were used to explore associations between coagulation properties and the aforementioned variables. Results demonstrated that incorporating microbial loads into the models improves their fit and the relative quality of the outcomes. An important seasonality is demonstrated by an increase in CY and A60, along with a decrease in RCT and k20 during autumn and winter, contrasting with spring and summer. BAB concentration resulted in a reduction of A60 and an increase in RCT, whereas SPC concentration led to an enhancement of A60 and a reduction in RCT. An increase in GPCNC concentration was associated with an increase in k20 and a decrease in CY.

Keywords: coagulation traits; dairy industry; microbiological quality; milk sheep quality; tank milk.

https://doi.org/10.3390/foods13060873

Abstract

Sheep milk from local breeds is important for the production of high-quality cheeses throughout the Mediterranean region, such as Manchego cheese in Spain. To maintain sustainable and efficient production, it is necessary to reach a better understanding of how the composition and hygiene of the milk affect the coagulation process with the aim of optimizing production yield. This study implements a stochastic production frontier function to estimate the potential production of curd and efficiency using data from the four seasons of a study of 77 Manchega sheep farms. The Cobb-Douglas production frontier model was estimated using the maximum likelihood estimation method. The results show that the content of protein, lactose, and fat exhibited increasing returns to scale, with protein content being the most significant factor for curd production. Approximately half of the inefficiency was due to factors related to the technological properties and hygiene of the milk. pH, curd firmness, and concentration of lactic acid bacteria improve the efficiency of coagulation, while the concentration of spores of lactate-fermenting Clostridium spp., Pseudomonas spp., staphylococci, and catalase-negative gram-positive cocci favor the inefficiency of the coagulation process. To date, this is the first study to evaluate the effect of different factors, such as microbial groups, milk composition, and technological properties, on the efficiency of the coagulation process in dairy sheep.

Keywords: coagulation efficiency; Stochastic Frontier Analysis (SFA); Manchego cheese; dairy industry.

https://doi.org/10.3390/ani14060850

Abstract

The aim of this study was to assess the carcass and meat quality of female Lidia cattle slaughtered at different ages, in order to deepen our understanding of the breed's unique characteristics. The effect of slaughter age on carcass traits and meat quality attributes of m. Longissimus was investigated in Lidia heifers (n=200) and cows (n=100) reared and finished in an extensive system. The animals were slaughtered at 24-36 months (Heifer I), 36-48 months (Heifer II) or > 48 months (Cull cow). Carcasses (~120 kg) presented poor conformation (O, O+) and medium fatness (2, 2+). The dissection of the 6th rib yielded mean values of 58.6%, 14.3% and 24.8% for lean, fat and bone, respectively. Cows had a higher proportion of dissectible fat (p<0.05). Subcutaneous fat was classified as dark and yellowish, and meat (aged for 21 days) as dark (L* = 25.5), reddish (a* = 14.4), moderately yellowish (b* = 12.9), with acceptable water-holding capacity (TL = 5.34%; DL = 0.97%; PL = 8.9%; CL = 22.1%) and intermediate tenderness (WBSF = 4.6 kg/cm2). The b* value of meat was higher (p<0.05) in cull cows. Meat of cull cows was more yellowish (p<0.05) and obtained higher scores for flavor (p<0.05), juiciness p<0.01), overall tenderness (p<0.001) and overall acceptance (p<0.001).

Keywords: Lidia cattle; Carcass traits; Meat quality; Sensory panel; Local breeds

https://doi.org/10.3390/foods13040610

Abstract

This study explores the interrelationships between the composition, coagulation, and colour of sheep, goat, and cow milk to identify their similarities and differences and to assess whether the relationships between the variables are common to all species or whether they emerge from species-specific relationships. For this purpose, 2400 individual milk samples were analysed. The differences and similarities between the species were determined using discriminant analysis and cluster analysis. The results show a clear differentiation between species. Sheep milk stands out for its cheesemaking capacity and shows similarities with goat milk in composition and coagulation. Nonetheless, colorimetry highlights a greater similarity between sheep and cow milk. Composition and colorimetry were more discriminating than coagulation, and the variables that differed the most were fat, protein, curd yield, lightness, and red–green balance. Using canonical correlation, the interrelationships between the different sets of variables were explored, revealing patterns of common variation and species-specific relationships. Colorimetric variables were closely related to milk solids in all species, while in sheep milk, an inverse relationship with lactose was also identified. Furthermore, a strong relationship was revealed for all species between colour and curd yield. This could be modelled and applied to estimate the technological value of milk, proving colorimetry as a useful tool for the dairy industry.

Keywords: milk; dairy; cow; goat; sheep; coagulation; colour values; technological quality

https://doi.org/10.1016/j.smallrumres.2023.107106

Abstract

Milk from Manchega sheep is the raw material for the elaboration of Protected Designation of Origin (PDO) Queso Manchego, a hard-pressed cheese with one of the most established quality marks on the market worldwide. For this reason, milk quality control in this breed is one of the main targets of the dairy sheep sector. However, pricing systems still continue to apply criteria based only on milk composition and the current legislation on food hygiene. The aim of this study is to explore bulk tank sheep milk quality, estimating milk coagulation properties and their relationship with composition, somatic cell counts, and differential microbiological quality. For this purpose, 308 bulk tank milk samples were collected with seasonal periodicity, and analyses were performed for the aforementioned traits. The obtained results highlight the variability in composition, microbiology, and coagulation properties in different samples, which prevents clear relationships between milk quality parameters. However, there was evidence of a group of milk samples whose coagulation would be desirable for cheesemaking, based on values for fat, protein and total solids. Outcomes also stand out casein content as an important parameter to affect curd yield, proving the interest of using casein as trait for genetic improvement in dairy sheep breeds.

Keywords: composition; microbiology; milk coagulation properties; sheep

https://doi.org/10.3390/ani13020255

Abstract

Understanding the factors that determine and regulate cheese yield would allow, through deterministic parametric efficiency models, the determination of the most appropriate milk characteristics for the industry, and the estimation of a technological value for these characteristics. The present study aims to evaluate coagulation performance of Manchega sheep milk intended for cheesemaking and explores two models to determine milk technological efficiency. For this purpose, 1200 Manchega sheep milk samples were collected, and analyses were performed for composition, milk coagulation properties (MCP), somatic cell count (SCC), and milk color values. A first model was built based on curd yield (CE) and a second one based on dry curd yield (DCE). GLM and MANCOVA analyses were used to identify the factors that determine curd yield efficiency, which mainly depended on pH, casein, and lactose content and, to a lesser extent, on the speed of coagulation and curd firmness. When comparing both models, differences were linked to the water retention capacity of the curd. Based on this, the DCE model was considered much more accurate for prediction of coagulation efficiency in a wider variety of cheeses, as it does not seem to be affected by moisture loss.

Keywords: sheep milk; coagulation efficiency; curd yield; deterministic parametric efficiency models; Manchega

https://doi.org/10.3390/ani12010006

Abstract

Conjoint analysis was used to estimate the relative importance of some of the main extrinsic attributes and quality labels of beef in three Spanish cities (Córdoba, Marbella, and Santa Pola) in a study performed with 300 individuals. Consumers were segmented according to their frequency of consumption. Willingness to pay for different meats was also calculated from the conjoint analysis results. Consumer liking of beef that had been finished with an alternative concentrate rich in agro-industrial by-products and aged for three different durations as compared to conventionally finished beef was also evaluated using the same consumers. The most important attribute for Spanish consumers was the price (28%), followed by origin (25%), animal welfare certification (19%), protected geographical indication (14%), and organic agriculture certification (14%). Most consumers preferred beef from Spain at the lowest possible price and with the highest number of quality labels. Consumers were willing to pay a premium of 1.49, 3.61, and 5.53 EUR over 14 EUR/kg for organic certification, protected geographical indication, and animal welfare certification, respectively. Sensory analysis revealed that, for regular consumers, beef finished with an alternative concentrate rich in agro-industrial by-products offered several hedonic advantages (color, flavor, and tenderness) when compared to beef finished using a conventional diet, while occasional consumers did not find any difference between the two kinds of meat.

Keywords: aging; animal welfare; beef; by-products; conjoint; consumer; finishing heifers; meat; organic farming; quality label

https://doi.org/10.1186/s13620-021-00207-0

Abstract

Background. Selective dry cow therapy (SDCT) is widely promoted in dairy farming as a method to reduce antimicrobial usage. New legislation introduced by the European Union will restrict and regulate the prophylactic and metaphylactic use of antibiotics from January 2022. Blanket dry cow therapy continues to be a practice engaged in by many farmers in Ireland and for many of these farmers, moving towards SDCT would require a significant infrastructural, behavioural and/or cultural change on their farm. Existing research has reported the important need to understand farmers’ motivations to initiate any substantial behaviour change. However, it is currently unknown what farmers know, think and believe about SDCT in Ireland. The aim of this study was to use qualitative methods to explore what barriers and facilitators farmers perceived to exist with SDCT and explore if they had chosen to implement SDCT after voluntarily participating in a funded dry cow consult with a trained veterinarian, with the objective of maximising the dry period udder health performance and moving safely to SDCT.

Results. In this study, 19 farmers were contacted, and telephone interviews were conducted regarding farmers’ beliefs about the consequences of SDCT. Audio recordings were professionally transcribed verbatim and analysed qualitatively using an inductive thematic analysis. The analysis identified 6 barriers and 6 facilitators to implementing SDCT. A significant fear of increasing mastitis incidence was evident that caused reluctance towards SDCT and reliance on antibiotics. Mixed perceptions on SDCT, infrastructure limitations, a perceived lack of preventive advice as well as peer influence were presented as barriers to SDCT. Farmers can build confidence when a graded approach to SDCT is implemented, which could help overcome the fear of SDCT and reliance on antibiotics. Regulatory pressure, high standards of farm hygiene and use of targeted veterinary consults were found to facilitate SDCT. Education was suggested to motivate farmers in the future uptake of SDCT. Despite cited negative influences, peer influence can be utilised to encourage the farming community.

Conclusions. This study prioritises areas to facilitate the major behaviour change required as a dairy industry in order to move from blanket dry cow therapy to SDCT.

Keywords: aging; animal welfare; beef; by-products; conjoint; consumer; finishing heifers; meat; organic farming; quality label

https://doi.org/10.3168/jds.2021-20303

Abstract

This study approaches the interrelation patterns between composition of milk and whey, curd yield, chromaticity, syneresis, and technological quality of Manchega sheep milk using multivariate factor analysis. In addition, the effect of the main husbandry components (flock, prolificacy, season of the year, stage of lactation, and parity) on the common latent factors that define the pattern of variation of Manchega milk was assessed. For this purpose, 1,200 individual Manchega ewe milk samples from 4 different flocks registered under the Protected Designation of Origin Queso Manchego were analyzed (50 ewes/flock). Samples were collected in 2 different seasons of the year (spring and autumn) and at 3 time points per season: early, mid-, and late lactation. The obtained results suggested that curd yield mainly depends on milk composition, and the retention of water in the curd is related to coagulation traits. Thus, composition and moisture content could be useful indicators to assess the efficiency and quality of milk intended for cheesemaking, regardless of the analysis of coagulation properties. Finally, in terms of husbandry, a direct effect of flock and stage of lactation was observed on all analyzed factors, with a lower influence of season and parity.

Keywords: sheep milk; factor analysis; covariation factor; technological quality; curd yield

https://doi.org/10.3168/jds.2020-19187

Abstract

Characteristics of sheep milk are of great interest for the dairy industry, as almost the totality of production is intended for cheesemaking. However, the existing relationships between these variables are complex. This study assessed composition, hygienic quality, coagulation properties, and curd yield of 1,200 individual Manchega sheep milk samples. The aim was to compare the effect of composition and hygienic quality on coagulation and curdling, and to evaluate the relationship between curd yields and the coagulation process and the effect of other features by using path analysis methodologies. Outcomes proved path analysis to be a useful and effective tool to assess these relationships through direct and indirect paths within the same model. Results showed that the factors that had a direct influence on milk coagulation were lactose concentration, casein content, and initial pH of milk. Contrastingly, somatic cells did not seem to have any effect (direct or indirect) on the coagulation process. Factors that directly affected curd yield were fat content, lactose concentration, casein content, and curd moisture. However, technological parameters showed little effect over curd yield.

Keywords: Manchega sheep; curd yield; path analysis; syneresis; multivariate analysis

https://doi.org/10.3168/jds.2019-17201

Abstract

This study explores the relationships between composition, hygienic quality, and color values of milk to evaluate whether colorimetry could be used as a valid predictor of the quality of raw milk and its coagulation. For this purpose, we performed analyses in 1,200 individual samples of Manchega sheep milk from 4 flocks from the region of Castilla–La Mancha, Spain. Based on the measured variables, we determined the differences and similarities between coagulating and noncoagulating samples using discriminant analysis techniques. The variables with a higher discriminant ability were lactose content, somatic cell score, pH, and the color values lightness (L*) and red/green value (a*). The model based on color values showed a predictive ability similar to that found in the model based on milk composition and hygienic quality. Canonical correlation analysis allowed us to explore the relationships between both sets of variables. Canonical correlations for the first and second pair of canonical values were 0.794 and 0.438, respectively. Both values were significant and represented 92.82% of the observed variability. The correlation structure showed that color values had a strong correlation with fat and protein content and with total solids, and they had a weak correlation with lactose content and somatic cell score. The 2 first combinations of standardized canonical variability could be considered a predictable measure of the composition and, to a lesser extent, the hygiene of milk. Measurement of color values could be a rapid and effective means of supplementing standard analyses when determining the coagulation ability of Manchega sheep milk.

Keywords: sheep; multivariate analysis; colorimetry; milk coagulation

https://doi.org/10.1016/j.prevetmed.2019.104754

Abstract

Dear Editor-in-chief,

We have read with deep interest the letter of comments presented by Bruno Cabral Pires, Anahi Souto Vieira and Walter Lilenbaum.

On the field of bovine reproductive diseases, leptospirosis is considered as a cause of infertility, abortion and reproductive failure together with trichomoniasis and campylobacteriosis. However, these agents have scarcely been studied in order to analyse shared risk factors in endemic areas such as Argentina and Brazil.

The main bovine reproductive diseases generally share common characteristics. Consequently, focusing on these features should improve effectiveness and efficiency of disease control programs. This was the approach on which it is based the joint Control and Eradication Program for trichomoniasis and campylobacteriosis described in Molina et al. (2018).

As mentioned above, we agree with the authors in the convenience of also considering leptospirosis under this scheme. In fact, we also have developed a small pilot study that suggests the need to further investigate the role that leptospirosis and neosporosis play on reproductive efficiency in bovine herds in La Pampa (Argentina).

According to the authors, systems where natural reproduction is practiced are predominant in countries such as Argentina or Brazil and are subject to particular production conditions that can difficult the diagnosis of venereal diseases. We believe that in the future the importance of bovine reproductive diseases will increase, due to the current trend (especially in western countries) towards more extensive and traditional farming systems.

Finally, we would like to show our appreciation to the authors for the comments and contributions reflected in their letter.

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Abstract

The venereal diseases Bovine Trichomoniasis (BT) and Bovine Genital Campylobacteriosis (BGC) cause economic losses in endemic areas, such as the province of La Pampa in Argentina, where bovine production is typically extensive. This study has used data compiled from 2007 to 2013 by the Official Program for the Control and Eradication (PCE) of venereal diseases, aiming to determine the prevalence, incidence and persistence of BT and BGC and to provide projections until 2020. Fourteen univariate models were used to adjust each time series. The prevalence and incidence of both diseases have significantly decreased during the studied period, while the persistence has remained constant. The prevalence of BT has diminished from 7.48% in 2007 to 3.03% in 2013, while the prevalence of BGC has diminished from 9.36% to 3.15%. The incidences have been reduced to an annual average of 0.60 for BT and 0.67 for BGC. Although the estimation models are not able to predict accurately the future epidemiologic rates of BT and BGC in La Pampa, projections show a significant decreasing trend of the prevalence and incidence of BT and BGC. The persistence of BGC is expected to remain close to the 2007-2013 average, while the persistence of BT did not adjust to any of the 14 models used. These results indicate that PCE has been effective to reduce the infection of disease-free herds. However, in order to reduce the ratio of persistent herds, other preventive and management measures should be considered.

Keywords: bovine; bovine genital campylobacteriosis; venereal diseases monitoring; bovine trichomoniasis; modelling

https://doi.org/10.3168/jds.2018-14752

Abstract

In Spain, ewe milk is mainly used for cheesemaking, and farming systems have traditionally been based on the use of autochthonous breeds. However, in recent years, the progressive introduction of highly productive foreign breeds in Spanish farms has led to an increasing interest in the characterization of dairy sheep breeds to evaluate whether genetic selection schemes should focus on productivity or milk technological aptitude. The purpose of this work was to explore milk composition and coagulation to classify 4 of the main dairy sheep breeds used in Spain. This study included 832 individual ewe milk samples from the breeds Manchega, Assaf, Merino de Grazalema, and Merino de Los Pedroches. Samples were analyzed for native pH, composition (fat, protein, lactose, and total solids), coagulation properties, and individual laboratory curd yield. An indicator of coagulation efficiency was also determined. Canonical discriminant analysis was performed to establish differences and similarities among breeds based on the measured variables. In addition, cluster analysis was performed to study and quantify the concrete relationships among the discriminated groups. Discriminant analysis proved to be a powerful tool to accurately draw distinctions between breeds. In all cases, discrimination among breeds was evident and the 4 breeds could be easily differentiated. Cluster analysis showed greater similarity between Merino de Grazalema and Assaf compared with the other breeds, and F-statistics indicated a higher discriminating ability for the variables related to milk composition. However, Merino de Grazalema and Manchega were difficult to separate according to milk composition, but the coagulation process differenced them clearly. Coagulation also evidenced similarities between Manchega and Merino de Los Pedroches, although the latter was revealed to be the most different breed of all 4, which could lay the ground for its differentiation as an independent breed in the Official Catalogue of Spanish Livestock Breeds.

Keywords: sheep; milk coagulation; breed; multivariate analysis

https://doi.org/10.1371/journal.pone.0201739

Abstract

The venereal diseases bovine trichomoniasis (BT) and bovine genital campylobacteriosis (BGC) cause economic losses in endemic areas like La Pampa province in Argentina where beef cattle are usually extensively managed. This study used data compiled between 2007 and 2014 by a Provincial Program for the Control and Eradication of venereal diseases in order to develop and analyze retrospective models of time series for BT and BGC. Seasonality and long-term trend were explored with decomposition and simple regression methods. Autoregressive Integrated Moving Average models (ARIMA) were used to fit univariate models for the prevalence and persistence of BT and BGC. Autoregressive Integrated Moving Average with Explanatory Variable models (ARIMAX) were used to analyze the association between different time series, replacement entries and herd samplings. The prevalence and persistence of BT and BGC have decreased from 2007 to 2014. All the BT and BGC time series are seasonal and their long-term trend is decreasing. Seasonality of BT and BGC is similar, with higher rates of detection in autumn-winter than is spring-summer. Prevalence and persistence time series are correlated, indicating their changes are synchronic and follow a similar time pattern. Prevalence of BT and BGC showed the best fitting with the ARIMA (0,0,1)(0,1,1)12 model. While for persistence of BT and BGC, the best adjustment was with the same model with no seasonal difference where the current number of cases depends on the moving averages of the month and the previous season. Including covariates improve the fitting of univariate models, in addition, estimations using ARIMAX models are more precise than using ARIMA models. The time distribution of the samplings could be increasing the false negative ratio. According to the obtained results, the ARIMA and ARIMAX models can be considered an option to predict the BT and BGC prevalence and persistence in La Pampa (Argentina).

Keywords: bovine; bovine genital campylobacteriosis; venereal diseases monitoring; bovine trichomoniasis; modelling

https://doi.org/10.3168/jds.2017-13816

Abstract

Milk coagulation, especially in small ruminant species, is often hard to evaluate, as coagulation traits are normally considered individually and several factors related to udder health might distort yield calculation. Due to the lack of studies about these factors, our objective was to determine milk coagulation efficiency (CE) and its determinants using a deterministic technical efficiency approach, an ordinary least square regression model, and ANOVA. Milk from 300 Manchega ewes was collected and analyzed for composition, milk coagulation properties, and hygienic quality. The study results indicate that the estimated CE in Manchega ewes was 0.69, implying an important proportion of the animals produce poorly coagulating milk. The results of the ordinary least square regression model and ANOVA revealed that the main factor causing inefficiency was the initial pH of milk. Crude protein, casein and plasmin activity had moderate effects on CE, and, finally, other factors such as freezing point depression, somatic cell count, colony-forming units, and fat concentration had minor effects.

Keywords: sheep milk; coagulation efficiency; Manchega; hygienic quality

https://doi.org/10.1016/j.smallrumres.2017.10.005

Abstract

Milk from 40 Manchega ewes was collected monthly and analysed during a complete lactation (5 months). Milk samples were classified by their origin in 3 categories, termed PR (primiparous ewes), M1 (multiparous ewes with no damage of the udder in the previous lactation) and M2 (multiparous ewes with udder damage in the previous lactation). The influence on plasmin of several factors as stage of lactation, parity, somatic cell count and udder health status was studied, as well as the effect of plasmin activity on milk composition and rennet coagulation. Plasmin activity decreased throughout lactation but was not affected by parity or somatic cell count (P > 0.05). A strong negative correlation was found between plasmin activity and protein (especially casein), presumably due to the proteolysis of ß-casein. Plasmin also worsened rennet coagulation, increasing rennet clotting time (RCT) and negatively affecting curd firmness (A60), especially in multiparous ewes. However, the good health condition in the herd may have camouflaged some effects of plasmin over renneting.

Keywords: dairy sheep; plasmin; udder health; rennet coagulation

https://doi.org/10.1016/j.smallrumres.2017.10.005

Abstract

Milk from 40 Manchega ewes was collected monthly and analysed during a complete lactation (5 months). Milk samples were classified by their origin in 3 categories, termed PR (primiparous ewes), M1 (multiparous ewes with no damage of the udder in the previous lactation) and M2 (multiparous ewes with udder damage in the previous lactation). The influence on plasmin of several factors as stage of lactation, parity, somatic cell count and udder health status was studied, as well as the effect of plasmin activity on milk composition and rennet coagulation. Plasmin activity decreased throughout lactation but was not affected by parity or somatic cell count (P > 0.05). A strong negative correlation was found between plasmin activity and protein (especially casein), presumably due to the proteolysis of ß-casein. Plasmin also worsened rennet coagulation, increasing rennet clotting time (RCT) and negatively affecting curd firmness (A60), especially in multiparous ewes. However, the good health condition in the herd may have camouflaged some effects of plasmin over renneting.

Keywords: dairy sheep; plasmin; udder health; rennet coagulation

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Abstract

Improvement of milk quality is one of the principal objectives in dairy sheep productionsystems. Regulator Council of PDO Manchego Cheese and National Association of Manche-ga Breeders take part in some milk quality research projects from Dairy Laboratory of theRegional Selection and Animal Reproduction Center, belonging to the Regional Governmentof Castilla-La Mancha, has developed. The study aims are to find the relationship between themanagement characteristics of the farms and the quality of bulk tank sheep milk (in differentialfeatures of composition, microbiology and technological components). Knowledge of theserelationships informs about the main aspects to consider (preservation of milk, feeding systemsof sheep, associations, etc.) in sheep milk production for cheese making.

Keywords: milk; quality; Manchega sheep

https://doi.org/10.15567/mljekarstvo.2015.0208

Abstract

The relationship between somatic cell count (SCC) and raw milk composition and its coagulation properties measured at native or standardised pH values were investigated in Manchega ewes’ milk. A total of 84 bulk tank milk samples from flocks included in the National Association of Manchega Sheep Breeders were used. According to their SCC, milk samples were divided into three terciles named low (562±138 cells/mL), medium (956±115 cells/mL) and high (1705±428 cells/ mL) SCC groups. Within each SCC group, two pH treatments were applied before determining coagulation properties (rennet clotting time, curd firming time and curd firmness): no acidification of milk (coagulation at native pH) and acidification of milk at pH 6.5. Native milk pH significantly increased (P<0.05) as SCC rose. With respect to raw milk composition, fat contents were not affected (P>0.05) by SCC, protein content tended to be higher in the high SCC group (P=0.05) and lactose content was significantly lower (P<0.05) in that group. At native pH, the high SCC group had longer rennet clotting time, higher curd firming time and lower curd firmness after 30 min of rennet addition than the low and medium SCC groups (P<0.05). Standardising milk pH at 6.5 prior to rennet addition clearly cancelled out (P<0.05) the negative effects of high SCC on milk coagulation properties. In conclusion, despite the fact that acidification before renneting improved the coagulation properties of milk with high SCC, more research would be needed to determine the sensorial properties of cheese manufactured under such conditions.

Keywords: sheep; somatic cell count; milk composition; milk clotting

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