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Hestebønner er et interessant alternativ til soja- og rapsprodukter som proteinkilde til konventionelle og økologiske malkekøer. Resultaterne af de kemiske analyser viser relativ stor variation i indholdet af protein og stivelse, og det anbefales derfor at få lavet en foderanalyse, inden hestebønnerne tages indi foderplanen. Nylonposemålinger af ufordøjeligt protein samt nedbrydningshastighed af protein afspejlede de forskellige konserverings- og behandlingsmetoder og har suppleret eksisterende data og bidraget til opdatering af NorFor fodermiddeltabel, så standardfoderværdierne afspejler hvilke værdierfor AAT, PBV og foderværdi, der kan forventes ved fodring med hestebønner afhængig af behandling. Vurderet på næringsstofparametrene er hestebønner et godt alternativ til soja- og rapsprodukter.

EKM-ydelsen påvirkes ikke af at gå ned på 25 pct. tørstof fra grovfoder, viser’tørke-forsøg’ fra Foulum.

Salivary flow and net jugular flux of metabolites were studied during resting and rumination in 3 lactating dairy cows (BW 548 ± 17.2 kg, days in milk 113 ± 4 d). The method was based on the concentration difference between arterial and jugular blood, and jugular blood flow measured by downstream dilution of p-aminohippuric acid (pAH). Cows were surgically prepared with a permanent arterial catheter in A. intercostales dorsales before the trial. On sampling days, cows were prepared with left and right side jugular, and ear vein catheters for blood sampling and infusion of pAH, respectively. Blood was sampled simultaneously from the 2 jugular veins and artery during periods of rest and rumination. Secretion of saliva was set equal to the net water extraction calculated from the increased hemoglobin concentration in jugular blood compared with arterial blood. Arterial and jugular blood flow summed for both sides of the head doubled (P < 0.001) during rumination (437 ± 19, 424 ± 18 L/h, respectively) compared with resting (210 ± 19, 202 ± 18 L/h, respectively), consequently doubling the saliva secretion (P < 0.001, resting = 7.6 ± 0.8 L/h, rumination = 13.8 ± 0.8 L/h). The extraction of inorganic phosphate (Pi) from arterial blood during resting periods was greater compared with rumination (P = 0.004; resting = 21.7% ± 0.9%; rumination = 15.6% ± 0.9%), resulting in a greater Pi concentration in saliva secreted during resting. The concentrations of Pi in saliva were 4.5 ± 0.3 and 3.7 ± 0.3 times the arterial concentration during resting and rumination (P = 0.09), respectively. The urea concentration in saliva was 0.63 ± 0.04 times the arterial level, showing that urea is less efficiently transferred from blood than water, resulting in a greater numerical urea concentration in jugular compared with arterial blood. The water extraction method presented in the present paper offers an alternative way of estimating saliva secretion without the chewing activity constraints associated with other methods, for example, allowing for determination of saliva flow during rumination. Salivary flow and net jugular flux of metabolites were studied during resting and rumination in 3 lactating dairy cows (BW 548 ± 17.2 kg, days in milk 113 ± 4 d). The method was based on the concentration difference between arterial and jugular blood, and jugular blood flow measured by downstream dilution of p-aminohippuric acid (pAH). Cows were surgically prepared with a permanent arterial catheter in A. intercostales dorsales before the trial. On sampling days, cows were prepared with left and right side jugular, and ear vein catheters for blood sampling and infusion of pAH, respectively. Blood was sampled simultaneously from the 2 jugular veins and artery during periods of rest and rumination. Secretion of saliva was set equal to the net water extraction calculated from the increased hemoglobin concentration in jugular blood compared with arterial blood. Arterial and jugular blood flow summed for both sides of the head doubled (P < 0.001) during rumination (437 ± 19, 424 ± 18 L/h, respectively) compared with resting (210 ± 19, 202 ± 18 L/h, respectively), consequently doubling the saliva secretion (P < 0.001, resting = 7.6 ± 0.8 L/h, rumination = 13.8 ± 0.8 L/h). The extraction of inorganic phosphate (Pi) from arterial blood during resting periods was greater compared with rumination (P = 0.004; resting = 21.7% ± 0.9%; rumination = 15.6% ± 0.9%), resulting in a greater Pi concentration in saliva secreted during resting. The concentrations of Pi in saliva were 4.5 ± 0.3 and 3.7 ± 0.3 times the arterial concentration during resting and rumination (P = 0.09), respectively. The urea concentration in saliva was 0.63 ± 0.04 times the arterial level, showing that urea is less efficiently transferred from blood than water, resulting in a greater numerical urea concentration in jugular compared with arterial blood. The water extraction method presented in the present paper offers an alternative way of estimating saliva secretion without the chewing activity constraints associated with other methods, for example, allowing for determination of saliva flow during rumination.

To test the hypothesis that dietary N concentrations affect gut epithelial urea transport by modifying the expression of urea transporter B (UT-B) and aquaporins (AQP), the mRNA expression and protein abundance of UT-B and AQP3, AQP7, AQP8, and AQP10 were investigated in ruminal papillae from 9 lactating dairy cows. Ruminal papillae were harvested from cows fed low N (12.9% crude protein) and high N (17.1% crude protein) diets in a crossover design with 21-d periods. The mRNA expression was determined by real-time reverse transcription-PCR and protein abundance by immunoblotting. The mRNA expression of UT-B was not affected by dietary treatment, whereas mRNA expression of AQP3, 7, and 10 were greater in the high N compared with the low N fed cows. Using peptide-derived rabbit antibodies to cow AQP3, 7, and 8, immunoblotting revealed bands of approximately 27, 27, and 24 kDa in ruminal papillae, respectively. A peptide-derived chicken antibody to cow UT-B detected a band of approximately 30 to 32 kDa in ruminal papillae. The abundance of UT-B and AQP3 and 7 were not affected by dietary treatment. In contrast, the abundance of AQP8 was greater in high N compared with low N diets. In conclusion, AQP3, 7, and 8 were found to be expressed in bovine rumen papillae. None of the investigated transcripts or proteins correlated to the increased rumen epithelial urea permeability observed with low dietary N concentration.