EFFECT OF FEEDING CHOPPED AND UNCHOPPED GROUNDNUT HAULM (HARAWA) ON NUTRIENT UTILIZATION AND THE PRODUCTION OF SOME RUMEN METABOLITES IN YANKASA LAMBS

The effect of feeding chopped and unchopped groundnut haulm (Harawa) on nutrient intake, metabolism and utilization was determined in 24 (12 each of male and female) growing Yankasa lambs. Feeding of chopped harawa significantly (P 0.05) Increased feed intake, the digestibility of nutrients and liveweight gains. It also had an ap­preciable effect on nitrogen retention and the pro­duction of total rumen nitrogen, rumen ammonia-nitrogen and volatile fatty acids. The availability of digestible energy did not differ significantly under the two feeding regions. There was a better feed effi­ciency for lambs fed chopped hay.

Effects of Zeolite Supplementation on Dairy Cow Production and Ruminal Parameters – A Review

In recent years, the use of both natural and synthetic zeolites in livestock feeds fed to lactating cows has increased, mainly to improve their performance, health, and to protect against mycotoxins intoxication. Data of scientific literature were compiled to analyze the effects of the incorporation of non-nutritional adsorbent zeolite on production performance and ruminal environment parameters of lactating cows. At moderate levels (200–400 g/cow/day), milk yield was increased by zeolite. Milk fat and protein contents and DMI were not altered and all ruminal parameters were improved: acetate was enhanced, propionate was reduced and consequently, acetate to propionate ratio was increased. The rumen pH was increased and rumen ammonia nitrogen was reduced. When the level of zeolite exceeded 400 g/d/cow, all production and ruminal parameters were negatively altered. These data suggest that zeolite level in the diet has a significant effect on the response of dairy production and ruminal environment characteristics.

Different forms and frequencies of soybean oil supplementation do not alter rumen fermentation in grazing heifers

Over the productive cycle, the performance of cattle in grazing systems may be compromised, and feed supplementation is a strategy to establish nutritional balance and maximise the performance of grazing animals. The objective of this study was to evaluate the effect of different supplementation frequencies (i.e. daily supplementation (DS) versus Monday, Wednesday and Friday (MWF)) with different forms of soybean oil (i.e. soybean grain (SG), soybean oil (SO) and rumen-protected fat (RPF)) on the nutrient digestion and rumen fermentation of heifers grazing Brachiaria brizantha cv. Marandu pastures. Twelve crossbred heifers (1/4 Nellore × 1/4 Santa Gertrudis × 1/2 Braunvieh) with an initial bodyweight of 236.3 ± 27.6 kg were distributed in a completely randomised design with a factorial arrangement 3 × 2 (three diets and two supplementation frequencies). There was no interaction among the SO form or supplementation frequency on dry matter intake and dry matter digestibility (P > 0.05). The animals supplemented with SG exhibited lower nitrogen intake and absorption compared with animals that were fed SO (P < 0.05). The efficiency of microbial synthesis was not influenced by the diet or supplementation frequency (P > 0.05). Forms of SO affected the rumen pH; animals fed SO showed pH values similar to those of animals receiving SG but lower values than animals fed RPF (P < 0.05). Animals supplemented with DS exhibited higher levels of rumen ammonia nitrogen relative to those supplemented MWF. The reduction of supplementation frequency (from DS to MWF k) in our experimental conditions can be used to increase the efficiency of pasture utilisation without effects in fermentation activity of the rumen microbial population. Supplementation with SO is a strategy to increase propionic acid concentration and reduce A : P ratio, which is an indicator of improvement of the efficiency of the ruminal energy utilisation.

Intake and digestibility in cattle fed low-quality tropical forage and supplemented with nitrogenous compounds

The objective of this study was to evaluate the effects of supplementation with nitrogenous compounds on intake, digestibility, and rumen microbial synthesis in cattle fed low-quality tropical forage. Five crossbred heifers, averaging 209 kg and fitted with ruminal fistulla, were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 5.08%, as dry matter (DM) basis. The five treatments were defined according to the increasing level of CP in the diet (0, 3, 5, 7, and 9 percentile points above the forage CP level). The supplement consisted of the following nitrogen sources: urea, ammonium sulfate and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.28, 8.08, 9.82, 11.87, and 13.63% on DM basis. The intakes of DM, organic matter (OM), and neutral detergent fiber (NDF) showed a quadratic response according to CP levels in the diet, with maximum responses at 10.83%, 10.78%, and 10.37% CP, respectively. The digestibility coefficients of OM and NDF showed a linear-response-plateau response according to CP levels, with the plateau beginning (maximum response) at 7.93% and 7.55% CP, respectively. The average daily concentration of rumen ammonia nitrogen (RAN) was positively related with CP levels. The RAN estimate associated with the maximum DM intake was 15.33 mg/dL. It was observed that intestinal flow of microbial nitrogenous compounds and nitrogen intake became equivalent to each other at 7.13% of CP.

The nutrition of ruminants grazing native and improved pastures. II.* Responses of grazing cattle to molasses and urea supplementation

Hereford heifers grazing native and fertilized phalaris pastures were supplemented with ureamolasses mixtures for 2 years. The liveweight of heifers grazing phalaris pastures did not respond to supplementation, but the liveweight gain of heifers grazing native pasture increased significantly by 6 g/day/g nitrogen consumed as urea during July, August and September and by 0.16 g/day/g digestible organic matter consumed as molasses at other times of year. Supplement consumption varied between animals, with a coefficient of variation of ±37%. Urea–molasses supplementation increased the rumen ammonia nitrogen levels of cattle grazing native pasture from 6.7 to 16.1 mg/100 ml. The application of superphosphate and introduction of white clover increased rumen ammonia nitrogen to 15.7 mg/100 ml. The effects of supplementation on liveweight gain were small relative to the changes which could be induced by pasture improvement. There was a curvilinear relationship between the digestibility of the diet and liveweight gain when pasture availability was not limiting intake. It was calculated from this relationship that the annual liveweight gains of cattle grazing native pasture, native pasture dressed with superphosphate and oversown with white clover, and two phalaris pastures were 223 498, 726 and 763 g/day respectively when forage was available ad libitum. ____________________ *Part I, Aust. J. Agric. Res., 29: 863 (1978).

Corrigendum - The effect of formaldehyde treatment of a casein supplement on urea excretion and on digesta composition in sheep

The urinary excretion of urea, the fate of an intravenous dose of urea, overall nitrogen metabolism and the composition of rurnen and abomasal samples were studied in crossbred sheep given a basal roughage diet to which supplements of starch, casein or formaldehyde-treated casein were added. Urea excretion was closely related to plasma urea level (r = 0.935) and to the filtered load of urea (r = 0.957). The amount of urea reabsorbed by the kidney increased as'the amount filtered increased; the relationship was improved when values obtained at urine flow rates less than 1 rnl/rnin were omitted. When sheep were given the starch and treated casein diets, the rate at which they cleared a small dose of urea from their plasma was greater than the renal clearance rate; only 75% of a large dose was recovered in the urine. The capacity to dispose of exogenous urea by extra-renal pathways was apparent only when rumen ammonia nitrogen levels were less than about 200 mg/l. Formaldehyde treatment reduced nitrogen digestibility but reduced urine nitrogen excretion to a greater extent so that nitrogen retention increased. Treatment was associated with reduced plasma urea levels, reduced rumen and abomasal ammonia levels, reduced total VFA levels, increased proportions of acetic acid and decreased proportions of isobutyric, isovaleric and n-valeric acids, and more protein in abomasal contents.