Twenty lactating cows of two to five parity having an average live weight of 290.00 to 330.00 kg and an average milk production of 4.54 kg/head/day to 4.66 kg/head/day were selected from the Central Cattle breeding St...Twenty lactating cows of two to five parity having an average live weight of 290.00 to 330.00 kg and an average milk production of 4.54 kg/head/day to 4.66 kg/head/day were selected from the Central Cattle breeding Station and Dairy Farm. The four dietary treatment were： SlooTo （Straw 100： Triticale 0 as control）; $5oT5o （Straw 50： Triticale 50）; $25T75 （Straw 25： Triticale 75） and SoTloo （Straw 0： Triticale 100）. It was observed that the roughage dry matter intake （DMI） （2.61 ~ 0.07 kg） in percent live weight was significantly （P 〈 0.05） higher in $25T75 and the lowest （1.76 ~ 0.018 kg） in the control group （SlooTo） and the differences were significant among the dietary treatments except $5oT5o and SoTloo. The total DMI was significantly （P 〈 0.05） higher in SoT^oo （13.36 i 0.13 kg） followed by $25T75, $5oT5o and SlooTo, respectively. The digestibility of crude protein （CP） was slightly higher in $25T75 （75.48 ~ 0.96） compared to SoTtoo （75.31 ~ 1.45） and the difference was non-significant （P 〉 0.05）. Milk production was significantly （P 〈 0.05） the highest in $5oT5o and the lowest in SlooTo followed by SoTloo, $25T75, respectively. The percent increased in milk yield was also the highest in $5oT5o （67.68%） and the lowest in SlooTo （28.85%）. The 4% fat corrected milk was also significantly （P 〈 0.05） higher in $5oT5o followed by SoTloo, $25T75 and SlooTo, respectively. Therefore, it can be concluded that triticale and straw at a ratio of 50：50 may be fed for better production performance of dairy cows.展开更多
Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, ...Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.展开更多
The aim of the study was to evaluate the impact of organic selenium supplementation （selenium yeast） vs. inorganic selenium （selenium selenite） on the expression of selected defensin genes in milk somatic cells （...The aim of the study was to evaluate the impact of organic selenium supplementation （selenium yeast） vs. inorganic selenium （selenium selenite） on the expression of selected defensin genes in milk somatic cells （MSC） of dairy cows. Sixteen Polish Holstein-Friesian cows in second parity, with similar milk yield and milk composition were randomly divided into two equal groups. At the beginning of experiment, the animals were in the middle of their lactation curve （150, standard deviation （SD） = 26 d） and this experiment lasted 90 d. The basic diet, for both groups, consisted of corn silage, wilted grass silage and concentrates. The diet of control group was supplemented with commercial mineral and vitamin mixture with inorganic selenium and the for the experimental group daily selenium need was covered by the addition of Se-yeast （6 mg Se/cow/d）. Milk samples were collected three times during experiment （before experiment; on day 55; after the end the experiment）. Total RNA was isolated from milk somatic cells and the levels of transcripts of bovine β1-defensin （DEFB1）, β4-defensin （BNBD4）, β5-defensin （BNBDS）, β10-defensin （BNBD10） and lingual antimicrobial peptide （LAP） were measured with real time PCR, using glyceraldehyde 3-phosphate dehydrogenase （GAPDH） as a reference gene. The expressions of almost all studied genes were influenced by environmental conditions （very low and negative temperature）. However, BNBD4 （P 〈 0.05） and LAP （P ≤ 0.001 ） genes were influenced by selenium supplementation but in opposite ways, depending on the form of Se. These findings support that selenium is an important factor affecting the mRNA level in MSC, but the effect of the form of selenium might depend on genes.展开更多
[Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature ...[Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature and temperature zone. [Method] Records of yield and reproduction from 8 868 Chinese Holstein first lacta- tion cows from 21 herds were utilized to evaluate genetic parameters for Hei- Iongjiangs＇ Chinese Holsteins. Restricted maximum likelihood （REML） method was used with an animal model. [Result] The heritabilities were 0.16 to 0.34 for yields and fat percentage, 0.38 for reproduction （age at the first freshening）, which were similar to estimates for temperate areas from similar methods, except for constituent percentage. Also, the estimates of genetic correlation were high between milk yield and fat yield （0.97）, but were low between milk yield and fat percentage （-0.24）, age at the first freshening （-0.29） and generally antagonistic. [Conclusion] Thus, es- timates of genetic parameters in this frigid and frigid-temperate environment did not differ appreciably from those that occur in temperate dairy areas.展开更多
文摘Twenty lactating cows of two to five parity having an average live weight of 290.00 to 330.00 kg and an average milk production of 4.54 kg/head/day to 4.66 kg/head/day were selected from the Central Cattle breeding Station and Dairy Farm. The four dietary treatment were： SlooTo （Straw 100： Triticale 0 as control）; $5oT5o （Straw 50： Triticale 50）; $25T75 （Straw 25： Triticale 75） and SoTloo （Straw 0： Triticale 100）. It was observed that the roughage dry matter intake （DMI） （2.61 ~ 0.07 kg） in percent live weight was significantly （P 〈 0.05） higher in $25T75 and the lowest （1.76 ~ 0.018 kg） in the control group （SlooTo） and the differences were significant among the dietary treatments except $5oT5o and SoTloo. The total DMI was significantly （P 〈 0.05） higher in SoT^oo （13.36 i 0.13 kg） followed by $25T75, $5oT5o and SlooTo, respectively. The digestibility of crude protein （CP） was slightly higher in $25T75 （75.48 ~ 0.96） compared to SoTtoo （75.31 ~ 1.45） and the difference was non-significant （P 〉 0.05）. Milk production was significantly （P 〈 0.05） the highest in $5oT5o and the lowest in SlooTo followed by SoTloo, $25T75, respectively. The percent increased in milk yield was also the highest in $5oT5o （67.68%） and the lowest in SlooTo （28.85%）. The 4% fat corrected milk was also significantly （P 〈 0.05） higher in $5oT5o followed by SoTloo, $25T75 and SlooTo, respectively. Therefore, it can be concluded that triticale and straw at a ratio of 50：50 may be fed for better production performance of dairy cows.
文摘Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.
文摘The aim of the study was to evaluate the impact of organic selenium supplementation （selenium yeast） vs. inorganic selenium （selenium selenite） on the expression of selected defensin genes in milk somatic cells （MSC） of dairy cows. Sixteen Polish Holstein-Friesian cows in second parity, with similar milk yield and milk composition were randomly divided into two equal groups. At the beginning of experiment, the animals were in the middle of their lactation curve （150, standard deviation （SD） = 26 d） and this experiment lasted 90 d. The basic diet, for both groups, consisted of corn silage, wilted grass silage and concentrates. The diet of control group was supplemented with commercial mineral and vitamin mixture with inorganic selenium and the for the experimental group daily selenium need was covered by the addition of Se-yeast （6 mg Se/cow/d）. Milk samples were collected three times during experiment （before experiment; on day 55; after the end the experiment）. Total RNA was isolated from milk somatic cells and the levels of transcripts of bovine β1-defensin （DEFB1）, β4-defensin （BNBD4）, β5-defensin （BNBDS）, β10-defensin （BNBD10） and lingual antimicrobial peptide （LAP） were measured with real time PCR, using glyceraldehyde 3-phosphate dehydrogenase （GAPDH） as a reference gene. The expressions of almost all studied genes were influenced by environmental conditions （very low and negative temperature）. However, BNBD4 （P 〈 0.05） and LAP （P ≤ 0.001 ） genes were influenced by selenium supplementation but in opposite ways, depending on the form of Se. These findings support that selenium is an important factor affecting the mRNA level in MSC, but the effect of the form of selenium might depend on genes.
文摘[Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature and temperature zone. [Method] Records of yield and reproduction from 8 868 Chinese Holstein first lacta- tion cows from 21 herds were utilized to evaluate genetic parameters for Hei- Iongjiangs＇ Chinese Holsteins. Restricted maximum likelihood （REML） method was used with an animal model. [Result] The heritabilities were 0.16 to 0.34 for yields and fat percentage, 0.38 for reproduction （age at the first freshening）, which were similar to estimates for temperate areas from similar methods, except for constituent percentage. Also, the estimates of genetic correlation were high between milk yield and fat yield （0.97）, but were low between milk yield and fat percentage （-0.24）, age at the first freshening （-0.29） and generally antagonistic. [Conclusion] Thus, es- timates of genetic parameters in this frigid and frigid-temperate environment did not differ appreciably from those that occur in temperate dairy areas.
