Rumen-protected choline and methionine during the periparturient period affect choline metabolites, amino acids, and hepatic expression of genes associated with one-carbon and lipid metabolism.

Feeding supplemental choline and Met during the periparturient period can have positive effects on cow performance; however, the mechanisms by which these nutrients affect performance and metabolism are unclear. The objective of this experiment was to determine if providing rumen-protected choline, rumen-protected Met, or both during the periparturient period modifies the choline metabolitic profile of plasma and milk, plasma AA, and hepatic mRNA expression of genes associated with choline, Met, and lipid metabolism. Cows (25 primiparous, 29 multiparous) were blocked by expected calving date and parity and randomly assigned to 1 of 4 treatments: control (no rumen-protected choline or rumen-protected Met); CHO (13 g/d choline ion); MET (9 g/d DL-methionine prepartum; 13.5 g/d DL-methionine, postpartum); or CHO + MET. Treatments were applied daily as a top dress from ∼21 d prepartum through 35 d in milk (DIM). On the day of treatment enrollment (d -19 ± 2 relative to calving), blood samples were collected for covariate measurements. At 7 and 14 DIM, samples of blood and milk were collected for analysis of choline metabolites, including 16 species of phosphatidylcholine (PC) and 4 species of lysophosphatidylcholine (LPC). Blood was also analyzed for AA concentrations. Liver samples collected from multiparous cows on the day of treatment enrollment and at 7 DIM were used for gene expression analysis. There was no consistent effect of CHO or MET on milk or plasma free choline, betaine, sphingomyelin, or glycerophosphocholine. However, CHO increased milk secretion of total LPC irrespective of MET for multiparous cows and in absence of MET for primiparous cows. Furthermore, CHO increased or tended to increase milk secretion of LPC 16:0, LPC 18:1, and LPC 18:0 for primi- and multiparous cows, although the response varied with MET supplementation. Feeding CHO also increased plasma concentrations of LPC 16:0 and LPC 18:1 in absence of MET for multiparous cows. Although milk secretion of total PC was unaffected, CHO and MET increased secretion of 6 and 5 individual PC species for multiparous cows, respectively. Plasma concentrations of total PC and individual PC species were unaffected by CHO or MET for multiparous cows, but MET reduced total PC and 11 PC species during wk 2 postpartum for primiparous cows. Feeding MET consistently increased plasma Met concentrations for both primi- and multiparous cows. Additionally, MET decreased plasma serine concentrations during wk 2 postpartum and increased plasma phenylalanine in absence of CHO for multiparous cows. In absence of MET, CHO tended to increase hepatic mRNA levels of betaine-homocysteine methyltransferase and phosphate cytidylyltransferase 1 choline, α, but tended to decrease expression of 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 and peroxisome proliferator activated receptor α irrespective of MET. Although shifts in the milk and plasma PC profile were subtle and inconsistent between primi- and multiparous cows, gene expression results suggest that supplemental choline plays a probable role in promoting the cytidine diphosphate-choline and betaine-homocysteine S-methyltransferase pathways. However, interactive effects suggest that this response depends on Met availability, which may explain the inconsistent results observed among studies when supplemental choline is fed.

Production responses to rumen-protected choline and methionine supplemented during the periparturient period differ for primi- and multiparous cows.

The objective of this experiment was to examine production performance responses to feeding rumen-protected choline (RPC) or methionine (RPM), or both, during the periparturient period. Fifty-four Holstein cows (25 primiparous, 29 multiparous) were used in a randomized block design experiment with a 2 × 2 factorial treatment structure. Cows were blocked by expected calving date and parity and assigned to 1 of 4 treatments: CON (no RPC or RPM); RPC (13.0 g/d of choline ion); RPM (9 g/d of dl-methionine prepartum; 13.5 g/d of dl-methionine postpartum); or RPC + RPM. Treatments were applied once daily as a top-dress from 3 wk before through 5 wk after calving. Dry matter intake and milk production were recorded daily, and milk samples were obtained once weekly. Data were analyzed for primi- and multiparous cows separately, using a repeated-measures mixed model that included random effects of cow and block and fixed effects of RPC, RPM, week, and their interactions; week served as the repeated effect. Initial BW and previous lactation milk yield were included as covariates in the statistical model for multiparous cows. Feeding RPC without RPM increased milk yield for multiparous cows by 8.7 kg/d, but this increase was not observed when RPC was fed with RPM. In multiparous cows, feeding RPM increased milk fat concentration and tended to increase milk fat yield. Because of this, RPM increased fat-corrected milk (FCM) by 2.8 kg/d at wk 2 postpartum, and this increase was sustained through wk 5 postpartum. In contrast, RPM did not affect overall milk fat yield and concentration for primiparous cows. Feeding RPC increased milk yield for primiparous cows by 3.5 kg/d irrespective of RPM inclusion, which is contrary to observations in multiparous cows, where RPC increased milk yield only in the absence of RPM. These results indicate that responses to RPC during the periparturient period may be dependent upon supply of methionine. Our observations also demonstrate that primi- and multiparous cows respond differently to RPC and RPM supplemented individually or simultaneously during the periparturient period. This variation in response could have been mediated by putative differences in choline and methionine requirements of primiparous versus multiparous cows, or by differences in the levels of milk production between the 2 groups (36 vs. 25 kg of FCM/d). However, cows in this study did not experience severe negative energy balance (mean nadirs of -6.6 and -5.0 Mcal/d for multiparous and primiparous cows, respectively), which likely affected their responses to RPC and RPM.

The decline in digestive efficiency of US dairy cows from 1970 to 2014.

Since the year 1970, US milk production per cow has more than doubled, in part because of large increases in feed intake. It is well established that increasing feed intake reduces diet digestibility in dairy cattle. Our objective was to determine whether the digestive efficiency of US dairy cows had also changed. We assembled a data set consisting of diet digestibility measured either by total collection of feces or by use of indigestible neutral detergent fiber (NDF) in lactating dairy cow studies published in the Journal of Dairy Science from July 1970 to July 2014. The data set contained 575 treatment means from 154 individual research trials conducted at 26 US institutions. Based on regression analysis, mean milk yield and dry matter intake (DMI) between 1970 and 2014 increased by 19.7 and 10.3 kg/d, respectively. Temporal effects on digestibility [dry matter (DM), crude protein (CP), and NDF] were determined using the regression model Yi = YEAR1970i + CPi + NDFi + ei, where YEAR1970i is the publication year minus 1970, CPi and NDFi are diet constituents (% of diet DM) that were included to account for their known effects on digestibility, and ei is the residual error. Dry matter digestibility decreased 0.07 percentage units/yr for a total reduction of 3.08 percentage units since 1970. Furthermore, CP and NDF digestibilities decreased 0.04 and 0.17 percentage units/yr, respectively. To account for the potential effect of feed intake on digestibility, DMI as a percentage of body weight was added to the regression model. With DMI as a percentage of body weight in the model, temporal changes in DM, CP, and NDF digestibilities were no longer significant. This suggested that the apparent decline in DM digestibility could be mostly accounted for by simultaneous increases in level of feed intake. Despite lower apparent digestive efficiency, the modern dairy cow has greater production efficiency than the 1970s dairy cow because she produces more milk per unit of feed consumed and digested.

Effect of short-term feed restriction on temporal changes in milk components and mammary lipogenic gene expression in mid-lactation Holstein dairy cows.

Investigations of the temporal changes in mammary gene expression that occur during sudden diet change have been limited by the use of mammary tissue as the source of RNA because of the invasive nature of mammary biopsy procedures. However, the cytosolic crescent, present in 1% of the largest milk fat globules, contains mammary epithelial cell RNA that has become trapped between the inner and outer milk fat globule membranes during final formation and secretion of milk fat into the lumen of the mammary alveoli. We hypothesized that cytosolic crescent RNA extracted from milk fat could be used as an alternative source of mammary epithelial cell RNA to measure the immediate temporal changes in gene expression as a result of changes in diet. In this experiment, feed restriction was used to mimic the state of negative energy balance observed in early lactation and induce a rapid change in milk fat yield and lipogenic gene expression. Ten multiparous Holstein dairy were fed a basal diet ad libitum during a 14-d preliminary period followed by a 4-d experimental period where 5 cows remained on ad libitum feeding and 5 cows were fed at 60% of their d 8-14 intakes (restricted) on d 15 to 18 and then returned to ad libitum feeding on d 19 to 21. Milk samples were collected from each milking on d 13 to 20 and the milk fat was immediately isolated, mixed with Trizol LS, and stored at -80°C for subsequent extraction of RNA that was used for measurement of gene expression. Feed restriction tended to increase milk fat percentage. However, total milk and milk fat production were reduced by 21 and 18%, respectively. Consistent with increased use of body fat for milk synthesis, serum nonesterified fatty acids increased 6-fold (0.78 mEq/L in the feed restriction vs. 0.13 mEq/L ad libitum group), whereas the milk fatty acids

The effect of cation source and dietary cation-anion difference on rumen ion concentrations in lactating dairy cows.

Many studies have focused on the influence of dietary cation-anion difference (DCAD) on animal performance but few have examined the effect of DCAD on the rumen ionic environment. The objective of this study was to examine the effects of DCAD, cation source (Na vs. K), and anion source (Cl vs. bicarbonate or carbonate) on rumen environment and fermentation. The study used 5 rumen-fistulated dairy cows and 5 dietary treatments that were applied using a 5×5 Latin square design with 2-wk experimental periods. Treatments consisted of (1) the basal total mixed ration (TMR); (2) the basal TMR plus 340mEq/kg of Na (dry matter basis) using NaCl; (3) the basal TMR plus 340mEq/kg of K using KCl; (4) the basal TMR plus 340mEq/kg of Na using NaHCO3; and (5) the basal TMR plus 340mEq/kg of K using K2CO3. On the last day of each experimental period, rumen samples were collected and pooled from 5 different locations at 0, 1.5, 3, 4.5, 6, 9, and 12h postfeeding for measurement of rumen pH and concentrations of strong ions and volatile fatty acids (VFA). Dietary supplementation of individual strong ions increased the corresponding rumen ion concentration. Rumen Na was decreased by 24mEq/L when K was substituted for Na in the diet, but added dietary Na had no effect on rumen K. Rumen Cl was increased by 10mEq/L in diets supplemented with Cl. Cation source had no effect on rumen pH or total VFA concentration. Increased DCAD increased rumen pH by 0.10 pH units and increased rumen acetate by 4mEq/L but did not increase total VFA. This study demonstrated that rumen ion concentrations can be manipulated by dietary ion concentrations. If production and feed efficiency responses to DCAD and ionophores in the diet are affected by rumen Na and K concentrations, then manipulating dietary Na and K could be used either to enhance or diminish those responses.

Intake, milk production, ruminal, and feed efficiency responses to dietary cation-anion difference by lactating dairy cows.

Previous meta-analyses of the effects of dietary cation anion difference (DCAD; mEq/kg; Na + K - Cl - S) in lactating dairy cow diets used studies conducted after the development of the DCAD concept. Dietary buffers, such as NaHCO3 and K2CO3, increase DCAD and have been used in lactating dairy cow diets for several decades. However, most published studies on buffer feeding were conducted before the development of the DCAD concept. Our objective was to determine the intake, milk production, ruminal, and feed efficiency responses to DCAD using previous studies with dietary buffer addition and more recent studies that focused on DCAD as dietary treatments. The database consisted of 43 articles that were published between 1965 and 2011. The studies included 196 dietary treatments and 89 treatment comparisons with a range in DCAD from -68 to 811mEq/kg of diet DM, with the vast majority between 0 and 500mEq/kg of diet DM. For studies that lacked analyses of one or more of the dietary strong ions (Na, K, Cl, or S), ion percentages were estimated from ingredient composition using the 2001 dairy National Research Council software. Two basic models were used to evaluate DCAD responses using the NLMIXED procedure in SAS 9.2 (SAS Institute Inc., Cary, NC): (1) a simple linear model, Y=A + B × (DCAD), where A=intercept and B=the increment (slope) in performance per unit DCAD (mEq/kg of diet DM); and (2) a nonlinear model, Y=A + M[1 - e((K × DCAD))], where M=maximal increment in performance from DCAD and K=the rate constant. In both models, study was designated as the random effect. The DCAD effects best described by the linear model included milk fat percent, fat yield, ruminal pH, NDF digestibility, and feed efficiency [3.5% fat-corrected milk (FCM; kg)/dry matter intake (DMI; kg)] where a 100mEq/kg increase in DCAD resulted in respective increases of 0.10%, 36g/d, 0.032 pH units, 1.5% NDF digestibility, and 0.013 FCM/DMI units. The DMI, milk yield, and 3.5% FCM were best described by the nonlinear model where the maximal responses were 1.92, 1.11, and 4.82kg/d, respectively. The expected increments in DMI, milk production, and 3.5% FCM by increasing DCAD from 0 to 500mEq/kg were 1.7, 1.2, and 3.4kg/cow per day, respectively. The results of this meta-analysis suggest that DCAD has significant effects on intake, milk production and composition, digestion, and feed efficiency in lactating dairy cows.

The effect of milking reinitiation following extended nonmilking periods on lactation in primiparous dairy cows.

In dairy cows, extended periods of nonmilking results in reduced milk secretion, modifications in milk composition, and eventually involution of the mammary glands. The aim of this study was to determine the effect of extended nonmilking periods on the recovery of milk yield and composition, and levels of prolactin and insulin-like growth factor-I in pasture-fed cows after resuming milking. Pasture-fed, primiparous, nonpregnant, Friesian dairy cows at mid lactation (mean ± standard deviation, 97 ± 2d in milk, 14.0 ± 2.5 L/d) were divided into 3 groups (n=6 per group). The cows were subjected to nonmilking periods of 7, 14, or 28d. Twice-daily milking was resumed for 7d following the nonmilking periods. Milk yield recoveries at the end of the 7-d remilking period were 91, 51, and 29% for the 7, 14, and 28-d nonmilked groups, respectively. The somatic cell count declined to less than 400,000 cells/mL by d 3 and 6 of remilking for the 7- and 14-d-nonmilked groups, respectively, but remained greater than 800,000 cells/mL in the 28-d-nonmilked group through the 7-d remilking period. By d 7 of remilking, the somatic cell count for the 7-d-nonmilked group was not different from pretrial values. Upon remilking, the milk fat content returned to pretrial values for the 7- and 14-d-nonmilked groups, although it remained lower than pretrial for the 28-d-nonmilked group. All 3 nonmilked groups had a higher milk protein content following 7d of remilking, compared with pretrial values. The lactose content returned to pretrial values for the 7-d-nonmilked group but remained lower for the 14- and 28-d-nonmilked groups. Circulating prolactin concentrations increased once remilking was resumed, compared with the pretrial and nonmilking periods. Prolactin concentrations did not majorly differ between the groups, with the levels upon 7d of remilking remaining higher than the pretrial concentrations and the nonmilked periods. Plasma concentrations of insulin-like growth factor-I increased during the nonmilking period and were greater in all 3 nonmilked groups on d 1 of remilking than pretrial values and returned to pretrial concentrations following remilking for the 7-d-nonmilked group, whereas the 14- and 28-d-nonmilked groups remained higher than the pretrial values. These data indicate that the process of involution is fully reversed after remilking following 7d of milk stasis but more extended periods of nonmilking prevent the complete recovery of lactation. However, even after 28d of milk stasis, the milk synthesis capacity of the mammary gland could still be partially recovered.

The effect of dietary cation-anion difference concentration and cation source on milk production and feed efficiency in lactating dairy cows.

Feed costs currently account for 55% or more of the total cost of milk production in US dairy herds, and dairy producers are looking for strategies to improve feed efficiency [FE; 3.5% fat-corrected milk (FCM) per dry matter (DM) intake]. Increasing dietary cation-anion difference [DCAD; Na+K-Cl (mEq/kg of DM)] has been shown to increase milk production, FCM, and FE. However, the optimal DCAD concentration for maximal FE has yet to be determined. The objectives of this research were to test the effects of DCAD concentration and cation source on dairy FE. Sixty Holstein dairy cows (20 cows per experiment) were used in three 4×4 Latin square design experiments with 3-wk experimental periods. In experiments 1 and 2, we tested the effect of DCAD concentration: cows were fed a basal diet containing ~250 mEq/kg of DM DCAD that was supplemented with potassium carbonate at 0, 50, 100, and 150 mEq/kg of DM or 0, 125, 250, and 375 mEq/kg of DM in experiments 1 and 2, respectively. In experiment 3, we tested the effect of cation source: sodium sesquicarbonate replaced 0, 33, 67, and 100% of the supplemental potassium carbonate (150 mEq/kg of DM DCAD). The DCAD concentration had no effect on milk production, milk protein concentration, or milk protein yield in experiments 1 and 2. Dry matter intake was not affected by DCAD concentration in experiment 1 or by cation source in experiment 3. However, DMI increased linearly with increasing DCAD in experiment 2. We detected a linear increase in milk fat concentration and yield with increasing DCAD in experiments 1 and 2 and by substituting sodium sesquicarbonate for potassium carbonate in experiment 3. Increased milk fat concentration with increasing DCAD led to increases in 3.5% FCM in experiments 1 and 2. Maximal dairy FE was achieved at a DCAD concentration of 426 mEq/kg of DM in experiments 1 and 2 and by substituting Na for K in experiment 3. The results of these experiments suggest that both DCAD concentration and the cation source used to alter DCAD concentration have effects on milk fat content and yield and dairy FE.

Milk fat responses to butterfat infusion during conjugated linoleic acid-induced milk fat depression in lactating dairy cows.

During diet-induced milk fat depression (MFD), the short and medium-chain fatty acids (SMCFA), which are synthesized de novo in the mammary gland, are reduced to a much greater extent than the long-chain fatty acids (LCFA) that originate from the circulation. Our hypothesis was that increased availability of SMCFA might rescue conjugated linoleic acid (CLA)-induced MFD in lactating dairy cows. To test that hypothesis, 4 rumen-fistulated lactating Holstein cows (128 ± 23 d in milk) were used in a 4 × 4 Latin square design with 3-wk experimental periods. Treatments were applied during the last 2 wk of each period and included 3× daily abomasal infusion of a total of (1) 230 g/d of LCFA (blend of 59% cocoa butter, 36% olive oil, and 5% palm oil); (2) 420 g/d of butterfat (BF); (3) 230 g/d of LCFA with 27 g/d of CLA (LC-CLA), containing 10 g/d of trans-10,cis-12 CLA; and (4) 420 g/d of butterfat with 27 g/d of CLA (BF-CLA). Butterfat provided 50% of C16 (115 g/d) and similar amounts of C18 FA as found in LCFA, such that the difference between the BF and LCFA treatments was 190 g/d of SMCFA. No treatment effects were observed for DMI or milk yield. Milk fat content was reduced by 41 and 32%, whereas milk fat yield was reduced by 41 and 38% with LC-CLA and BF-CLA, respectively, compared with their respective controls. Abomasal infusion of CLA reduced de novo synthesized fatty acid (DNFA; SMCFA and 50% C16:0) concentration, whereas DNFA tended to be greater with BF infusion. An interaction was observed between SMCFA and CLA as the increased availability of SMCFA reduced stearoyl-CoA-desaturase-1 gene expression, whereas it tended to reduce lipoprotein lipase (LPL), 1-acylglycerol-3-phosphate O-acyltransferase 6 (AGPAT-6), sterol regulatory element-binding protein cleavage-activating protein (SCAP), and peroxisome proliferator-activated receptor γ (PPAR-γ) gene expression in the presence of CLA. The mRNA expression of genes involved in de novo fatty acid synthesis [acetyl-coenzyme A carboxylase α (ACACA) and fatty acid synthase (FASN)], fatty acid uptake (LPL), and triglyceride synthesis [AGPAT-6 and diacylglycerol O-acyltransferase 1 (DGAT-1)] along with protein abundance of the ACC and FASN were reduced with CLA. However, the increased availability of SMCFA had no effect on lipogenic gene expression except for LPL, whose expression was increased with BF infusion. The nutritional manipulation by increasing the intestinal availability of SMCFA was not sufficient to rescue CLA-induced MFD.

Milk fat responses to dietary supplementation of short- and medium-chain fatty acids in lactating dairy cows.

Short-and medium-chain fatty acids (SMCFA), which are synthesized de novo in the mammary gland, are reduced to a much greater extent than the long-chain fatty acids during diet-induced milk fat depression. Our hypothesis was that SMCFA are limiting for milk fat synthesis even under conditions when milk fat is not depressed. Our objective was to test the potential limitation of SMCFA on milk fat synthesis via dietary supplementation. Sixteen lactating Holstein cows (107±18 d in milk) were fed a corn silage-based total mixed ration. Cows were randomly assigned to groups of 4 per pen and supplemented with 1 of 4 dietary fat supplements (600 g/d) supplied in a 4×4 Latin square design with 21-d experimental periods. Treatments consisted of fat supplements containing mixtures of calcium salts of long-chain fatty acids (Megalac; Church & Dwight Co. Inc., Princeton, NJ) and an SMCFA mixture (S; 3.3% C8, 7.6% C10, 9.85% C12, 32.12% C14, and 47.11% C16) that contained 0, 200, 400, and 600 g/d of S substituted for Megalac (S0, S200, S400, and S600, respectively). No treatment effects were observed for dry matter and fat-corrected milk. However, milk yield was decreased with S600. Milk fat increased linearly by 0.17, 0.25, and 0.33 percentage units for the respective S treatments. However, fat yield peaked at S200 and milk protein concentration and yield was significantly decreased at the higher S levels because of a linear trend toward decreased milk yield in the S600 treatment. In conclusion, SMCFA supplementation linearly increased milk fat concentration but decreased milk production at the higher levels of supplementation. The dietary inclusion of SMCFA had no effects on total milk fat yield.

Transfer rate of α-linolenic acid from abomasally infused flaxseed oil into milk fat and the effects on milk fatty acid composition in dairy cows.

The objectives of the present study were to evaluate the transfer efficiency of α-linolenic acid (ALA) from the abomasum into milk fat, its interaction with milk fat content and yield, and the relationship between ALA and C16:0 in milk fat. Three rumen-fistulated multiparous Holstein cows at midlactation were used in a 3×3 Latin square design. Treatments consisted of abomasal infusion of (1) 110 mL of water/d (control), (2) 110 mL of flaxseed oil/d (low flaxseed oil, LFO), and (3) 220 mL of flaxseed oil/d (high flaxseed oil, HFO). Experimental periods were continued for 2 wk and fat supplements were infused abomasally during the last 7 d of each period. Average dry matter intake and milk yield were not affected by oil infusion. Milk fat and lactose content tended to be greater with flaxseed infusion compared with the control. Plasma ALA was 2.9- and 4.0-fold greater with LFO and HFO, respectively. The apparent transfer efficiency of ALA to milk was 44.8 and 45.7% with LFO and HFO, respectively. The C16:0 content in milk fat was decreased by 3.59 and 5.25 percentage units, whereas the ALA content was increased by 1.68 and 3.09 percentage units with LFO and HFO, respectively. Similarly, C18:2n-6 was increased by 0.95 and 1.31 percentage units with LFA and HFO, respectively, without changes in other fatty acids (FA). Total polyunsaturated FA was 4.4 and 2.7% lower in the HFO and LFO, respectively, than in the control. Furthermore, C16:0 content in the milk fat was reduced to a greater extent than the increase in ALA content, as a 1.68 and 3.09 percentage unit increase occurred in ALA compared with a 3.6 and 5.25 percentage unit decrease in C16:0 for LFO and HFO, respectively, such that a negative correlation existed between ALA and C16:0 (r=-0.72). In conclusion, abomasal infusion of flaxseed oil dramatically increased the ALA content in plasma and milk fat. Because the replacement of C16:0 with ALA and C18:2n-6 occurred without changes in other FA presumed to be synthesized de novo in the mammary gland, this suggests that the preformed C16:0 was replaced, rather than being caused, by an overall suppression of de novo FA synthesis in the mammary gland.

Epigenetics: a possible role in acute and transgenerational regulation of dairy cow milk production.

A potential role for epigenetic mechanisms in the regulation of mammary function in the dairy cow is emerging. Epigenetics is the study of heritable changes in genome function that occur because of chemical changes rather than DNA sequence changes. DNA methylation is an epigenetic event that results in the silencing of gene expression and may be passed on to the next generation. However, recent studies investigating different physiological states and changes in milk protein gene expression suggest that DNA methylation may also play an acute, regulatory, role in gene transcription. This overview will highlight the role of DNA methylation in the silencing of milk protein gene expression during mastitis and mammary involution. Moreover, environmental factors such as nutrition may induce epigenetic modifications of gene expression. The current research investigating the possibility of in utero, hence cross-generational, epigenetic modifications in dairy cows will also be discussed. Understanding how the mammary gland responds to environmental cues provides a potential to enhance milk production not only of the dairy cow but also of her daughter.

Clinical and scientific progress related to the interface between cardiology and psychology: lessons learned from 35 years of experience at the Thoraxcenter of the Erasmus Medical Center in Rotterdam.

In November 1975, as the first in the Netherlands, a full-time psychologist was employed at the Department of Cardiology of the Thoraxcenter of the Erasmus Medical Center. This innovative decision was consistent with a view to treat the patient as a whole rather than the heart as a single body part in need of repair, combined with the understanding that the heart and mind interact to affect health. The present selective review addresses the broad range of contributions of 35 years of psychology to clinical cardiology and cardiovascular research with a focus on research, teaching, psychological screening and patient care. The review ends with lessons to be learned and challenges for the future with respect to improving the care and management of patients with heart disease in order to enhance secondary prevention and the role of behavioural and psychological factors in this endeavour.

Corn silage versus corn silage:alfalfa hay mixtures for dairy cows: effects of dietary potassium, calcium, and cation-anion difference.

Corn silage (CS) has replaced alfalfa hay (AH) and haylage as the major forage fed to lactating dairy cows, yet many dairy producers believe that inclusion of small amounts of alfalfa hay or haylage improves feed intake and milk production. Alfalfa contains greater concentrations of K and Ca than corn silage and has an inherently higher dietary cation-anion difference (DCAD). Supplemental dietary buffers such as NaHCO(3) and K(2)CO(3) increase DCAD and summaries of studies with these buffers showed improved performance in CS-based diets but not in AH-based diets. We speculated that improvements in performance with AH addition to CS-based diets could be due to differences in mineral and DCAD concentrations between the 2 forages. The objective of this experiment was to test the effects of forage (CS vs. AH) and mineral supplementation on production responses using 45 lactating Holstein cows during the first 20 wk postpartum. Dietary treatments included (1) 50:50 mixture of AH and CS as the forage (AHCS); (2) CS as the sole forage; and (3) CS fortified with mineral supplements (CaCO(3) and K(2)CO(3)) to match the Ca and K content of the AHCS diet (CS-DCAD). Feed intake and milk production were equivalent or greater for cows fed the CS and CS-DCAD diets compared with those fed the AHCS diet. Fat percentage was greater in cows fed the CS compared with the AHCS diet. Fat-corrected milk (FCM; 3.5%) tended to be greater in cows fed the CS and CS-DCAD diets compared with the AHCS diet. Feed efficiencies measured as FCM/dry matter intake were 1.76, 1.80, and 1.94 for the AHCS, CS, and CS-DCAD diets, respectively. The combined effects of reduced feed intake and increased FCM contributed to increased feed efficiency with the CS-DCAD diet, which contained 1.41% K compared with 1.18% K in the CS diet, and we speculate that this might be the result of added dietary K and DCAD effects on digestive efficiency. These results indicate no advantage to including AH in CS-based diets, but suggest that improving mineral supplementation in CS-based diets may increase feed efficiency.

Encouraging psychological outcomes after altruistic donation to a stranger.

In a growing number of transplant centers worldwide, altruistic donors are accepted to anonymously donate a kidney to a stranger. An important hesitation to expand these transplantation programs is the fear of evoking psychological distress in the altruistic donor after donation. To what extent this fear is justified has not yet been systematically investigated. In this study, 24 altruistic donors were interviewed on average 2 years after donation. Lifetime mental health history, current psychological complaints, satisfaction with and impact of the donation on well-being, motives for donation, communication with recipient and donation experience were assessed. Altruistic donors report a considerable positive impact of donation on psychological well-being, whereas negative impact was limited. Satisfaction with donation was very high. Although a history of a psychiatric diagnosis was ascertained in almost half of the donors, psychological complaints before and after donation were comparable to national average norm scores. Motives for donation were genuine and the experience of donation generally conformed to their expectations. In conclusion, living kidney donation to a stranger does not appear to exacerbate psychological complaints. Moreover, altruistic donors report considerable satisfaction and personal benefit. The exceptional gift of altruistic donors can contribute toward solving the current organ shortage issue.

Altruistic donor triggered domino-paired kidney donation for unsuccessful couples from the kidney-exchange program.

Between January 2000 and July 2009, 132 individuals inquired about altruistic kidney donation to strangers. These donors were willing to donate to genetically and emotionally unrelated patients. Some altruistic donors wished to donate to a specific person, but most wished to donate anonymously. In domino-paired donation, the altruistic donor donates to the recipient of an incompatible couple; the donor of that couple (domino-donor) donates to another couple or to the waiting list. In contrast to kidney-exchange donation where bilateral matching of couples is required, recipient and donor matching are unlinked in domino-paired donation. This facilitates matching for unsuccessful couples from the kidney-exchange program where blood type O prevails in recipients and is under-represented in donors. Fifty-one altruistic donors (39%) donated their kidney and 35 domino-donors were involved. There were 29 domino procedures, 24 with 1 altruistic donor and 1 domino-donor, 5 with more domino-donors. Eighty-six transplantations were performed. Donor and recipient blood type distribution in the couples limited allocation to blood type non-O waiting list patients. The success rate of domino-paired donation is dependent on the composition of the pool of incompatible pairs, but it offers opportunities for difficult to match pairs that were unsuccessful in the kidney-exchange program.

Meta-analysis of milk protein yield responses to lysine and methionine supplementation.

Previous reports on milk protein responses to AA supplementation focused on Lys and Met concentrations expressed as a percentage of metabolizable protein, not the amounts of AA supplied. The objective of this study was to quantify the milk protein yield (MPY; g/d) response in studies in which Met or Lys was supplied either by postruminal infusion or in a rumen-protected form. A meta-analysis using a logistic regression model fitted using nonlinear mixed model procedures was performed on results from 23 published studies involving postruminal supplementation of Lys (18 experiments) and Met (35 experiments) in lactating dairy cows. Variance caused by study effect was removed by designation of individual study as subject within the random component within the nonlinear model. Milk protein responses to supplemental Met decreased from 16 to 4 g of milk protein per gram of metabolizable Met intake as Met intake varied from 25 to 70 g per cow per day. Similarly, milk protein responses to supplemental Lys decreased from 5.0 to 3.2 g of milk protein per gram of metabolizable Lys intake as Lys intake varied from 80 to 203 g per cow per day. Assuming Met and Lys concentrations of 2.76 and 7.63 g/100 g of milk protein, respectively, the implied marginal efficiencies of metabolizable AA use for MPY decreased from 44 to 12% for Met and from 39 to 25% for Lys over the range of metabolizable AA intakes. Although the estimated efficiencies were low compared with previous estimates, a low marginal efficiency of amino acid utilization would be expected when amino acid supply is at or near to the animal's requirement, as was the case in these experiments. This suggests that current models that assume both a constant MPY response and constant AA utilization efficiency are inadequate. Models that assume a constant efficiency of AA use will overestimate production responses to individual AA supply, especially when high amounts of metabolizable AA are fed.

Peroxisome proliferator-activated receptor-gamma activation and long-chain fatty acids alter lipogenic gene networks in bovine mammary epithelial cells to various extents.

Several long-chain fatty acids (LCFA) are natural ligands of nonruminant peroxisome proliferator-activated receptor-gamma (PPARG), which, along with its lipogenic target genes, is upregulated in bovine mammary tissue during lactation. Thus, PPARG might represent an important control point of bovine milk fat synthesis. We tested lipogenic gene network expression via quantitative PCR of 19 genes in bovine mammary epithelial cells cultured with 16:0, 18:0, cis-9 18:1, trans-10 18:1, trans-10,cis-12 18:2 [t10c12 conjugated linoleic acid (CLA)], 20:5, ethanol (control), and the PPARG agonist rosiglitazone (ROSI). Triplicate cultures were maintained for 12 h with 50 muM ROSI or 100 muM LCFA. Responses common to 16:0 and 18:0 relative to the control included significantly greater expression of INSIG1 (+298%, +92%), AGPAT6 (+137%, +169%), FABP3 (+755%, +338%), and FABP4 (+171%, 157%). These were coupled with greater intracellular lipid droplet formation and mRNA of ACSS2, LPIN1, SCD, and SREBF2 in response to 16:0, and greater DGAT1 and THRSP with 18:0. Trans-10 18:1 and t10c12 CLA reduced expression of FASN (-60%, -31%), SCD (-100%, -357%), and SREBF1 (-49%, -189%). Furthermore, t10c12 CLA downregulated ACSS2, FABP3, INSIG1, SREBF2, and THRSP expression. Expression of SREBF1 was lower with cis-9 18:1 (-140%) and 20:5 (-125%) compared with the control. This latter LCFA also decreased SCD, SREBF2, and LPL expression. No effects of LCFA or ROSI on PPARG were observed, but ROSI upregulated (+39% to +269%) expression of ACACA, FASN, LPIN1, AGPAT6, DGAT1, SREBF1, SREBF2, and INSIG1. Thus, these genes are putative PPARG target genes in bovine mammary cells. This is the first report showing a direct effect of trans-10 18:1 on bovine mammary cell lipogenic gene expression. The coordinated upregulation of lipogenic gene networks in response to ROSI and saturated LCFA offers support for PPARG activation in regulating bovine milk fat synthesis.

Identification of internal control genes for quantitative polymerase chain reaction in mammary tissue of lactating cows receiving lipid supplements.

Dietary lipid supplements affect mammary lipid metabolism partly through changes in lipogenic gene expression. Quantitative PCR (qPCR) is a sensitive, reliable, and accurate technique for gene expression analysis. However, variation introduced in qPCR data by analytical or technical errors needs to be accounted for via normalization using appropriate internal control genes (ICG). Objectives were to mine individual bovine mammary microarray data on >13,000 genes across 66 cows from 2 independent studies to identify the most suitable ICG for qPCR normalization. In addition to unsupplemented control diets, cows were fed saturated or unsaturated lipids for 21 d or were infused with supplements (butterfat, conjugated linoleic acid mixture, long-chain fatty acids) into the abomasum to modify milk fat synthesis and fatty acid profiles. We identified 49 genes that did not vary in expression across the 66 samples. Subsequent gene network analysis revealed that 22 of those genes were not co-regulated. Among those COPS7A, CORO1B, DNAJC19, EIF3K, EMD, GOLGA5, MTG1, UXT, MRPL39, GPR175, and MARVELD1 (sample/reference expression ratio = 1 +/- 0.1) were selected for PCR analysis upon verification of goodness of BLAT/BLAST sequence and primer design. Relative expression of B2M, GAPDH, and ACTB, previously used as ICG in bovine mammary tissue, was highly variable (0.9 +/- 0.6) across studies. Gene stability analysis via geNorm software uncovered MRPL39, GPR175, UXT, and EIF3K as having the most stable expression ratio and, thus, suitable as ICG. Analysis also indicated that use of 3 ICG was most appropriate for calculating a normalization factor. Overall, the geometric average of MRPL39, UXT, and EIF3K is ideal for normalization of mammary qPCR data in studies involving lipid supplementation of dairy cows. These novel ICG could be used for normalization in similar studies as alternatives to the less-reliable ACTB, GAPDH, or B2M.

Abomasal infusion of butterfat increases milk fat in lactating dairy cows.

The objective of this study was to compare the effects of abomasal infusion of butterfat containing all fatty acids (FA) present in milk, including the short- and medium-chain FA, with infusion of only the long-chain FA (LCFA) present in milk, on the FA composition and milk fat yield in lactating dairy cows. Eight rumen-fistulated Holstein cows, in early lactation (49 +/- 20 days in milk) were used in a replicated 4 x 4 Latin square design. Treatments were abomasal infusion of the following: 1) no infusion (control), 2) 400 g/d of butterfat (butterfat), 3) 245 g/d of LCFA (blend of 59% cocoa butter, 36% olive oil, and 5% palm oil) providing 50% of the 16:0 and equivalent amounts of C18 FA as found in 400 g of butterfat, and 4) 100 g/d of conjugated linoleic acid (CLA, negative control), providing 10 g of trans-10, cis-12 CLA. Fat supplements were infused in equal portions 3 times daily at 0800, 1400, and 1800 h during the last 2 wk of each 3-wk experimental period. Daily dry matter intake and milk production were unaffected by the infusion treatments. Butterfat infusion increased milk fat percentage by 14% to 4.26% and milk fat yield by 21% to 1,421 g/d compared with controls (3.74% and 1,178 g/d). Milk fat percentage and fat yield were decreased by 43% by CLA. Milk protein percentage was higher (3.70%) in CLA-infused cows than in control (3.30%), butterfat (3.28%), or LCFA (3.27%) treatments. Although LCFA had no effect on fat synthesis, abomasal infusion of butterfat increased milk fat percentage and yield, suggesting that the availability of short- and medium-chain FA may be a limiting factor for milk fat synthesis.