Heritability and Genetic Correlations of Test Day Milk Yield and Composition, Individual Laboratory Cheese Yield, and Somatic Cell Count for Dairy Ewes

Milking speed data were obtained for 2604 Holstein-Friesian cows, identified by sire, in test herds located in Quebec and Ontario. Milk samples were collected from each cow and analyzed for somatic cell count. Completed or projected lactation production records were available for this sample of cows. Two-minute yield and total milking time were adjusted for the effect of milk yield at sampling and the raw cell counts were transformed to the natural log scale. Sire and error variances were obtained by maximum likelihood (ML) methods and used to estimate heritabilities of and correlations between traits. The heritability estimate for the adjusted 2-min. yield, 0.23, was higher than that for the adjusted total milking time (0.13), with the estimates for the two unadjusted measures being intermediate (0.18). The phenotypic correlations between milking speed and somatic cell count were small. However, there were two distinct linear phases to the relationship between the adjusted 2-min yield and cell count. Small but significant phenotypic correlations were observed between unadjusted measures of milking speed and lactation production (0.11–0.22); however, correlations were not significant when adjustments were made for the milk yield at sampling. Genetic correlations between milking speed and somatic cell count were moderate to large and indicated an antagonistic relationship between faster milking speed and cell count. Also, the genetic correlations suggested some antagonism between increasing 2-min yield and lactation production, while the relationship between lactation traits and milking time was small. Key words: Milking speed, somatic cell count, correlations, heritabilities, Holsteins

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Connection of somatic cell count and milk yield as well as composition in dairy ewes

Archives Animal Breeding ◽

10.5194/aab-53-95-2010 ◽

2010 ◽

Vol 53 (1) ◽

pp. 95-100

Author(s):

J. Olechnowicz ◽

Z. Sobek ◽

J. M. Jaśkowski ◽

P. Antosik ◽

D. Bukowska

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Somatic Cell Count ◽

Threshold Value ◽

Milk Composition ◽

Milk Samples ◽

Dairy Ewes ◽

Cell Counts ◽

Daily Milk

Abstract. The aim of this study was to determine the effect of somatic cell count (SCC) on milk yield and composition using a threshold value of 250 ∙103 cells/ml in dairy ewes of line 05. A total of 1 512 milk samples from udder halves were collected throughout milking periods at monthly intervals. In the present study milk composition (from halves of the udder) and daily milk yield (from udders) was examined in terms of SCC in ewe milk in three groups: from both halves of the udder below 250 ∙103 cells/ml, from one halves of the udder below 250 ∙103 cells/ml and from second half udder above 250 ∙103 cells/ml and from both halves of the udder above 250 ∙103 cells/ml. Milk yield from udders, somatic cell count in milk samples from udder halves and milk composition depended on the level of SCC recorded for halves of the udder. Somatic cell counts in milk from one or both halves of udders exceeding 250 ∙103 cells/ ml resulted in a statistically significant (P<0.01) decrease in daily milk production of ewes, by approx. 15.89 and 30.22 %, respectively. The analysis of variance showed also a significant effect of parity and stage of lactation of ewes on somatic cell count (log SCC) and milk composition from udder halves below 250 ∙103 cells/ml.

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Genetic Parameters of Bovine Milk Fatty Acid Profile, Yield, Composition, Total and Differential Somatic Cell Count

Animals ◽

10.3390/ani10122406 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2406

Author(s):

Tania Bobbo ◽

Mauro Penasa ◽

Martino Cassandro

Keyword(s):

Animal Models ◽

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Milk Fat ◽

Fixed Effects ◽

Somatic Cell Count ◽

Genetic Parameters ◽

Genetic Correlations ◽

Bovine Milk

The growing interest of consumers for milk and dairy products of high nutritional value has pushed researchers to evaluate the feasibility of including fatty acids (FA) in selection programs to modify milk fat profile and improve its nutritional quality. Therefore, the aim of this study was to estimate genetic parameters of FA profile predicted by mid-infrared spectroscopy, milk yield, composition, and total and differential somatic cell count. Edited data included 35,331 test-day records of 25,407 Italian Holstein cows from 652 herds. Variance components and heritability were estimated using single-trait repeatability animal models, whereas bivariate repeatability animal models were used to estimate genetic and phenotypic correlations between traits, including the fixed effects of stage of lactation, parity, and herd-test-date, and the random effects of additive genetic animal, cow permanent environment and the residual. Heritabilities and genetic correlations obtained in the present study reflected both the origins of FA (extracted from the blood or synthesized de novo by the mammary gland) and their grouping according to saturation or chain length. In addition, correlations among FA groups were in line with correlation among individual FA. Moderate negative genetic correlations between FA and milk yield and moderate to strong positive correlations with fat, protein, and casein percentages suggest that actual selection programs are currently affecting all FA groups, not only the desired ones (e.g., polyunsaturated FA). The absence of association with differential somatic cell count and the weak association with somatic cell score indicate that selection on FA profile would not affect selection on resistance to mastitis and vice versa. In conclusion, our findings suggest that genetic selection on FA content is feasible, as FA are variable and moderately heritable. Nevertheless, in the light of correlations with other milk traits estimated in this study, a clear breeding goal should first be established.

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Genotype by Environment Interaction and Genetic Correlations Among Parities for Somatic Cell Count and Milk Yield

Journal of Dairy Science ◽

10.3168/jds.s0022-0302(90)78942-4 ◽

1990 ◽

Vol 73 (9) ◽

pp. 2563-2573 ◽

Cited By ~ 69

Author(s):

G. Banos ◽

G.E. Shook

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Somatic Cell Count ◽

Genetic Correlations ◽

Genotype By Environment Interaction ◽

Environment Interaction ◽

Genotype By Environment

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Genetic parameters of the linear body conformation traits and genetic correlations with udder traits, milk yield and composition, and somatic cell count in dairy ewes

Canadian Journal of Animal Science ◽

10.4141/cjas2010-031 ◽

2011 ◽

Vol 91 (4) ◽

pp. 585-591 ◽

Cited By ~ 11

Author(s):

L. Fernando de la Fuente ◽

Carlos Gonzalo ◽

Juan Sánchez ◽

Roberto Rodríguez ◽

Juan Carriedo ◽

...

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Somatic Cell Count ◽

Genetic Parameters ◽

Genetic Correlations ◽

Dairy Sheep ◽

General Body ◽

Body Conformation ◽

Linear Body

de la Fuente, L. F., Gonzalo, C., Sánchez, J. P., Rodríguez, R., Carriedo, J. A. and San Primitivo, F. 2011. Genetic parameters of the linear body conformation traits and genetic correlations with udder traits, milk yield and composition, and somatic cell count in dairy ewes. Can. J. Anim. Sci. 91: 585–591. This study was designed to estimate the inheritance of linear body conformation traits and their genetic correlations with linear udder traits, milk yield and composition, and somatic cell count (SCC) in dairy sheep. A total of 10 189 records of five body conformation traits, five linear udder traits, milk yield, protein and fat content, and SCC were obtained from 3977 adult ewes that were daughters of 268 sires belonging to 23 commercial flocks enrolled in the Churra breed selection nucleus. All type traits were scored on a nine-point linear scale. Genetic correlations and heritabilities were estimated using a repeatability multitrait animal model. Body conformation (stature, rear leg-rear view, feet angle, rump width, and general body score) had heritabilities (0.19, 0.18, 0.24, 0.14 and 0.17) and repeatabilities (0.34, 0.42, 0.42, 0.36, and 0.35), which indicate good potential for selection. For udder traits (udder depth, udder attachment, teat placement, teat length and udder shape) heritabilities varied between 0.09 and 0.26, and repeatabilities between 0.35 and 0.53. General body score (composite trait) had high phenotypic and genetic correlations with rear leg-rear view (0.64 and 0.80) and rump width (0.42 and 0.58). The phenotypic and genetic correlation between general body score and udder shape (composite trait) was 0.23 and 0.44, respectively. In addition, phenotypic and genetic correlations between body conformation traits and milk yield, protein and fat percentages, and SCC were low in most cases; therefore, no significant correlated genetic response is expected in body conformation traits when selecting for milk yield, protein and fat percentages, and SCC variables, in Churra breed. In conclusion, the heritability and repeatability values found in this study for body conformation traits, combined with the ease of recording by linear scale, make improvement by selection possible in dairy sheep.

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Daily and between-milking variations and repeatabilities in milk yield, somatic cell count, fat, and protein of dairy ewes

Small Ruminant Research ◽

10.1016/s0921-4488(96)00927-3 ◽

1997 ◽

Vol 24 (2) ◽

pp. 133-139 ◽

Cited By ~ 10

Author(s):

L.F. de la Fuente ◽

F.San Primitivo ◽

J.A. Fuertes ◽

C. Gonzalo

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Somatic Cell Count ◽

Dairy Ewes

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Genetic and environmental relationships among milk yield, persistency of milk yield, somatic cell count and calving interval in Holstein cows

Revista Colombiana de Ciencias Pecuarias ◽

10.17533/udea.rccp.v32n2a01 ◽

2019 ◽

Vol 32 (2) ◽

pp. 81-89

Author(s):

Arash Chegini ◽

Abdol Ahad Shadparvar ◽

Navid Ghavi Hossein-Zadeh ◽

Behrooz Mohammad-Nazari

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Gamma Function ◽

Somatic Cell Count ◽

Genetic Correlations ◽

Calving Interval ◽

Environmental Correlations ◽

Environmental Relationships ◽

Total Milk

Background: Fertility and health traits, other than production traits, have a major role in the profitability of dairy cattle. Therefore, it seems necessary to include the afore mentioned traits in breeding programs. Hence, genetic parameters are needed to establish breeding plans. Objective: To estimate heritabilities as well as genetic and environmental relationships among total milk yield (TMY), persistency of milk yield (PMY), mean somatic cell count (SCC), mean loge somatic cell count (LnSCC), standard deviation of somatic cell count (stdSCC), and calving interval (CI) using two-trait and multi-trait analyses in Iranian Holstein. Methods: The dataset consisted of 25,883 first lactation records collected from 2002 to 2007 in 97 Holstein dairy herds in Iran. Four criteria of persistency of milk yield (PMY) were calculated using the Wood's gamma function. The WOMBAT1.0 software was used to estimate the (co)variance components using the Average Information Restricted Maximum Likelihood algorithm. Results: Total milk yield (TMY) resulted in the highest heritability estimate (0.29). Heritability estimates for different criteria of persistency of milk yield (PMY) ranged from 0.05 to 0.10. The unfavorable genetic correlation between TMY and calving interval (CI) was 0.71, while that of PMY with CI was 0.46. The estimated environmental correlations were lower than the genetic correlations for all traits, but the trends were generally similar. Conclusion: The results indicate that including PMY in the breeding goals could increase TMY and CI, and decrease somatic cell count (SCC).Keywords: breeding goal, correlation, fertility, heritability, Wood's gamma function. ResumenAntecedentes: Las características de fertilidad y salud, además de las de producción, tienen un papel importante en la rentabilidad de los hatos lecheros. Por lo tanto, parece necesario incluir los rasgos mencionados en los sistemas de mejoramiento. Por ende, los parámetros genéticos son necesarios para establecer planes de cría. Objetivo: Estimar la heredabilidad, así como las relaciones genéticas y ambientales entre el rendimiento total de leche (TMY), la persistencia del rendimiento lechero (PMY), el recuento medio de células somáticas (SCC), el recuento de células somáticas de loge promedio (LnSCC), la desviación estándar del recuento de células somáticas (stdSCC) y el intervalo de partos (CI) en vacas Holstein mediante análisis de dos rasgos y análisis múltiples. Métodos: Se analizaron registros de primera lactancia de 25.883 vacas Holstein, recolectados entre 2002 y 2007 en 97 rebaños lecheros de Irán. Se calcularon cuatro criterios de persistencia del rendimiento lacteo utilizando la función gamma de Wood. El software Wombat1.0 se utilizó para estimar los componentes de (co)varianza que emplean el algoritmo de máxima verosimilitud restringida de información promedio. Resultados: El rendimiento de leche (TMY) obtuvo la mayor heredabilidad estimada (0.29). Las estimaciones de heredabilidad para diferentes criterios de persistencia del rendimiento de la leche variaron de 0,05 a 0,10. La correlación genética desfavorable entre TMY e intervalo entre partos fue 0,71, mientras que la de PMY con el CI fue de 0,46. Las correlaciones ambientales estimadas fueron inferiores a las correlaciones genéticas para todos los rasgos, pero las tendencias fueron, en general, similares. Conclusión: Incluir el PMY en la meta de cría podría aumentar el TMY y CI, además de disminuir el recuento de células somáticas (SCC).Palabras clave: correlación, fertilidad, función gamma de Wood, heredabilidad, objetivo de cría. ResumoAntecedentes: As características de fertilidade e saúde, além das características de produção, têmum papel importante narentabilidade das vacas leiteiras. Por isso, parece necessário incluir as características já mencionadas nos sistemas de melhoramento genético. Assim, são necessários parâmetros genéticos para estabelecer planos de melhoramento genético. Objetivo: Estimar herdabilidade, bem como as relações genéticas e ambientais entre a produção total de leite (TMY), persistância da produção de leite (PMY), contagem médiade células somáticas (SCC), contagem média de células somáticas loge (LnSCC), desviopadrao da contagem média de células somáticas (stdSCC) e intervalo de pertosem (CI) vacas Holstein por duas análises de características e traços multiplos. Métodos: O conjunto de dados consistiuem registros de 25.883 vacas Holstein de primeira lactação coletadas de 2002 a 2007 em 97 rebanhos leiteiros em Iran. Foram calculados quatrocritérios de persistência da produção de leite utilizando a função gama de Wood. O software Wombat1.0 foi usado para estimar os componentes de (co)variância que empregam o algoritmo de máxima verossimilhança com informações restritas. Resultados: A maior herdabilidade (0.29) foi estimada para produção de leite. As estimativas de herdabilidade para diferentes critérios de persisténcia da produção de leite variaram 0,05 a 0,10. A correlação genética desfavorável entre o intervalo TMY eo intervalo de parto foi de 0,71 enquanto que a de PMY com CI foi de 0,46. As correlações ambientais estimadas foram inferiores às correlações genéticas para todos os traços, mas as tendencias foram geralmente semelhantes. Conclusão: Os resultados indicaram que a inclusão de PMY na meta de reprodução poderia aumentar TMY e CI, no entanto, diminuir a contagem de células somáticas.Palavras chave: correlação, fertilidade, função gama do Wood, herdabilidade, objetivo de criação.

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Effect of Palpable Udder Defects on Milk Yield, Somatic Cell Count, and Milk Composition in Non-Dairy Ewes

Animals ◽

10.3390/ani11102831 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2831

Author(s):

Mandefrot M. Zeleke ◽

Paul R. Kenyon ◽

Kate J. Flay ◽

Danielle Aberdein ◽

Sarah J. Pain ◽

...

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Milk Yield ◽

Defect Detection ◽

Mixed Models ◽

Somatic Cell Count ◽

Potential Effect ◽

Milk Composition ◽

Dairy Ewes ◽

History Of

In non-dairy ewes, udder defects hinder the survival and weight gain of their pre-weaned lambs. The objectives of this study were to determine the effects of palpable udder defects on milk yield, somatic cell count (SCC), and milk composition in non-dairy Romney ewes. Ewes with a history of udder defects or normal udders were selected for the study. Of a total of 48 ewes that lambed, 30 ewes reared at least one lamb, and were milked six times, once weekly, for the first six weeks of lactation. Udder halves were palpated and scored at each milking event. Multivariate linear mixed models examined the impacts of udder defects on udder-half and whole-udder milk yield, SCC, and milk composition (fat, protein, lactose, total solids, and solids non-fat (SNF)). Across the six examinations, 24.7% of the total 352 udder-half examinations were observed to be defective. Udder halves that were defective at least once produced on average 57.9% less (p < 0.05) milk than normal udder halves, while normal udder halves with a contralateral defective half yielded 33.5% more (p < 0.05) milk than normal udder halves. Successive occurrence of both hard and lump udder defect categories in an udder-half, udder defect detection early in lactation, and a high frequency of udder defect detection were all associated with udder-half milk yield loss (p < 0.05). At the whole-udder level, no differences in milk yield (p > 0.05) were observed between those with one udder-half defective and both normal udder-halves. However, udders in which one udder half was categorised as hard but progressed to lump and remained as lump until 42 days of lactation produced less (p < 0.05) milk compared with normal udders. With the exception of SNF, there were no significant associations (p > 0.05) between milk composition parameters and udder defect. Overall, these findings emphasise the importance of udder health in non-dairy ewes and the potential effect of udder defects on their lambs.

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