Effect of dexamethasone on milk yield
and composition in dairy cows

Shamay, Avi; Shapiro, Fira; Barash, H.; Bruckental, I.; Silanikove, Nissim

doi:10.1051/animres:2000125

Cited by 31 publications

(39 citation statements)

References 19 publications

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“…That is, it transports glucose-6-phosphate in one direction and phosphorus in the other. Glucose is needed for lactose synthesis in mammary cells and lactose controls milk volume because it is the major osmotic component of milk [14]. In support of an antiporter hypothesis the allele that increases SLC37A1 expression (the derived ‘T’ allele [15] for rs109254133) increases milk yield (+37.6 L/lactation) and decreases phosphorus concentration (−41.8 mg/kg).…”

Section: Resultsmentioning

confidence: 99%

Leveraging genetically simple traits to identify small-effect variants for complex phenotypes

et al. 2016

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BackgroundPolymorphisms underlying complex traits often explain a small part (less than 1 %) of the phenotypic variance (σ2 P). This makes identification of mutations underling complex traits difficult and usually only a subset of large-effect loci are identified. One approach to identify more loci is to increase sample size of experiments but here we propose an alternative. The aim of this paper is to use secondary phenotypes for genetically simple traits during the QTL discovery phase for complex traits. We demonstrate this approach in a dairy cattle data set where the complex traits were milk production phenotypes (fat, milk and protein yield; fat and protein percentage in milk) measured on thousands of individuals while secondary (potentially genetically simpler) traits are detailed milk composition traits (measurements of individual protein abundance, mineral and sugar concentrations; and gene expression).ResultsQuantitative trait loci (QTL) were identified using 11,527 Holstein cattle with milk production records and up to 444 cows with milk composition traits. There were eight regions that contained QTL for both milk production and a composition trait, including four novel regions. One region on BTAU1 affected both milk yield and phosphorous concentration in milk. The QTL interval included the gene SLC37A1, a phosphorous antiporter. The most significant imputed sequence variants in this region explained 0.001 σ2 P for milk yield, and 0.11 σ2 P for phosphorus concentration. Since the polymorphisms were non-coding, association mapping for SLC37A1 gene expression was performed using high depth mammary RNAseq data from a separate group of 371 lactating cows. This confirmed a strong eQTL for SLC37A1, with peak association at the same imputed sequence variants that were most significant for phosphorus concentration. Fitting any of these variants as covariables in the association analysis removed the QTL signal for milk production traits. Plausible causative mutations in the casein complex region were also identified using a similar strategy.ConclusionsMilk production traits in dairy cows are typical complex traits where polymorphisms explain only a small portion of the phenotypic variance. However, here we show that these mutations can have larger effects on secondary traits, such as concentrations of minerals, proteins and sugars in the milk, and expression levels of genes in mammary tissue. These larger effects were used to successfully map variants for milk production traits. Genetically simple traits also provide a direct biological link between possible causal mutations and the effect of these mutations on milk production.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3175-3) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Leveraging genetically simple traits to identify small-effect variants for complex phenotypes

et al. 2016

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“…A basic feature of mammary secretion is that the total osmotic pressure of the secretion is approximately constant and equal to that of blood (Holt, 1993). As lactose is the main osmotic component in milk, the secretion volume closely follows changes in the secretion of lactose (Shamay et al 2000). Thus, based on the decrease in lactose concentration in the infected glands, it is assumed that subclinical mastitis is associated with reduced milk yield also in goats.…”

Section: Discussionmentioning

confidence: 99%

Effect of subclinical intramammary infection on somatic cell counts, NAGase activity and gross composition of goats' milk

Leitner¹,

Merin²,

Silanikove

et al. 2004

Journal of Dairy Research

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The study was aimed at identifying the pathogens causing subclinical udder infections in representative Israeli dairy goat herds and determining their effect on milk quality. Five hundred goats in ten flocks of various breeds and crossbreeds were surveyed. Of the 500 goats, 13 . 4% were in their first lactation, 36 . 4 % were in their second lactation and 50 . 2% were in their third or higher lactation. Percentages of udder halves with subclinical intramammary infection in the flocks ranged from 35 to 71 %. The effect of the bacteriological infection on somatic cells count (SCC) was significant (P <0 . 001). Various species of coagulase-negative staphylococci (CNS), mainly Staphylococcus caprae and Staphylococcus epidermidis, were the main pathogens in infected udder halves. Lactation number did not significantly influence either infection rate of udder halves or SCC, although the percentage of udder halves with no bacteriological findings was higher at the first lactation than at the third lactation. Milk composition (fat, protein and lactose) varied among flocks, with lower mean total protein in uninfected halves than in infected ones and higher lactose in uninfected than infected halves.

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“…Mammary secretions were prepared for Na and K analysis as described by Shamay et al (2000), and the concentrations of these minerals were measured by using inductively coupled plasma-atomic emission spectrometry (Spectro, Kleve, Germany).…”

Section: Sampling and Laboratory Proceduresmentioning

confidence: 99%

Early mammary gland metabolic and immune responses during natural-like and forceful drying-off in high-yielding dairy cows

Silanikove

Merin

Shapiro

et al. 2013

Journal of Dairy Science

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The present work compared metabolic and immune responses in genetically high-producing cows that produced a low amount of milk before expected involution and in cows with the same genetic potential that produced copious amounts of milk before their scheduled drying-off. Ten multiparous lactating Israeli Holstein cows producing approximately 10,500 L in the current lactation, without bacterial infection and scheduled for drying-off approximately 60 d before their expected parturition, were studied. Five of the cows that exhibited a sharp, spontaneous reduction in milk yield at the end of their lactation and produced less than ~14L/d were defined as cows approaching natural involution (ANI), and 5 cows that produced between 25 and 35 L/d were defined as cows approaching forced involution (AFI). Three days before scheduled drying-off, milking was stopped and milk samples were collected from each quarter. After milking cessation, only modest swelling was observed in the udders of the ANI cows. In the ANI cows, lactose and fat concentrations decreased and the fat:lactose concentration ratio indicated that on d 1 and 2 fat concentrations decreased faster than lactose concentration, whereas on d 3, the rate of reduction was about the same for lactose and fat. In contrast, in AFI cows, fat concentrations increased on d 1 and the fat:lactose ratio indicated that changes in fat secretion were minor compared with those of lactose secretion. Rennet clotting time of milk after drying-off in the ANI cows increased, whereas curd firmness decreased rapidly, such that mammary secretions did not coagulate on d 3. In the AFI cows, such significant changes were observed only on d 3. The inflammatory response increased in both groups, but at each stage the increase was greater in ANI cows than in AFI cows. On d 1, the increase in leukocyte numbers in the ANI cows was made up of mononuclear cells (i.e., T lymphocytes and macrophages). In contrast, in the AFI cows, we observed a marked increase in leukocyte numbers, mainly in the form of polymorphonuclear cells. Our data indicate that the abrupt mammary involution induced in AFI cows provoked signs of distress, which were associated with neutrophilia in milk. In contrast, in the ANI cows, cessation of milking occurred without evidence of engorgement of the udder. Physiological differences in ANI and AFI cows are distinct and are reflected in the differences in the leukocyte populations in milk.

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Effect of dexamethasone on milk yield and composition in dairy cows

Cited by 31 publications

References 19 publications

Leveraging genetically simple traits to identify small-effect variants for complex phenotypes

Leveraging genetically simple traits to identify small-effect variants for complex phenotypes

Effect of subclinical intramammary infection on somatic cell counts, NAGase activity and gross composition of goats' milk

Early mammary gland metabolic and immune responses during natural-like and forceful drying-off in high-yielding dairy cows

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