Dairy Diets Research Articles

Energy intensity in livestock operations – Modeling of dairy farming systems in Germany

The world’s population and food consumption are increasing drastically while natural resources are decreasing. In particular, energy use is an important component of reaching sustainability in agricultural production processes because of its shortage as resource, its influence on air pollution and its role in the economics of production. This study used system modeling to examine interactions between crop and livestock procedures and between levels of different input factors and their effects on yields in order to determine agricultural energy intensity. A method based on direct and indirect energy inputs within the livestock operation and plant production is used. A sensitivity analysis is done to investigate the influence of site conditions on the energy intensity of milk production and to highlight recommendations for management practices in livestock operations to reduce the energy use on dairy farms in Germany. An uncertainty analysis is used to evaluate the results of this study.Plant production, which consists of feed-supply and diet composition, constitutes the main influence on energy intensity in dairy farming. The energy intensity of feed-supply is strongly dependent on the quality of land and its management. An increasing use of concentrate in the dairy diet leads to a higher energy intensity for the process. Livestock operation accounts for one third of the energy intensity in milk production.The rearing period of a heifer at a dairy farm requires an energy input of 13–16GJ. The share of the energy intensity of the rearing period of the heifer per kg of milk changes, depending on the service life of the dairy cow. The service life of the cow increases, while the share of the energy intensity of the process section replacement decreases.Noting the influence of the energy intensity of machines and technical facilities in dairy farming is useful for overall energy use reduction. Here, also, the pasture is shown as a possibility for reducing the fossil energy input on-farm. The animal houses influence the energy intensity only marginally.Based on the sensitivity analysis of farm management and land quality, the energy intensity varies between 3.0 and 3.6MJkg−1 energy corrected milk for an average milk yield of 8000kg ECM cow−1 year−1. Increasing milk yields lead to a reduction of the energy intensity per kg ECM. But this effect is reduced with rising milk yields because of higher energy inputs needed for the feed-supply, due to a higher share of concentrate and a typically higher replacement rate for the herd.

Elevated dairy fat intake by lactating women increases milk fat and alters fatty acid profile, but does not change gene expression in the milk fat globule transcriptome

Previous work has demonstrated that increased intake of dairy fat by lactating women increases milk fat percent and alters milk fatty acid profile. To investigate the effects of dairy fat consumption on cellular function in the mammary gland, we provided 15 lactating women with diets rich in full‐fat or non‐fat dairy products for 14 d in a randomized, crossover design. Milk fat was reduced when women consumed the non‐fat dairy diet compared to when they consumed the full‐fat dairy diet (2.41 ± 0.31 vs. 3.35 ± 0.28%, mean ± SEM, P < 0.05); concentrations of over 20 fatty acids also differed. Microarray analysis of gene expression in the milk‐fat globule transcriptome performed on samples from 6 of the subjects demonstrated only minor changes. Subsequent rt‐PCR validation of potential genes of interest revealed no alterations in gene expression. These data suggest that, despite treatment effects on milk fat percent and fatty acid profile, alterations in gene expression in the lactating mammary gland as a result of increased dietary dairy fat intake are minimal. Funded by the United Dairymen of Idaho.Grant Funding Source : United Dairymen of Idaho

Dairy consumption and working memory performance in overweight and obese adults

All individuals will experience some degree of cognitive impairment in their later years. Diet is one readily modifiable factor that may influence cognitive function and psychological well-being. Very little research has considered the potential role of dairy foods in modulating cognitive and psychological functions. The objective of this study was to determine the effect of a high intake of reduced fat dairy food on cognitive performance. Overweight adults with habitually low dairy intakes (<two serves/day) were recruited for a 12month crossover dietary intervention trial and randomised to a high (four serves/day) or low (one serve/day) intake of reduced fat dairy, crossing over to the alternate diet after 6months. Participants were tested at the end of each 6month diet period on multiple measures of cognitive performance, including memory, information processing speed, executive function, attention and abstract reasoning. In 38 participants who completed the trial (average age=52±2years; BMI=31.5±0.8kg/m2), spatial working memory performance was marginally better following 6months of the high dairy diet compared with the low dairy diet. Increasing the dairy intake of habitually low dairy consumers may have the potential to improve working memory.

Regulation of Uric Acid Excretion by the Kidney

It has been known for many years that the kidney plays a major role in uric acid homeostasis, as more than 70% of urate excretion is renal. Furthermore, hyperuricemia in gout is most commonly the result of relative urate underexcretion, as the kidney has enormous capacity for urate reabsorption. A clear understanding of the mechanisms of renal handling of urate has been hampered by the differences between humans and animal models. The power of human genetics and genome-wide association studies has now provided new insight into the molecular mechanisms of urate transport by identifying the transporters that have critical roles in urate transport. This review surveys the new evidence for a molecular model of urate transport in the renal proximal tubule and uses these data to refute the popular four-component model for urate transport that has long been in vogue. It also discusses data that help us understand the relation of diuretics to hyperuricemia, losartan-induced uricosuria, variations in uric acid levels in hyperglycemia, and the effects of dairy diets on serum urate levels. In the end, several of these clinical findings are explained, and the remaining gaps in our knowledge will become evident.

Dairy consumption and cardiometabolic health: outcomes of a 12-month crossover trial

BackgroundA growing body of research suggests that regular consumption of dairy foods may counteract obesity and other components of the metabolic syndrome. However, human intervention trials are lacking. We aimed to determine the cardiometabolic health effects of increasing the consumption of reduced fat dairy foods in adults with habitually low dairy intakes in the absence of energy restriction.MethodsAn intervention trial was undertaken in 61 overweight or obese adults who were randomly assigned to a high dairy diet (HD, 4 serves of reduced fat dairy/day) or a low dairy control diet (LD, ≤1 serve/day) for 6 months then crossed over to the alternate diet for a further 6 months. A range of anthropometric and cardiometabolic parameters including body composition, metabolic rate, blood lipids, blood pressure and arterial compliance were assessed at the end of each diet phase.ResultsTotal energy intake was 1120 kJ/day higher during the HD phase, resulting in slight weight gain during this period. However, there were no significant differences between HD and LD in absolute measures of waist circumference, body weight, fat mass or any other cardiometabolic parameter.ConclusionRecommended intakes of reduced fat dairy products may be incorporated into the diet of overweight adults without adversely affecting markers of cardiometabolic health.Trial RegistrationThe trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12608000538347) on 24th October, 2008.

Circulating inflammatory and atherogenic biomarkers are not increased following single meals of dairy foods

Inflammation characterizes obesity and is nutritionally modifiable. The hypothesis of this study is that full-fat dairy foods influence circulating inflammatory and atherogenic biomarkers according to fermentation status. Thirteen overweight subjects participated in five test meals. Single breakfasts containing control low-fat milk or 45 g fat from butter, cream, yoghurt or cheese were tested over 3 weeks. Plasmas obtained 3 and 6 h were later analyzed for inflammatory markers interleukin (IL)-6, IL-1β, tumor necrosis factor-α and high-sensitive C-reactive protein, and atherogenesis-related markers monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. A 4-week study in 12 subjects compared the effects on these biomarkers of diets containing ≈50 g dairy fat daily as either butter, cream and ice cream (non-fermented) or cheese plus yoghurt (fermented) dairy foods. In single-meal study, one outlier subject showed marked increments in biomarkers, hence the following results apply to 12. Within group analysis includes significant falls at 3 h in four inflammatory markers after cream, butter and low fat, and three atherogenesis-related biomarkers after cream. Changes were few after cheese and yoghurt. By 6 h, most values returned to baseline. However, between group analysis showed no differences between the five meals. The 4-week study showed no significant differences in fasting biomarker concentrations between non-fermented and fermented dairy diets. Single high-fat meals containing sequentially four different full-fat dairy foods did not increase eight circulating biomarkers related to inflammation or atherogenesis. Among subjects, significant falls occurred at 3 h in inflammatory biomarkers after cream and butter but were not specific for full-fat dairy foods. We could not confirm the reported increments in inflammation after fat meals.

Quantitative analysis of microbial fermentation under normal or high ruminal temperature in continuous cultures

<h2>ABSTRACT</h2> A dual-flow, continuous-culture system was used to investigate effects of ruminal temperature and forage-to-concentrate ratio in lactation dairy diets on in vitro fermentation characteristics. The experiment was performed in a 2 × 2 factorial design (n = 4). Diets were formulated to maintain different forage-to-concentrate ratios (60:40 or 40:60, DM basis) in the high-forage (HF) or the low-forage (LF) diet, respectively. Four treatments were tested: HF under normal ruminal temperature (NRT; 39°C), LF under NRT, HF under high ruminal temperature (HRT; 41°C), and LF under HRT. Each independent run lasted 11 d (8 d of treatment adaptation and 3 d of data and sample collection). The temperature of the HRT treatment was chosen to mimic ruminal fermentative environment when cows are under heat stress. The HRT increased (P < 0.01) culture pH from 5.73 to 5.82 on average. Total VFA concentration decreased (P = 0.05) in the HRT compared with the NRT; however, ruminal temperature did not affect molar proportion of VFA. Feeding the LF diet increased DM, OM, and NDF digestibilities regardless of fermentative temperature. Digestibilities of DM and NDF were not affected by ruminal temperature, whereas the HRT tended to decrease (P = 0.14) OM digestibility compared with the NRT (66.6 vs. 67.4%). However, the increases in DM and OM digestibilities due to feeding the LF diet were less in the HRT than in the NRT, indicated by the fermentative temperature and diet interactions (P < 0.04). The HRT increased (P < 0.01) methane production and ammonia-N concentration. The HRT treatment also increased the concentration of ruminal C18:0 (P = 0.02) but decreased that of C18:1 trans-11 (P = 0.02). Overall results in this study suggest that during HRT as experienced by cows under heat stress, nutrient digestion, energy utilization, and microbial protein synthesis are altered.

Effects of forage legumes containing condensed tannins on methane and ammonia production in continuous cultures of mixed ruminal microorganisms

It has been reported that some condensed tannin (CT) containing forage legumes may reduce ruminal CH4 emissions as a result of direct and/or indirect inhibition of methanogens. Dual flow continuous fermentors (working volume of 700ml) were used to determine effects of CT containing legume hays in dairy total mixed rations (TMR) on ruminal fermentation, with an emphasis on CH4 and ammonia N production. Fermentors were inoculated with filtered rumen contents and allowed to adapt to experimental diets for 6d, followed by 3d of sampling and data collection. All dietary treatments were formulated for lactating dairy cows in early lactation. Five TMR were evaluated being: (1) alfalfa (AFT), (2) cicer milkvetch (CMVT), (3) Norcen birdsfoot trefoil (NBFTT), (4) Oberhaunstadter birdsfoot trefoil (OBFTT) and (5) sainfoin (SFT). The experiment was a 5×5 Latin square design. Compared to AFT, culture pH was not influenced by most forages, but was increased (P<0.01) by feeding SFT. Compared to AFT, the molar proportion of propionate increased (P=0.03) with CMVT, but decreased (P=0.05) with SFT. Feeding CMVT decreased (P<0.01) the molar proportion of butyrate relative to AFT. Acetate to propionate ratio decreased with CMVT (P<0.01) and OBFTT (1.65; P=0.01), but increased with SFT (P<0.01) compared to AFT. Apparent digestibility of dry matter or neutral detergent fiber (aNDF) was not influenced by forage source. Compared to AFT, CH4 production decreased with other treatments (P<0.01), whereas CH4 production (expressed as mM/g aNDF digested) was only reduced (P<0.05) by CMVT and OBFTT. NH3–N concentration was lower (P<0.01) with CMVT and SFT, but not affected by NBFTT or OBFTT compared to AFT. Legume forages eliciting reductions in CH4 and NH3–N production may offer advantages in lactating dairy diets to improve nutrient utilization and environmental sustainability of dairy cattle production.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Effects of supplementing condensed tannin extract on intake, digestion, ruminal fermentation, and milk production of lactating dairy cows

A lactation experiment was conducted to determine the influence of quebracho condensed tannin extract (CTE) on ruminal fermentation and lactational performance of dairy cows. The cows were fed a high forage (HF) or a low forage (LF) diet with a forage-to-concentrate ratio of 59:41 or 41:59 on a dry matter (DM) basis, respectively. Eight multiparous lactating Holstein cows (62±8.8 d in milk) were used. The design of the experiment was a double 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments, and each period lasted 21 d (14 d of treatment adaptation and 7 d of data collection and sampling). Four dietary treatments were tested: HF without CTE, HF with CTE (HF+CTE), LF without CTE, and LF with CTE (LF+CTE). Commercial quebracho CTE was added to the HF+CTE and the LF+CTE at a rate of 3% of dietary DM. Intake of DM averaged 26.7kg/d across treatments, and supplementing CTE decreased intakes of DM and nutrients regardless of forage level. Digestibilities of DM and nutrients were not affected by CTE supplementation. Milk yield averaged 35.3kg/d across treatments, and yields of milk and milk component were not influenced by CTE supplementation. Negative effects of CTE supplementation on feed intake resulted in increased feed efficiency (milk yield/DM intake). Although concentration of milk urea N (MUN) decreased by supplementing CTE in the diets, efficiency of N use for milk N was not affected by CTE supplementation. Feeding the LF diet decreased ruminal pH (mean of 6.47 and 6.33 in HF and LF, respectively). However, supplementation of CTE in the diets did not influence ruminal pH. Supplementing CTE decreased total volatile fatty acid concentration regardless of level of forage. With CTE supplementation, molar proportions of acetate, propionate, and butyrate increased in the HF diet, but not in the LF diet, resulting in interactions between forage level and CTE supplementation. Concentration of ammonia-N tended to decrease with supplementation of CTE. The most remarkable finding in this study was that cows fed CTE-supplemented diets had decreased ruminal ammonia-N and MUN concentrations, indicating that less ruminal N was lost as ammonia because of decreased degradation of crude protein by rumen microorganisms in response to CTE supplementation. Therefore, supplementation of CTE in lactation dairy diets may change the route of N excretion, having less excretion into urine but more into feces, as it had no effect on N utilization efficiency for milk production.

Effects of Bacillus Subtilis and Yeast Culture for Feed Intakeand Milk Production

An experiment was conducted to study the effects of mixture of Bacillus subtilis and yeast culture market named Chusuyi(XSY) added into dairy diet on intake and milk production. The results indicated that the milk production and feed intake was higher among experimental groups than that of control groups. The dry matter, fat protein and milk sugar content in every milk samples is higher but no statistical significant. The economic return of experimental group was higher than that of control group.

Effects of dairy consumption on SIRT1 and mitochondrial biogenesis in adipocytes and muscle cells

BackgroundRecent data from this laboratory suggest that components of dairy foods may serve as activators of SIRT1 (Silent Information Regulator Transcript 1), and thereby participate in regulation of glucose and lipid metabolism. In this study, an ex-vivo/in-vitro approach was used to examine the integrated effects of dairy diets on SIRT1 activation in two key target tissues (adipose and muscle tissue).MethodsSerum from overweight and obese subjects fed low or high dairy diets for 28 days was added to culture medium (similar to conditioned media) to treat cultured adipocytes and muscle cells for 48 hours.ResultsTreatment with high dairy group conditioned media resulted in 40% increased SIRT1 gene expression in both tissues (p < 0.01) and 13% increased enzyme activity in adipose tissue compared to baseline. This was associated with increased gene expression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF1), cytochrome oxidase c subunit 7 (Cox 7), NADH dehydrogenase and uncoupling protein 2 (UCP2) in adipocytes as well as uncoupling protein 3 (UCP3), NRF1 and Cox 7 in muscle cells (p < 0.05). Further, direct incubation of physiological concentrations of leucine and its metabolites α-Ketoisocaproic acid (KIC) and β-hydroxy-methylbuteric acid (HMB) with recombinant human SIRT1 enzyme resulted in 30 to 50% increase of SIRT1 activity (p < 0.05).ConclusionsThese data indicate that dairy consumption leads to systemic effects, which may promote mitochondrial biogenesis in key target tissues such as muscle and adipose tissue both by direct activation of SIRT1 as well as by SIRT1-independent pathways.

Effects of Supplementation of Natural Zeolite on Intake, Digestion, Ruminal Fermentation, and Lactational Performance of Dairy Cows

ABSTRACT A lactating dairy cow experiment was conducted to determine the influence of a ruminal buffer product containing magnesium-exchanged zeolite on ruminal fermentation and lactational performance. The experimental TMR diet consisted of 38% alfalfa hay, 19% corn silage, 14% corn grain, and 30% concentrate mix on a DM basis, and it was fed ad libitum. Thirty primiparous and multiparous lactating Holstein cows (52 ± 23.0 DIM) were assigned to 1 of 3 dietary treatments with 10 cows in each treatment: control (TMR diet without ruminal buffer), TMR diet with 1.4% sodium bicarbonate (SBD), and TMR diet with 1.4% zeolite product (ZD). The experiment was a completely randomized design performed over 12 wk. Intake of DM was similar (26.5 kg/d) across treatments. Milk yield was similar among the 3 treatments (40.7 kg/d on average), and efficiency (4% FCM/DMI) was not affected by treatments. Milk fat concentration did not differ among treatments, whereas milk protein concentration tended to be higher for the ZD than for the control and the SBD (P = 0.15). Although feeding the ZD resulted in a tendency of increased milk protein concentration, feed nitrogen (N) efficiency for milk N did not differ among the 3 treatments. In addition, milk urea N concentration was not influenced by feeding the ZD. Ruminal pH tended to increase (P = 0.11) when feeding the SBD or the ZD compared with the control. Concentration of ammonia N did not differ among treatments. Feeding the ZD tended to decrease (P = 0.14) total VFA production compared with feeding the control and the SBD, whereas molar proportions of acetate and propionate were not affected by the treatments. The zeolite product used in this study would cost-effectively replace sodium bicarbonate as a ruminal buffer additive in a lactating dairy diet, but its efficacy needs to be further assessed when supplemented in a high-concentrate lactating dairy diet whereby animals may experience subacute ruminal acidosis.

Pigeon peas as a supplement for lactating dairy cows fed corn silage-based diets

Holstein rumen-cannulated cows [n=7; initial body weight (BW) 640.56±71.43kg] were fed a corn silage basal diet with 1 of 3 concentrates (C=control; P10=10% pigeon peas; P20=20% pigeon peas). Cows were randomly assigned to treatments in a replicated 3×3 Latin square and individually fed using Calan gates. Each experimental period was 21 d with 7 d for adaption and 14 d for sample collection. Ruminal fluid samples were taken the last day of each experimental period and analyzed for pH, ammonia, long-chain fatty acids, and volatile fatty acids (VFA). Consecutive a.m. and p.m. milk samples were taken during the last 2 wk of the 21-d period and analyzed for fat, protein, long-chain fatty acids, and somatic cell count. Dry matter intake (kg/d) was reduced during the second period and was greater for P10 diets. Milk protein was greater for cows fed P20 compared with P10. Energy-corrected milk was greater for cows fed the control diet compared with P10. Treatment had no effect on milk yield. Ruminal fluid pH decreased over sampling times; however, pH remained at or above 5.5. Diets did not affect ruminal fluid pH; however, pH was different for sampling periods. Ruminal ammonia decreased until 8h postfeeding at which time it peaked consistent with changes in ammonia concentrations that usually peak 3 to 5h postfeeding on diets high in plant proteins. Dietary treatments altered ruminal fluid VFA with reduced concentrations of acetate and greater concentrations of propionate for control diet, resulting in reduced acetate:propionate ratio. Isobutyrate exhibited an hour by treatment interaction, in which isobutyrate decreased until 8h postfeeding and then tended to be greater for P10 than for other treatments. Animals fed the P10 diet had greater concentrations of ruminal isovalerate. Ruminal cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid (CLA) isomers were not affected by dietary treatments. The P10 diet had greatest ruminal synthesis of cis-9,trans-11, but control cows had greatest ruminal synthesis of trans-10,cis-12. Milk CLA isomers were similar among treatments. Trends were observed for greater cis-9,trans-11 and trans-10,cis-12 for the P10 diet. Pigeon peas may be used as a protein supplement in dairy diets without affecting milk production, dry matter intake, or ruminal environment when they replace corn and soybean meal.

Attenuation in Weight Gain with High Calcium- and Dairy-Enriched Diets Is Not Associated with Taste Aversion in Rats: A Comparison with Casein, Whey, and Soy

A systematic evaluation of the effects of calcium (Ca) and protein source on food intake and taste aversion (TA) in rats is lacking. The purpose of this research was twofold: (1) to determine if Sprague-Dawley rats display TA to standard rat chow supplemented with 2.4% Ca and (2) to determine if short (24-hour) and long-term (weekly) food intake and weight gain are altered when rats are given access to diets containing various protein sources (casein, whey, dairy, or soy). Rats were assigned to one of two diet groups to examine high (2.4%) versus low (0.67%) Ca or to one of four groups to examine taste preference of diets where the sole protein was one of casein, soy, whey, or complete dairy. A crossover design was used to ensure rats consumed all test diets. Food intake and behavioral sequence of satiety were measured. There was no TA to the 2.4% Ca diet or to any protein source. Food intake did not differ between the two Ca diets or between the four protein diets. The dairy diet attenuated weekly weight gain compared to all other diets except whey. Overall, this study suggests that the levels of Ca and types of protein used in previous work addressing changes in body weight in rats do not influence food intake or trigger TA.

“Global” and “local” predictions of dairy diet nutritional quality using near infrared reflectance spectroscopy

The objective of the study was to evaluate performance of classic (global) and innovative (local) calibration techniques to monitor cattle diet, based on fecal near infrared reflectance spectroscopy (NIRS). A 3-yr on-farm survey (2005–2008) was carried out in Vietnam and La Reunion Island to collect animal, feed intake, and feces excretion data. Feed and feces were scanned by a Foss NIRsystem 5000 monochromator (Foss, Hillerød, Denmark) to estimate diet characteristics and nutrient digestibility. A data set including 1,322 diet-fecal pairs was built and used to perform global and local calibrations. Global equations gave satisfactory accuracy [coefficient of determination (R2) >0.8, 10% ≤ relative standard error of prediction (RSEP) ≤20%], whereas local equations gave good accuracy (R2 >0.8, RSEP <10%) or excellent accuracy (R2 >0.9, RSEP <10%) for the prediction of diet intake, quality, and digestibility. When validating the equations using the external individual data, both techniques were robust, with similar RSEP (8%) and R2 (0.82) values. The predictive performance of global and local equations was improved (RSEP = 5% and R2=0.90) when averaged animal data from farm, visit, and similar milk production were used. In particular, local equations reduced RSEP by 43% and increased R2 by 15%, on average, compared with those obtained from individual data. The low RSEP (4%), high R2 (0.96), and good ratio performance deviation (RPD=5) illustrated the excellent accuracy and robustness of the local equations. Findings suggest the ability of fecal NIRS to successfully and more accurately predict diet properties (intake, quality, and digestibility) with local calibration techniques compared with classic global techniques, especially on an averaged data set. Local calibration techniques represent an alternative promising method and potentially a decision support tool to decide whether diets meet dairy cattle requirements or need to be modified.

Milk yield and quality in Guernsey cows fed cottonseed cake-based diets partially substituted with baobab (Adansonia digitata L.) seed cake

The objective of this study was to determine the effects of partially substituting cottonseed cake with graded levels of baobab (Adansonia digitata L.) seed cake (BSC) on milk yield and quality in Guernsey cows. Sixteen cows in mid-lactation and in their third parity were allocated to diets containing 0% (control), 5%, 10%, and 15% BSC in a completely randomized design. Each cow was given a daily feed ration of 6kg and a basal diet of soya bean stover ad libitum. There were no differences in daily feed intake (P > 0.05), but basal intake differed among all treatment groups with cows on the control diet having the highest intake (30 ± 0.34kg/day). Mean daily milk yield differed (P < 0.05) among all treatment groups. However, the control had higher milk yield of 12.1 ± 0.73kg/day, and the 15% BSC had the least yield of 7.46 ± 0.73kg/day. Cows on the control diet had higher milk butterfat content (6.12%; P < 0.05) than those on the BSC-based diets. Protein content differed (P < 0.05) across all treatment groups with cows on 15% BSC producing the highest protein content (3.43%) while the control had the least (2.6%). The concentration of milk total solids for cows fed on 15% BSC was higher (P < 0.05) than that from cows on other diets. Lactose content was not affected by the diets (P > 0.05). These results indicate that BSC can substitute soya bean cake in dairy diets, but milk production and butterfat content are compromised.

Effects of low-fat dairy consumption on markers of low-grade systemic inflammation and endothelial function in overweight and obese subjects: an intervention study

Although increased concentrations of plasma inflammatory markers are not one of the criteria to diagnose the metabolic syndrome, low-grade systemic inflammation is receiving large attention as a metabolic syndrome component and cardiovascular risk factor. As several epidemiological studies have suggested a negative relationship between low-fat dairy consumption and the metabolic syndrome, we decided to investigate the effects of low-fat dairy consumption on inflammatory markers and adhesion molecules in overweight and obese subjects in an intervention study. Thirty-five healthy subjects (BMI>27 kg/m²) consumed, in a random order, low-fat dairy products (500 ml low-fat milk and 150 g low-fat yogurt) or carbohydrate-rich control products (600 ml fruit juice and three fruit biscuits) daily for 8 weeks. Plasma concentrations of TNF-α were decreased by 0.16 (SD 0.50) pg/ml (P = 0.070), and soluble TNF-α receptor-1 (s-TNFR-1) was increased by 110.0 (SD 338.4) pg/ml (P = 0.062) after the low-fat dairy period than after the control period. s-TNFR-2 was increased by 227.0 (SD 449.0) pg/ml (P = 0.020) by the dairy intervention. As a result, the TNF-α index, defined as the TNF-α:s-TNFR-2 ratio, was decreased by 0.000053 (SD 0.00012) (P = 0.015) after the dairy diet consumption. Low-fat dairy consumption had no effect on IL-6, monocyte chemoattractant protein-1, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 concentrations. The present results indicate that in overweight and obese subjects, low-fat dairy consumption for 8 weeks may increase concentrations of s-TNFR compared with carbohydrate-rich product consumption, but that it has no effects on other markers of chronic inflammation and endothelial function.

Supplementing Barley-Based Dairy Cow Diets with Saccharomyces cerevisiae

<h2>ABSTRACT</h2> Active dry yeast and yeast cultures based on Saccharomyces cerevisiae are widely used in commercial dairy production in North America and Europe to improve milk yield. These products have been extensively evaluated in corn-based diets, but their effectiveness may depend on the type of diet. The objective of this study was to determine the potential benefits of supplementing barley-based dairy diets with yeast for milk yield and production efficiency in dairy cows. Forty lactating Holstein dairy cows were randomly assigned to 1 of 2 treatments: 1) a control diet (no yeast) or 2) a yeast-supplemented diet. All cows were fed the control diet for 3 wk, followed by a 6-wk period on their assigned diets. The control diet consisted of 23% barley silage, 23% alfalfa silage, 6% alfalfa hay, and 48% of a ground barley-based concentrate (DM basis). For the treatment diet, an active dry yeast (Levucell SC-1077, Lallemand Animal Nutrition, Milwaukee, WI) was added to the concentrate to provide 0.5g Levucell/d per animal (1 x 10¹⁰cfu/d per animal). There was no difference in final BW (623 vs. 621kg; P=0.85), ADG (0.530 vs. 0.377kg/d; P=0.35), NE output (36.6 vs. 36.5 Mcal/d; P=0.95), or efficiency of NE output (1.58 vs. 1.65 Mcal/kg DMI; P=0.20) for cows on the control diet compared with those on the yeast-supplemented diet. There was also no difference (23.2 vs. 22.7kg/d; P=0.30) in DMI, 3.5% FCM (35.6 vs. 36.6kg/d; P=0.34), or efficiency of FCM production (1.55 vs. 1.64kg FCM/kg DMI; P=0.28) for yeast-supplemented cows compared with control cows. However, because FCM yield and efficiency of FCM production were numerically greater with yeast supplementation of the barley-based diet, the revenue over feed (including yeast) cost was increased by $0.77/d per animal compared with no supplementation.

Response of lactating dairy cows to high protein distillers grains or 3 other protein supplements

This study compared high protein dried distillers grains (HPDDG) with soybean meal (SBM), canola meal (CM), and dried distillers grains with solubles (DDGS) as protein supplements in dairy diets. A lactation trial used 12 multiparous cows averaging 78 d in milk at the start of the experiment in a 4 × 4 Latin square design with 28-d periods. Weeks 1 and 2 of each period were used for adjustment and wk 3 and 4 for data collection. Each treatment diet consisted of 55% forage and one of the 4 protein supplements in a concentrate mix. Total mixed diets averaged 15.3% crude protein, with 38% of the protein from one of the 4 protein supplements. Dry matter intake (24.4 kg/d) and crude protein intake (3.57 kg/d) were similar for all 4 diets. Milk production (31.8 kg/d), protein yield (1.05 kg/d), fat yield (1.29 kg/d), and protein percentage (3.31) were similar for all 4 treatment diets. Milk fat percentage was lower when fed DDGS (3.78) than when fed SBM or HPDDG (4.21), but similar with CM (4.07). Feed efficiency (1.44kg of energy-corrected milk/kg of dry matter intake) and nitrogen efficiency (0.29) were not affected by diet. Total milk nitrogen and true milk protein were highest when fed the HPDDG diet. Molar proportions of acetate, propionate, and the acetate to propionate ratio in ruminal contents and ruminal ammonia concentrations were similar for all diets. Arterial and venous concentrations of total essential AA tended to be lower when fed CM, reflecting lower concentrations of His, Ile, Leu, and Val when fed the CM diet. Extraction efficiency of AA from blood by the mammary gland indicated that Met was the first limiting AA when fed the SBM diet, whereas Lys was first limiting for the other diets. Phenylalanine was third limiting with all diets. Feeding HPDDG was equally as effective as feeding SBM, CM, and regular distillers grains as a protein supplement for lactating cows.

The effects of ruminally degraded protein on rumen fermentation and ammonia losses from manure in dairy cows

This experiment investigated the effect of dietary crude protein (CP) and ruminally degraded protein (RDP) levels on rumen fermentation, digestibility, ammonia emission from manure, and performance of lactating dairy cows. The experiment was a replicated 3 × 3 Latin square design with 6 cows. Three diets varying in CP concentration were tested (CP, % of dry matter): 15.4 (high CP, control), 13.4 (medium CP), and 12.9% (low CP). These diets provided metabolizable protein balances of 323, −44, and 40 g/d and RDP balances of 162, −326, and −636 g/d (high, medium, and low, respectively). Both the medium and low CP diets decreased ruminal pH compared with high CP, most likely because of the higher nonfiber carbohydrate concentration in the former diets. Ruminal ammonia pool size (rumen ammonia N was labeled with 15N) and the concentration of total free amino acids were greater for the high CP diet than for the RDP-deficient diets. Apparent total-tract nutrient digestibilities were not affected by treatment. Both the medium and low CP diets resulted in lower absolute and relative excretion of urinary N compared with the high CP diet, as a proportion of N intake. Excretion of fecal N and milk yield and composition were not affected by diet. Milk N efficiency (milk N ÷ N intake) and the cumulative secretion of ammonia-15N in milk protein were greater for the RDP-deficient diets, and milk urea N concentration was greater for the high CP diet. Both medium and low CP diets decreased the irreversible loss of ruminal ammonia N compared with the high CP diet. The rate and cumulative ammonia emissions from manure were lower for the medium and low CP diets compared with the high CP diet. Overall, this study demonstrated that dairy diets with reduced CP and RDP concentrations will produce manure with lower ammonia-emitting potential without affecting cow performance, if metabolizable protein requirements are met.