Renal and mammary PD excretion in Holstein/Friesian dairy cows: Its potential as a non-invasive index of protein metabolism

The significance and contribution of rumen synthesised MCP (MCP) in the context of current metabolisable protein (MP) systems and variations in the energetic efficiency of MCP synthesis reported in the literature are reviewed. The estimation of MCP supply from urinary PD (PD) excretion is discussed and reviewed in detail, with the conclusion that it is a reliable non-invasive technique. HPLC methodologies were developed to determine PD, pseudouridine and creatinine in bovine urine and allantoin in bovine milk. A series of experiments were conducted to evaluate the potential of the PD technique using spot urine samples or measurements of allantoin in milk as on-farm diagnostics of MCP supply. Prediction of daily mean urinary molar ratios of PDs to creatinine (PD/c) ratios from spot urine samples was poor due to diurnal variations, the extent of which was influenced by feeding regimen. Furthermore, prediction of urinary PD excretion from daily mean PD/c ratios was poor due to between-cow variations in urinary creatinine excretion. On this basis the spot urine sampling technique was considered unreliable and a total urine collection proved necessary. Variabilty of urinary creatinine excretion precludes its use as a urinary output marker for individual cows. Urinary pseudouridine excretion was independent of nutrient supply but appeared to be influenced by metabolic changes occurring during lactation. In two experiments, dietary fermentable metabolisable energy (FME) supply was manipulated during early and late lactation. For both experiments, individual cow urinary PD excretion was poorly predicted from calculated FME intake or MCP supply. Based on mean treatment values, urinary PD excretion was accurately predicted from calculated MCP. Individual cow milk allantoin excretion or concentration were poorly correlated with urinary PD excretion, calculated FME intake or MCP. Relationships derived using mean treatment values indicated that milk allantoin excretion or concentration were strongly correlated with urinary PD excretion or calculated MCP. Variability precludes the use of milk allantoin as an index of MCP supply for individual cows, but it appears as reliable as urinary PD excretion when used on a herd or group feeding basis

Effect of extruded linseeds alone or in combination with fish oil on intake, milk production, plasma metabolite concentrations and milk fatty acid composition in lactating goats

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Comparison of the nutritional regulation of milk fat secretion and composition in cows and goats.

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Taxon abundance, diversity, co-occurrence and network analysis of the ruminal microbiota in response to dietary changes in dairy cows

We thank Mari Talvisilta and the staff in the metabolism unit at Natural Resources Institute Finland for technical support, care of experimental animals and assistance in sample collection. We thank Paula Lidauer for ruminal cannulation surgeries, Richard Hill from Aberystwyth University, UK for performing qPCR and Aurélie Bonin from Laboratoire d'Ecologie Alpine, CNRS, France for preparing archaea amplicon libraries for sequencing. Kevin J. Shingfield passed away before the submission of the final version of this manuscript. Ilma Tapio accepts responsibility for the integrity and validity of the data collected and analyzed. Funding: Study was funded by the Finnish Ministry of Agriculture and Forestry as part of the GreenDairy Project (Developing Genetic and Nutritional Tools to Mitigate the Environmental Impact of Milk Production; Project No. 2908234). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Rapeseed or linseed in dairy cow diets over 2 consecutive lactations:Effects on adipose fatty acid profile and carry-over effects on milk fat composition in subsequent early lactation

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Maidontuotannon ympäristövaikutusten rajoittaminen eläingenetiikan ja ravitsemuksen työkaluja kehittämällä

MAKERA -hankkeen loppuraportti, hankkeen dnro 2667/312/2009