Diet digestibility and growth of holstein calves fed acidified milk replacers containing soy protein concentrate

Three experiments were conducted to determine the effects of acidification of milk replacers containing soy protein concentrate on diet digestibility and growth of Holstein bull calves. In Experiment 1, six calves (6 wk old) were fed at 10% of BW/d either acidified milk replacer containing soy protein concentrate or untreated milk replacer containing soy protein concentrate. Replacers were reconstituted to 12.5% DM for 10-d adjustment and 4-d collection periods to determine digestibility and N balance. Digestibilities of DM, ether extract, and N were similar between treatments. Nitrogen retention and N retention as a percentage of that absorbed were higher for calves fed the acidified diet. In Experiment 2, 20 calves (1 wk old) were fed diets identical to those diets fed in Experiment 1 at 20% of BW/d for 4 wk. Calves were allowed to adjust to the diet for 5 d. Growth parameters were measured and amount of feed offered was adjusted weekly. Calves fed the untreated diet had higher daily weight gains, girth gains, height gains, and better feed utilization. In Experiment 3, 21 calves were fed either the aforementioned diets or a replacer based on milk proteins at 10% of BW/d (12.5% DM) for 4 wk. Growth parameters were measured and DM intakes were adjusted weekly. Growth and feed conversion were similar across diets. Replacers containing soy protein concentrate or large amounts of whey may need to be supplemented with additional methionine to maximize rate of gain.     

Postweaning performance of heifers fed starter with and without hay during the milk-feeding period

This study assessed the carryover effects of providing forage during the milk-feeding period on postweaning feed intake and growth of heifers. At 11 wk of age, heifers previously (3 to 77 d of age) reared on starter (n=8) or starter plus grass hay (n=8) were switched to a single diet consisting of restricted amounts of concentrate [60% of the starter required to support daily body weight (BW) gain of 800 g] with ad libitum access to coarsely chopped orchardgrass hay. Feed intake and growth were measured from 11 to 18 wk of age. Starter dry matter (DM) intake averaged 2.14 ± 0.15 kg/d for both treatments. Forage consumption and total (starter plus hay) DM, neutral detergent fiber, crude protein, and metabolizable energy intakes were greater in heifers previously fed forage compared with those provided no forage. Initial and final BW were similar for the 2 treatments (108.2 ± 9.1 and 149.6 ± 9.3 kg, respectively). Overall average daily gain in heifers previously fed starter alone (0.92 ± 0.05,kg/d) tended to be greater than those previously fed starter plus hay (0.79 ± 0.06,kg/d). Total DM intake (starter plus hay) was lower in heifers previously fed starter alone than those fed starter plus hay (3.55 ± 0.13 vs. 4.08 ± 0.15 kg/d, respectively). Feed efficiency (BW gain/DM intake) after switching to a common diet was greater in calves previously fed starter alone than in those previously fed starter plus hay (0.26 ± 0.01 vs. 0.19 ± 0.01, respectively). However, heifers provided access to hay had a smaller body barrel (an indicator of gut fill) at 15 wk (127.7 ± 1.7 vs. 134.3 ± 2.7 cm) and 17 wk (132.4 ± 1.9 vs. 141.0 ± 2.2 cm) of age and had greater blood β-hydroxybutyrate (0.22 ± 0.04 vs. 0.32 ± 0.04 mmol/L) compared with heifers that did not have access to hay earlier in life. These results indicate that provision of hay early in life promotes forage intake when heifers are switched to a high forage diet. However, greater feed consumption did not translate into live BW gain. Higher feed efficiency after switching to a common diet in heifers previously fed starter alone compared with those fed starter plus hay must be viewed with caution because intestinal content likely varied between treatment groups.     

Starch source evaluation in calf starter: I. Feed consumption, body weight gain, structural growth, and blood metabolites in Holstein calves

Holstein calves were fed pelleted iso-starch (25% of starter dry matter) diets containing barley (n = 16), corn (n = 16), oat (n = 16), and wheat (n = 16) starch for 12 wk of age. Feed consumption, nutrient intake, body weight (BW) gain, skeletal growth, and selected blood metabolites in calves during preweaning (d 1 to 49) and postweaning (d 50 to 84) periods were measured. Average daily starter consumption during pre-weaning and postweaning periods was the greatest in calves fed corn died followed by those fed a wheat diet and then in those fed barley and oat diets. During the preweaning period, the calves provided corn and wheat diets consumed greater amount of mixed grass hay than those fed barley and oat diets. During the postweaning period, mixed grass hay intake was the greatest in calves provided corn diet followed by those fed a wheat diet and then in those fed barley and oat diets. Nutrients (dry matter, crude protein, starch, and neutral detergent fiber) intake followed the solid feed consumption pattern in calves. Body weight and body measurements (body length, body barrel, heart girth, wither height, and hip height) at birth and at weaning (d 49) in calves fed different starch sources were similar. Body weight and body measurements at postweaning (d 84) were the greatest in calves fed a corn diet followed by those fed a wheat diet and then in those fed barley and oat diets. Overall average BW gain and total dry matter intake were the greatest in calves fed a corn diet than in those fed wheat, barley, and oat diets. Feed efficiency was greater in calves fed corn and wheat diets than in those fed barley and oat diets. Blood glucose, blood urea N, triglycerides, cholesterol, and creatinine were reduced with the advancing age of calves. Lesser blood glucose and greater blood urea N concentrations at wk 8, 10, and 12 of age were noticed in calves fed corn diet than in those fed barley, oat, and wheat diets. Occurrence of diarrhea was more frequent in calves fed oat diet than in those provided barley, corn, and wheat diets. Starch sources did not influence respiratory score, rectal temperature, and general appearance score. In conclusion, the calves on corn diet consumed more solid feed and gained greater BW than those fed barley, oat, and wheat diets.     

Measuring residual feed intake in dairy heifers fed an alfalfa (Medicago sativa) cube diet

Selection for divergence between individuals for efficiency of feed utilization (residual feed intake, RFI) has widespread application in the beef industry and is usually undertaken when animals are fed diets based on silages with grain. The objective of this research was to develop a feeding system (using Gallagher, Hamilton, New Zealand, electronics) to measure RFI for growth in Holstein-Friesian heifers (aged 5-9 mo), and identify divergent individuals to be tested for RFI during lactation. A dry forage diet (alfalfa cubes) was fed because intakes could be measured accurately, and the New Zealand dairy industry (4.4 million milking cows in lactation) relies heavily on forage feeding. The evaluation was undertaken over 3 yr with 1,052 animals fed in a facility for 7 wk, and weighed 3 times weekly. The mean age at the start of measurements was 215 d, body weight (BW) 189 kg, and mean daily dry matter intakes averaged 6.7 kg. Body weight gain (all animals) averaged 0.88 kg/d. The RFI was determined as the residuals from the regression of mean intake on mean BW(0.75) and daily BW gain of individuals. Actual and fitted intakes were strongly related (R(2) = 0.82). In terms of gross efficiency (feed intake/BW gain), RFI+year explained 43% of the variation, BW gain+year explained 66%, and RFI+BW gain+year explained 79% of the variation (all P<0.001). Daily BW gains (kg) of the most and least efficient 10% averaged (± standard deviation) 0.88 ± 0.15 and 0.88 ± 0.12 (P = 0.568), respectively, and the divergence between mean intakes was 1.46 kg of dry matter/d. The most and least efficient animals will be tested for RFI during lactation and genetic markers will be identified for the trait.     

Effects of dietary consumption of cranberry powder on metabolic parameters in growing rats fed high fructose diets

The effect of dietary consumption of a cranberry powder (CP) containing increased amounts of procyanidins and other phytochemicals on metabolic parameters associated with metabolic syndrome was investigated in growing rats fed a high fructose diet. Dietary treatments were control (starch based), high fructose (HF), and HF containing either 3.3, 6.6, or 33 g CP/kg diet. Fasting plasma glucose and triglycerides tended to be higher with HF feeding and were reduced by feeding CP. The area under curve following an oral glucose tolerance test was 35-50% higher in animals fed HF diet vs. control and was decreased to control levels by the low or medium but not high CP diet. Feeding CP tended to lower fasting plasma insulin. Homeostatic models of insulin resistance (HOMA-IR) and β-cell function (HOMA-BCF) were lowest in animals fed low or medium CP diets (p < 0.05). Rats fed the control starch diet had slightly higher food intake, final body weight, and abdominal fat compared to animals fed other diets. Kidney weight was higher in HF group and feeding CP decreased kidney weight to normal levels. In the fed state, plasma triglyceride was increased with HF diet, whereas insulin was lower in animals fed HF diet. Overall, inclusion of CP in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome and the medium level of CP in the diet produced a better response than the lower and higher CP levels.     

Intake of isoflavone-supplemented soy yogurt fermented with <Emphasis Type="Italic">Enterococcus faecium</Emphasis> lowers serum total cholesterol and non-HDL cholesterol of hypercholesterolemic rats

The aim of this study was to obtain an isoflavone-supplemented soy yogurt, fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus ssp jugurti, with suitable sensory properties and to assess the effects of the final product on blood lipids in hypercholesterolemic rats. Four isoflavone supplementation procedures were tested, in which the isoflavone was added at these stages: (1) before heat-treatment; (2) after heating and before fermentation; (3) after fermentation and (4) in the okara (by-product of soy milk) flour stirred into the fermented product when consumed. The products were subjected to a test of sensory acceptability. To assess their potential hypocholesterolemic properties in vivo, four groups of rats were used: control (C), hypercholesterolemic (H), hypercholesterolemic plus fermented product (HF) and hypercholesterolemic plus isoflavone-supplemented fermented product (HFI). Hypercholesterolemia was induced in rats of groups H, HF and HFI by feeding them on a commercial rat chow to which cholesterol and cholic acid had been added. Total, HDL and non-HDL cholesterol and triglycerides were measured in the blood of the rats. No significant sensorial differences were detected among the samples of soy yogurt supplemented with isoflavones at various processing stages. Rats fed a fermented soy product enriched with isoflavones (HFI group) had significantly (P < 0.05) less serum total cholesterol (15.5%) compared with rats fed a hypercholesterolemic diet (H group). Non-HDL cholesterol was less (P < 0.05) in rats fed a fermented soy product enriched or not with isoflavones (27.4 and 23.2%) compared to H group. The HDL-C and triglyceride concentrations did not differ significantly among the groups. It was possible to obtain an isoflavone-supplemented soy yogurt with satisfactory sensory characteristics. The resulting supplemented soy yogurt was capable of producing a lipid-lowering effect in hypercholesterolemic rats, relative to the animals that did not consume this product.     

Pine needle extract suppresses adiposity via mediating adipogenic gene expressions of white adipose tissue in high fat diet-fed rats

Effect of pine needle extract (PNE) on adiposity was examined through morphologic examination and adipogenic gene expression of white adipose tissue (WAT) in high fat diet (HFD)-fed rats. Four type diets; normal diet (ND), HFD, and diets respectively supplemented with PNE in both ND and HFD, were fed for 8 weeks. The adipose fat mass and the sizes in WAT were significantly lower in PNE-supplemented HFD group than in HFD group. The serum levels of PNE-supplemented HFD group were similar to those of ND group. The supplementation of PNE to HFD markedly increased adiponectin mRNA, but decreased those of leptin and tumor necrosis factor (TNF)-α in WAT, respectively. PNE enhanced glucose uptake of epididymal WAT under insulin stimulation. The results suggest that the beneficial effect of PNE supplementation on adipose fat and serum profiles in HFD-fed rats is partly modulated by adipogenic genes, such as adiponectin, leptin, and TNF-α mRNA in WAT.     

Effects of plane of nutrition and feed deprivation on insulin responses in dairy cattle during late gestation

Nonlactating Holstein cows (n=12) in late pregnancy were used to determine effects of plane of nutrition followed by feed deprivation on metabolic responses to insulin. Beginning 48 d before expected parturition, cows were fed to either a high plane (HP) or a low plane (LP) of nutrition (162 and 90% of calculated energy requirements, respectively). Cows were subjected to an intravenous glucose tolerance test [GTT; 0.25 g of dextrose/kg of body weight (BW)] on d 14 of treatment and a hyperinsulinemic-euglycemic clamp (HEC; 1 μg/kg of BW/h) on d 15. Following 24 h of feed removal, cows were subjected to a second GTT on d 17 and a second HEC on d 18 after 48 h of feed removal. During the feeding period, plasma nonesterified fatty acid (NEFA) concentrations were higher for cows fed the LP diet compared with those fed the HP diet (163.6 vs. 73.1 μEq/L), whereas plasma insulin was higher for cows fed the HP diet during the feeding period (11.1 vs. 5.2 μIU/mL). Glucose areas under the curve during both GTT were higher for cows fed the LP diet than for those fed the HP diet (4,213 vs. 3,750 mg/dL × 60 min) and was higher during the GTT in the feed-deprived state (4,878 vs. 3,085 mg/dL × 60 min) than in the GTT during the fed state, suggesting slower clearance of glucose during negative energy balance either pre-or post-feed deprivation. This corresponded with a higher dextrose infusion rate during the fed-state HEC than during the feed-deprived-state HEC (203.3 vs. 90.1 mL/h). Plasma NEFA decreased at a faster rate following GTT during feed deprivation compared with that during the fed state (8.7 vs. 2.9%/min). Suppression of NEFA was highest for cows fed the HP diet during the GTT conducted during feed deprivation, and lowest for cows fed the HP diet during the fed-state GTT (68.6 vs. 50.3% decrease from basal). Plasma insulin responses to GTT were affected by feed deprivation such that cows had a much lower insulin response to GTT by 24 h after feed removal (995 vs. 3,957 μIU/mL × 60 min). During the fed-state HEC, circulating concentrations of NEFA were 21% below basal for cows fed the HP diet and 62% below basal for cows fed the LP diet; during feed deprivation, NEFA were 79 and 59% below basal for the HP and LP diets, respectively (diet × HEC). Cows that are fed below energy requirements or are feed deprived have slower clearance of glucose and greater NEFA responses to glucose challenge. Additionally, feed deprivation had a large effect on insulin secretion. Overall, effects of feed deprivation were larger than effects of plane of nutrition.     

Critical Issues in R&D of Soy Isoflavone-enriched Foods and Dietary Supplements

ABSTRACT: Increasing consumer awareness of soy as a healthy food ingredient has led to a tremendous growth in sales of soy isoflavone‐enriched foods and dietary supplements in the past 3 y. Because of their weak estrogenic activity, isoflavones are believed to have preventive effects for several hormone‐dependent diseases. This article discusses some critical issues to be considered in any R&D program of novel soy and isoflavone products for the healthy‐food market, such as (1) Which isoflavone compounds should be in the product? (2) Which individual isoflavones are the most beneficial ones? (3) Can certain isoflavone groups be targeted to specific disease prevention goals? (4) Are there any safety concerns in isoflavone consumption? (5) How are isoflavones affected by thermal processing and storage? (6) How should isoflavones be analyzed? These questions may affect the choice of isoflavone source, processing conditions, quality control procedures, and marketing considerations.     

Reduced mammary tumor progression in a transgenic mouse model fed an isoflavone-poor soy protein concentrate

Dietary exposure to soy has been associated with reduced breast cancer incidence. Soy isoflavones and protein components, such as protease inhibitors and the lunasin peptide, have been indicated as potential agents reducing carcinogenesis. In this study, the effect of soy-based diets was evaluated in a transgenic mouse model of breast carcinoma, overexpressing the neu oncogene. Neu female mice were fed for 20 wk a soy- and isoflavone-free diet (IFD), 4RF21 laboratory mouse diet, soy-based, thus isoflavone-rich (STD), or AIN-76-based semisynthetic diets with a soy protein isolate (SPI) or an isoflavone-poor soy protein concentrate (IPSP) as protein source. Mice were then sacrificed and tumors removed. Mammary tumor weights were not different in SPI versus IFD and STD fed mice. In contrast, mice fed IPSP showed reduced tumor progression versus IFD and STD groups (p < 0.05). Moreover, IPSP fed mice showed lower bromo-2'-deoxyuridine (BrdU) incorporation into breast tumor cells compared to STD and SPI fed animals (p < 0.02). Lung metastases were detected in 80% of IFD fed mice, in 70% of mice fed STD and SPI, and only in 50% of the IPSP fed animals. These results indicate that a diet containing an isoflavone-poor soy protein concentrate may inhibit breast tumor progression and metastasis development.     

Effects of diet and injection of bovine somatotropin on prepubertal growth and first-lactation milk yields of Holstein cows

To determine effects of rapid prepubertal growth on first-lactation milk production, Holstein heifers were randomly assigned to one of three treatments. Thirty-five heifers were fed a standard diet to meet NRC recommendations and produce 0.8 kg of body weight (BW) gain/d (standard). Thirty-five heifers were fed a diet with higher energy (2.8 Mcal of metabolizable energy/kg) and protein (19.7% crude protein; high diet) to produce 1.2 kg of BW gain/d (high). Thirty-five heifers were fed the high diet and injected daily with bovine somatotropin (bST) (25 microg/kg of BW; high-bST). Diets were fed and bST was injected from 135 kg of BW until pregnancy was confirmed. Heifers were inseminated after BW exceeded 363 kg. Pregnant heifers were commingled and fed similar diets through gestation, parturition, and lactation. High and high-bST heifers had greater prebreeding average BW gains than standard heifers. Conversely, standard heifers had a greater average BW gain during gestation than high and high-bST heifers. High and high-bST heifers were approximately 90 d younger than standard heifers at first insemination and first parturition. Postpartum BW, body condition scores, and withers heights at parturition, and calving ease scores were not different among treatments. Standard heifers produced 14% more milk than high heifers but not more than high-bST heifers. The high-protein, high-energy diet decreased age at first parturition and first-lactation milk production, but did not affect reproduction. Injection of bST during the prepubertal growth period combined with the high diet decreased age at first parturition without reducing milk production.     

Quality traits and lipid composition of meat from Nellore young bulls fed with different oils either protected or unprotected from rumen degradation

The qualitative characteristics, lipids and chemical composition of the meat of 35 Nellore young bulls were analyzed. These bulls had an average slaughter weight and fat thickness of 532.17 ± 30.2 kg, and 7.00 mm, respectively. Significant differences were found only in the meat's water holding capacity (WHC), which was higher for animals fed with fresh linseed oil. More conjugated linoleic acid (CLA) was found in the meat of animals fed with unprotected soybean oil, while better omega-6/omega-3 ratios were noted for those fed unprotected linseed oil. The addition of different vegetable oils to the bulls' diet (soybean or linseed, either protected or not protected from rumen digestion) did not interfere with the qualitative characteristics of their meat while improving the lipid composition of the longissimus muscle. Of the oils examined, unprotected linseed oil most improved the omega-6/omega-3 ratio, thus producing the healthiest meat for human consumption.     

Effect of source of neutral detergent fiber and starch on nutrient utilization by dairy cows

Two diets were formulated to contain 30% NDF (DM basis) but differed in source of NDF and type of concentrate. One diet contained approximately 70% alfalfa silage and 30% corn grain (89% of NDF from forage) and the other diet contained about 50% alfalfa silage and 50% barley grain (65% of NDF from forage). Diets were fed to 12 cows in a short production trial, a total collection digestion experiment, and a rate of passage study. Cows fed the alfalfa-corn diet produced more 4% FCM (22.4 vs. 20.7 kg/d) than did cows fed the alfalfa-barley diet. Intake of DM (3.7% of BW), NE1 (35 Mcal), and NDF (1.1% of BW) were similar between diets, but due to differences in diet composition, intake of ADF was greater by cows fed alfalfa-corn than by cows fed alfalfa-barley. Digestibilities of DM, NDF, and CP were not affected by diet, but hemicellulose digestion was higher and cellulose and ADF digestibilities were lower by cows fed alfalfa-barley diets. Cows fed alfalfa-corn diet had a higher ruminal acetate to propionate molar ratio. No effect of diet was observed on turnover kinetics of the forage, concentrate, or liquid markers. These data show that forage to grain ratio and source of starch must be considered prior to recommending that diets be balanced for NDF.     

Dietetic and hypocholesterolaemic action of black soy peptide in dietary obese rats

To investigate the effect of peptides from black soy (rat's eye) bean (Rhynchosia volubilis Lour.) on weight gain and lipid composition, Sprague–Dawley male rats were fed either a black soy peptide (BSP; 2, 6 or 10% of energy)‐containing diet or a casein control diet (20% of energy) enriched with 36% fat and 1% cholesterol for 28 days. Compared with the casein group, the BSP groups showed significant attenuation of body, liver and epididymal adipose tissue weight gains (P < 0.05). Moreover, rats that consumed BSP had a lower total cholesterol concentration and low‐density lipoprotein/high‐density lipoprotein (LDL/HDL) ratio in serum and a lower level of hepatic triglycerides as well as higher excretion of faeces compared with those fed only casein (P < 0.05). Molecular weights of peptides from black soy were mainly below 10 kDa, and Arg/Lys and Gly/Met ratios in BSP were five and three times of those in casein respectively. It is concluded that BSP can be a potent nutraceutical component for anti‐obesity and hypolipidaemic benefits. Copyright © 2007 Society of Chemical Industry     

Effect of peripartum energy concentration on production performance of Holstein cows

Ninety multiparous Holstein cows were used to measure the effect of energy during the prepartum and postpartum periods. During the prepartum period (63 d) half of the cows were fed grass silage ad libitum and a concentrate (16% protein) was offered daily at .25% of BW. The other half of the cows were offered the silage ad libitum but concentrate at .75% of BW. At calving each of the two prepartum groups was subdivided into three subgroups and fed corn silage for ad libitum consumption, 4.5 kg of hay/d and concentrate (20% protein) at .25 or .75% of BW daily, or ad libitum. After 112 d of lactation, all cows were switched to a diet consisting of corn silage fed ad libitum and 1 kg of concentrate (20% protein)/4 kg of milk. Roughage intake was reduced with an increase of concentrate consumption. Body measurements, calf weight, milk yield, feed efficiency, services per conception, and incidence of diseases were not influenced by the prepartum regimen. However, the interval from parturition to conception was 24 d longer for cows on the higher prepartum energy concentration (.75% of BW). None of the cows was able to meet its nutrient requirement in early lactation. Milk yield increased with each increment of concentrate in the postpartum diet. Reproduction and health were not affected by the postpartum regimen.     

Effect of dietary energy source and concentration on performance of dairy cows during early lactation

Eighteen Holstein heifers were placed into groups of 3 according to projected calving date, prepartum BW, and prepartum condition score. Following parturition, animals within each group were assigned randomly to one of three diets and remained on the experiment for 45 d. Diets consisted of forage:concentrate ratios of 72:28, 53:47, or 73:27 (isocaloric to the 53:47 ratio by addition of 8% soybean oil). Diets were fed twice daily as total mixed rations. Blood, rumen fluid, and adipose tissue were sampled at -7, 5, 20, and 45 d of lactation. Performance means were, respectively: DM intake (kg/d) 13.9, 14.9, and 12.4; milk (kg/d) 24.5, 25.8, and 18.6; milk fat (%) 3.77, 3.59, and 3.62; milk protein (%) 3.03, 2.99, and 3.11; body condition score (0 = thin, 5 = fat) 1.53, 1.87, and 1.99; and BW (kg) 514, 523, and 505. Cows fed soybean oil had higher ruminal isoacids than those fed the other diets and higher acetate than cows on the 53:47 diet. Diets had no effect on blood metabolites or activity of adipose glycerol-P dehydrogenase (EC 1.1.1.8). The soybean oil diet reduced short-chain fatty acids and increased long-chain fatty acids in milk. Feed intake and milk production were highest for cows receiving the 53:47 diet. As expected, animals on the 72:28 diet did not consume adequate energy to maintain high production which concurrently resulted in lower body condition scores.     

L-肉碱对肥胖大鼠体脂含量及肥胖基因表达产物的影响

为探讨L -肉碱对肥胖大鼠体重、体脂、胰岛素及肥胖基因表达产物 (瘦素 )等水平的影响 ,以高脂饲料诱导大鼠肥胖模型 ,将肥胖模型鼠随机分为 4组 :对照组与 12 5、2 5 0、5 0 0mg kgBW 3个剂量的L -肉碱组 ,每天 1次经口给予 ,共 6周。观察大鼠体重、睾丸 肾脂肪垫重量、胰岛素(INS)及瘦素 (Leptin)水平等的变化。结果显示 3个肉碱组的体重均低于对照组 ,2 5 0与5 0 0mg kgBW组的睾丸 肾脂肪垫重量、胰岛素和瘦素显著低于对照组 (P <0 0 5 ) ,提示L -肉碱具有抑制肥胖大鼠肥胖的作用。     

Comparison of 3-breed rotational crossbreds of Montbéliarde,Viking Red,and Holstein with Holstein cows fed 2 alternative diets for dry matter intake,production, and residual feed intake

The objective of this study was to compare 3-breed rotational crossbred (CB) cows of the Montbéliarde, Viking Red, and Holstein (HO) breeds with HO cows fed 2 alternative diets for dry matter intake (DMI), fat plus protein production (CFP), body weight (BW), body condition score (BCS), feed efficiency, and residual feed intake (RFI) from 46 to 150 days in milk (DIM) during first lactation. The CB cows (n = 17) and HO cows (n = 19) calved from September 2019 to March 2020. Cows were fed either a traditional total mixed ration diet (TRAD) or a higher fiber, lower starch total mixed ration diet (HFLS). The HFLS had 21% more corn silage, 47% more alfalfa hay, 44% less corn grain, and 43% less corn gluten feed than the TRAD. The 2 diets were analyzed for dry matter content, crude protein, forage digestibility, starch, and net energy for lactation. The BW and BCS were recorded once weekly. Daily milk, fat, and protein production were estimated from twice monthly milk recording with random regression. Measures of efficiency were CFP per kilogram of DMI and DMI per kilogram of BW. The RFI from 46 to 150 DIM was the residual error from regression of DMI on milk energy, metabolic BW, and the energy required for change in BW. Statistical analysis of all variables included the fixed effects of diet, breed group, and the interaction of diet and breed group. The CB cows fed HFLS had less DMI (?12%) and lower DMI/BW (?14%) compared with the HO cows fed TRAD. For CFP, CB and HO cows were not different when fed TRAD or HFLS. Furthermore, the CB cows fed HFLS had higher BW (+50 kg) compared with HO cows fed HFLS. The CB cows fed TRAD had higher BCS than HO cows fed TRAD and HO cows fed HFLS (+0.46 and +0.62, respectively). The HO cows fed TRAD had more DMI (+14%) and lower CFP per kilogram of DMI (?12%) compared with the HO cows fed HFLS. In addition, mean RFI from 46 to 150 DIM was lower and more desirable for CB cows fed HFLS (?120.0 kg) compared with HO cows fed TRAD (85.3 kg). Dairy producers may feed either TRAD or HFLS to CB cows without loss of CFP.     

Effects of plane of nutrition and 2,4-thiazolidinedione on insulin responses and adipose tissue gene expression in dairy cattle during late gestation

Specific mechanisms by which dry period dietary energy affects transition cow metabolism have been intensively investigated but those of thiazolidinedione (TZD) administration have not. We hypothesized that effects of both are mediated via changes in insulin, glucose, or fatty acid metabolism. The objective of this experiment was to determine the effects of the insulin-sensitizing agent TZD and dietary energy level on glucose and fatty acid metabolism during late gestation in dairy cows. Multiparous Holstein cows (n = 32) approximately 50 d before expected calving date were dried-off and assigned to 1 of 2 dietary energy levels for 3 wk (high: 1.52 Mcal/kg of NE_L, or low: 1.34 Mcal/kg of NE_L) and treated daily during the final 14 d with 4.0 mg of TZD/kg of body weight (BW) or saline in a completely randomized design. Cows fed the low energy diet had lower dry matter intake (12.8 vs. 16.1 kg/d) and higher plasma nonesterified fatty acid (NEFA) concentrations (103.3 vs. 82.4 μEq/L) compared with cows fed the high energy diet. Cows administered TZD had higher plasma glucose concentrations (62.5 vs. 59.6 mg/dL) than saline controls and cows fed the high energy diet had higher plasma insulin concentrations (35.1 vs. 25.3 μU/mL) compared with those fed the low energy diet. After 2 wk of TZD treatment, all cows were subjected to an intravenous glucose tolerance test (GTT; 0.25 g of dextrose/kg of BW) followed 110 min later by an insulin challenge (IC; 1.0 μg of insulin/kg of BW). Differences in plasma glucose response to GTT were minimal based on diet; however, cows fed the low energy diet had more negative NEFA areas under the curve (AUC; −4,838 vs. −2,137 μEq/L × min over 90 min) and greater rates of NEFA decrease (1.35 vs. 0.63%/min) during GTT, suggesting differential responses of tissue glucose and fatty acid metabolism in response to dietary energy level. During IC, the TZD-treated cows tended to have more negative glucose AUC (−45.0 vs. −12.1 mg/dL × min over 15 min) than controls, suggesting that TZD-treated cows had greater responses to insulin. Limited interactions were observed between dietary and TZD treatments in all response variables measured. Adipose tissue biopsies performed on the final day of treatment suggested higher expression of peroxisome proliferator-activated receptor-γ (0.71 vs. 0.50 relative expression) and lipoprotein lipase (0.71 vs. 0.40 relative expression) in cows fed the high energy diet as measured by quantitative real-time PCR. These results indicate that energy level and insulin-sensitizing agents affect glucose and lipid metabolism during the dry period.     

Protein level for alfalfa and corn silage-based diets: II. Nitrogen balance and manure characteristics

This N balance study was completed with 48 multiparous Holstein cows (body weight [BW] = 653 kg; days in milk = 89) blocked by calving date and assigned to a 2 x 2 factorial arrangement of dietary treatments. The total mixed ration included alfalfa silage (AS) or corn silage (CS) as the primary forage source (41 and 14% vs. 14 and 41% of diet dry matter (DM), respectively) and were formulated for recommended (RP) or excessive (HP) amounts of rumen degradable protein (RDP) and rumen undegradable protein (RUP) according to the guidelines of the National Research Council (NRC). Crude protein (CP) averaged 16.5, 18.0, 16.4, and 17.3% for the AS-RP; AS-HP; CS-RP; and CS-HP diet, respectively (DM basis). Regardless of primary forage source, the reduction in dietary CP to the NRC guidelines tended to improve milk yield (43.4 vs. 41.0 kg/d) but did not alter 3.5% fat-corrected milk (37.0 kg/d) or milk true protein yield (1167 g/d). In this trial, cows fed the CS-based diets consumed less DM than those fed the AS-based diets in part because of rumen acidosis. The adverse effect of low rumen pH was accompanied by an increase in urinary N (UN) as a percentage of N intake, but did not alter milk yield. Notwithstanding partial confounding, fecal N (FN) was 49 g/d lower (213 vs. 164 g/d), UN was unchanged (229 g/d), but milk N tended to be higher (194 vs. 206 g/d) when cows were fed the CS-based diets compared with AS-based diets. Compared with the HP diets, cows fed the RP diets had similar FN (189 g/d) and milk N (200 g/d), but UN and urine urea N were reduced by 41 g/d (249 vs. 208 g/d) and 40 g/d (210 vs. 171 g/d), respectively. Fecal N concentration was higher for CS-based diets, but urinary N concentration was higher for AS-based diets. The reduction in dietary CP did not influence these concentrations but lowered urine volume. The metabolic relationships between energy and protein in determining the fate of excess dietary N (primarily in the form of excess RUP in this trial) was illustrated by a 17% increase in the UN to FN ratio for cows fed AS-HP compared with the AS-RP diet and a 42% increase in the UN to FN ratio for CS-HP compared with CS-RP diet, when cows' energy status was compromised because of rumen acidosis. In this trial, UN ranged from 150 to 320 g/d, and was best predicted as UN (g/d) = 0.0283 x BW (kg) x milk urea N (mg/dL). The NRC protein guidelines should not be exceeded to avoid unnecessary losses of manure N and, in particular, urine urea N.