• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1400-1410
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• 2004

Eight crossbred (75% Holstein Friesian) cows in mid-lactation were randomly assigned to a switchback design with a 2x2 factorial arrangement to evaluate two nonstructural carbohydrate (NSC) sources (corn meal and cassava chips) with different rumen degradability and used at two levels of NSC (55 vs. 75%) with protein source (supplied by urea in the concentrate mix). The treatments were 1) Low degradable low level of corn (55%) 2) Low degradable high level of corn (75%) 3) High degradable low level of cassava (55%) and 4) High degradable high level of cassava (75%). The cows were offered the treatment concentrate at a ratio to milk yield at 1:2. Urea-treated rice straw was offered ad libitum as the roughage and supplement with 1 kg/hd/d cassava hay. The results revealed that total DM intake, BW and digestion coefficients of DM were not affected by either level or source of energy. Rumen fermentation parameters; NH3-N, blood urea nitrogen and milk urea nitrogen were unaffected by source of energy, but were dramatically increased by level of NSC. Rumen microorganism populations were not affected (p>0.05) by source of energy, but fungal zoospores were greater for cassava-based concentrate than corn-based concentrate. Milk production and milk composition were not affected significantly by diets containing either source or level of NSC, however concentrate than corn-based concentrate averaging (4.4 and 4.2, respectively). Likewise, income over feed, as estimated from 3.5% FCM, was higher on cassava-based concentrate than corn-based concentrate averaging (54.0 and 51.4 US$/mo, respectively). These results indicate that feeding diets containing either cassava-based diets and/or a higher of oncentrates up to 75% of DM with NPN (supplied by urea up to 4.5% of DM) can be used in dairy rations without altering rumen ecology or animal performance compared with corn-based concentrate.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.5
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• pp.660-665
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• 2017

Objective: The objective of the study was to determine the effects of increasing levels of metabolizable protein (MP) on lactation performance and nitrogen (N) efficiencies in lactating dairy cows. Methods: Nine multiparous cows in mid lactation [$113{\pm}25$ days in milk] received three treatments in a $3{\times}3$ Latin square design with a period length of 21 days. The treatments were three diets, designed to provide similar energy and increasing supply of MP (g/d) (2,371 [low], 2,561 [medium], and 2,711 [high] with corresponding crude protein levels [%]) 15.2, 18.4, and 20.9, respectively. Results: Increasing MP supplies did not modify dry matter intake, however, it increased milk protein, fat, and lactose yield linearly. Similarly, fat corrected milk increased linearly (9.3%) due to an increase in both milk yield (5.2%) and milk fat content (7.8%). No effects were observed on milk protein and lactose contents across the treatments. Milk nitrogen efficiency (MNE) decreased from 0.26 to 0.20; whereas, the metabolic efficiency of MP decreased from 0.70 to 0.60 in low to high MP supplies, respectively. The concentration of blood urea nitrogen (BUN) increased linearly in response to increasing MP supplies. Conclusion: Increasing MP supplies resulted in increased milk protein yield; however, a higher BUN and low MNE indicated an efficient utilization of dietary protein at low MP supplies.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.63-71
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• 2011

This study was conducted to determine the effects of increasing the dietary levels of conjugated linoleic acid (CLA) which is produced from bio diesel by-products, on milk yield, milk composition, and blood metabolites of mid-lactating dairy cows. A total of 20 mid-lactating dairy cows ($631{\pm}25.0kg$) were assigned to one of four treatment groups and fed twice daily an equal amount of a basal diet ($NE_L$ 32 Mcal/d, CP 17%) contained 12kg/d of concentrate, 15kg/d of corn silage and 4kg/d of the hay mixture (tall fescue+orchard grass). Conjugated linoleic acid were fed for 2 weeks of adaptation periods and 4 weeks of collection periods at 0 (Control), 50 (T1), 100 (T2) and 150g/d (T3), respectively. By the increases of dietary CLA supplementation, milk yield and 4% fat corrected milk increased, whereas milk fat content decreased (p<0.05). The concentrations of stearic acid and oleic acid decreased with increasing dietary CLA supplementation, while the concentrations of total CLA increased (p<0.05). In conclusion, this study shown that the supplementation of dietary CLA manufactured from bio diesel by-products could improve milk yield and CLA concentrations of milk in mid-lactating dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.49-56
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• 2009

The objective was to determine the effects of supplementation of protected conjugated linoleic acid (CLA), CLA-20 comprising 10% each of cis-9, trans-11 and trans-10, cis-12, on milk production and fatty acid profiles in plasma and milk in lactating dairy cows. Five mid-lactation, multiparous crossbred Holstein Friesian cows with average 402${\pm}$20 kg BW were used in a 5${\times}$5 Latin square design for 21-d periods. Cows were given a total mixed ration (TMR) and supplemented with CLA-20 at 0, 20, 40, 80 and 160 g/d. The results showed that dry matter intake depression occurred in cows supplemented with CLA-20 at 160 g/d. Milk production slightly increased when CLA-20 supplementation was at 20, 40 and 80 g/d. However, 3.5% fat-corrected milk (FCM) was not affected by CLA-20 supplementation. Increased levels of CLA-20 supplementation resulted in a significantly decreased percentage of milk fat. Plasma concentrations of fatty acid were not altered by the amounts of CLA-20 supplementation except for the concentration of trans-10, cis-12 CLA. For all dietary treatments, percentages of fatty acids (C4:0, C6:0, C8:0, C13:0, C14:0 C14:1 C15:0 C15:1 C16:0, C16:1, C18:1n9t, C18:2n6t, C18:2n6c, C20:0, C18:3n6, C18:3n3, C20:1 and C20:3n6) in milk fat were similar. Concentrations of C10:0, C11:0, C12:0 and C18:1n9c were decreased cubically and C18:0 was elevated linearly (p<0.01) according to the increased amounts of CLA-20 supplemented. The linear increase was observed for cis-9, trans-11 CLA (0.62, 1.17, 1.94, 1.87 and 1.82% of total fatty acid), trans-10, cis-12 CLA (0.01, 0.63, 0.67, 0.93 and 0.95% of total fatty acid) and total CLA (0.80, 2.25, 3.16, 3.97 and 3.94% of total fatty acid) in milk fat from 0 to 160 g/d of CLA-20 supplement. In conclusion, concentration of cis-9, trans-11 CLA in milk fat was concomitantly elevated at an increasing rate with the increased amounts of CLA-20. Based on the results in this study, supplementation of CLA-20 at 80 g/d optimally enhanced total CLA in milk fat.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.5
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• pp.670-677
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• 2004

Sixteen multiparous Holstein-Friesian crossbred cows in mid-lactation were blocked according to days in milk (DIM) and previous lactation and randomly assigned according to a Randomized Complete Block (RCB) design with four replications to receive four dietary treatments. The dietary treatments consisted of T1: No cassava hay (CH) or stylo 184 hay (SH) supplementation, supplementation of concentrate to milk yield at 1:2 (control), T2: Supplementation of 1 kg of CH/hd/d, supplementation of concentrate to milk yield at 1:2, T3: Supplementation of 1 kg of CH+SH/hd/d, supplementation of concentrate to milk yield at 1:2, T4: Supplementation of 2 kg of CH+SH/hd/d, supplementation of concentrate to milk yield at 1:3. All animals received Ruzi grass from a cut-and-carry system as roughage source. The feeding trial lasted for 9 weeks. The results revealed that DMI of concentrate of supplemented treatments were significantly lower (p<0.05) than those in the control, but there was no significant difference between T2 and T3. There was no significant difference in forage DM intake between the control and supplemented treatments. CP and NDF digestibility of supplemented treatments were significantly (p<0.05) greater than the control and there were no significant differences among supplemented treatments. Milk yield and 3.5% FCM (14.3, 14.5, 14.7 and 14.8; 13.9, 14.3, 14.3 and 14.6 kg/hd/d, respectively) were not significantly different among treatments. Milk protein percentage of supplemented treatments was significantly (p<0.05) higher than the control, but there were no significant differences among supplemented treatments. There was no significant difference in milk fat percentage between the control and supplemented treatments. However, milk fat percentage tended to be higher for supplemented animals as compared to the control group. There were also no significant differences in lactose, solids-not-fat and total solids percentages among treatments. Cows in supplemented treatments gave incomes over supplement cost (IOSC) of 2.72, 2.74 and 2.93 US$/hd/d, respectively which were greater than for cows on control treatment. Furthermore, IOSC were greatest for cows in T4 as compared to other treatments. Based on this study it was concluded that, feeding cassava hay solely or in combination with stylo 184 hay as a supplemental protein source could be a potential valuable strategy in small-holder dairy farming systems in the tropics. This strategic supplementation significantly reduced concentrate use, which resulted in improved milk yields and milk quality for the supplemented cows. Moreover, it resulted in higher economical returns through increased productivity and lower ratios of concentrate to milk yield, from 1:2 to 1:3.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1763-1769
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• 2003

Two experiments were conducted to examine the production and quality of cassava hay and its utilization in diets for dairy cows. In experiment I, a $2{\times}2$ Factorial arrangement in a randomized complete block design with 4 replications was carried out to determine the effects of different initial (IC) and subsequent cutting (SC) on yield and composition of cassava plant. The results revealed that cassava could produce from 4 to 7 tonne of DM and 1.2 to 1.6 tonne of CP for the first six months after planting. CP content in cassava plant ranged from 20.8 to 28.5% and was affected by different SC regimes. Condensed tannin in cassava foliage ranged from 4.9 to 5.5%. Initial cutting at 2 months with subsequent cutting at 2 month intervals was the optimal to obtain high dry matter and protein yield. In the second experiment, five crossbred Holstein-Friesian cows in mid lactation with an initial live-weight of 505${\pm}6.1kg$ and average milk yield of 10.78${\pm}1.2kg/d$ were randomly assigned in a $5{\times}5$ Latin square design to study the effects of 2 levels of CH (1 and 2 kg/hd/d) and concentrate (1 to 2 kg of milk and 1 to 3 kg of milk) on milk yield and milk composition. The results showed that cassava hay increased rumen $NH_3-N$ and milk urea nitrogen (MUN) (p<0.05). Cassava hay tended to increase milk production and 4% FCM. Milk protein increased in cows fed cassava hay (p<0.05). Moreover, cassava hay could reduce concentrate levels in dairy rations thus resulting in increased economic returns. Cassava hay can be a good source of forage to reduce concentrate supplementation and improve milk quality.

• Korean Journal of Agricultural Science
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• v.48 no.1
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• pp.45-57
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• 2021

This study aimed to determine the effects if ambient temperature (Ta), relative humidity (RH), and temperature-humidity index (THI) on milk production parameters such as milk yield, fat, protein, milk urea nitrogen (MUN), and lactose. A total of fifty (50) mid-lactating Korean Holstein cows (144 - 150 days postpartum) were randomly assigned to two groups in equal numbers (n = 25) according to the type of diet received: conventional feed, a mixture of 56: 44 ratio of roughage and concentrate mix, and organic feed containing 100% organic roughage. Temperature, RH, and THI were recorded daily and averaged monthly. Conventional group showed higher dry matter intake throughout the experiment and thus, showed higher total milk yield and milk composition such as milk fat, protein, and lactose content than organic milk. Milk of the conventional group showed higher polyunsaturated fatty acid concentration. Highest milk yield was observed in September (21.7℃, 82.4%RH) in conventional group (27.69 kg·day^-1) and in June (21.4℃, 72.9%RH) in organic group (14.31 kg·day^-1). In conventional group, milk yield was positively correlated with Ta and THI, and milk protein was negatively correlated with Ta, RH, and THI. In organic feeding, only the MUN among milk composition parameters showed a significant correlation where it showed a negative correlation with Ta, RH, and THI. Conventional feeding showed significantly higher milk yield, fat, protein, and lactose than organic feeding throughout the experiment, although, organic feeding showed to be less likely affected by Ta, RH, and THI than the conventional feeding.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.45-51
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• 2006

This study was carried out to investigate effect of claw trimming on milk yield and its composition in Holstein at different lactation stages. 1 . There was no difference in daily milk yield between control and claw trimming in early, mid and late lactating Holsteins. 2. Somatic cell count (SCC) was lower in early lactation and it was higher in late lactation when claws were trimmed in Holstein. However, claw trimming did not affect SCC during mid lactation in Holstein. 3. Milk fat, protein and total solids were decreased during late lactation in Holstein after claw trimming. However, milk composition was not affected by claw trimming in early and mid lactating Holsteins.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.573-584
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• 2002

Milk urea nitrogen (MUN) and Milk protein (MP) are being used as indicators of the protein-energy balance and for actual farm feeding practices. The purpose of this study was to investigate the MUN and MP concentrations of individual cows and bulk tank milk to evaluate the dietary protein-energy balance from lactating Holstein cows. Mean MUN and MP concentrations in the milk samples obtained from 132,636 cows of 4,856 herd during Jan. 1999 to Dec. 2001 were 16.2 5.2mg/dl and 3.30 0.35%, respectively. The highest values were found during summer and lowest valued during winter in MUN. But, the average contents of MP were the highest during winter and the lowest during summer. In order to evaluate protein-energy balance for feeding, we set the level of recommended MP range of 2.90${\sim}$3.29% in early lactation considering a negative energy balance. The recommended level of MP in mid-lactation and late lactation were set as 3.10${\sim}$3.49%, and 3.30${\sim}$3.69%, respectively. Recommended MUN range of 12${\sim}$18 mg/dl was determined through the whole lactation period. Individual cows milk were analyzed by the 9 types based on this levels of MP and MUN in this study. Among the total cows investigated, 26.8%, 25.8%, and 22.2% have shown the recommended criteria of MP and MUN values, respectively. Also, of total herds surveyed, 11.6% had MUN values lower than 12.0 mg/dl and 32.9% had values higher than 18.0 mg/dl and 44.5% of total herd have not met with the recommended criteria of MP values in bulk tank milk. In case of MP, out of the total herd surveyed, 26.0% had MP values lower than 3.10% and 24.0% had values higher than 3.30% and 50.0% had MP values outside the recommended interval (3.1${\sim}$3.3%). This study has indicates that many dairy farms are under improper feeding management practice of the dietary protein-energy balance.