• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.692-696
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• 1998

An experiment was conducted with eight growing sheep (average initial weight 20.6 kg and average final weight 23.7 kg) in a $4{\times}4$ Latin square design to study the effect of type of forage supplementation to a basal diet of rice straw (ad libitum) and cassava (Manihot esculanta, approximately 9 g of dry matter $(DM).kg^{-0.75}{\cdot}day^{-1}$) on voluntary intake, digestion, rumen microbial protein synthesis and daily weight gain. Forages used were Leucaena (L, Leucaena leucocephala), Gliricidia (G, Gliricidia maculata) and Tithonia (T, Tithonia diversifolia, wild sunflower) at a DM supplementation level of approximately $13g.kg^{-0.75}.day^{-1}$. Organic matter intake was 40.4, 55.5, 55.0 and $54.9g{\cdot}kg.^{-0.75}{\cdot}day^{-1}$ for control (C, ad libitum straw and cassava), L, G and T. respectively, significantly lower for C than for the supplemented diets. Intake of supplementary forage had also a significantly positive effect on voluntary rice straw intake. All forage supplemented diets showed a significantly higher whole diet organic matter digestion than C ($488g{\cdot}kg^{-1}$), while T ($557g{\cdot}kg^{-1}$) differed significantly from L ($516g{\cdot}kg^{-1}$) but not from G ($526g{\cdot}kg^{-1}$). Daily weight gain was -1.7, 5.2, 5.4 and $4.7g{\cdot}kg^{-0.75}$, for C, L, G and T. respectively, significantly lower for C than for the forage-supplemented diets. Efficiency of microbial protein synthesis estimated from urinary excretion of purine derivatives was lower for C (3.8 g microbial N. (kg digestible organic matter intake $(DOMI))^{-1}$ than for the forage supplemented diets (11.3, 9.0 and 9.4 g microbial $N.(kg\;DOMI)^{-1}$ for L, G and T. respectively).

• Asian-Australasian Journal of Animal Sciences
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• 제25권4호
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• pp.502-514
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• 2012

When ruminants consume dry forage, they also drink large volumes of water. The objective of this study was to clarify which factor produced when feed boluses enter the rumen is mainly responsible for the marked increase in water intake in the second hour of the 2 h feeding period in large-type goats fed on dry forage for 2 h twice daily. Six large-type male esophageal- and ruminal-fistulated goats (crossbred Japanese Saanen/Nubian, aged 2 to 6 years, weighing $85.1{\pm}4.89kg$) were used in two experiments. In experiment 1, the water deprivation (WD) control and the water availability (WA) treatment were conducted to compare changes in water intake during and after dry forage feeding. In experiment 2, a normal feeding conditions (NFC) control and a feed bolus removal (FBR) treatment were carried out to investigate whether decrease in circulating plasma volume or increase in plasma osmolality is mainly responsible for the marked increase in water intake in the second hour of the 2 h feeding period. The results of experiment 1 showed that in the WA treatment, small amounts of water were consumed during the first hour of feeding while the majority of water intake was observed during the second hour of the 2 h feeding period. Therefore, the amounts of water consumed in the second hour of the 2 h feeding period accounted for 82.8% of the total water intake. The results of experiment 2 indicated that in comparison with the NFC control, decrease in plasma volume in the FBR treatment, which was indicated by increase in hematocrit and plasma total protein concentrations, was higher (p<0.05) in the second hour of the 2 h feeding period. However, plasma osmolality in the FBR treatment was lower (p<0.05) than compared to the NFC control from 30 min after the start of feeding. Therefore, thirst level in the FBR treatment was 82.7% less (p<0.01) compared with that in the NFC control upon conclusion of the 30 min drinking period. The results of the study indicate that the increased plasma osmolality in the second hour of the 2 h feeding period is the main physiological stimulating factor of water intake during and after dry forage feeding in large-type goats.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.366-370
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• 2002

The objective of this study was to examine whether feeding induced hypovolemia (decrease in plasma volume) acts on the regulation of feed intake in goats fed on dry forage. In order to prevent feeding induced hypovolemia, a 2 h intravenous infusion (16-18 ml/min) of isotonic mannitol solution was begun 1 h prior to feeding and continued until 1 h after the start of the 2 h feeding period. The intravenous infusion of isotonic mannitol solution (MI) decreased plasma osmolality by 1.0%, plasma total protein concentration by 4.2% and hematocrit by 5.9%, respectively. In comparison with no infusion (NI), MI significantly decreased thirst level by approximately 13%. At the completion of the 2 h feeding period, cumulative feed intake had been increased by 43% by MI. In conclusion, feeding induced hypovolemia in goats fed on dry forage increased thirst level more than the increase in plasma osmolality did. The results demonstrate that feeding induced hypovolemia is one of the factors controlling feed intake in goats fed on dry forage.

• 한국초지조사료학회지
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• 제16권3호
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• pp.230-234
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• 1996

This study was conducted to compare the intake, digestibility and utilization of nitrogen by goats consuming high and low tannin diets. Low tannin diets were 100% grass(GS) and 50% grass + SO% alfalfa (GA), and high tannin diets were 50% grass + 50% lespedeza(GL) and 50% grass + 50% oak browse(G0). Dry matter intake did not differ among all diets, but digestibility of dry matter, cellular constituents, NDF and ADF showed slightly lower for high tannin diets(GO) than low tannin diets(GS and GA), but those were not differ between GL and low tannin diets with the exception of ADF digestibility. Total faces and urinary N were lower for high tannin diets than for low tannin diets. Apparently digested N was high in GA diets, but low in GO diets(P

• Asian-Australasian Journal of Animal Sciences
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• 제22권2호
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• pp.225-231
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• 2009

The objective of this experiment was to study the effects of grass maturity at harvest on the nutritive value of grass silage (GS) in relation to voluntary intake, digestibility, nitrogen (N) utilization and in sacco dry matter (DM) degradability. Silage was cut from a sward dominated by orchardgrass (Dactylis glomerata L.) at the late-vegetative (early-cut), internode elongation (mediumcut) and flowering (late-cut) stages of growth. The DM yield at harvest was the lowest for early-cut silage (5.4 t/ha) and increased to 6.5 and 7.0 t/ha for the medium and late-cut silage respectively. As the crop matured, the crude protein (CP) concentration decreased significantly (p<0.05) and there was a marked increase in acid detergent fiber (ADF) concentration (p<0.001). The three different silages were offered to four 18-month old Charolais wether sheep to measure the voluntary intake, in vivo digestibility and N retention over four 21-day periods in an incomplete changeover design. Silage degradability characteristics were determined using four fistulated sheep to measure DM degradability over 3, 6, 12, 24, 48 and 72 h. There was a linear decrease in the voluntary intake of silage fresh matter, DM, organic matter (OM) and neutral detergent fiber (NDF), digestibility of DM, OM, NDF, ADF and CP, and digestibility of OM in DM (Dvalue) ($P_L<0.01$) as harvesting of grass was delayed. Nitrogen intake, N output in urine, N output in faeces and N balance also linearly decreased ($P_L<0.01$) with postponed harvesting of grass for silage. DM degradability and effective degradability (ED) significantly decreased with increasing maturity of grass at harvest. The results suggest that harvesting date has a significant influence on the nutritive value of GS in terms of intake, digestibility, N balance and in sacco degradability in the rumen. It was concluded that early harvest GS ensured higher intake, digestibility, N intake and DM degradability in comparison with the medium and the late cut GS as a result of improved rumen N efficiency and utilization probably due to a better balance of available energy and protein.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1736-1744
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• 2008

Two experiments were conducted in central Vietnam to test the hypothesis that supplementation with a concentrate, comprising rice bran (45% fresh basis), maize (49%), fish meal (3%), urea (2%) and salt (1%), up to 2% of live weight (LW)/d (dry matter (DM) basis) would linearly increase digestible organic matter intake and LW gain of yellow cattle. In both experiments, there were five treatments, namely a basal diet of fresh grass fed at 1.25% of LW (experiment 1, elephant grass, Pennisetum purpureum; experiment 2, native grass) and rice straw (Oryza sativa) fed ad libitum or this diet supplemented with concentrate at about 0.3, 0.7, 1.3 or 2.0% LW. There were 4 male growing cattle per treatment in experiment 1 and 3 in experiment 2. Diets were fed for 44 (experiment 1) or 49 (experiment 2) days, with feed intake recorded daily, LW measured about weekly and digestibility measurements made over 7 days commencing on day 24 (experiment 1) or day 10 (experiment 2). The elephant grass and native grass had neutral detergent fibre (NDF) concentrations of 82 and 73% DM, and nitrogen concentrations of 1.3 and 1.8% DM, respectively. The rice straw used had a NDF concentration of 79-84% DM and nitrogen concentration of 0.8% DM. The concentrate had NDF and nitrogen concentrations of 33 and 2.8% DM. In both experiments, DM intake increased (p<0.001) linearly as the amount of concentrate consumed increased. Rice straw intake declined (p<0.001) (experiment 1: 1.24 to 0.48 kg DM/d; experiment 2: 0.95 to 0.50 kg DM/d) as concentrate intake increased. Grass intake was not significantly affected by concentrate intake in either experiment. The lowest amount of concentrate supplement increased forage intake, after which substitution rate increased as the amount of concentrate consumed increased. However, substitution rates at the highest amount of concentrate consumed were modest at 0.3 to 0.5 kg DM reduction in forage intake/kg DM supplement consumed. In both experiments, digestible organic matter intake increased linearly (p<0.001) (experiment 1: 1.16 to 2.38 kg/d; experiment 2: 1.30 to 2.49 kg/d) as the amount of supplement consumed increased, as did LW gain (experiment 1: 0.15 to 0.81 kg/d; experiment 2: 0.15 to 0.77 kg/d). This was associated with significant (p<0.01) linear increases in organic matter intake and apparent organic matter digestibility. Neutral detergent fibre digestibility declined as concentrate intake increased, but the effect was not significant (p = 0.051) in experiment 2. These results are discussed in relation to existing literature and potential to improve the profitability of cattle fattening in central Vietnam.

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.60-69
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• 2007

Ruminants eating dry forage secrete large volumes of saliva which results in decreased plasma volume (hypovolemia) and the loss of $NaHCO_3$ from the blood. The present research investigated whether or not hypovolemia and the loss of $NaHCO_3$ from the blood in goats brought about by dry forage feeding actually depresses feed intake and saliva secretion, respectively. The present experiment consisted of three treatments (NI, ASI, MI). In the control treatment (NI), a solution was not infused. In the ASI treatment, i.v. infusion of artificial parotid saliva was initiated 1 h before feeding and continued for the entire 2 h feeding period. In the MI treatment, iso-osmotic mannitol solution was infused. The NI treatment showed that hematocrit and plasma total protein concentration were increased due to decreased circulating plasma volume brought about by feeding. In the ASI treatment, the fluid and $NaHCO_3$ that were lost from the blood because of a feeding-induced acceleration of saliva secretion was replenished with an intravenous infusion of artificial parotid saliva. This replenishment lessened the levels of suppression on both feeding and parotid saliva secretion. When only the lost fluid was replenished with an intravenous infusion of iso-osmotic mannitol solution in the MI treatment, the degree of feeding suppression was lessened but the level of saliva secretion suppression was not affected. These results indicate that the marked suppression of feed intake during the initial stages of dry forage feeding was caused by a feeding-induced hypovolemia while the suppression of saliva secretion was brought about by the loss of $NaHCO_3$ from the blood due to increased saliva secretion during the initial stages of feeding.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.116-123
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• 2003

Forages are the most important feed resource for ruminants worldwide, whether fed as pastures, forage crops or conserved hay, silage or haylage. There is large variability in the quality of forages so measurement and prediction of feeding value and nutritive value are essential for high levels of production. Within a commercial animal production system, methods of prediction must be inexpensive and rapid. At least 50% of the variation in feeding value of forages is due to variation in voluntary feed intake. Identification of the factors that constrain voluntary feed intake allows these differences to be managed and exploited in forage selection. Constraints to intake have been predicted using combinations of metabolic and physical factors within the animal while simple measurements such as the energy required to shear the plant material are related to constraints to intake with some plant material. Animals respond to both pre- and post-ingestive feedback signals from forages. Pre-ingestive signals may play a role in intake with signals including taste, odour and texture together with learned aversions to nutrients or toxins (post-ingestive feedback signals). The challenge to forage evaluation is identification of the factors which are most important contributors to these feedback signals. Empirical models incorporating chemical composition are also widely used. The models tend to be useful within the ranges of the datasets used in their development but none can claim to have universal application. Mechanistic models are becoming increasingly complex and sophisticated and incorporate both feed characteristics and use of biochemical pathways within the animal. Improvement in utilisation through the deliberate selection of pasture plants for high feeding value appears to have potential and has been poorly exploited. Use of Near Infrared Reflectance Spectroscopy is a simple method that offers significant potential for the preliminary screening of plants with genetic differences in feeding value. Near Infrared Reflectance Spectroscopy will only be as reliable as the calibration sets from which the equations are generated.

• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1182-1189
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• 2007

An intracerebroventricular (ICV) infusion of somatostatin 1-28 (SRIF) was used as a thirst-controlling peptide antagonist to investigate whether or not thirst-controlling peptides are involved in the significant decrease in feed intake during the initial stages of feeding large-type goats on dry forage. A continuous ICV infusion of SRIF was conducted at a small dose of $4{\mu}g$ ml/h for 27 h from day 1 to day 2. Goats (n = 5) were fed roughly crushed alfalfa hay cubes for 2 h twice daily and water was given ad libitum. Feed intake was measured during ICV infusion of artificial cerebrospinal fluid (ACSF) and SRIF. The feed intake during SRIF infusion increased significantly compared to that during ACSF infusion. In comparison to the ACSF treatment, plasma osmolality during the SRIF treatment significantly decreased during the first half of the 2 h feeding period. The factor causing the decrease in plasma osmolality during the ICV infusion of SRIF was a decrease in plasma Na, K, Cl, and Mg concentrations. In comparison to the ACSF infusion treatment, parotid saliva secretion volumes during the 2 h feeding period in the SRIF infusion treatment were significantly larger. While there was no significant difference in cumulative water intake (thirst levels) between the SRIF and the ACSF treatments upon conclusion of the 2 h feeding period, based on the plasma osmolality results it is thought that thirst level increases brought about by alfalfa hay cube feeding in the first half of the feeding period were reduced. It is thought that the somatostatin-induced increases in feed intake during the 2 h feeding period in the present experiment were caused by decreases in plasma osmolality brought about by the somatostatin infusion. As a result, it is suggested that the significant decrease in feed intake during the initial stages of feeding in large-type goats given roughly crushed alfalfa hay cubes, was due to the actions of thirst-controlling peptides.

• 한국초지조사료학회지
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• 제17권4호
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• pp.399-406
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• 1997

This research was carried out to investigate the effect of zeranol injection on dry matter(DM) and nutrient intake requirement by growth stage of early castrated bull with 3 treatments(bul1, steer, steer+zeranol) with 28 Holstein bull at National Livestock Research Institute. The main results were as follows: DM intake at growing and fatting stage was the highest in steer groups, that the highest in bull groups at finishing stage and overall mean DM intake was 5% lower at steer+zeranol groups compared to bull and steer, respectively. Net energy intake at finishing stage was the highest as 35.49 Mcal at bull groups, while overall mean net energy intake was 101 - 109% of NRC requirement without significant difference. Concentrate intake to body weight was 1.68- 1.82, 1.91 -2.08 and 1.81 -2.05% at growing, fatting and finishing stage, respectively. Overall mean concentrate intake to body weight at steer groups was 1.94%, which is 1.8 and 1.81% higher compared to bull and steer+zeranol groups, respectively. Feed conversion ratio(DM) during overall period was the worst at steer groups as 9.321g, and also net energy conversion ratio was similar to DM conversion ratio.