High-grain Ration Research Articles

Influence of Sucrose on Rumen Fermentation Pattern and Milk Fat Content of Cows Fed a High-Grain Ration

Milk fat content was not increased by replacing milo with sucrose at levels representing 5,10, and 15% of the dry matter in rations containing 10% alfalfa hay and fed in excess of National Research Council requirements. The experiment involving 16 cows was conducted in randomized block design. It consisted of a standardization period of two weeks, a transition period of four weeks, and a comparison period of sixteen weeks. During the standardization period the cows received ad libitum a ration comprised of 40% alfalfa hay (estimated net energy basis) and 60% ground milo plus minerals.There were no significant differences among the covariant-adjusted treatment means for milk and solids-corrected milk production, milk fat, and solids-not-fat content, or production efficiency. In the rumen contents pH was lower (P<0.05) and lactate concentration was higher (P<0.10) with sucrose in the ration. The mean proportions of rumen volatile fatty acids were not significantly different among treatments.

Intensive finishing of steers on rations containing high levels of either wheat, barley, or sorghum grain. Effect of level of roughage and sodium chloride

The effects of type of grain (wheat, barley, or sorghum), level of roughage (0, 1, and 2 kg of oaten chaff/head/day) and sodium chloride free choice on the performance of steers of a mean (� S.E.) body weight of 241 � 2 kg fed in yards for a mean period of 133 � 4 days were examined in a factorial experiment. The type of grain, the level of chaff offered to the steers, or the provision of sodium chloride had no significant effect on daily body weight gain (1.08 � 0.03 kg) or efficiency of conversion of feed dry matter (D.M.) to body weight or carcase weight gain (6.5 and 9.7 kg feed D.M./kg gain respectively). Steers fed wheat had a significantly (P&lt;0.01) lower daily D.M. intake than those fed either barley or sorghum grain. The incidence of persistent laminitis, the death of a steer fed barley and the greater number of steers fed wheat not attaining slaughter weight of 385 kg by 180 days indicated that sorghum was probably a 'safer' grain to feed in high-grain rations than either wheat or barley. The level of oaten chaff offered to the steers did not appear to affect the incidence of digestive disturbances. Carcase weight gain represented a mean of 66.8 � 0.7 per cent of the body weight gain during finishing.

The concentrations of urea, phosphorus, sodium, and other constituents in the blood of steers intensively finished on high-grain rations

The concentrations of urea, inorganic phosphorus, haemoglobin, plasma chloride, sodium, and potassium and the packed cell volume were determined on samples of blood from 70 Hereford steers that had been intensively finished on high-grain rations based on either wheat, barley, or sorghum grain. Oaten chaff was used as the roughage and half the steers had free access to sodium chloride. The inorganic phosphorus levels of 6.5 to 7.1 mg/100 m1 of blood were higher than those recorded in grazing cattle and were significantly different for the grain types. Blood urea levels were affected by roughage level, grain types, and access to sodium chloride. Plasma sodium but not chloride was affected by the type of grain and by sodium chloride.

Blood Lipid Changes in Cows of Different Breeds Fed Rations Depressing Milk Fat Test

Blood lipid changes in response to a high-grain ration that depressed milk fat test were studied in four cows each of the Guernsey, Holstein, and Jersey breeds. Milk fat percentage decreased from 4.9 to 3.7 in Guernseys, 3.3 to 2.2 in Holsteins, and 5.3 to 4.3 in Jerseys. Protein content of the milk increased. Although there were some significant breed differences in levels of the blood lipid components, within-breed variations were considerable. Plasma levels of phospholipids, cholesterol esters, free cholesterol, free fatty acids, and acetate decreased during the experimental period in all the breeds. Over-all mean arteriovenous differences exceeded 10% of the arterial level only in acetate, triglycerides, and ketone bodies.Arteriovenous differences for acetate decreased significantly during the experimental period to almost one-third of the original level, whereas the uptake of triglycerides and ketone bodies was not changed significantly. Levels of blood plasma acetate and triglycerides and blood ketone bodies during the post-experimental period exceeded the original levels and were accompanied by arteriovenous differences exceeding the original levels. The milk fat test recovered to the original level 3 wk after returning to a normal ration. Higher levels of propionate and lower levels of acetate in the rumen during the experimental period appeared to be the key factors responsible for the observed changes.

Relation of Milk Fat-Depressing Rations and Subclinical Mastitis to Milk Proteins

Two continuous feeding trials involving 28 cows were used to study the influence of a pelleted, high-grain ration, of dietary supplementation with unsaturated oils (safflower and cod liver oil), and of subclinical mastitis under these conditions, on milk total proteins, casein, whey proteins, solids-notfat (SNF), and fat. Milk samples from 512 udder quarters were analyzed. Total milk protein and casein contents were elevated by each nutritional regime. Whey protein and SNF contents increased while feeding the high-grain ration, but both showed only minor changes during the oil supplementation. A net gain in milk protein synthesis of 15% was obtained during the high-grain regime, but protein yields during the oil regime were lower because of reduced milk production. Milk fat percentages and fat yields were depressed by each regime.Ratios of casein content to total protein content of milk were significantly related to Wisconsin Mastitis Test (WMT) scores (r = —0.45). Intraclass correlation coefficients within udder quarters for WMT scores on whey protein per cent, SNF per cent, casein yield, milk yield, total protein yield, fat per cent, casein per cent, whey protein yield, and total protein per cent were, in decreasing order, 0.45, —0.41, —0.34, —0.33, —0.29, —0.19, —0.18, —0.14, and 0.08, respectively.

Effect of Molasses in Normal- and High-Grain Rations on Utilization of Nutrients for Lactation

Molasses added to ground ear-corn at a level of 10% and fed with wilted silage (66% moisture) in a 40:60 ratio of grain-to-roughage (dry basis) depressed milk and fat-corrected milk (FCM) yields and milk fat content. Molasses was not detrimental with haylage (47% moisture) or with a 60:40 ratio of grain-to-roughage. Molasses had no measurable effect on dry matter intake or efficiency of estimated net energy (ENE) utilization. Increasing the grain from 40 to 60% in the haylage ration increased dry matter intake, but decreased feed efficiency. However, raising the grain level to 60% with the wilted silage increased milk fat percentage. FCM yield, and lowered consumption, resulting in improved efficiency.In a subsequent experiment, addition of 6% sucrose to rations of alfalfa hay and 40 or 60% grain reduced the milk fat content in a manner similar to molasses in the first experiment. Interaction effects of sucrose with grain-to-roughage ratios on milk fat content, solids-corrected milk yield, and efficiency were also similar to the interaction effects observed with molasses. Sucrose increased ruminal butyrate, but decreased acetate and the aeetate-to-butyrate ratio.This similarity in lactation responses suggests that the influence of molasses is via its sucrose content.

Finishing steers on high-grain rations. Effects of type of silage, level of urea, vitamin A and cobalt supplementation on body-weight gain, feed efficiency and carcass composition

1. A 23 factorial with a split-plot allocation of treatments was used to investigate the effects of silage type, (sweet v. grain sorghum); level of urea, (60ν. 120 g. per head per day); vitamin A,(0ν. 40,000 i.u. per head per day), and intraruminal cobalt oxide pellet on the performance of steers fed rations of 90% sorghum grain, 10% sorghum silage.

Measurement of Certain Metabolic Organic Acids in Forage, Silage, and Ruminal Fluid by Gas-Liquid Chromatography

Gas-liquid chromatography was found applicable for measuring lactic, oxalic, malonic, fumaric, succinic, malic, alphaketoglutaric, and citric acids in forage, silage, and ruminal fluid. Aqueous extracts of ground and dried forage, extracted at 55C, were lyophilized and the organic acids contained in the residue esterified with methanol and hydrochloric acid. Esters of the acids were then chromatographed. Aqueous extracts of silage and protein-free filtrates of ruminal fluid, prepared by acetone-ethanol precipitation, were analyzed.Recoveries of all acids by adding known amounts of organic acids were near 100%. Two groups of forage samples, containing both freeze- and oven-dried samples, contained similar amounts of organic acids and the differences due to method of drying were analogous for both groups. Lactic acid measured in silage samples was comparable to that measured in the same samples by the FeCl3 and p-hydroxydiphenyl methods. Interfering peaks were encountered when some ruminal fluid samples were chromatographed. This interference may have been due to incomplete protein precipitation and was greatest with samples from an animal receiving high-grain ration,in contrast to samples from animals receiving a corn silage ration.

The relationship between concentrations of plasma and hepatic vitamin A in steers intensively finished on high-grain rations low in carotene

Data on plasma and liver vitamin A concentrations were obtained from 84 Hereford steers approximately two years of age and approximately 900 lb in body-weight. The animals were sampled from two experiments : 57 received high-grain rations low in carotene for 150 � 15 days, 27 received similar rations for 154 � 6 days. Plasma vitamin A levels in 18 animals were below 20 �g/100 ml, and these values were associated with hepatic levels of less than 10 �g/g. The regression of plasma vitamin A on the logarithm of liver vitamin A was significant (P&lt;0.01) and the regression coefficients were not significantly different between experiments. The equation was y = -30.506 + 19.705 log x. This equation has only limited value for prediction over the whole range tested due to the large standard error (9.24) and the limited magnitude of the correlation coefficient (0.80).

Effect Of Pelleting Rations And Hay:Grain Ratio on Salivary Secretion and Ruminal Characteristics of Steers

Esophageal and ruminal fistulated steers were used in studies on the influence of ration pelleting and roughage level on salivary and ruminal characteristics. Rate of salivary secretion was less when equal amounts of a high-roughage ration were fed pelleted rather than as a coarsely ground mixture. Rate of salivary secretion appeared to respond less to increased intake when rations were pelleted. Ingesta VFA concentrations tended to be higher and pH values lower when pelleted or high-grain rations were fed. Molar percent of VFA×time values were not altered by feeding pellets. Liters of ruminal fill tended to be less when pelleted or low-roughage rations were fed and greater when feed was offered ad libitum.

Digestibility and Nitrogen Utilization of Rolled and Moist-Heat-Treated Sorghum Grain

Roll cracked and moist-heat treated sorghum grains were compared at two feeding levels in a 5×5 Latin-square digestion and nitrogen balance trial, using yearling dairy steers. The roughage ration consisted of alfalfa and prairie hays in one to three ratio. Grains were substituted for hay in quantities calculated to supply 22 and 66% of ration net energy. Crude fiber digestibility of the ration was depressed by the heat-treated grain at the high feeding level. Protein digestibility of the high-grain ration was depressed by heat treatment. Nitrogen balance was not influenced by grain treatment, but a greater proportion of ingested nitrogen was absorbed from the cracked-grain ration at the high-grain level and voided in the urine.

Effect of Grain Level and Protein Content of the Grain for Grazing Cows on Milk Composition and Yield, and Certain Blood and Rumen Constituents

Two concentrate mixtures, containing 8.3 and 22.6% crude protein, were fed at 1kg per 1.75, 3.5, and 7.0kg of milk produced during standardization to 48 lactating Holstein cows grazing medium-quality Blue-grass pasture. Milk was sampled for composition analyses at ten-day intervals. Jugular blood samples were taken for determination of serum protein and protein fractions, and rumen contents sampled for VFA analyses.Milk yields were significantly related to levels of dietary protein and grain. Per cent SNF, protein, and lactose-mineral in the milk increased as level of feeding increased, but were not affected by ration protein. No interaction between dietary protein and energy was noted for milk constituents. The high-grain ration resulted in depressed milk fat and increased rumen propionate. Neither rumen acetate, butyrate, nor any of the blood protein fractions were significantly affected by grain level. The high-protein ration resulted in higher concentrations of total VFA, acetate, propionate, and butyrate in rumen fluid; and in higher albumin and NPN and lower alpha globulin in blood serum.

ROLE OF THE RUMEN CILIATES IN BLOAT IN CATTLE.

BLOAT (tympanites) in ruminants is characterized by distension of the forestomachs following interference with the normal elimination of gas produced by the microbial digestion of food in those organs. Bloat occurs in cattle usually when fresh legumes are fed, but it may also develop when high-grain rations are supplied in the feed. Many hypotheses have been put forward to explain the ailment, but all have been inadequate in view of its variable nature1. Not all animals bloat readily and not all legume pastures produce bloat in susceptible animals.

Relationship of Certain Milk Fat Depressing Diets to Changes in the Proportions of the Volatile Fatty Acids Produced in the Rumen

Summary Twelve high-producing Holstein cows were used to study the effect of feeding cod liver oil and a high-grain restricted roughage ration on milk and fat production, fatty acid composition of the milk fat, and the proportions of volatile fatty acids in the rumen. The cod liver oil and high-grain rations did not significantly alter milk production when compared to a control diet; however, these rations did significantly lower the fat content of the milk produced. When cod liver oil was added to a normal ration of hay and grain, the proportions of the volatile fatty acids in the rumen were unaltered; whereas, the high-grain diet caused a significant decrease in the proportion of acetate and a significant increase in propionate. As a result of these findings, it was concluded that cod liver oil exerts its effect on milk fat production somewhere beyond the rumen, whereas the fat depressing effect of high-grain feeding must be attributed to the significant changes occurring in the rumen fermentation.

Effect of Feeding Different Roughage Levels and Sodium Acetate in High-Grain Rations on Milk Production, Milk Constituents, and Rumen Volatile Fatty Acids

Summary Two trials, ten animals in Trial 1 and 12 animals in Trial 2, were conducted to study the effect of feeding program on milk production, milk constituents, and rumen volatile fatty acids. A switchback design was used consisting of 7-wk periods, 3-wk changeover periods, and 4-wk comparison periods. Treatments in Trial 1 were (1) 10lb pineapple bran plus concentrate, (2) Treatment 1 with 2.91% sodium acetate in concentrate, (3) 12lb pineapple bran, 50lb chopped Napier grass and concentrate. Treatments in Trial 2 were (1) 10lb pineapple bran plus concentrates, (2) Treatment 1 with 2.83% sodium acetate in concentrate, (3) Treatment 1 with 5.66% sodium acetate in concentrate. Data from cows in Trial 1 on Treatments 1, 2, and 3, respectively, were: 4% FCM 35.35 a , 37.13 a , and 39.74 a lb; milk fat 2.79 a , 2.94 a , and 3.79 b %; total solids 11.05 a , 11.10 a , and 12.44 b %; SNF 8.22 a , 8.16 a , and 8.45 b %. In Trial 2, the values for Treatments 1, 2, and 3, respectively, were: 4% FCM 30.30 a , 32.85 b , and 34.17 e lb; milk fat 3.42 a , 3.96 b , and 4.18 b %; total solids 11.94 a , 12.49 b , and 12.63 b %; SNF 8.50 a , 8.50 a , and 8.43 a %. Values in the same category with different superscripts are significantly different by Duncan's multiple range test. No significant differences were observed in pounds of milk produced daily and body weight change in either trial. Rumen fluid from cows on Treatment 3 in Trial 1 contained significantly more acetic and less propionic, valeric, and longer-chain acids than from cows on Treatment 1.

Effect of Physical Form of the Ration on Steer Performance and Certain Rumen Phenomena

The results of three separate experiments dealing with the use of ground and pelleted rations for feeding beef cattle are reported. In the first experiment, Coastal Bermuda-grass (Cynodon dactylon) hay was compared in the long, ground, and pelleted forms as a wintering feed for beef calves. The calves on the ground hay consumed 24.8% more feed and gained 52.0% faster and those on the pellets consumed 32.0% more feed and gained 99.0% faster than did those on the long hay. A definite preference was displayed by the calves for the pelleted hay. In the other two experiments, a complete high-grain ration was compared in the conventional, ground, and pelleted forms for finishing steer calves. In both tests, those steers receiving their entire ration in the pelleted form consumed less total feed and gained slower than did those on either the conventional or ground ration. However, feeding approximately one and one-half pounds of oat straw per head daily caused calves receiving basic ration pellets in addition to consume 26.1% more pellets and to gain 37.2% faster than did those calves receiving pellets only. No normal rumination and cud chewing were noted among animals receiving pellets only or the completely ground ration. An abnormal rumen wall condition resulted among the last two groups. The condition was corrected by the feeding of straw. Significantly lower rumen pH levels were found among those steers receiving pellets only. An inadequate secretion of saliva is offered as an explanation of this phenomenon.

Physical and Chemical Changes in Bovine Saliva and Rumen Liquid with Different Hay-grain Rations1,2

Summary Saliva and rumen liquid samples were collected from two cows that were fed 20, 40, 60, 80, and 100% hay rations. The viscosity of saliva (mean 99 c.p.) was greater 3 hr. after feeding than before feeding and the pH (mean 8.2) increased as the proportion of hay increased. The ash of saliva (mean 0.73%) was greater with the high-grain rations. Total salivary nitrogen was 20.1 mg. % for the 20% hay ration and averaged 14.9 mg. % for the 40 to 100% hay rations. Hexosamines (mean 4.3 mg. %) were higher on the high-grain rations. The rumen liquid samples were centrifuged at 25,000 × G. and the supernatant analyzed. The mean dry matter content was 1.71% and the ash content was 0.79%. Sodium (mean 234 mg. %) increased as the hay content increased and was higher for the cow which tended to bloat than for the one which did not. Hexosamines (mean 3.7 mg. %) were also greater for the bloaty cow, but tended to increase in both cows with increasing proportions of grain. The total nitrogen of rumen liquid (mean 37.1 mg %) was highest on the 20% hay rations, was higher after feeding than before, and was higher for the bloaty cow than for the one which did not bloat.