Factors Affecting the Utilization of Food by Dairy Cows

Cc, Balch; Vw, Johnson

doi:10.1079/bjn19500061

Cited by 51 publications

(7 citation statements)

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“…elapsed before half the marker had left the rumen. We believe that these times may be assumed to apply to the feed residues as well as to the marker, and the figures reported here are thus in keeping with results of studies of fermentation rates of various feed constituents as reported by Balch & Johnson (1950), Phillipson (1952), andHeald (1953).…”

Section: Variation Between Feedssupporting

confidence: 87%

Measurement of feed intake of grazing sheep: I. Rate of passage of inert reference materials through the ruminant digestive tract

Lambourne¹

1957

J. Agric. Sci.

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Experiments are described which give some basic information on the rate and pattern of marker excretion by sheep on pastures ranging in digestibility from 70 to 80% and on hay of barely 50% digestibility.The faeces output of individual sheep varied from 100 g. to more than 400 g. daily, and the estimated feed intake from below 400 to over 1,900 g. daily.Despite these wide ranges a typical pattern for the passage of single doses of markers was quite consistently repeated in the trials on pastures:1. Markers first appeared in the faeces 5–8 hr. after dosing.2. Concentrations rose rapidly to peak values about 10–18 hr. after dosing.3. Concentrations fell thereafter by about 50% each 6–10 hr. until 60–70 hr. after dosing when marker content could no longer reliably be determined by the methods used.Factors affecting the basic pattern1. The overall quality of the feed was of prime importance, in that peak concentrations occurred progressively later on poorer pastures and on hay.2. For any given feed a high level of (estimated) feed intake was often associated with earlier appearance of marker in the faeces, an earlier peak of concentration, and slightly faster fall in marker concentration.3. There was evidence that the time of administration might slightly affect rate of passage, presumably through its relation to grazing periods, for doses given at or near times of greatest feed intake were passed rather more rapidly.4. It did not appear that there was any considerable retention of either marker within the tract beyond 72–96 hr. after dosing.

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Section: Variation Between Feedssupporting

confidence: 87%

Measurement of feed intake of grazing sheep: I. Rate of passage of inert reference materials through the ruminant digestive tract

Lambourne¹

1957

J. Agric. Sci.

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“…The slower rate of cellulose digestion may have been due to the drier rumen contents, since Balch & Johnson (1950) found that the rate of cellulose digestion was favoured by more Auid conditions in the rumen. The slower rate of passage of food may also have been due to this cause.…”

Section: Discussionmentioning

confidence: 99%

“…The sheep were fitted with harness and bags for faecal collections. The rate of passage of food was determined by the method of Balch (1950) with the modifications described by Coombe & Tribe (1963), and was expressed as the mean retention time. The rate of cellulose digestion was determined by the cotton-thread technique of Hoflund, Quin & Clark (1948) with the modifications described by Coombe & Tribe (1963).…”

Section: '64mentioning

confidence: 99%

“…I n these experiments additional recordings of the dry matter and pH of the rumen contents were made. Balch (1950) noted that the rumen contents of cows given ground hay were of even consistency throughout and apparently not divided into well-defined dry and liquid layers. The diets used in Expts 3 and 6 had been ground, and therefore it is probable that the samples taken from the rumen were representative of the whole of the contents.…”

Section: '64mentioning

confidence: 99%

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Parotid saliva and rumen digestion in the sheep

Wilson

1964

Br J Nutr

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The importance of saliva for the function of the rumen is well recognized. This recognition has arisen from consideration of the volume and composition of ruminant saliva and the needs of the rumen microbial population. Recent estimates indicate that the total salivary secretions of sheep and cattle are of the order of 10 and 150 l./day respectively (Kay, 1960; Bailey, 1961). These volumes represent more than twice the volume of fluid usually present in the rumen at one time. The inorganic constituents of saliva, principally sodium bicarbonate and phosphate, act as a buffer within the range pH 5'5-7 (Turner & Hodgetts, 1955). Microbial digestion is thus favoured by the fluid conditions and the stable pH of the rumen contents.McManus (1962) reported that when saliva was collected from sheep the concentrations of volatile fatty acids (VFA) in the rumen were abnormally high. However, in his work there were no control experiments to measure other effects, such as lateral recumbency, upon the concentration of VFA in the rumen, and no experiments to show that the quantity of VFA, as distinct from concentration, had been altered. This paper describes a number of experiments in which several features of rumen digestion were recorded in sheep, before and after section of the parotid nerves and ducts. The parotid glands were chosen for this work because they normally secrete from 40 to 50% of the total saliva (Kay, 1960). E X P E R I M E N T A LA summary of the experiments is given in Table I . The sheep used were all Corriedale wethers, and in Expts I , 3 and 6 each sheep was fitted with a rumen fistula.The lucerne given in Expt 3 was similar to that given in Expts I, 2 and 7 , except that it was passed through a hammer mill. The straw given in Expts 5 and 6 differed only in the degree to which it was milled.Operation to section parotid nerve and duct Each sheep was anaesthetized with pentobarbital sodium. An incision was made on the cheek above the masseter muscle, and the parotid duct, together with its associated nerve, was tied with silk and sectioned. After the operation, a swelling developed around the gland, but it subsided within 24 h. In Expts I A and 7, the operation was performed on only one gland at a time, but in the other experiments it was performed on both glands at the same time. Ad lib. feeding Expts 1-6. In each experiment there was a preliminary feeding period of at least 2 weeks. It was followed by a period of 2-3 weeks, during which the amount of dry matter eaten was recorded. Once daily each sheep was offered an amount of food that allowed about 15 % to be left uneaten. Samples of the foods and residues were dried at 100' for 24 h, to determine their dry-matter contents. T h e measurement of food intake was repeated after each operation. ExptSheep no.no. Expts I , 3 and 6. In these experiments, recordings of the rate of passage of food through the digestive tract, the rate of cellulose digestion, the digestibility of the dry matter, and water consumption were made in addition to recording the food...

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“…Losses of water through respiration and excreta left 40% not accounted for. It would appear, as might be expected, that the ruminant gut, and no doubt the gut of other species, has an elutriating effect on food particles such that the probable sojourn in the rumen will be longer for a larger particle than for a smaller one and will be longer for a heavier particle than for a lighter one, as Balch & Johnson (54) have found. Herefords drank somewhat more water than Brahmans when in a warm environment, with drinking water at 88-2° F. (44).…”

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confidence: 74%

Section A. Physiology of dairy cattle: Part II. Physiology and Biochemistry of Rumination

Owen

1954

Journal of Dairy Research

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Since the time of the previous review in this series by the present author it has been increasingly realized that the ruminant's adaptation to its herbivorous diet is very far-reaching. The biochemical consequences of its need for coarse roughage are still being worked out and have necessitated a reassessment of the causes of bovine ketosis, of the function of lower fatty acids in its blood and of the reasons for its large requirement of cobalt. Recent work on all these three aspects of ruminant metabolism is discussed in this review. The cow's chief function is to convert into milk vegetable materials, many of which are unsuitable for human consumption. Ac-, cordingly, some of the nutritional aspects of this conversion process have been discussed in the review. The literature on the subject has been reasonably well listed, but the author cannot claim that he has not perhaps inadvertently omitted certain pertinent new work. GENERAL Sherwood & Jones(l) found that alfalfa hay plus a mixture of wheat, barley and oats gave 20% more milk than the hay alone. Milk yield was also enhanced by adding the succulents squash and Jerusalem artichoke to the hay diet. Groups of cows receiving the concentrates needed 5-6 lb. more total digestible nutrients to produce 100 lb. milk, and the authors conclude that feeding of succulents is profitable only if they produce nutrients as cheaply as does hay. Watson, Davidson, Kennedy & Sylvestre(2) compared the digestibility of rations of hay plus increasing amounts of oats. As oats increased the digestibility decreased. This effect was most marked with barley, not so marked with oats and was only slight with linseed oil meal. Feeding standards are still the subject of informed criticism in Europe(3,4,5). Nehring(3) concludes that Kellner's starch equivalents cannot be used for pigs without prior respiration calorimetry. Blaxter(4) finds large discrepancies between different methods of computing rations for livestock, and Nicholls(5) enters a plea for food recording as a complement to milk recording. The trouble with all attempts to define standards for grazing animals is the extreme variability from year to year, from field to field, from treatment to treatment and from animal to animal of the nutrients provided by grass and hay or silage. Much current research all over the world is designed to measure more accurately the nutrient intake of cattle and sheep from pasture, with a view to striking a better balance between protein and fibre in the diet, always remembering that the content of fibre biologically best for maximal production per cow may not necessarily give the maximal production per acre. This may come from more cows per acre at somewhat more fibre per cow than would give maximal production per cow. In this connexion the observations of Hancock (6) are pertinent. He points out that the maximum production per animal does not necessarily yield the greatest net returns. In practice this can be achieved by a number of cows per acre too high for maximum productivity per cow or fo...

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Factors Affecting the Utilization of Food by Dairy Cows

Cited by 51 publications

References 1 publication

Measurement of feed intake of grazing sheep: I. Rate of passage of inert reference materials through the ruminant digestive tract

Measurement of feed intake of grazing sheep: I. Rate of passage of inert reference materials through the ruminant digestive tract

Parotid saliva and rumen digestion in the sheep

Section A. Physiology of dairy cattle: Part II. Physiology and Biochemistry of Rumination

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