Spelling suggestions: "subject:"ruminants -- breeding anda needs."" "subject:"ruminants -- breeding anda seeds.""
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The use of nitrogen solubility in assessing the value of treatment (formaldehyde and heat) of rapeseed and soybean meals for ruminants.Phillip, LeRoy E. January 1976 (has links)
No description available.
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Effects of feeding lasalocid and monensin upon mineral status of steers, and partial absorption and renal handling of minerals in sheepKirk, David J. January 1989 (has links)
Studies were conducted to determine the effects of feeding lasalocid and monensin upon mineral status of ruminants, changes in digestive and renal physiology which bring about altered mineral status, and the effects of dietary K upon the actions of ionophores. Two 84-d grazing trials were conducted with steers fed no ionophore, 200 mg lasalocid, or 150 mg monensin. Monensin tended to increase gain of steers, but lasalocid had no effect. Feeding supplemental lasalocid and monensin altered Ca, P, Mg, Na, K, Cu, Fe and Zn status of grazing steers, but effects were not consistent.
Twenty-four crossbred steers were individually fed in a 147-d finishing trial to study a possible K x monensin interaction. Steers were fed diets ad libitum containing .4% or 2.3% K, with or without 23 ppm monensin, dry basis. Feeding monensin with low K increased serum Na, Mg, inorganic P, Cu and Zn, but monensin fed with high K had no effect or decreased these serum minerals.
Fifteen wethers, fitted with abomasal and ileal cannulae, were fed a basal diet alone or supplemented with 23 ppm lasalocid or monensin; Apparent absorption of Mg, K and Fe increased when ionophores were fed. Magnesium flow through the small and large intestines was decreased by lasalocid and monensin. Effects of lasalocid and monensin differed for metabolism, digestive tract flow and (or) partial absorption of Ca, P, Cu, Fe and Zn.
Twelve ewe lambs were used in a renal clearance experiment. Lambs were fed a basal diet with no ionophore, 23 ppm lasalocid, or 23 ppm monensin, dry basis. Ionophores were fed starting on d 1 of the experimental period. Serial collections of blood and urine were made during d 1 and d 5 of the experimental period. Monensin reduced urine flow rate at d 1 and d 5. Feeding monensin lowered serum clearance and urinary excretion rates of Na and K at d 5. Serum clearance and urinary excretion rates of Ca were lower in sheep fed ionophores at d 1. Feeding monensin decreased serum clearance and urinary excretion rates of Cu at d 1. At d 5, urinary excretion rates of Zn were greater when lasalocid was fed, and lower when monensin was fed, compared to feeding no ionophore.
These studies indicate that dietary lasalocid and monensin can alter mineral status of ruminants, although their effects may differ. The effects of ionophores may be dependent upon dietary K levels. / Ph. D.
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Fungal enzymes as animal feed additivesLakay, Francisco Martin 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The use of fungal enzymes as ruminant feed digestibility enhancers was investigated. Currently,
ruminants may not digest 38 to 80 % of fibrous forages' content. A renewed interest in the potential
of feed enzymes for ruminants was prompted by the high costs of livestock production, together
with the availability of newer enzyme preparations. Direct application of enzyme preparations can
improve in vitro dry matter (DM) and neutral detergent fibre (NDF) degradation, indicating that
direct-fed fibrolytic enzymes may be effective in enhancing in vivo digestion of forages.
Two commercial enzyme products, Fibrozyme and Celluclast, and fungal extracellular
enzyme extracts from Aureobasidium pullulans, Trichoderma reesei, Aspergillus aculeatus, and
Thermomyces lanuginosus were evaluated for enhancing in vitro feed digestibility. Fibrozyme
addition to both wheat straw and lucerne hay did not improve their in vitro digestibilities, even after
a two hour pre-incubation period. The four fungal enzyme extracts did not enhance wheat straw's
digestibility, but marginal increases were evident for lucerne hay. Celluclast addition resulted in
marginal increases in the digestibility of both oat hay and oat silage, with no enhanced effect on
lucerne hay and NaOH-treated wheat straw. No relationship could be found between the level of
enzyme activity and the degree of feed digestion in the in vitro assay.
Enzyme hydrolysis with Celluclast, in the absence of rumen fluid, gave more conclusive
results. All the feed samples tested showed a positive response to Celluclast addition, even the less
digestible feeds, namely sugarcane bagasse and wheat straw.
In vitro results show that the assays were unsuccessful, because almost all of the
experiments conducted showed inconclusive results. Alternative feed evaluation assays, which
include the in vivo, in sacco and in situ methods of analysis, as well as gas production measurement
and in vitro analysis with the DAISyII system, should be evaluated. A more detailed study of feed
digestibility should be motivated by determining which feeds are hydrolysable, their chemical
composition, i.e. how accessible the feeds are, and also evaluation of feed mixtures. The enzyme
supplements also need to be evaluated for optimum temperature and pH, as well as the compilation
of enzyme cocktails. / AFRIKAANSE OPSOMMING: Die gebruik van swamensieme om die verteerbaarheid van herkouervoere te verhoog, is ondersoek.
Tussen 38 en 80 % van veselagtige voere se inhoud is tans onverteerbaar. 'n Hernieude
belangstelling in die potensiaal van voerensieme vir herkouers word deur die hoë koste van
veeproduksie, asook die beskikbaarheid van nuwe ensiempreparate gedryf Direkte byvoeging van
ensiempreparate kan die in vitro droëmateriaal (DM) en neutrale onoplosbare vesel (NOV)
vertering verbeter, wat daarop dui dat fibrolitiese ensieme wat direk gevoer word, effektief mag
wees tydens die in vivo vertering van voer.
Twee kommersiële ensiemprodukte, Fibrozyme en Celluclast, en die vier ekstrasellulêre
ensieme van vier swamme, naamlik Aureobasidium pullulans, Trichoderma reesei, Aspergillus
aculeatus, en Thermomyces lanuginosus is vir hul vermoë om die in vitro verteerbaarheid van voere
te verbeter getoets. Byvoeging van Fibrozyme by beide koringstrooi en lusernhooi het geen
verbetering in hulonderskeie in vitro verteerbaarheid tot gevolg gehad nie, selfs nie eens na 'n twee
uur vooraf inkubasieperiode nie. Koringstrooi se verteerbaarheid is nie verbeter deur die byvoeging
van die vier swam-ensiempreparate nie, maar 'n minimale verbetering is wel waargeneem in die
verteerbaarheid van lusernhooi. Byvoeging van Celluclast het 'n minimale verbetering in beide
hawerhooi en hawerkuilvoer se verteerbaarheid tot gevolg gehad, maar geen effek op lusernhooi of
NaOH-behandelde koringstrooi se verteerbaarheid nie. Geen verwantskap is tussen die vlak van
ensiemaktiwiteit en die mate van vertering tydens die in vitro toets gevind nie.
Ensiematiese afbraak met Celluclast, in die afwesigheid van rumenvloeistof, het meer
konkrete resultate gelewer. Al die voermonsters het 'n positiewe respons op die byvoeging van
Celluclast getoon, selfs ook die minder verteerbare voere, nl. suikerrietbagasse en koringstrooi.
In die wyer konteks was die resulate van die in vitro verteringstoetse egter onbeduidend as
gevolg van groot variasie in die metings. Alternatiewe voerontledingstoetse, wat moontlik beter
resultate mag lewer, sluit in in vivo, in sacco en in situ analises, asook die meting van gasproduksie
en in vitro analise met die DAISyII sisteem. 'n Meer uitgebreide studie van voerverteerbaarheid wat
die bepaling van die afbraak van voere, hul chemiese samestelling, met ander woorde
toeganklikheid van voere, en die ondersoek van voermengsels behels, behoort aandag te geniet. Die
ensiemmengsels behoort ook ten opsigte van samestelling, optimum temperatuur en pH ondersoek
teword.
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Development and evaluation of polymer coated urea as a potential slow-release urea supplement for ruminantsUpton, Erlanda January 1999 (has links)
Thesis (MScAgric)--Stellenbosch University, 1999. / ENGLISH ABSTRACT: The rate of hydrolysis of urea in the rumen of animals is a major limitation when
considering the substitution of natural protein with urea in the formulation of rations.
The aim of this study was to evaluate polymer coated urea prills with variable coating
thickness and evaluate its potential as a slow-release NPN compound. A new slowrelease
urea compound, made by coating prilled feedgrade urea with a co-polymer
of urea-formaldehyde resin and a castor-coconut alkyd was initially evaluated for
urea-nitrogen concentration in distilled water in order to evaluate its potential as a
slow-release urea product for ruminants. Amino/alkyd or polyester blends are
among the cheapest of the modern synthetic systems and are considered because it
is non-toxic, low-cost, biodegradable and easy to manufacture. A 2 x 2 x 2 x 2
factorial design was used and 16 individual products were made and evaluated. The
Wurster method was used to encapsulate urea prills. The slopes of the urea release
curves represented the release rate of the encapsulated products and were
compared to identify the process variables, which had an effect on release rate. Two
of the coating variables, coating weight and alkyd: resin ratio, had a major effect (P =
0.0001) on the release rate of urea. The crushing strength of encapsulated products
was significantly (P = 0.0001) higher than that of untreated urea. Results motivated
the evaluation of the products in the rumen of sheep in terms of rumen ammonia and
blood urea N concentrations. Four slow-release products were made after
interpreting results from the first study, and differed on account of the coating weight and the composition of the co-polymer. Fifteen fistulated wethers were randomly
allotted into 5 groups and intraruminally received an equivalent of 15g urea. Rumen
ammonia and blood ammonia were taken at 0, 1, 2, 4, 6, 8, 12, 16, 20, 24, 36 and 48
h after administration of the various treatments. Slow release urea (SRU) resulted in
significantly lower rumen ammonia peaks (P = 0.0001) than untreated urea, while the
peaks were also significantly delayed. Untreated urea resulted in the maximum
concentration at two hours after administration of the urea (P = 0.0685) while the
SRU's reached a maximum at six hours after administration in the rumen. No
significant differences between the four different SRU types were found. Responses
in blood urea-N was similar to that observed for rumen ammonia nitrogen. The
encapsulation was effective in decreasing the rate of ammonia release from the urea
for up to six hours after administration. In a third trial four Dehne Merino wethers
were used in a 2 x 2 Latin square design. They received a SRU product equivalent to
0.4 g urea per kg body weight orally. Rumen liquor and blood samples were taken at
0, 1, 2, 4, 6, 8, 12, 16, 20, 24, 36 and 48 h after intake. Difficulty was initially
experienced with ingestion and palatability of the SRU products due to the strong
formaldehyde and butanone odour present in the coating. The maximum rumen
ammonia (NH3) concentration for the SRU were lower than that of untreated urea
(17.5 mg N/dl vs. 66.9 mg N/dl). The time to reach blood urea levels also differed
considerably (6 h vs. 24 h for blood urea nitrogen) between treatments.
The encapsulation of urea prills shows potential solutions to reduce the solubility of
urea and also reduce the hygroscopic nature of urea and improve the palatability and
storage characteristics thereof.
Keywords: Slow-release urea, encapsulate, copolymer, urea formaldehyde rumen
ammonia, blood urea nitrogen, solubility, palatability, storage characteristics. / AFRIKAANSE OPSOMMING: Die vinnige tempo waarteen ureum in die rumen na ammoniak omgesit word, is die
grootste beperking in die optimale benutting van ureum, as vervanging van
natuurlike protein in herkouerrantsoene. Die doel van hierdie studie was om 'n
stadig vrystellende ureumproduk te ontwikkel wat die rumenammoniakvlak
gedurende 'n aansienlike periode van die dag bokant 'n sekere vlak kan hou. 'n
Nuwe stadig vrystellende ureumproduk, vervaardig deur ureumkorrels met 'n
kopolimeer van ureum-formaldehiedhars en 'n kastor-en klapperalkied te bedek, is
geevalueer om die potentiaal as stadig vrystellende nie-protein stikstof (NPN)-produk
vir herkouers te ondersoek. Die veiligheid, biodegradeerbaarheid, lae koste en
maklike vervaardiging van amino/alkied-kopolimere maak dit een van die
goedkoopste sintetiese sisteme om vir stadig vrystellende sisteme te oorweeg. 'n 2
x 2 x 2 x 2 Faktoriale antwerp is gebruik om 16 individuele produkte te vervaardig.
Die Wurster-metode is gebruik om individuele korrels te enkapsuleer met die
polimeer en die potentiaal van die produkte is aanvanklik geevalueer deur die
ureumstikstofvrystelling in gedistilleerde water te meet. Die hellings van die
vrystellingsgrafieke is vergelyk om die veranderlikes te bepaal wat die grootste
invloed op die vrystellingstempo van ureum uit die ge·inkapsuleerde produkte het.
Resultate dui dat twee verandelikes 'n betekenisvolle effek het op die vrystellingstempo, nl. dikte van die omhulsel, en die samestelling van die kopolimeer
(P = 0.0001 en P = 0.0135, onderskeidelik) het. Die samedrukbaarheid van die ge
·lnkapsuleerde produkte was ook betekenisvol hoer (P = 0.0001) as die van
onbehandelde ureumkorrels, wat lei tot verbeterde bergings- en
hanteringseienskappe. lnterpetering van resultate lei tot die vorming van vier stadig
vrystellende produkte. Vyf groepe van 3 volwasse rumengefistuleerde
Dohnemerinohamels is in 'n proef gebruik om die potentiaal van die produkte verder
te ondersoek. 'n Ekwivalent van 15 g ureum is direk in die rumen van elke dier
geplaas en ammoniak-en bloed monsters is 0, 1, 2, 4, 6, 8, 12, 16, 20, 24, 36 & 48
ure na dosering geneem. Die stadig vrystellende ureumprodukte het 'n betekenisvol
laer maksimum waardes vir beide ammoniak-en bloedstikstofureum getoon (P =
0.0001 ). Onbehandelde ureum het 'n maksimum rumenammoniakstikstof
konsentrasie reeds twee ure na toediening bereik in vergelyking met ses ure vir die
stadig vrysellende produkte. Geen betekenisvolle verskille in hierdie parameters is
tussen die ge·lnkapsuleerde produkte gevind nie, terwyl geen interaksie is tussen
hoofeffekte voorgekom het nie. In 'n derde proef is vier Dohnemerinohamels gebruik
om die vrystellingstempos, in terme van rumenammoniak-en bloedureumstikstof te
bepaal waar die stadig vrystellende produk en onbehandelde ureum direk aan die
diere gevoer is . 'n Ekwivalent van 0.4 g ureum/kg liggaamsmassa is gevoer.
Aanvanklik is inname- en smaakliksheidprobleme ondervind, moontlik as gevolg van
die sterk butanoon-en formaldehiedreuk van die omhulsel. Die
rumenammoniakstikstof het 'n laer maksimum (17.5 vs. 66.9 mg N/1 00 ml) as die
van onbehandelde ureum gehad terwyl die tyd wanneer maksimum konsentrasie
bereik word ook aansienlik later was. Die polimeer inkapsulering van ureumkorrels
toon potensiaal as 'n stadig vrystellende ureumproduk deurdat dit die oplosbaarheid
van ureum in die rumen verlaag. Bykomende voordele is dat die omhulsel die
higroskopisiteit verlaag en die samedrukbaarheid verhoog, beide eienskappe wat die
hantering-en bergingseienskappe bevorder.
Sleutelwoorde: Stadig vrystellende ureum, enkapsulering, kopolimeer, ureumformaldehied,
rumenammoniak, bloed ureum stikstof, oplosbaarheid, smaaklikheid,
bergingseienskappe.
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The effect of synchronization of protein and starch degradation in the rumen on nutrient utilization and milk production in dairy cows.Herrera y Saldana, Rolando Ernesto January 1988 (has links)
Four studies were conducted to determine the effect of synchronization of protein and starch degradation on nutrient utilization, microbial protein synthesis and milk production in dairy cows. In Experiment 1, five cereal grains and five protein supplements were compared for extent of solubility and degradability of their starch and nitrogen fractions. Results indicated large differences which permitted their ranking from high to low degradability as follows: grains, oats > wheat > barley > corn > milo protein supplements, soybean meal > cottonseed meal, (CSM) > corn gluten meal > brewers dried grains, (BDG) > blood meal. In Experiment 2, the five grains were incubated for varying times in vitro (with added amylase) or in situ to determine rate and extent of degradation of dry matter, crude protein and starch. Results showed that rate of starch degradation followed a similar, but slightly different trend than in trial 1 (wheat > barley > oats > corn > milo). Rates for DM and CP degradation were similar than those for starch. In Experiment 3, high (barley, HS) and low (milo, LS) degradable starch sources were combined with a high (CSM, HP) and a low (BDG, LP) degradable protein sources to formulate four diets; HSHP, HSLP, LSHP and LSLP. Diets were fed to 32 cows, starting two to four weeks postpartum, for a 60-d milk production and digestibility study. Apparent digestibility was calculated using chromium oxide. Organic matter digestibility was higher (P < .05) was found in nutrient output to the small intestine among diets and microbial CP synthesis was higher (P > .05) for barley diets.
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EVALUATION OF JOJOBA MEAL AS A PROTEIN SOURCE FOR RUMINANTSGarcia-Puebla, Manuel Rogelio January 1982 (has links)
No description available.
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Rumen microbial degradation of diaminobutyric acid, a non-protein amino acid : thesis submitted for the degree of Doctorate of Philosophy in the University of Adelaide, South Australia / by Hai Hong Peng.Peng, Hai Hong January 2003 (has links)
"January 2003" / Includes bibliographical references (leaves 172-204) / xx, 204 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2003
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Improving the nutritive value of low quality roughage for ruminants by ensiling with citrus pulp and poultry litterMigwi, Perminus K. January 1997 (has links) (PDF)
Bibliography: leaves 107-130. This study evaluates quality of fermentation of the silage and also its nutritive value to ruminants on the basis of "in vitro" and "in sacco" digestability. Animal response to the silage is also evaluated in an "in vivo" digestability and nitrogen balance trial with Australian Merino sheep. The objective of this thesis is to investigate the opportunities for utilising citrus pulp and poultry litter to improve the nutritive value of wheat straw.
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The nutritive value of high fiber canola meal for ruminantsMustafa, Arif Fouad 01 January 1996 (has links)
Five trials were conducted to assess the nutritive value of high fiber canola meal (HFCM) as a protein supplement for ruminants. Trial one determined the chemical composition of HFCM relative to low fiber canola meal (LFCM) and canola meal in a completely randomized design using samples obtained from five different crushers. In the second trial, the in situ nylon bag technique was used to determine disappearance of dry matter (DMD), crude protein (CPD), neutral (NDFD) and acid (ADFD) detergent fiber from canola meal, LFCM and HFCM samples derived from five different crushers following 24 h of nunen incubation. The effect of crushing plant of origin on in situ nutrient disappearance in the three meals was also determined. In the third trial, rumen nutrient kinetic parameters and effective degradabilities were determined for the blended canola meal, LFCM and HFCM. In situ disappearance of different amino acids canola meal, LFCM and HFCM following 12 h of rumen incubation was determined in the fourth study. The fifth trial was designed to determine nutrient digestibility coefficients by growing lambs of seven diets containing dehydrated alfalfa and 0, 25, 50 and 75% HFCM or canola meal in a randomized complete block design. Milk yield and composition responses of early to mid lactation dairy cows to diets supplemented with HFCM, canola meal or soybean meal were also determined. Results of the first trial indicated that tail-end dehulling of canola meal resulted in more fractionation of fiber than protein between HFCM and LFCM. Results of the second trial showed differences in CPD and DMD within LFCM and HFCM but not within canola meal samples. However, no meal by crusher interaction was observed indicating that in situ nutrient disappearances in the three meals were consistent across crushers. At 5% h<sup>-1</sup> rumen flow rate, effective DM degradability (trial three) was higher (P $<$ 0.05) in LFCM than in canola meal and was higher in canola meal than in HFCM while effective CP degradability was higher in LFCM and canola meal than in HFCM. Effective NDF degradability was higher (P $<$ 0.05) in LFCM than in canola meal and MFCM. However, effective ADF degradability was higher in LFCM than in canola meal and was higher in canola meal than in HFCM. Tail-end dehulling had little effect on in situ disappearance of amino acids from canola meal, LFCM and HFCM following 12 h of rumen incubation. Results from the fifth trial indicated that at 75% inclusion rate, the diet containing HFCM had lower (P $<$ 0.05) DM, CP and gross energy digestibility coefficients relative to canala meal diet. Results of the dairy trial showed no treatment effect on feed intake. (Abstract shortened by UMI.)
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Effect of urea-ammoniation of dietary roughage and concentrate ratio on ruminal microbial activity in Jersey cows.Tesfayohannes, Simon Tesfaldet. January 2003 (has links)
The effect of untreated roughages on digestibility and rumen fill of the gut was
reviewed as physical mechanism influencing the regulation of roughage intake. The
review of literature also focused on identifying factors that affect the way in which urea-ammoniation
alters the roughage intake, digestibility and performance of ruminant
animals. Trials were carried out with fistulated cows to address to what extent
concentrate proportion and urea-ammoniation affected microbial colonization and
degradation of roughage diets in the rumen. One interest of this study was to develop a
model that would help to predict the benefit associated with urea-treatment of
roughages.
The first trial (Chapter 3) investigated the effect of urea-ammoniation of roughage and
concentrate proportion of the diet on degradation of roughages, and the benefit
associated with the treatment of roughages. Four rumen-fistulated Jersey cows were fed
on a basal diet composed of either urea treated (3 kg of urea per 100 kg of straw) or
untreated Eragrostis curvula hay. These basal diets were supplemented with concentrate
composed of maize meal (78%) and cotton seed cake (22%). The concentrate
contributed 0, 25, 50 and 75% of the total ration and hay the rest. The experiment
consisted of 6 periods. Each period lasted 19 days, comprising 12 days of adaptation to
the experimental diet followed by 6 days degradability measurements and 1-day rumen
fluid collection. During each period the 4 Jersey cows were randomly allocated to 4 of
the 8 dietary treatments, ensuring that each diet was fed to 3 animals during the entire
experimental period.
The experimental roughages used in this trial were wheat (Triticum sativum) straw,
barley (Hordeum Vulgare) straw, coastcross (k11) (Cynodon hybrid) hay, veld hay
(natural grass), oat (Avena sativa) straw, oat (Avena sativa) hay, maize (Zea mays)
stover, kikuyu (Pennisetum clandestinum) grass, weeping love grass (Eragrostsis
curvula) and Italian rye (Lolium multiflorum) grass. Each roughage (sample) was
subdivided into two equal portions, one of which was then treated with urea. The urea
solution was prepared by dissolving 30 g of urea in 0.4 liter of water. The solution was
fully distributed over I kg of roughage. Treated roughages were sealed tightly and
stored at room temperature for 5 weeks in plastic bags. Immediately after opening, the
different roughages, including the untreated ones, were sun dried, chopped fine by hand
and ground through a 2-mm screen in a laboratory mill. About 3 g of each sample was
weighed into labeled nylon bags. The bags were tied to a stainless steel disc with 10
evenly spaced small holes drilled through the periphery of the disc serving as anchor
points. The bags were incubated (in duplicate per time interval) in the rumen for 120,
96, 72, 48, 24, 12, 6 and 3 h, sequentially. The treated samples were incubated in
animals fed treated hay, while untreated samples were incubated in animals given
untreated hay. Immediately after removal from the rumen, the bags, including the 0 hour
ones, which had not been incubated but soaked in warm water for I hour, were washed
in 6 cycles (each lasting 4 minutes) in a semi-automatic washing machine. The washed
bags were then dried in a forced draught oven at 60 degrees C for 48 hours, cooled in a
desicator and weighed.
The pH of the rumen fluid ranged between 6.5 and 6.8 for all diets. Rumen ammonia
concentration was higher (P<0.002) when the basal diet consisted of urea treated hay.
Increasing the concentrate proportion in the diet had the desired effect of increasing
rumen ammonia concentration without severely affecting pH. Urea-ammoniation
increased (P<O.OOO1) the slowly degradable fraction (B), potential degradability (PD),
effective degradability (ED) of dry matter and neutral detergent fiber (NDF), decreased
(P>0.05) lag time (LT) but had no effect on the rate of degradation (c) of dry matter.
Concentrate proportions affected (P<0.05) the slowly degradable fraction, potential
degradability, lag time and effective degradability but had no effect (P>0.05) on the rate
of degradation of dry matter (DM). Maximum and minimum values of the slowly
degradable fraction, potential degradability and effective degradability of DM and NDF
were obtained at the 25 and 75% concentrate levels, respectively. Within urea-ammoniation,
roughage type affected (P<O.OO1) the B-fraction, PO and EO of OM and
NDF degradation. Rate of degradation of DM of untreated roughages varied from 0.022 h(-1)
in wheat straw to 0.087 h(-1) in rye grass, while for urea treated roughages it varied
from 0.022 h(-1) in oat straw to 0.082 h(-1) in rye grass. Rye grass degraded almost three to
four times faster than urea treated oat or untreated wheat straw. Urea-ammoniation was
less effective in increasing DM and cell wall degradation rates (c) of rye grass compared
to wheat straw. The results showed that low quality roughages such as wheat straw
benefited relatively the most from urea-ammoniation.
The effect of urea-ammoniation and dietary manipulation on microbial colonization
(Chapter 4) of fiber particles in the rumen of animals was also investigated in two
experiments. In Experiment 1, the cows were fed on rations comprising either urea-ammoniated
or untreated Eragrostis curvula hay supplemented with concentrate at hay
to concentrate ratio of 100:0, 75:25, 50:50, 25:75, resulting in eight different rumen
environments. The experiment consisted of two periods. Each period lasted 12 days of
adaptation to the experimental diet followed by one-day incubation of urea-ammoniated
and untreated barley straw. Experiment 2 consisted of two urea-ammoniated (7.5 kg of
urea per 100 kg of hay) hay levels (20 and 40% of the total ration) and concentrate
levels (60 and 80%). Fistulated Jersey cows were adapted for 12 days after assigning to
the dietary treatment. Feed was given at the rate of 9.0 kg day(-1) per animal portioned
into equal meals of 4.50 kg each and offered at 08:00 and 16:00 every day. About 3 g of
urea-ammoniated or untreated barley (Hordeum vulgare) straw, ground through a 2-mm
screen, was weighed into a labelled nylon bag and incubated for 3, 6 or 12 h in the
rumen of the fistulated cows. Microbes adhering to incubated fiber particles were
examined under the Environmental Scanning Electron Microscopy (ESEM) and
analysed on the image analyser. Depending on morphology , the microbes were divided
into three groups: bacilli (rod), cocci (round) and others (spiral, fimbrea and cluster ; not
specifically defined or undefined microbes).
Urea-ammoniation of dietary roughage decreased (P<O.OO1) bacilli counts and total
bacteria count but had no effect on count of the undefined group of microbes on fiber
particles in the rumen of cows (Experiment 1). Concentrate proportions had no effect
(P>0.05) on bacilli, cocci and total bacterial count on fiber particles. However, the
results from electron micrograph observations revealed that the total bacterial count
tended to decrease as the concentrate level increased in the diet of cows. Bacilli, cocci,
undefined group of microbes and total count of microbes increased (P<0.05) as length
of incubation increased. In Experiment 2, incubated feed, concentrate proportion and
time of incubation had no effect (P>O.05) on bacilli , others (undefined group of
microbes) and total count of fiber-adhering microbes in the rumen of cows. However,
increasing concentrate in the diet of cows tended to decrease (P<O.07) the count of
fiber-adhering cocci. The total count of microbes on fiber particles was higher in
animals fed 80% concentrate as compared to 60% concentrate.
The benefit derived from urea treatment in terms of B-fraction, effective degradability
and potential degradability of DM and fiber of roughages increased with increasing the
NDF content. Therefore, the important conclusions drawn from the results of the
present study is that urea-ammoniation of roughages should be done strategically and
that high quality roughages may give little return per unit of cost of ammoniation. This
means that the benefit associated with urea-ammoniation would be justified for poor
quality roughages only. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
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