49 research outputs found
Dominance and parent-of-origin effects of coding and non-coding alleles at the acylCoA-diacylglycerol-acyltransferase (DGAT1) gene on milk production traits in German Holstein cows
<p>Abstract</p> <p>Background</p> <p>Substantial gene substitution effects on milk production traits have formerly been reported for alleles at the K232A and the promoter VNTR loci in the bovine acylCoA-diacylglycerol-acyltransferase 1 (<it>DGAT1</it>) gene by using data sets including sires with accumulated phenotypic observations of daughters (breeding values, daughter yield deviations). However, these data sets prevented analyses with respect to dominance or parent-of-origin effects, although an increasing number of reports in the literature outlined the relevance of non-additive gene effects on quantitative traits.</p> <p>Results</p> <p>Based on a data set comprising German Holstein cows with direct trait measurements, we first confirmed the previously reported association of <it>DGAT1 </it>promoter VNTR alleles with milk production traits. We detected a dominant mode of effects for the <it>DGAT1 </it>K232A and promoter VNTR alleles. Namely, the contrasts between the effects of heterozygous individuals at the <it>DGAT1 </it>loci differed significantly from the midpoint between the effects for the two homozygous genotypes for several milk production traits, thus indicating the presence of dominance. Furthermore, we identified differences in the magnitude of effects between paternally and maternally inherited <it>DGAT1 </it>promoter VNTR – K232A haplotypes indicating parent-of-origin effects on milk production traits.</p> <p>Conclusion</p> <p>Non-additive effects like those identified at the bovine <it>DGAT1 </it>locus have to be accounted for in more specific QTL detection models as well as in marker assisted selection schemes. The <it>DGAT1 </it>alleles in cattle will be a useful model for further investigations on the biological background of non-additive effects in mammals due to the magnitude and consistency of their effects on milk production traits.</p
Field trial on glucose-induced insulin and metabolite responses in Estonian Holstein and Estonian Red dairy cows in two herds
<p>Abstract</p> <p>Background</p> <p>Insulin secretion and tissue sensitivity to insulin is considered to be one of the factors controlling lipid metabolism <it>post partum</it>. The objective of this study was to compare glucose-induced blood insulin and metabolite responses in Estonian Holstein (EH, n = 14) and Estonian Red (ER, n = 14) cows.</p> <p>Methods</p> <p>The study was carried out using the glucose tolerance test (GTT) performed at 31 ± 1.9 days <it>post partum</it> during negative energy balance. Blood samples were obtained at -15, -5, 5, 10, 20, 30, 40, 50 and 60 min relative to infusion of 0.15 g/kg BW glucose and analysed for glucose, insulin, triglycerides (TG), non-esterified fatty acids (NEFA), cholesterol and β-hydroxybutyrate (BHB). Applying the MIXED Procedure with the SAS System the basal concentration of cholesterol, and basal concentration and concentrations at post-infusion time points for other metabolites, area under the curve (AUC) for glucose and insulin, clearance rate (CR) for glucose, and maximum increase from basal concentration for glucose and insulin were compared between breeds.</p> <p>Results</p> <p>There was a breed effect on blood NEFA (<it>P </it>< 0.05) and a time effect on all metabolites concentration (<it>P </it>< 0.01). The following differences were observed in EH compared to ER: lower blood insulin concentration 5 min after glucose infusion (<it>P </it>< 0.05), higher glucose concentration 20 (<it>P </it>< 0.01) and 30 min (<it>P </it>< 0.05) after infusion, and higher NEFA concentration before (<it>P </it>< 0.01) and 5 min after infusion (P < 0.05). Blood TG concentration in ER remained stable, while in EH there was a decrease from the basal level to the 40<sup>th </sup>min nadir (<it>P </it>< 0.01), followed by an increase to the 60<sup>th </sup>min postinfusion (<it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Our results imply that glucose-induced changes in insulin concentration and metabolite responses to insulin differ between EH and ER dairy cows.</p
Behavioural and physiological responses of individually housed dairy calves to change in milk feeding frequency at different ages
peer reviewedThis study aimed to use a range of non-invasive monitoring technologies to investigate the behavioural and
physiological responses of individually housed dairy calves to age at change in milk replacer (MR) feeding frequency.
Forty-eight Holstein Friesian calves were individually penned and fed MR (625 g/d) as solids in one of three feeding
regimes: (i) once-a-day feeding commencing at age 14 d (OAD14), (ii) once-a-day feeding commencing at age
28 d (OAD28) and (iii) twice-a-day feeding (TAD). Several behavioural (automatic activity sensors), physiological
(infrared [IR] thermography and heart rate variability [HRV]) and haematological indicators were used to examine
calf responses. Reduction in milk feeding frequency at 14 or 28 d of age increased daily concentrate intakes and
drinking water consumption throughout the pre-wean period. Calf lying behaviour was unaffected by reduction
in milk feeding frequency; however, TAD calves recorded a significant decrease in total daily lying time during
the post-wean period compared with OAD28s. There was no effect of treatment on IR eye or rectal temperature
throughout the experiment; however, there was an effect of age, with IR temperature decreasing as calf age
increased. OAD14 calves tended to have decreased HRV at days 14 and 16, which is suggestive of an increased
stress load. The findings suggest that under high levels of animal husbandry and whilst maintaining the same
amount of milk powder/d (625 g/d), reduction in milk feeding frequency from twice to once daily at 28 d can occur
without significant impact to behavioural, performance and physiological parameters assessed here
Morphology, Proliferation and Apoptosis of the Intestine as well as Metabolic and Endocrine Traits in Preterm and Term Calves
Bucket-Fed, Automate-Fed and Calves Suckling on Their Dams: Effects of Feeding Colostrum and Milk with Different Frequency and Intensity
Hematological, metabolic, and endocrine effects of feeding vitamin A and lactoferrin in neonatal calves
Tumor necrosis factor-alpha and nitrite/nitrate responses during acute mastitis induced by Escherichia coli infection and endotoxin in dairy cows.
Diurnal variation of NMR based blood metabolites in calves fed a high plane of milk replacer: a pilot study
Effects of Feeding Milk Replacer Ad Libitum or in Restricted Amounts for the First Five Weeks of Life on the Growth, Metabolic Adaptation, and Immune Status of Newborn Calves
Metabolic adaptation during early lactation: key to cow health, longevity and a sustainable dairy production chain
Enhancing longevity by reducing involuntary culling and consequently increasing productive life
and lifetime production of dairy cows is not only a strategy to improve a farm’s profit, but is also
related to improved animal welfare. High rates of involuntary culling in dairy cows are currently
attributed to fertility problems, mastitis and locomotive disorders. Disease incidence is high in
particular in the early-lactation period. The high disease incidence in early lactation has been
attributed to metabolic stress related to the high metabolic priority for lactation and the inability
of the cow to adapt effectively to the new lactation. Several biological mechanisms interact in the
peripartum period of dairy cows and can result in this inability to adapt effectively to lactation.
Biological mechanisms reviewed are metabolic adaptation, oxidative stress, immune function and
inflammation, and feed intake capacity. Although relationships between these mechanisms become
increasingly clear, these relationships are complex and not yet completely understood. Appro-
priate management of dairy cows in the peripartum period can facilitate cows to adapt to a new
lactation. Nutritional and management strategies to ease adaptation are divided into strategies to
restrict energy intake in the dry period, to improve energy intake in early lactation, alter repar-
titioning of energy between milk and body tissue, and strategies to support fat or carbohydrate
metabolism. The success of various strategies, however, is often hampered by the complexity of
interactions and high between-cow variation. We advocate for a multidisciplinary approach to
understand and manage adaptation to a new lactation aiming at an improvement of cow welfare
and longevit