Effects of total replacement of corn silage with sorghum silage on milk yield,composition, and quality

Background： In the last years, difficulties occurring in corn cultivation（i.e., groundwater shortages, mycotoxin contamination） have been forcing dairy farmers to consider alternative silages. Some experiments conducted on lactating cows have proven that the total replacement of corn silage with sorghum silage did not reduce milk yield.However, this kind of substitution involves supplementing sorghum-based diets with grains, to compensate for the lower starch content of sorghum silage compared to corn silage. Change of silage type and inclusion of starch sources in the diet would influence rumen fermentations, with possible effects on milk composition（i.e., fatty acid profile） and coagulation properties. A worsening of milk coagulation properties would have a negative economic impact in Italy, where most of the milk produced is processed into cheese.This study was designed to compare milk composition and quality, with emphasis on fatty acid profile and coagulation properties, in dairy cows fed two diets based on corn or sorghum silage.Results： The sorghum diet reduced milk yield（P = 0.043） but not 4% fat corrected milk（P = 0.85）. Feeding sorghum silage did not influence milk contents of protein（P = 0.07） and lactose（P = 0.65）, and increased fat content（P = 0.024）.No differences emerged for milk concentrations of saturated（P = 0.61） and monounsaturated fatty acids（P = 0.50）,whereas polyunsaturated fatty acids were lower（P 〈 0.001） for the sorghum diet. Concentrations of n-6（P 〈 0.001） and n-3 fatty acids（P = 0.017） were lower in milk of cows fed the sorghum diet. Milk coagulation properties did not differ between the two diets, except the ＂a30＂（the curd firmness, expressed in mm, 30 min after rennet addition）, that was lower（P = 0.042） for the sorghum diet.Conclusions： Feeding a forage sorghum silage, properly supplemented with corn meal, as total replacement of corn silage maintained milk composition and did not influence negatively milk coagulation properties, which have a great economic relevance for the Italian dairy industry. Thus, silages obtained from forage sorghums could have a potential as substitute of corn silages in dairy cow diets.

Relationship of Somatic Cell Count with Milk Yield and Composition in Chinese Holstein Population

The objective of this study was to analyze the relationship of somatic cell count （SCC） with milk yield, fat and protein percentage, fat and protein yield using analysis of variance and correlation analysis in Chinese Holstein population. The 10 524 test-day records of 568 Chinese Holstein Cattle were obtained from 2 commercial herds in Xi＇an region of China during February 2002 to March 2009. Milk yield, fat percentage, fat and protein yield initially increased and then dropped down with parity, whereas protein percentage decreased and SCC increased. Analysis of variance showed highly significant effects of different subclasses SCC on milk yield and composition （P〈 0.01）. Compared with milk yield with SCC ≤ 200 000 cells mL-1, milk yield losses with SCC of 200 000-500 000 cells mL-1, 501000-1 000 000 cells mL-1, ≥ 1 000 000 cells mL-1 were 0.387, 0.961 and 2.351 kg, respectively. The highly significant negative correlation coefficient between somatic cell score （SCS） and milk and protein yield, milk yield and fat and protein percentage, protein percentage and fat yield were -0.084, -0.037, -0.061, -0.168, and -0.088, respectively （P〈 0.01）. The highly significant positive correlation coefficients between SCS and fat yield and fat and protein percentage, milk yield and fat and protein yield, fat percentage and protein percentage and fat yield, protein yield and protein percentage and fat yield were 0.041, 0.177, 0.105, 0.771, 0.865, 0.122, 0.568, 0.318, and 0.695, respectively （P〈 0.01）. There was no significant relationship between fat percentage and protein yield （P 〉 0.05）. The results of the present study first time provide the relevant base-line data for assessing milk production at Xi＇an region of China.

The Effects of Graded Abomasal Glucose Infusion on Milk Yield and Composition in Lactating Goats

Four non-pregnant multiparous lactating goats were used in a 4 × 4 latin square experiment in the present study. The four treatments were abomasal infusion of 0, 50, 100, and 150 g d^-1 glucose. The results showed that graded glucose infusion increased milk yield （P 〈 0.01）. The highest milk yield was observed when 50 g d^-1 glucose was infused. An infusion of glucose at 100 or 150 g d^-1 failed to increase milk yield further and milk yield of the 100 g d ^-1 glucose infusion treatment was even significantly lower than that of the 50 g d^-1 treatment （P 〈 0.01）. Though milk fat content was gradually decreased by graded glucose infusions and milk fat yield of the 100 and 150 g d 1 treatments were lower than that of the control （P 〈 0.01）; milk fat yield of the 50 g d i treatment was not depressed and was higher than that of the control （P 〈 0.01）. Graded glucose infusion did not change the contents of milk protein and non-fatty solids. Yields of milk protein （P 〈 0.05）, lactose （P 〈 0.01）, non-fat solids （P 〈 0.01）, and lactose content （P 〈 0.01） of the 50 g d^-1 treatment were higher than those of the control but had no difference among the other three treatments. Contents of those de novo synthesized fatty acids in milk fat remained unchanged or increased and those preformed fatty acids remained unchanged or decreased by graded glucose infusion. Glucose infusion decreased the total yields of C16 ＋ C16：1 and 〉 C16 fatty acids and had no influence on the yield of C4-C14：1 fatty acids （P 〈 0.05）. Results of the present study implied that increased glucose supply had positive effects on the production of milk, milk protein, milk fat, and lactose only when glucose was a limiting factor for milk synthesis. Excessive glucose supply had no further beneficial effects and might depress milk fat synthesis.

The Effect of Organo-Mineral Fertilizer Applications on the Yield of Winter Wheat, Spring Barley, Forage Maize and Grass Cut for Silage

Biosolids were applied with urea to produce a granulated organo-mineral fertiliser (OMF) for application by farm fertiliser equipment to a range of agricultural crops. The recommended rates of nitrogen, phosphate and potash were calculated for the test crops using “The Fertiliser Manual”, which assesses the nutrient requirement based on previous cropping, rainfall and soil index. The OMF produced similar crop yields compared to ammonium nitrate fertiliser when applied as a top-dressing to winter wheat, forage maize and grass cut for silage in the cropping years 2010 to 2014. In 2012 the grain yield of spring barley top-dressed with OMF was significantly lower than the conventional fertiliser treatment, due to dry conditions following application. For this reason it is recommended that OMF is incorporated into the seedbed for spring sown crops and The Safe Sludge Matrix guidelines followed. The experimental work presented shows that OMF can be used in sustainable crop production systems as a source of nitrogen and phosphorus for a range of agricultural crops.

Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations

Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate （2 mg kg-1 of body weight （BW） d-1, on day 1 to 14）, progesterone （0.10 mg kg-1 of BW, on day 1 to 7）, lfumethasone （0.03 mg kg-1 of BW, on day 18 to 20） and recombinant bovine somatotropin （rbST;500 mg per cow, on day 1, 6, 16 and 21）. At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artiifcially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk （DIM） did not differ between the ifrst and second induced lactations （（9 710 ＆#177;1 728） vs. （9 309＆#177;2 150） kg;mean＆#177;SD）. Total milk yield （（12 707＆#177;3 406） vs. （12 306＆#177;4 218） kg;mean＆#177;SD） and lactation length （（405＆#177;100） vs. （410＆#177;91） d;mean＆#177;SD） were not different between the ifrst and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon （n=334）, 18-mon （n=164） and 29-mon （n=22） lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl （Y=ab1/xxc）, Wood （Y=axb exp（cx）） and Dhanoa （Y=ax（bc）exp（cx）） models were equally suitable to describe 12-mon lactations. An exponential model with ifve parameters （Y=exp（a＋bx＋cd2＋e/x）） showed the best ift for milk yield for 18-mon lactations. The rational model （Y=a＋bx/1＋cx＋dx2） was found to produce the closest ift for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the ifrst cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artiifcial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for iftting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation.

Effects of Rumen Protected Methionine on Milk Yield and Milk Composition in Earlier Lactating Cow

A total of 12 mature healthy Holstein dairy cows of the nearly body weight （580±30） kg, milk yield （22.5±2.8） kg in the early stages of lactation were selected in this experiment. The cows were randomly divided into 2 groups, every group had 6 cows, every group had 6 repeats, and every repeat had 1 cow. Added 20 g protected methionine in earlier lactating cow food every day. The results showed that protected methionine increased milk yield by 10.83%, testing group milk yield was significantly different than that of control （P〈0.05）; protected methionine increased milk fat by 5.98%, testing group milk fat was significantly different than that of control （P〈0.05）; Milk protein increased by 2.15%, but bad insignificantly different （P〉0.05）; dry matter of milk had the tendency of decrease, but had insignificant difference （P〉0.05）.

Study on the Milk Yield Pattern of Maiwa Yak

The change in lactation of Maiwa yak was studied based on the data of locating Maiwa yak in warm seasons during 2003- 2009. The results showed that the milk yield was increasing gradually during days 30- 70 after calving,reached the peak at days 70- 110,and decreased gradually to no milking whenafter. The milk yield of Maiwa yak was greatly influenced by lactation age rather than the yearly effect.

Effects of Chinese Herb Additive on Milk Yield and Anti-heat Stress Ability of Holstein Cows

[Objective] To explore the effects of Chinese herb additive on milk yield and anti-heat stress ability of Holstein diary cow. [Method] A total of 36 Holstein cows at same parity and with similar milk yield were randomly divided into three groups, namely, control group, Chinese medi- cine group I and Chinese medicine group I1. The cows in the Chinese medicine group I were fed basal diet containing 4% compound Chinese herb additive; those in the Chinese medicine group II were fed basal diet containing 3% compound Chinese herb additive; and those in the control group were fed common basal diet. All cows in the three groups were analyzed comparatively. [Result] Supplementing some compound Chinese herb ad- ditive into basal diet increased milk yield and anti-heat stress ability of Holstein cows, besides, it also decreased cow diseases like cow mastitis. The Chinese medicine group I generated the highest economic benefit of practical production. [ Conclusion] Supplementing Chinese herb additive in- to basal diet is an effective way to relieve heat stress and increase milk yield.

Comparative Study on Biomass Yield,Morphology,Silage Quality of Hybrid Napier and Pakchong and Their Utilization in Bull Calves

This work was conducted to compare the potentiality between BLRI Napier-3(BN-3)and Pakchong(PK)fodders.In a completely randomized design(CRD)layout,10 plots(5 m′5 m each)were prepared and stem cuttings were transplanted.Fodder plants were harvested at 70,80 and 90 days after plantation(DAP)followed by making silage.Ten Red Chittagong Cattle(RCC)growing bull calves were selected and equally divided into two treatment groups fed only silages for nutrient utilization and growth evaluation.The highest biomass yield(69.3 ton/ha)and plant height(104.6 cm)were observed in PK at 90 DAP.The highest leaf weight(498.6 g/plant)and leaf to stem ratio(LSR)(1.53)were observed in BN-3 at 70 DAP,which was decreased gradually in progressing maturity.Conversely,stem weight was increased with progressing maturity.Dry matter(DM)(24.71%),total ash(8.35%)and acid detergent fiber(ADF)(61.89%)in PK silage were significantly higher.On the other hand,crude protein(CP)(9.86%),organic matter(OM)(91.65%)and neutral detergent fiber(NDF)(88.06%)in PK silage did not differ with BN-3 silage.Dry matter intake(DMI)and crude protein intake(CPI)from PK silage(2.25 kg/day/animal and 0.22 kg/day/animal)were significantly higher.Digestibility of DM(55.07%),CP(62.35%),OM(57.85%),total ash(30.89%),ADF(73.02%)and NDF(78.19%)for PK silage were significantly higher.N-intake(35.57 g/d)from PK silage was significantly higher,although,N-retention did not differ significantly.There were no significant differences in weight gain of calves fed PK(117 g/d)and BN-3(68 g/d).It can be concluded that PK silage is comparatively better than BN-3 in respect to biomass yield,digestibility and nutrient utilization in growing bull calves.

Carcass Traits, Meat Yield and Primal Meat Cuts from Arsi, Harar, Ogaden and F1 Jersey*Horro Crossbred Bulls Fed Corn Silage Based Similar Finishing Diet

This study was conducted with the objective to determine carcass traits, meat yield, and primal meat cuts of Arsi, Harar, Jersey*Horro crossbred, and Ogaden cattle breeds at Haramaya University, Ethiopia. A total of 12 bulls of four cattle breeds (3 Arsi, 3 Harar, 3 F1 Jersey*Horro crossbred and 3 Ogaden) with almost similar ages were randomly assigned to four treatments in a completely randomised design (CRD). Data on carcass traits, meat yield, and primal meat cuts were analyzed using the General Linear Model (GLM) of the Statistical Analysis Software (SAS) 9.4 version. The overall averages of live body weight, hot carcass weight, chilled carcass weight, dressing percentages based on hot carcass weight, and rib eye area of experimental cattle breeds were 215.58 kg, 102.93 kg, 99.56 kg, 47.61%, and 8.13 inch2, respectively. The hot carcass weight and chilled carcass weight of the Ogaden (136.57;133.30 kg, resp.) breed were higher (p < 0.01) compared to other experimental cattle breeds. Dressing percentages based on hot carcass weight were higher (p < 0.05) for the Ogaden (49.61%) and Arsi (49.82%) cattle breeds compared to Harar and Jersey*Horro crossbred (45.73%, 45.27%, resp.) cattle breeds. The average meat yield and proportion of meat yield of cattle breeds were 77.52 kg and 77.46%, respectively. With a linear regression coefficient of prediction (R2) ranging from 52.26% to 93.58%, primal meat cuts significantly (p dicted meat yield. In conclusion, the breed of cattle had a significant (p 0.05) influence on live body weight, hot and chilled carcass weight, dressing percentage, rib eye area, subcutaneous fat thickness, meat yield, and the weights of most primal meat cuts. The Ogaden cattle breed had a higher and better meat yield, carcass traits, and most primal meat cuts compared to other experimental cattle breeds. Furthermore, the inclusion of corn silage in the diet of fattening bulls improved the carcass and meat yield. Therefore, the performance of Ogaden cattle compared to other and previous studies suggests the possibility of using this breed for export purposes in addition to Borana and Harar cattle breeds in the future.

Effect of Pennisetum purpureum Schum cv. Guiminyin on Milk Yield and Quality of Jersey Cattle at Lactation Stage

The study aimed to research the forage value of Pennisetum purpureum Schum cv.Guiminyin in dairy industry and then provide scientific support for feeding jersey cattle with P.purpureum Schum cv.Guiminyin.Totally 20 jersey cattle at lactation stage were selected and divided into two groups randomly,10 cattle each group.The cattle were fed with P.purpureum Schum cv.Guiminyin and P.purpureum cv.Mott×（P.americanum×P.purureum）cv.Guimu No.1,respectively.The results showed that P.purpureum Schum cv.Guiminyin performed well in both nutritional value and palatability,and received remarkable effects on jersey cattle.The milk yield was 5.4%higher than that of before test,and the average daily milk yield was（11.65±0.07）kg/cattle.Compared with control group,milk fat percentage,lactoprotein content and overall milk-solid content were improved somewhat.Feeding jersey cattle with P.purpureum Schum cv.Guiminyin at lactation stage could increase their milk yield and milk quality.

A Study on the Correlation of Milk Yield of Cows with Seismicity and ULF Magnetic Field Variations

A statistical study on the basis of one-year data of 2014 has been performed in order to find whether abnormal animal behavior is related with seismic activity and also whether the ULF (Ultra Low Frequency) electromagnetic radiation might be a possible sensory mechanism of abnormal animal behavior. Abnormal animal behavior has been studied with the use of digitally recorded milk yield of cows at Ibaraki Prefecture Livestock Station, and the ULF magnetic field changes have been studied with the data at a magnetic observatory of Kakioka. As the result of correlation analyses, clear responses are observed for both the milk yield of cows and ULF magnetic field changes (both ULF radiation (ULF emissions from the lithosphere) and ULF depression (as an indicator of lower ionospheric perturbations)) for most powerful and not distant earthquakes (EQs) with magnitude > 6, that is, the milk yield of cows is found to exhibit a conspicuous depletion about 17 - 18 days before an EQ, though the correlation coefficient is not so big. Another important objective in this paper is to identify that ULF radiation is the main agent of abnormal behavior so that we have compared the temporal evolutions of milk yield of cows, ULF radiation and ULF depression for three major EQs. As a result, it is found that ULF radiation happens, at least, during the periods of abnormal depletion of milk yield of cows.

Effect of Bospro on High and Mid-to-Low Milk Yielding Chinese-Holstein Cow

A total of 90 cows from two farms (farm A 30 cows, farm B 60 cows) were used to study the effect of Bospro on milk production, milk quality and subclinical mastitis incidence. The cows in the test group were supplied with 20 g of Bospro per head per day and meanwhile, the percentage of milk fat, protein and lactose and moisture of the milk samples were analysed. The results showed that the milk yield of both high production and mid-to-low milk producting cows increased by 3.3% to 5.3% respectively compared with their control group of cows, but there was no changes on the milk content between the treated and the control cows. The treated cows also showed an increased body weight (P>0.05) and significantly reduced incidence of mastitis, as Compared with that of the control group.The experiment dcmonstrats that Bospro can increase milk yield, but not at the expense of milk quality and body weight.

An Essential Oil Blend Decreases Methane Emissions and Increases Milk Yield in Dairy Cows

This study was conducted to investigate the effect of a commercial essential oil (EO) additive on milk production and methane (CH4) emissions from dairy cows. Early lactation Holstein-Friesian dairy cows were fed grass, whole crop wheat and corn silage total mixed ration. Cows were allocated to one of two experimental treatments: Control (no additive, CON) or 1 g/head/day of EO. Cows were housed in a free stall barn, split into two pens for the duration of the experiment. Two gas data loggers units used to measure CH4 emissions were provided per pen for the duration of the 22 week-long study. Milk yield was determined daily, and milk components were analyzed every two weeks. CH4 was recorded continuously, and daily values were tabulated. Body weight and body condition score were determined at the start and bi-weekly. Results were analyzed as a randomized complete block trial. In total, 149 cows participated in the study (76 CON, 73 EO). Milk yields were greater (P < 0.05) for the test treatment (28.3 CON, 31.2 EO) with no change in milk component concentrations. Milk component concentrations were unaffected (P > 0.05) by treatment. Yields of fat, protein, lactose, and solids were higher for EO fed cows (P 4 output was reduced with the EO compared to the CON treatment (411 g/day vs 438 g/day;13.8 g/L of milk vs 17.2 g/L of milk, P < 0.05) over the duration of the trial. There were no effects of treatment on reproductive performance or the occurrence of mastitis. Feeding EO to dairy cows reduced CH4 emissions whilst also increasing performance.

Milk Yield and Composition and Pasture Ruminal Digestion in Grazing Dairy Cows Receiving Three Levels of Energy Concentrate Supplementation

The objective of the experiment was to determine the effect of feeding three levels (T3.5, T7.0 and T10.5) of energy concentrate (3.5, 7.0 and 10.5 kg cow-1 day-1) on total dry matter (DM) and energy intakes, milk yield and composition, nutritional value of milk and rumen pasture neutral detergent fiber (NDF) digestion in grazing dairy cows. Twenty-one multiparous Holstein cows in early lactation (70.2 ± 13 days postpartum) producing 37.1 (±4.7) kg of milk were assigned to a 3 treatments (7 cows/treatment) × 3 periods Latin square design. Parameters of ruminal environment and pasture NDF degradation were obtained using 3 additional cows of the same breed fitted with rumen cannulae. On a wet basis, concentrate was composed by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral nucleus with monensin. Pasture (Medicago sativa, sp) was used in a rotational grazing system with an herbage allowance of 30 kg DM cow-1 d-1. Yield (kg cow-1 d-1) of fat corrected milk (4% FCM) resulted higher (p < 0.05) in T7.0 (29.0) compared to T3.5 (26.8) but similar to T10.5 (30.2). Milk and protein yields were linearly increased (p < 0.01) by concentrate intake. Milk fat (3.13 g/100g) and total solid contents (11.79 g/100g) did not differ whereas milk protein (p < 0.03) and casein (p < 0.01) levels (g/100g) increased linearly from 3.05 to 3.10 (protein) and from 2.42 to 2.47 (casein). Pasture intake decreased but total DM and energy consumption were enhanced showing addition effects after concentrate feeding. Body weight (BW) loss and plasmatic levels of non esterified fatty acids (NEFA) decreased with concentrate intake. Circulating levels of insulin-like growth factor-I (IGF-I) were higher (p < 0.05) in T10.5 while those of glucose, plasma urea nitrogen, insulin and somatotrophin were not affected. Ruminal pH and acetate concentration resulted lower (p < 0.05) in T10.5 when compared to T3.5. The acetate:propionate ratio decreased (p < 0.01) from 4.25 in T3.5 to 3.08 in T10.5 and ruminal ammonia nitrogen levels tended (p < 0.07) to be lower as concentrate intake increased. Kinetics parameters of NDF degradation remained unchanged. The potential hypercholesterolemic fatty acids (FA) of milk (C12:0 to C16:0.) remained unchanged as concentrate intake increased. Milk content of linolenic acid decreased and the n-6:n-3 ratio increased with concentrate intake from 1.56 (T3.5) to 2.57 (T10.5) remaining below the recommended values for human health (<4:1). Milk content of antioxidant vitamins was not significantly altered even when pasture DM intake fall in T10.5 compared to T3.5. Increased consumption of a starch-rich concentrate up to 40% of DM intake of cows showed additive effects on total DM and energy intakes improving milk yield, milk protein and casein contents without negative effects on milk fat concentration or yield. Pasture fiber digestion and nutritional parameters linked to healthy value of milk fat were not affected.

Use of Random Regression Test-Day Model to Estimate Genetic Parameters of Milk Yield in Holstein Cows

(Co) variance components and genetic parameters were estimated for milk yield of Iranian Holstein cows. A total number of 68,945 milk test-day records of first, second and third lactations of 8515 animals from 100 sires and 7743 dams originated from 34 herds collected during 2007 to 2009 by Iranian animal breeding center were used. The ASReml computer program was used to analyze the milk test-day records using the random regression procedure. Herd test date (HTD), milking times per day (milking frequency), number of lactations, year of birth, year of calving, age of animal at calving and days in milk (DIM) considered as fixed effects and additive genetic effects and animal permanent environmental effects were considered as the random effects. Additive genetic variance, animal permanent environment variance, residual variance, phenotypic variance, heritability and repeatability were estimated during different months of lactation between 5.7 - 19.6, 15.3 - 27.1, 31.4 - 17.2, 45.8 - 64.83, 0.1 - 0.32 and 0.4 - 0.6, respectively. Genetic correlation and phenotypic correlation were also estimated between months of lactation in range of -0.35 - 0.98 and 0.03 - 0.67, respectively. Genetic correlation and phenotypic correlation both showed the same changing pattern and they decreased as the interval between months of lactation increased.

Bayesian genetic analysis of milk yield in Tunisian Holstein dairy cattle population

The genetic determinism of 305-d milk yield and its genetic parameters were investigated in Tunisian Holstein dairy cattle population through Bayesian segregation analyses using a Monte Carlo Markov Chains (MCMC) method. Data included 49,709 records of 305-d milk yield collected between 1996 and 2003 from 114 dairy herds. The postulated major gene was assumed to be additive biallelic locus with Mendelian transmission probabilities and priors used for variance components were uniform. Gibbs sampling was used to generate a chain of 500,000 samples, which were used to obtain posterior means of genetic parameters. Estimated marginal posterior means ± posterior standard deviations of variance components of milk yield were 402866.28 ± 23629.97, 271256.66 ± 34477.83, 68276.83 ± 233027.62 and 1098855.75 ± 10009.52 for polygenic variance (σ2u), permanent environmental variance (σ2ne), major gene variance (σ2G) and error variance (σ2e), respectively. The main finding of this paper showed the postulated major locus was not significant, since the 95% highest posterior density regions (HPDs95%) of most major gene parameters included 0, and particularly for the major gene variance. Estimated transmission probabilities for the 95% highest posterior density regions (HPDs95%) were overlapped. Genetic parameters of 305-d milk yield were very similar under both mixed inheritance and polygenic models. These results indicated that the genetic determinism of milk yield in Tunisian Holstein dairy cattle population is purely polygenic. Based on 50,000 Gibbs samples, heritability and repeatability estimates using polygenic model were h2 = 0.22 ± 0.012 and r = 0.38 ± 0.006, respectively.

Dry Season Feeding Technologies: Assessing the Nutritional and Economic Benefits of Feeding Hay and Silage to Dairy Cattle in South-Western Uganda

South-western Uganda annually experiences prolonged drought that results in dramatic drop in milk production of dairy cattle. This study was conducted to assess the nutritional value and economic benefits of feeding silage and hay to dairy cattle in the sub-region. The cross-sectional study covered seven districts with 105 farmers interviewed during the wet and 45 others in the dry season. Up to 88 soil samples were collected and analyzed for soil texture, soil pH, organic matter and total Nitrogen, Phosphorus, Potassium, Calcium, Sodium and Magnesium. Likewise, 148 forage (105 fresh, 25 silage and 18 hay) tissues from 21 pasture species were collected and analyzed for nutritional values. Using a questionnaire, data on production costs and milk revenues were collected for cost-benefit analysis. Results showed that silage of Napier grass treated with molasses (10.2 MJ/kg) and hay of naturally established pastures (10.6 MJ/kg) had the highest metabolisable energy (ME) values, while the lowest (8.30 MJ/kg) was for star grass. Hay of star grass presented the highest level of crude protein (21.4%) with maize (corn) showing the lowest (9.38%). Digestibility of hay of naturally established mixed pastures was the highest (64.4%), followed by that of silage of Napier grass treated with molasses (62.0%), while star grass hay had the lowest (52.6%). With exception of silage made from maize, all the other six forms of silage had a good crude protein (CP) content. Regardless of the good CP content (≥9.9%), all silage untreated with additives was poor in quality since its ME was less than 9.9 MJ ME/kg and ration digestibility less than 67%. Nonetheless, feeding of silage and hay increased milk yield and farm productivity with a benefit-cost ratio of 5.5 and 2.7 for silage and hay respectively.

Yield and quality properties of silage maize and their influencing factors in China

Silage maize(Zea mays L.) is one of the most important forages in the world, and its yield and quality properties are critical parameters for livestock production and assessment of forage values. However, relationships between its yield and quality properties and the controlling factors are not well documented. In this study, we collected 5,663 observations from 196 publications across the country to identify the relationships between yield and quality properties of silage maize and to assess the impact of management practices and climatic factors on its yield and quality in China. The average dry matter yield of silage maize was(19.98±6.93) Mg ha^(-1), and the average value of crude protein, ether extract, crude ash, crude fiber, acid detergent fiber, neutral detergent fiber, nitrogen-free extract, and relative feed value was 7.86%±1.71%, 2.53%±1.01%, 5.05%±1.66%,23.97%±6.34%, 27.62%±7.12%, 51.60%±9.85%, 59.68%±7.72%, and 131.17±31.49, respectively. In general, its nutritive value decreased as its yield increased. Increasing planting density could increase the yield but inhibit the nutritive values, while increasing fertilization could benefit the nutritive values. Geographically, the yield increased and the nutritive value decreased from warm(south) to cold(north) regions. The length of growth duration was a major controlling factor for the patterns of these properties. Our findings provide insights for police-makers to make strategy for achieving high yield and good quality of silage maize and help local people to implement better management practices.