milk yield

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1 - Animal Factors Condition Milk Performance and Quality of Grazing Dairy Cows
آ.آی. روکا-فرناندز

The base of this review is to consider the relevant role that animal factors (potential milk yield, body weight, body condition score, state of lactation, parity and fertility) play on milk performance (considering the energy balance and the rumen function across the fu أکثر

The base of this review is to consider the relevant role that animal factors (potential milk yield, body weight, body condition score, state of lactation, parity and fertility) play on milk performance (considering the energy balance and the rumen function across the full lactation curve of animals) and milk quality (milk protein content, milk fat content, milk lactose content, vitamins, minerals, immunoglobulins, cells in milk, pathogenic bacteria and inhibitors) of grazing dairy cows (taking into account the substitution rate and the milk response at pasture of animals under different supplementation regimes). All this, looking for high individual milk production and paying attention to grassland management as the key point for sustainability of grazing dairy systems in order to maintain high pasture dry matter intake in the swards with high grass quality (high pasture levels of crude protein, water soluble carbohydrates and digestibility of organic matter but low pasture levels of acid and neutral detergent fibers) all over the grazing season to satisfy cow needs at all times thought the lactation curve of dairy cows. It is also necessary to consider the use of supplementation at pasture (normally at the peak of lactation, when cows are generally in a state of negative energy balance and the provision of silage / concentrate can help to alleviate this situation) to keep the animals within the desired levels of milk production. It seeks, thereby, to achieve an efficient conversion of grass into milk, in a competitive and profitable way taking into consideration the current context in which pasture-based milk production systems are developed in mostly of temperate regions worldwide and focusing our interest in the milk premium price got by dairy farmers in a humid area as Galicia (NW Spain)when we consider the quantity and the quality of the milk delivered to the dairy industry. تفاصيل المقالة

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2 - The Relationship between Body Condition Score and Milk Production, Udder Health and Reduced Negative Energy Balance during Initial Lactation Period: A Review
A.K. Singh C. Bhakat

Achieving improved milk yield from a healthy udder, with a minimum weight loss especially during initial lactation, is the aim of every dairy farmer. Body condition score (BCS) of dairy cows has been found to be significantly associated with body weight, milk performanc أکثر

Achieving improved milk yield from a healthy udder, with a minimum weight loss especially during initial lactation, is the aim of every dairy farmer. Body condition score (BCS) of dairy cows has been found to be significantly associated with body weight, milk performance and udder health status of dairy cow during the pre and post- partum period. Under and over body condition of dairy cows should be avoided. Both conditions lead to weight loss, loss of milk, poor udder health and metabolic disease in dairy animals. Cows should have balanced body condition before and after calving. Better management practices during the dry period and at calving may optimize production, and udder health in subsequent lactation. This review aims to highlight livestock management strategies during the dry period which may help in optimizing BCS at calving and during the subsequent lactation period, thus improving milk performance and udder health, and reducing weight loss in early lactation. تفاصيل المقالة

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3 - Induction of Lactation in Holstein Cows Using Progesterone Injections or Progesterone Vaginal Inserts
F. Rivera-Acuna E. Prado-Martinez P. Luna-Nevarez M.G. Mendez-Castillo L. Avendano-Reyes J.F. Hernandez-Chavez J.L. Espinoza-Villavicencio J. Hernandez-Ceron A. Correa-Calderon

The aim of this study was to evaluate the effect of replacing progesterone injections by progesterone vaginal inserts on productive and reproductive parameters of lactating cows with reproductive problems after prolonged periods of heat stress. Fifteen Holstein cows wer أکثر

The aim of this study was to evaluate the effect of replacing progesterone injections by progesterone vaginal inserts on productive and reproductive parameters of lactating cows with reproductive problems after prolonged periods of heat stress. Fifteen Holstein cows were randomly assigned to one of three treatments: 1) treated with two progesterone vaginal inserts (P4-INS); 2) treated with progesterone and estradiol via injections (P4-INJ) and 3) control, cows with gestation and parturition normally. All cows were subjected to a Presynch-Co-Synch timed artificial insemination protocol and then inseminated at 71 d in milk. Concentration of P4 in (P4-INS) and (P4-INJ) cows during the first 7 d of induction of lactation was similar (P>0.05) and then increased linearly in both groups. Adjusted milk yield, total milk yield, and average daily milk yield were similar (P>0.05) in treated cows, but cows from (P4-INJ) group produced less milk (P<0.05) than control cows. Days in milk and peak milk yield were similar (P>0.05) among all groups. Percentage of milk fat and protein, as well as days to peak milk yield were higher (P<0.05) in both treated groups compared to control. Body condition score, service per conception, conception to first service, total conception, days open and culling rate at the end of lactation were similar (P>0.05) among treatments. Progesterone administration by injection or by vaginal insertion resulted in similar production and reproduction parameters of dairy cattle with induced lactation. تفاصيل المقالة

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4 - Relationship between Peak Milk Yield and Udder Parameters of Dehong Crossbred Dairy Buffaloes
ز.بی. گو اس.ال. یانگ جی. وانگ سی. ما ی. چن وی.ال. هو اس.کا. تنگ اچ.اس. ژو سی.بی. لیو تی. چن ایکس.اچ. فو اس.اچ. زیو ز.پی. شی آر.اس. لی جی.دی. می اچ.ام. مااُ

To determine the relationship between udder traits and peak milk yield, udder parameters of 203 Dehong crossbred dairy buffaloes were measured. The average peak milk yield (kg/day) of buffaloes was 9.60 ± 2.73, with average udder dimensions of 16.51 ± 10.0 أکثر

To determine the relationship between udder traits and peak milk yield, udder parameters of 203 Dehong crossbred dairy buffaloes were measured. The average peak milk yield (kg/day) of buffaloes was 9.60 ± 2.73, with average udder dimensions of 16.51 ± 10.05, 8.07 ± 3.26, 8.68 ± 3.92, 50.74 ± 8.82, 11.38 ± 3.08, 7.18 ± 2.18 and 7.73 ± 2.15 cm for udder depth, rear udder width, rear udder height, udder length, distance of fore teats, distance of rear teats, and distance of fore-rear teats, respectively. The peak milk yield was negatively correlated with udder depth (r=-0.28, P تفاصيل المقالة

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5 - Effects of Milking Frequency on Milk Production and Composition of Holstein Cows during Their First Three Lactations
آی. بوجنانه

The objective of this study was to investigate the effect of milking frequency (two times daily vs. three times daily) on the 305-d lactation milk, fat and protein yield and fat and protein percentage of Holstein dairy cows in Morocco. Data analyzed were 31400 records c أکثر

The objective of this study was to investigate the effect of milking frequency (two times daily vs. three times daily) on the 305-d lactation milk, fat and protein yield and fat and protein percentage of Holstein dairy cows in Morocco. Data analyzed were 31400 records collected between 2009 and 2016 on 14272 cows raised in 194 herds. The frequency of milking had significant effects (P<0.05) on 305-d milk, fat and protein yield as well as fat percentage. The milk, fat and protein yield and fat percentage were higher by 265.1 kg, 13.3 kg, 5.8 kg, and 0.3 g/kg, respectively, i.e. 3,79%, 4.78%, 2.40%, and 0.75%, respectively, for cows milked thrice than those milked twice daily. However, the frequency of milking did not influence protein percentage (P>0.05). The interaction between parity and milking frequency was not significant (P>0.05) for any studied trait. Based on the results of this study, it can be concluded that increasing milking frequency increased milk, fat and protein yield as well as fat percentage regardless of parity. However, the additional milk yield obtained might not compensate for the cost of the labor generated by the extra milking. تفاصيل المقالة

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6 - DNA Polymorphisms at Candidate Gene Loci and Their Relation with Milk Production Traits in Murrah Buffalo (<i>Bubalus bubalis</i>)
دی.اس. کاله بی.آر. یاداو جی. پراساد

DNA polymorphism within diacylglycerol transferase 2 (DGAT2) / monoacyl glycerol transferases 2 (MOGAT2), leptin and butyrophilin genes were analysed using PCR-SSCP in Murrah buffalo. The single strand conformation polymorphism (SSCP) analysis of amplified gene fragment أکثر

DNA polymorphism within diacylglycerol transferase 2 (DGAT2) / monoacyl glycerol transferases 2 (MOGAT2), leptin and butyrophilin genes were analysed using PCR-SSCP in Murrah buffalo. The single strand conformation polymorphism (SSCP) analysis of amplified gene fragment in exon 5 of MOGAT2, exon 3 of leptin and intron 1 of butyrophilin gene revealed different patterns. A, B and C showed the following frequencies for each candidate gene in 53 (A=0.49, B=0.36 and C=0.15), 65 (A=0.38 and B=0.62) and 55 samples (A=0.6, B=0.31 and C=0.09) from Murrah buffaloes, respectively. The strand conformation polymorphism (SSCP) followed by DNA sequencing revealed one single nucleotide polymorphism (SNP) that was (c.193T>C) in MOGAT2, one single nucleotide polymorphism (SNP) (c.25 T>C) in leptin and one single nucleotide polymorphism (SNP) (c.184C>T>G) in butyrophilin gene confirmed BTI1 SSCP.The statistical analysis using general linear model procedure for association study, indicated that Murrah buffalo monoacyl glycerol transferases 2 (MOGAT2)(c.193T>C) single nucleotide polymorphism (SNP)and (c.25 T>C) in leptingenotypes were not significantly different (P>0.01) in Murrah buffalo for milk production traits milk yield, fat percentage and single nucleotide polymorphism (SNP)percentage. However, the statistical analysis for association study indicated BTI1 SSCP was significantly (P≤0.05) associated with 305-days lactation milk yield. The Murrah buffaloes with BTI1BB genotypes had 683.93 kg and 320.48 kg higher milk yield as compared to BTI1AA and BTI1CC genotypes, respectively. The positive association of butyrophilin single strand conformation polymorphism (SSCP) polymorphism with milk yield will be a useful tool for future selection and breeding strategies and genetic improvement of buffaloes for milk yield. تفاصيل المقالة

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7 - Estimation of Genetic Trends for Test-Day Milk Yield by the Logarithmic Form of Wood Function Using a Random Regression Model
ز. پزشکیان ع.ا. شادپرور س. جوزی شکالگورابی

Estimation of genetic trends is necessary to monitor and evaluate selection programs. The objective of this study was to estimate the genetic trends for milk yield in Iranian Holsteins cows using random regression test day model. Data set was consisted of 743205 test-da أکثر

Estimation of genetic trends is necessary to monitor and evaluate selection programs. The objective of this study was to estimate the genetic trends for milk yield in Iranian Holsteins cows using random regression test day model. Data set was consisted of 743205 test-day records from 1991 to 2008, which were collected by the Animal Breeding Centre of Iran. Breeding, environmental and phenotypic values were estimated using a random regression test-day model. The logarithmic form of Wood function was chosen to fit the additive genetic and permanent environmental effects of milk yield. Genetic, environmental, phenotypic trends were estimated by regressing the mean of breeding values, environmental values and phenotypic values on birth year. The genetic and phenotypic trends were positive and significant, whereas environmental trends were not significant. Genetic trends of sires and dams were estimated separately and it was positive and significant for dams, but it was not significant for sires. The phenotypic, environmental and genetic correlation between each days in milk and total 305 days were estimated. The correlations related to breeding values were weak and it showed that with the logarithmic transformation of milk yield, persistency can be improved independently from milk production. تفاصيل المقالة

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8 - Milk Production and Composition, and Intake of Holstein Lactating Cows Fed Diets with Partial Substitution of Soybean Meal with Flaked Field Pea
آ. پیرزاده نائینی م. دانش مسگران ع.ر. وکیلی ه. ابراهیمی

The objective of this study was to investigate the effect of a partial substitution of soybean meal with field pea (Pisum sativum) in Holstein lactating dairy cow diets on dry matter intake, milk yield and composition, blood metabolites, rumen ammonia-N concentration an أکثر

The objective of this study was to investigate the effect of a partial substitution of soybean meal with field pea (Pisum sativum) in Holstein lactating dairy cow diets on dry matter intake, milk yield and composition, blood metabolites, rumen ammonia-N concentration and pH. Eighteen lactating Holstein cows were randomly assigned into three groups based on parity, days in milk, and milk yield. Flaked field peas replaced soybean meal (SBM) at the levels of 0.0, 33 and 66% (P0, P33 and P66, respectively) and were fed to the animals for 33 days. Dry matter intake, milk yield, milk fat and protein content, blood metabolites, rumen ammonia-N concentration and pH were not significantly (P<0.05) affected by the diets. The results of this study demonstrated that field pea could safely replace soybean meal up to 66% in the diet of high-producing dairy cows. تفاصيل المقالة

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9 - Effect of Replacing Dietary Corn Silage with Hydroponic Barley Green Fodder on Holstein Dairy Cows Performance
H. Fazaeli H.A. Golmohammadi S.N. Tabatatbaei

The objective of this study was to investigate the effect of inclusion of hydroponic barley green fodder (HBGF) in the diet on the performance of lactating cows. Eight Holstein cows (with daily milk yield of 31.15±2.75 kg and 83.23±12.46 days in milk) were أکثر

The objective of this study was to investigate the effect of inclusion of hydroponic barley green fodder (HBGF) in the diet on the performance of lactating cows. Eight Holstein cows (with daily milk yield of 31.15±2.75 kg and 83.23±12.46 days in milk) were assigned to 1 of 4 diets in a 4 × 4 latin square design. Control diet (I) consisting of 62% concentrates, 20% alfalfa hay, and 18% maize silage (dry matter (DM) basis), where in diets II, III and IV the maize silage was replaced by 20, 40 and 60% HBGF, DM basis, respectively. The green fodder yield was 869 g per kg planted seed (DM basis), showing a loss of 131 g DM. Dry matter intake was 23.20, 22.98, 22.67 and 22.65 kg/d on diets I, II, II and IV, respectively. The dietary HBGF level did not affect the average daily milk yield (27.38, 27.62, 26.41 and 27.22 kg/d), as well as the fat, protein and milk total solid yield. Feed efficiency (milk yield per kg DM intake) was 1.26, 1.27, 1.28 and 1.31 which did not significantly affected by the treatments. Finally, inclusion of HBGF up to 60% of maize silage portion, equal to 10.5% of total diet (DM basis), did not affect the performance of lactating cows when compared with maize silage. However, the biomass yield (DM basis) of hydroponic barley green fodder per kg seed grain was lower than that of the initial grain which would increase the cost of feeding. تفاصيل المقالة

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10 - Effects of Dietary Protein and Energy Levels on Productive and Reproductive Performance of Lactating Buffaloes
H.M.A. Gaafar E.M. Abdel-Raouf M.M. Bendary G.H.A. Ghanem K.F.A. El-Riedy

Twenty eight lactating buffaloes were used in a completely randomized design with 2×2 factorial arrangement of four experimental diets including low protein–low energy (LP-LE), low protein–high energy (LP-HE), high protein–low energy (HP-LE) and أکثر

Twenty eight lactating buffaloes were used in a completely randomized design with 2×2 factorial arrangement of four experimental diets including low protein–low energy (LP-LE), low protein–high energy (LP-HE), high protein–low energy (HP-LE) and high protein–high energy (HP-HE). Results showed that the HP-HE diet recorded the highest digestibility coefficients of CP, EE, NFE, nutritive values, TDN and DCP intake, while HP-LE diet had the highest CF digestibility (P<0.05). The HP-HE diet had the highest (P<0.05) actual milk and 7% FCM yield and the contents of protein, lactose, SNF and TS in milk, HP-LE diet had the highest fat content (P<0.05). The HP-HE diet showed the lowest amounts of DM and TDN per kg, 7% FCM, while LP-HE diet had the lowest amount of DCP per kg 7% FCM (P<0.05). The LP-HE diet recorded the lowest average daily feed cost, while HP-HE diet showed the lowest feed cost/kg 7% FCM and the highest total revenue and economic efficiency (P<0.05). Buffaloes fed HP-HE diet showed short periods from parturition to first estrus and first service, service period, days open, the lowest number of services per conception and the highest conception rate (P<0.05). تفاصيل المقالة

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11 - Impact of Oxytocin-Milking Method on Lactation Performance and Lactation Length of Sheep
M. Nezamidoust S. Razzaghzadeh E. Ezati R. Ghorbani

Determination of milk yield potential using an accurate method is essential for assessing nutritional requirements, evaluation of genetic potential, lamb growth and survival, management decisions and improving performance traits of sheep flocks. Exogenous oxytocin injec أکثر

Determination of milk yield potential using an accurate method is essential for assessing nutritional requirements, evaluation of genetic potential, lamb growth and survival, management decisions and improving performance traits of sheep flocks. Exogenous oxytocin injection is applied to estimate milk secretion rate in sheep. Oxytocin is a neurohormone produced in the hypothalamo-neurohypophysial system, which is released into the blood in response to teat stimulation. It has a galactopoietic effect and plays an important role in lactation acting on milk ejection via the secretory activity and contraction of myoepithelial cells. One hundred singleton-bearing and rearing Makui breed ewes were assigned into two treatments: group I (hand milking and stripping following the intramuscular injection of 2.5 IU of oxytocin) and group II (hand milking and stripping). The study aimed to examine the effect of exogenous oxytocin injection on milk yield, milk composition and lactation length of ewes during the entire lactation period. Data were recorded at fortnightly intervals from post-partum day 14 onward. Oxytocin treatment group produced significantly more average daily milk yield (562.3 vs. 301.4 g) and total milk yield (93.6 vs. 38.5 kg) compared with non-treated animals (P<0.05). Lactation length was 145.7 days and 115.2 days for the oxytocin and the control group, respectively (P=0.038). Oxytocin injection increased milk peak yield and lactation persistency (P<0.05) while shorter peak time (34.1 vs. 39.2 days) was observed for oxytocin group (P=0.043). Oxytocin administration increased milk fat percentage (6.73 vs. 5.86) in treated compared to control ewes (P=0.029). However, no difference was detected in the percentage of protein and lactose associated to the oxytocin injection (P>0.05). The development of milk ejection inhibition throughout lactation during the exclusively sucklingperiod, followed by hand-stripping, entails the need for oxytocin to sustain mammary cells and lactation persistency in ewes. Itfurther confirms that oxytocin allows overcoming the negative feedback mechanisms exerted on milk ejection, enhancing the intracellular transfer of secretory vesicles and contraction of myoepithelial cells and thereby increasing milk production and lactation length, which is a useful technique to ensure complete alveolar milk let-down and optimum milk withdrawal from the cistern. تفاصيل المقالة

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12 - Productive Performance of Lactating Buffaloes Fed RationContaining Sugar Beet Tops and Corn Silages
H.M.A. Gaafar E.M. Abdel-Raouf M.M. Bendary G.H. Ghanem K.F. El-Reidy

Sixteen multiparous lactating buffaloes after 8 weeks of calving and weighing 500 to 600 kg were used in a complete switch-back design with four groups. Buffaloes in the first group were fed the control ration (R1) consisted of DM basis of 60% concentrate feed mixture ( أکثر

Sixteen multiparous lactating buffaloes after 8 weeks of calving and weighing 500 to 600 kg were used in a complete switch-back design with four groups. Buffaloes in the first group were fed the control ration (R1) consisted of DM basis of 60% concentrate feed mixture (CFM)+20% rice straw (RS)+20% berseem hay (BH), while in the other groups the rations consisted of DM basis of 40% CFM+20% RS+40% sugar beet tops silage (SBTS) and corn silage (CS) in different ratios; 2:1 (R2), 1:1 (R3) and 1:2 (R4), respectively. The digestibility coefficients of DM, OM, CF, EE and NFE, TDN value and the intake of DM and TDN increased significantly (P<0.05) with increasing the level of corn silage, however, CP digestibility, DCP value and CP and DCP intake increased (P<0.05) with increasing level of sugar beet tops silage in the rations. The pH value and NH3-N concentration increased (P<0.05) with increasing level of sugar beet tops silage, however, TVFA's concentration increased (P<0.05) with increasing level of corn silage in the rations. Buffaloes fed R3 recorded the highest (P<0.05) milk and 7% FCM yield, however, those fed R1, had the lowest yield. The percentages of fat, lactose and TS increased (P<0.05) with increasing the level of corn silage, however, the percentages of protein, SNF and ash increased (P<0.05) with increasing the level of sugar beet tops silage in rations. Animals fed R3 showed the lowest amounts of DM and TDN required per kg 7% FCM and R4 the lowest amounts of CP and DCP required per kg 7% FCM, however, those fed R1 revealed the highest amounts (P<0.05). تفاصيل المقالة

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13 - Milk Yield and Composition of Red Sokoto and Weast African Dwarf Does Raised Intensively in a Hot Humid Environment
F.O. Ahamefule O. Odilinye E.N. Nwachukwu

Six Red Sokoto (RS) and West African Dwarf (WAD) does, raised intensively in livestock farm of Michael Okpara University were evaluated for milk yield and composition in a ten-week study. The animals in their first parity were fed cut-and-carry forages in a cafeteria ar أکثر

Six Red Sokoto (RS) and West African Dwarf (WAD) does, raised intensively in livestock farm of Michael Okpara University were evaluated for milk yield and composition in a ten-week study. The animals in their first parity were fed cut-and-carry forages in a cafeteria arrangement between 07:00-08:00 h daily and also were allowed access to concentrate supplementation by 14:00 h. The forage consisted of a sward of Panicum maximum, Centrosema pubescens, Calapogonium mucunoides, Emilia sanchifolis, Tridax procumbens and Urenia lobata while the supplement was a 14.8% CP concentrate ration formulated from wheat, soya bean meal, maize offals, palm kernel cake. Drinking water was provided ad libitum. The does were hand milked daily from 6-8 am prior to feeding and yield determined for each group. Milk samples were bulked per animal per week and analyzed for total solids (TS), butterfat (BF), crude protein (CP), solids-not-fat (SNF) and total ash. Lactose was, however, determined daily from fresh milk samples and data obtained was analyzed using T-test. Results showed that lactose, CP and ash were not influenced (P>0.05) by species; however, butterfat, TS, SNF and milk yield differed significantly (P<0.05) between the small ruminant breeds. RS had relatively higher BF (4.81%) in milk than WAD goat (4.72%), but TS and SNF concentrations (%) were lower in the milk of RS (12.82, 8.22, respectively) than WAD (13.16, 8.59, respectively) goat. Macrominerals content of milk (calcium, potassium, magnesium, sodium and phosphorus) were also affected (P<0.05) by species. Calcium, magnesium and sodium concentrations (%) in milk were significantly higher (P<0.05) for RS (0.15, 0.11, 0.11, respectively) than WAD (0.12, 0.09, 0.09, respectively) goat; phosphorus and potassium levels in milk were, however, higher (P<0.05) in WAD (0.14, 0.11, respectively) than RS (0.13, 0.09, respectively) goat. Lactation performance for WAD and RS goats in the current investigation were relatively low when compared with existing records. Differences in yield and milk composition within and between species in this study, relative to earlier reports, were attributed to genetic make up, management and environmental factors. تفاصيل المقالة

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14 - Effects of Rebreeding Interval on Litter and DoePerformance of Rabbit in Baichi State Nigeria
P.A. Addass A. Midau M.A. Tizhe Z.B. Mshelia Y.M. Muktar H.D. Nyako

Eighteen primiparous rabbit does comprising of six per breed of New Zealand White (NZW), Chinchilla (CC) and Dutch Belted (DB). They were randomly allocated to three rebreeding interval groups of 7, 14 and 21 days postpartum. Three breeding males, one per breed were use أکثر

Eighteen primiparous rabbit does comprising of six per breed of New Zealand White (NZW), Chinchilla (CC) and Dutch Belted (DB). They were randomly allocated to three rebreeding interval groups of 7, 14 and 21 days postpartum. Three breeding males, one per breed were used giving a total of 21 rabbits. Significant (P<0.01) doe milk yield in week two (DMY WK2) was observed on rebreeding interval groups. Twenty one (21) day rebreeding group recorded highest (83.1±4.12 g) followed by seven day rebreeding group (72.4±2.30 g) while fourteen day group had the least (69.2±3.31 g). Doe milk yield variability (P<0.01) was evident on the third week with the 21 day rebreeding group had the highest (89.1±5.67 g) followed by fourteen day rebreeding group (77.4±4.56 g) while 7 day rebreeding group had the least (63.9±3.16 g). Doe milk yield in the fourth week also showed variability due to rebreeding groups. The 21 day rebreed group had the highest (61.1±3.57 g) next by 14 day rebreeding group (57.6±2.87 g) while 7 day group had the least (47.7±1.99 g). Significant doe milk yield week one (P<0.05) and week two (P<0.051) were observed to be affected by parity. In week one, parity 4 had the highest milk yield (79.8±5.03 g) followed by parity 5 (75.9±6.75 g) while parity 1 had the least (51.6±3.42 g). In the second week, milk yield was highest (84.9±8.30 g) in parity 5, followed by parity 4 (76.4±6.19 g) while parity 1 had the least (61.7±5.79 g). It was observed that milk yield of rabbits increase with increase in rebreeding interval as well as with increase in parity. Doe and litter parameters were observed better at increasing rebreeding interval among rabbit breeds. تفاصيل المقالة

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15 - Effect of Dietary Buffers Supplementation on Milk Yield and Composition in Dairy Cows: A Meta-Analysis of Randomized Controlled Trials
M. Hashemi F. Tavakolinasab

Feeding high concentrates to high producing animals usually change the rumen environment and compromises the productivity of ruminants. Different feed additives are used to prevent the occurrence of sub-acute ruminal acidosis, among these additives, buffers are commonly أکثر

Feeding high concentrates to high producing animals usually change the rumen environment and compromises the productivity of ruminants. Different feed additives are used to prevent the occurrence of sub-acute ruminal acidosis, among these additives, buffers are commonly used. The aim of this meta-analysis was to investigate the effects of buffer supplementation on milk yield and composition in dairy cows. PubMed, Scopus, Web of Science and Google Scholar databases were searched from 1969 to 2020. A total of 86, 91, 94, 85, 27 and 34 trials were included to buffer supplementation effects on dry matter intake (DMI), milk yield (MY), fat, crude protein (CP), solid not fat (SNF) and lactose, respectively. The magnitude of the effect (effect size) was assessed using standardized mean differences (SMD) for continuous results, between the buffer supplementation addition and control treatments. The addition of buffer supplementation had no significant effect on DMI (SMD=-0.002, P=0.16), MY (SMD=0.001, P=0.99), CP (SMD=-0.002, P=0.34) and SNF (SMD=0.006, P=0.32), respectively. Milk yield increased in the group receiving the buffer supplementation in comparison with the control group. The percentage of fat (SMD=-0.185, P=0.001) significantly decreased in the control group compared to the group receiving the buffer. The dietary buffers significantly increased the content of lactose (SMD=0.008, P=0.014) in dairy cows’ milk. This meta-analysis indicated that buffer supplementation improved milk yield and composition in dairy cows. تفاصيل المقالة

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16 - Factors Affecting the Dry Period Length and Its Effect on Milk Production and Composition in Subsequent Lactation of Holstein Cows
آی. بوجنانه

The study aimed to determine factors affecting the dry period length and effect of dry days on milk yield, milk composition and lactation length in the next lactation of dairy cows. Data used for analysis included 7264 lactation records collected from 2012 to 2016 on 47 أکثر

The study aimed to determine factors affecting the dry period length and effect of dry days on milk yield, milk composition and lactation length in the next lactation of dairy cows. Data used for analysis included 7264 lactation records collected from 2012 to 2016 on 4737 Holstein cows raised in 152 herds. The statistical model used to determine the factors influencing the dry period length showed that multiparous cows had a dry period 3.7 days longer than primiparous cows, and cows that calved from October to February had a dry period 2.5 days shorter than that of cows calved from March to September. The mixed model used to evaluate the influence of dry period on milk yield, milk composition and lactation length showed that the dry period influenced significantly milk yield and composition in the next 305 d lactation, but not the lactation length (P>0.05). Milk, fat and protein yields in the subsequent lactation were maximized with a 41 to 60-d dry period, whereas dry periods less than 20 d result in very pronounced losses in subsequent lactation yield. Fat and protein percentages were highest with the dry period classes greater than 80-d and less or equal than 20 d, respectively. The interaction between parity and dry length period was not significant (P>0.05) for any studied trait, indicating that dry days effects on milk yield and composition were consistent across lactations. It was concluded that dry period of 40 to 80 dry days does provide maximal performance in Holstein cows. تفاصيل المقالة

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17 - The Effect of Partial Replacing Solvent Soybean Meal with Poultry Blood Meal on Performance and Metabolic Status of Fresh Holstein Dairy Cows
I. Rahnama T. Amirabadi Farahani S. Karimi-Dehkordi

The objective of this study was to investigate the effect of replacing solvent soybean meal (SSBM) with poultryblood meal (PBM) on performance, metabolic status, and apparent digestibility of nutrients in Holstein fresh cows. Twenty-four Holstein cows (body weight (BW)& أکثر

The objective of this study was to investigate the effect of replacing solvent soybean meal (SSBM) with poultryblood meal (PBM) on performance, metabolic status, and apparent digestibility of nutrients in Holstein fresh cows. Twenty-four Holstein cows (body weight (BW)±SD; 669.5±42.59 kg) were blocked by body condition score (BCS) at calving and previous lactation milk yield and randomly assigned to 1 of 3 experimental diets from calving until 21 days in milk (DIM): diet without PBM (0PBM), replacing 2.5% DMSSBM with PBM (2.5PBM), and replacing 5% DMSSBM with PBM (5PBM). There were no significant effects (P>0.10) of treatments on dry matter intake (DMI), milk yield, and milk composition, but cows fed the 2.5PBM diets had significantlyhigher milk urea nitrogen (MUN) levels than cows fed the 0PBM and 5PBM diets (P<0.01). Cows fed the 5PBM diet had significantly higher serum globulin, non-esterified fatty acids (NEFA), and β-hydroxybutyrate (BHB) and lower serum cholesterol concentrations than cows fed the 0PBM and 2.5PBM diets (P<0.05). Blood urea nitrogen (BUN) concentration in cows fed the 2.5PBM diet was significantly(P=0.01) higher than cows fed the 0PBM and 5PBM diets. The apparent digestibility of dry matter in the 5PBM diet was significantly(P=0.03) lower compared to the 0PBM diet. However, there was no significant difference between the 5PBM and 2.5PBM diets. Overall,the lack of significant differences in performance, apparent digestibility of nutrients and serum metabolites between the 0PBM and 2.5PBM shows that the SSBM could replace up to 2.5% of DM with the PBM. However, levels higher than 2.5% of DM are not recommended due to low palatability and negative effects on the metabolic status of cows. تفاصيل المقالة

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18 - Investigating the Setbacks in Conventional Dairy Farms by the Follow-Up of Their Potential and Effective Milk Yields
م.ت. سرایری ی. سانیتو جی.ف. توراند

The present study investigates the gap between the daily milk production potential and the effective milk yields in six herds. These two parameters and their changes were observed in the Gharb irrigation scheme (northwest of Morocco), during a five months study period. أکثر

The present study investigates the gap between the daily milk production potential and the effective milk yields in six herds. These two parameters and their changes were observed in the Gharb irrigation scheme (northwest of Morocco), during a five months study period. They were analyzed in relation to the changes in the rations of the cows and in their live weights. Results reveal that under conventional cattle rearing conditions in Morocco, i.e. the vast majority of smallholder units and farms with an area less than 20ha, dairy production suffers from numerous setbacks. One of the most evident is farmer's lack of knowledge of cows’ dietary requirements and their changes throughout the lactation period. Moreover, dairy farmers seem to ignore the changes in forages net energy, rumen degradable and metabolizable protein contents, which induce many errors in providing concentrate supplements. Results also show that the effective milk yield is often inferior to the lactation potential, given the limited availability of forage coupled to errors in rations formulation. Finally, the results emphasize the need to reconsider the use of high genetic merit cows, because of their rising prices, in farms characterized by erratic fodder availability coupled to the absence of balanced rations formulation. تفاصيل المقالة

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19 - Genetic and Phenotypic Parameters for Milk Production Traits in the First and Second Lactation in Romanian Simmental Dairy Cows
E. Nistor V.A. Bampidis M. Pentea M. Matiuti V. Ciolac F. Adebambo

The aim of the present study was to estimate genetic and phenotypic parameters of milk production traits in the first and second lactations of Romanian Simmental dairy cattle. For the estimation of variance, heritability, genetic and phenotypic correlations among milk y أکثر

The aim of the present study was to estimate genetic and phenotypic parameters of milk production traits in the first and second lactations of Romanian Simmental dairy cattle. For the estimation of variance, heritability, genetic and phenotypic correlations among milk yield, fat yield, protein yield, and percentages of fat and protein, 3400 first and second lactation records over a period of five years (2005-2010) were evaluated. Genetic correlations of the yields of milk, fat, protein, and percentages of fat and protein in the first lactation were situated among the lowest value of -0.28 between milk yield and protein percentage and the highest value of 0.31 between milk and milk protein yield. Phenotypic correlations were situated from the lowest value of -0.02 registered among yields of milk, fat and protein and protein percentage, and the highest value of 0.98 for milk yield and fat percentage. Accordingly, if the selection goal is defined as maximizing the useful yield while maintaining fat and protein content, the selection criterion must include fat yield, protein yield, and protein content. تفاصيل المقالة

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20 - The Impact of Agricultural Credit and Farmer Trainings on Small Holder Dairy Production in Southern Region in Sri Lanka
P.H.G.J. De Silva A.L. Sandika

Potential growth of dairy sector is highest and more reliable compared to crop sector, indicating that dairy sector can play vital role to increase income among farmers in rural areas than crop sector in Sri Lanka. Credit and farmer training in management ability have b أکثر

Potential growth of dairy sector is highest and more reliable compared to crop sector, indicating that dairy sector can play vital role to increase income among farmers in rural areas than crop sector in Sri Lanka. Credit and farmer training in management ability have been major concerns of dairy development efforts. Therefore, this study wasconductedto assess the impact of credit and farmer training on small holder dairy sector and to estimate its contribution to farmer’s income. The study was carried out in southern region of Sri Lanka. Purposive sampling approach was adopted and data were collected from 119 farmers through pre-tested structured questionnaire by personnel interview. Twenty one percents of respondents had taken credit and 72% of farmers had received subsidies to develop their dairy production capacity. Almost 97% of farmers had received knowledge for different activities in dairy production and 45% of them had participated for trainings which related to dairy. The milk yield of studied sample had correlation with credit amount (r=0.500, p=0.018), value of subsidy (r=0.350, p=0.003) and extension and training (r=.453, p=.000) which received by farmers. The farmers with higher level knowledge on management practices were acquiring and demanding of credit and farmer training compared to farmers with low knowledge. Further herd size had strong positive correlation with the amount of credit obtained. The results clearly illustrated credit and farmer training in dairy sector could considerably facilitate to increase income of dairy farmers and assists to develop dairy sector in small holder context. تفاصيل المقالة

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21 - Effect of Two Types of Total Mixed Rations on Production Performances of Holstein Friesian Cows in Early Lactation
B.C. Kalansooriya R.M.A.S. Bandara H.M.G.P. Herath

The milk production of high producing European dairy cattle breeds in tropical environment is not in satisfaction level. In general, cows develop negative energy balance at the early lactation resulting poor production performances. The aim of the study was to assess th أکثر

The milk production of high producing European dairy cattle breeds in tropical environment is not in satisfaction level. In general, cows develop negative energy balance at the early lactation resulting poor production performances. The aim of the study was to assess the effect of total mixed ration feeding systems (TMR) over conventional feeding system to increase the production performances of cows in early lactation. Napier (Pennisetum purpureum) based conventional feeding system (CFS) versus two different types of total mixed rations as TMR1 (with the same ingredients and same quantity in CFS) and TMR2 (16% dry matter of napier in TMR1 was replaced with legume and non-legume) were studied on production performances of 15 Holstein Friesian cows in early lactation (n=5). The highest average daily milk yield was observed in TMR2 fed cows (17.88±3.03 L/d) while the lowest was observed in CFS fed cows (12.23±0.88 L/d, p <0.0001). The percentage of average daily weight gain was differed (P=0.01) among the treatments (CFS=1.53%, TMR1=2.79%, and TMR2=4.32%). The body condition score of the cows fed with TMR1 and TMR2 was increased by 0.1 and 0.25, respectively at the end of the experimental period whereas it was unchanged in the cows fed with CFS. Results revealed that feeding of TMR for Holstein Friesian cows in early lactation is a better way to achieve increased milk production with a better body condition in the tropics. TMR consisted of legume and non-legume fodder was more efficient. تفاصيل المقالة

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22 - Influence of Body Condition Score on Yield and Composition of Milk in Crossbred Dairy Cows
م.ای. حسین تی. چندا جی.کا. دبناث م.م. حسن آ.اچ. شایکات م.آ. هکو

The study was carried out for a period of 150 days on 120 Holstein Friesian crossbred dairy cows between mid to late lactation to quantify the influence of body condition score (BCS) on yield and composition of milk. Total 12 dairy farms having same housing systems and أکثر

The study was carried out for a period of 150 days on 120 Holstein Friesian crossbred dairy cows between mid to late lactation to quantify the influence of body condition score (BCS) on yield and composition of milk. Total 12 dairy farms having same housing systems and holding at least 20 crossbred dairy cows per farm between mid to late lactation were selected for this study purposes. BCS of individual cows was recorded in a 1-5 scale. Milk samples were collected from individual cow. Samples collected from cows having same BCS were mixed together to make composite sample. Chemical analyses of the samples were carried out in triplicate for fat, protein, lactose, ash, total solids (TS) and solids not fat (SNF). Results indicated that, BCS significantly (P<0.05) affected milk yield, milk fat and ash content in crossbred Holstein Friesian dairy cows. Highest milk yield (13.45±1.80 kg/day) was recorded with moderate BCS (3.00) followed by lower (2.75 to 2.25) and higher (3.25 to 4.00). Milk protein, lactose, TS, SNF and specific gravity (SG) increased non significantly (P>0.05) with increasing BCS up to 4.0. Correlation coefficient matrix indicated that BCS was negatively correlated with milk yield. However, there was a positive relationship of BCS with milk protein, lactose, TS, SNF and SG even though the strength of association was variable. تفاصيل المقالة

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23 - An Optimum Regression Model to Estimate Economic Values for Milk Yield, Milk Yield Persistency and Calving Interval in Dairy Cattle
S. Falahpour A.A. Shadparvar N. Ghavi Hossein Zadeh M. Mehdi Zadeh Stalkh Kohi

Emphasis on milk yield (MY) as well as milk yield persistency (MYP) and calving interval (CI) is necessary to achieve more sustainable productionin dairy cattle. Therefore the main objective of this study was to find an optimum regression model to estimate economic valu أکثر

Emphasis on milk yield (MY) as well as milk yield persistency (MYP) and calving interval (CI) is necessary to achieve more sustainable productionin dairy cattle. Therefore the main objective of this study was to find an optimum regression model to estimate economic values for MY, MYP and CI.Using a deterministic bio-economic model, seventyfiveproduction states differing mainly in MY, MYPand CIwere studied.For each production state, the total revenue comprised income from sold milk, calves of one week of age and manure. Feed costs were obtained from energy requirements for maintenance, growth, lactation and pregnancy. Non feed costs included costs of net replacement, health, artificial insemination and some others which were modeled as a function of CI.Multiple regression analyses of annual profits for production state on the means of MY, MYP and CI were used to estimate the economic values. Two different regression models were used. Both models included the linear effect of MY and the quadratic effect of MYP. However, in one model the effect of CI was linear (Model CIL) whilst it wasquadratic in the other (Model CIQ). Under both models, economic value for MY was positive (0.10 $ for model CIL and 0.32 $ for model CIQ) as was expected for the assumed milk pricing system. Economic values for MYP in the models had different signs (-118.2 $ for model CIL and 715.55 $ for model CIQ). Under model CIQ maximum profit was associated with a value of MYP greater than unity and was not consistent with the definition of persistency. Economic value of CI was negative under both models (-2.68 $ for model CIL and -6.36 for model CIQ). In the model CIQ, the profit function had a minimum value for CI (at 803 days) which was not consistent with the previously reported relationship between profit and CI. Estimates of economic values for MY,MYP and CIshowed that the model CIL was superior to the model CIQ due to a lower number of fitted effects and increased consistency with the real situation of dairy systems. تفاصيل المقالة

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24 - Effect of Rumex Sc on Ruminal Fermentation, Blood Metabolites and Performance of Lactating Dairy Cow
R. Khodabakhshi A. Afzalzadeh M. Rezaeian A.A. Khadem M.A. Norouzian

This study investigated the effect of Rumex Sc (commercial product which includes of Saccharomyces cervisiae, saponin and essential oils) on rumen fermentation, blood glucose, urea, milk yield and milk composition. Animals were offered a basal diet containing alfalfa ha أکثر

This study investigated the effect of Rumex Sc (commercial product which includes of Saccharomyces cervisiae, saponin and essential oils) on rumen fermentation, blood glucose, urea, milk yield and milk composition. Animals were offered a basal diet containing alfalfa hay (15.5%), corn silage (24%), beet pulp (7%) and concentrate (53.5%). Additionally, Rumex Sc was included in the experimental diet at a rate of 5 g/day/cow. Sampling of milk, ruminal liquid and blood was conducted for determination of milk composition, fermentation parameters and blood metabolites. Milk yield was significantly increased for the experimental group when compared to the control group (P<0.05), but milk composition was not affected by Rumex Sc. The number of protozoa, ammonia nitrogen concentration and pH in the rumen were decreased in the experimental group (P<0.05). Concentrations of volatile fatty acids in the rumen were affected to some extent by inclusion of Rumex Sc in the diet. Molar proportion of acetate was decreased and propionate was increased with a corresponding decrease in acetate: propionate ratio. In this study, blood glucose was significantly increased and urea decreased with the addition of Rumex Sc (P<0.05). It was concluded that using Rumex Sc can improve the milk yield performance of dairy cows, however further studies are needed. تفاصيل المقالة

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25 - The Effect of Climate Change on Milk Yield in New Zealand: A Case Study of Fonterra
Z. Shaheen Ali Z. Li

Climate change affects milk yield, which may have a profound impact on the dairy industry. Taking Fonterra as an example, this study analyses the climate data of 99 consecutive months from June 2012 to August 2020 and the corresponding monthly milk yield data of North I أکثر

Climate change affects milk yield, which may have a profound impact on the dairy industry. Taking Fonterra as an example, this study analyses the climate data of 99 consecutive months from June 2012 to August 2020 and the corresponding monthly milk yield data of North Island and South Island. The results show that the monthly milk yield correlates with the monthly mean temperature, the monthly extreme maximum temperature, the monthly extreme minimum temperature, the monthly mean relative humidity, and the monthly mean temperature and humidity index (THI). In addition, with the increase of annual mean temperature in New Zealand, the annual milk yield of North Island decreases with the increase of temperature. Fonterra needs to take measures to mitigate the negative impact of climate warming on milk yield. However, in the recent nine years, South Island's annual milk yield increases with annual mean temperature. Furthermore, regression equations with climate factors as independent variables and monthly milk yield as dependent variables are established for North Island and South Island. In North Island, the monthly milk yield changed periodically with time. The findings of the study show that the annual milk yield will decrease with the increase of temperature due to global warming in North Island. However, South Island needs to deal with the negative impact of high temperature on milk yield in summer. Therefore, Fonterra needs to take immediate measures to deal with the negative impact of climate change. تفاصيل المقالة

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26 - Influence of Dietary Energy and Protein Intake on Yield and Composition of Milk in Crossbred Dairy Cows
M.E. Hossain T. Chanda G.K. Debnath M.M. Hassan M.A. Haque

The study was carried out on 120 crossbred Holstein × Shahiwal dairy cows for a period of 150 days to quantify the influence of dietary energy and protein intake on yield and composition of milk. Total 12 dairy farms having similar housing systems and holding at l أکثر

The study was carried out on 120 crossbred Holstein × Shahiwal dairy cows for a period of 150 days to quantify the influence of dietary energy and protein intake on yield and composition of milk. Total 12 dairy farms having similar housing systems and holding at least 20 dairy cows in between mid to late lactation were selected for study purposes. The farms were located in the peri-urban and urban areas of Chittagong, Bangladesh. Milk samples were collected from individual cow. Milk from cows having same body condition scoring (BCS) were mixed together to make a composite sample. Chemical analyses of the samples were carried out in triplicate for fat, protein, lactose, total solids (TS), solids not fat (SNF) and ash. Dietary metabolizable energy (ME) and crude protein (CP) intake were measured by analyzing the amount of total mixed ration ingested by the individual cow. Results indicated that, ME intake (MJ/d) significantly (P<0.01) influenced milk yield, milk fat and TS content of milk in crossbred Holstein Friesian dairy cows. Similar to ME, CP intake (g/d) also influenced (P<0.01) milk yield, fat, protein, lactose, TS and ash content of milk. Correlation coefficient matrix indicated that, milk yield was positively correlated with ME and CP intake. However, there was a negative association between ME or CP intake and milk protein, lactose, TS and SNF of milk even though the strength of association was variable. It could therefore be inferred that, adequate dietary ME and CP intake is important to optimize milk yield and milk composition in crossbred Holstein × Shahiwal dairy cows reared under intensive farming systems in tropical regions. تفاصيل المقالة

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27 - Genetic Analysis of Milk Yield in Iranian Holstein Cattle by the Test Day Model
ی. نادری N. امام جمعه کاشان ر. واعظ ترشیزی م. امین افشار

Using monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood m أکثر

Using monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. The model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) and dam age (linear and quadratic) as fixed effects and random regression coefficients for additive genetic and permanent environmental effects. The average of 305 days milk yield was 9760 (±1324) kilogram. Differences of milk yield among provinces were significant (P<0.05). The average of heritability estimates of milk was 0.50. The genetic correlations between adjacent test-day records were high and decreased with increase in interval between tests. تفاصيل المقالة

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