Organic additives used in beef cattle feedlot: Effects on metabolic parameters and animal performance

Organic additives are recently being used in animal diets owing to their ability to control metabolic issues and result in better animal performance. Specifically, the organic additive Fator P^® presents an additional advantage that is to cause a lesser greenhouse gas emission. This study evaluated whether Fator P^® intake changes ruminal parameters or animal performance of beef cattle. Evaluations were carried out in a feedlot experiment divided into growing (46 days; two diets [control mix—CM and standard mix—SM] and finishing (lasted 83 days; four diets: CM, SM, Fator P^® + virginiamycin, and Fator P^® alone [FP]) trials. Animal performance study involved 48 animals allocated to 12 collective pens in completely randomized experimental design. Ruminal parameters were evaluated in separate metabolism study developed carried out using individual pen with four steers. During growing trial, FP diet resulted in higher (p < 0.05) dry matter intake (DMI) and ruminating time. In the finishing trial, diets containing Fator P^® resulted in higher DMI than obtained with CM. Most of the ruminal parameters did not differ (p > 0.05) among dietary treatments. Therefore, Fator P^® represents a viable and safe strategy for supplementation to beef cattle finished using high‐concentrate diet in feedlot systems.     

Effects of a dietary complex of humic and fulvic acids (FeedMAX 15) on the health and production of feedlot cattle destined for the Australian domestic market

OBJECTIVE: To examine the effects of a dietary humic and fulvic acid complex, FeedMAX 15, on the health, growth rate, feed conversion ratio, and carcase characteristics of feedlot cattle. DESIGN: Cattle, in eight pens of 125 animals each, were fed either a diet containing a humic and fulvic acid complex (FeedMAX 15, FeedMAX Industries, Toowoomba, Queensland) or the same diet without the additive. Control or FeedMAX 15 diets were allocated to each pen at random. Individual cattle were allocated alternately to control or treatment pens based on order of presentation. Comparisons of disease incidence, mortality, feed intake, growth rate, feed conversion ratio, fat depth, dressing percentage, meat colour, fat colour and marbling were made at the conclusion of the feeding period. RESULTS: No differences were found between cattle fed FeedMAX 15 and cattle not fed the additive in entry body weight (P = 0.99), exit body weight (P = 0.91), dressing percentage (P = 0.66), P8 fat depth (P = 0.57), meat colour (P = 0.67), marbling (P = 0.70), all diseases (P = 0.64), bovine respiratory disease (P = 0.91), or mortalities (P = 1.0). Cattle fed FeedMAX 15 reached the market specifications for body weight and fat depth in fewer mean days (P = 0.0001), had a greater average daily gain (P = 0.05), a lower feed conversion ratio (P = 0.05) and whiter fat (P < 0.0001). CONCLUSIONS: Feeding the humic and fulvic acid complex, FeedMAX 15, at 0.055 g per kg body weight per day, can increase growth rate and feed conversion efficiency in feedlot cattle.     

Rumen fermentation and liveweight gain in beef cattle treated with monensin and grazing lush forage

Objective To determine the prevalence of subacute rumen acidosis (SARA) in beef cattle grazing lush pasture and the effect of monensin on reducing SARA and improving animal performance. Design Commercial Angus and Murray Grey steers received a monensin slow‐release capsule (n = 19) or remained untreated (n = 19). Cattle grazed an oats crop or tetraploid ryegrass pasture for a total of 91 days. Rumen fluid pH, volatile fatty acids (VFA) and lactic acid concentrations and body weight data were collected prior to treatment and again 28, 56 and 91 days after treatment. Changes in measures over time were analysed using mixed model repeated measures analysis. Differences in average daily gain between treatment groups were determined. Results The prevalence of SARA was low during the study, with only one animal satisfying criteria for SARA at one time point. Cattle treated with monensin capsules were 11.9 kg heavier at the completion of the study compared with untreated controls (414.5 ± 3.88 kg vs 402.6 ± 4.03 kg, P = 0.04). Rumen VFA and L‐ and D‐lactate levels did not differ between cattle treated with monensin and untreated cattle. However, the ratio of propionate to acetate plus two times butyrate was higher (P < 0.001) when cattle were treated with monensin. Conclusions Subacute rumen acidosis was not consistently detected under the conditions of the study. The higher body weight of cattle treated with monensin may have been due to improved energy utilisation of the pasture, indicated by increased propionate proportions in the rumen, rather than prevention of SARA.     

The uptake of fenbendazole by cattle and buffalo following long-term low-level administration in urea-molasses blocks

Fenbendazole (Panacur bolus, Hoechst India Ltd) was incorporated at a rate of 0.5 g/kg into urea-molasses blocks made by two different processes. The concentration of the drug in blocks and its bioavailability were measured using plasma oxfendazole as marker. The recovery of the drug in blocks made by a warm process was 68% and the plasma oxfendazole concentration remained fairly stable at 0.2 and 0.12 µg/ml from day 6 of feeding in cattle and buffalo, respectively. The drug seemed to be inactivated in blocks made by a hot process, with reduced bioavailability. A low and sustained plasma concentration of the active metabolite of the drug could be maintained by self-medication using urea-molasses blocks as fenbendazole carrier.Abbreviations FBZ fenbendazole - HPLC high-performance liquid chromatography - MUMB medicated urea-molasses blocks - OFZ oxfendazole - UMB urea-molasses block     

Effects of injectable vitamins A, D, E and C on the health and growth rate of feedlot cattle destined for the Australian domestic market

OBJECTIVE: To examine the effects of injectable vitamins A, D and E at feedlot entry on health and growth rate and the effects of injectable vitamin C at the time of treatment for bovine respiratory disease (BRD) on cattle health. DESIGN: Systematic allocation of 2465 cattle at feedlot entry to: a commercial vitamin A, D and E preparation at the label dose rate; commercial vitamin A, D and E at twice the label dose rate; a formulation with no vitamin D, a lower concentration of vitamin A and a higher concentration of vitamin E; and the oil-based carrier alone at volumes corresponding to the above treatments. Comparisons of growth rate, disease and mortality were made between the groups at the conclusion of the feeding period. In a separate experiment, 176 cattle were alternately administered injectable vitamin C at the time of treatment for BRD, or were not injected with vitamin C, and mortality was compared between the groups. RESULTS: There were no differences between cattle administered vitamin A, D and E at feedlot entry and the controls in growth rate (P=0.11), all diseases (P=0.99), BRD (P=0.60) or mortalities (P=0.95). Cattle treated with the higher vitamin E and lower vitamin A preparation had a higher (P=0.02) incidence of anorexia than the other groups. Fewer cattle treated with 5 g of vitamin C by intramuscular injection at the time of treatment with antibiotics for BRD subsequently died (P=0.04). CONCLUSIONS: The routine injection of cattle with vitamins A, D and E at feedlot entry is unlikely to result in improvements in health and growth rate where cattle are provided with these vitamins in their diets at concentrations equal to the National Research Council recommendations. Mortality rate in cattle diagnosed with BRD may be reduced by intramuscular injection of vitamin C at the time of treatment with antibiotics.     

Promoting the use of home-mixed supplements as alternatives to commercial supplements in smallholder beef production systems in the subhumid region of Zimbabwe

The economic and performance effect of supplementing smallholder cattle by substituting commercial feed with iso-nitrogenous and iso-energetic diets based on alternative protein sources was investigated in two trials. In trial 1, three diets (commercial concentrate, commercial concentrate partially substituted with mucuna, and commercial concentrate partially substituted with lablab–cowpea) compared with veld grass were allocated to 12 cattle in a complete randomised block design. In trial 2, a double complete randomised block design with 40 cattle assigned to four forage legume-based diets, a poultry-based diet and a commercial beef concentrate was carried out. Diets were offered at 1.5% of body weight daily over 56 d. Average daily weight gain (ADWG) was measured weekly in trial 1 and fortnightly in trial 2. In trial 1, ADWG was significantly (p < 0.05) higher for animals on supplements compared with non-supplemented cattle. In trial 2, ADWG was significantly highest on the groundnut stover-based diet and least on the poultry litter diet. Supplementation had a positive effect on ADWG and economic performance of smallholder beef cattle. Substitution of commercial concentrates with alternative protein sources reduced diet costs and significantly improved gross margins.     

Effect of long-term feeding of graded levels of deoxynivalenol (DON) on growth performance,nutrient utilization,and organ health in finishing pigs and DON content in biological samples

The prevalence of deoxynivalenol (DON) is a concern for swine producers, and although there has been extensive research into the effects of DON in pigs, focus has been in young pigs and/or in short-term studies. The objective of the study was to determine the effect of long-term exposure to DON-contaminated diets in finisher pigs. A total of 200 pigs (76.6 ± 3.9 kg initial weight) were group housed (five pigs per pen; n = 10 pens/treatment) in a 6-wk trial. Pigs were fed a wheat-barley-soybean meal-based control (CONT) diet with no DON or the basal diet in which clean wheat was replaced by DON-contaminated wheat and wheat screenings to provide DON content of 1, 3, or 5 ppm (DON1, DON3, and DON5, respectively). Individual BW and pen feed intake were recorded weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Blood was collected on days 0, 14, and 43 and analyzed for indicators of liver and kidney health. Nitrogen (N)-balance was conducted immediately following the growth performance period to determine the effect of DON on nutrient utilization. Blood and urine samples collected during N balance were analyzed for DON content. Feeding DON reduced (P < 0.05) ADFI and ADG from days 0 to 28 compared with CONT, after which there was no effect of diet on ADFI and ADG. The G:F was lower (P < 0.05) in DON5 fed pigs compared with all treatments during days 0 to 7; however, no treatment effects on G:F was observed from days 8 to 42. Nitrogen retention was lower (P < 0.05) in DON3 and DON5 compared with DON1-fed pigs. Nitrogen retention efficiency was higher (P < 0.05) in DON1 compared with DON3 and DON5 and protein deposition for DON1 pigs was higher (P < 0.05) than all treatments. There were no treatment effects on indicators of liver and kidney health. As dietary DON intake increased, concentration of DON in blood and urine increased. Overall, although there was an initial decrease in ADG and ADFI in pigs receiving diets containing >1 ppm DON, pig performance recovered after a period of time, whereas nutrient utilization continued to be affected after recovery of performance. Moreover, the lack of DON on G:F indicates that the negative effects of DON on growth performance are largely due to reduced feed intake. Overall, although pigs maybe capable of adapting to intake of DON-contaminated diets, their final body weight will be reduced when fed diets containing >1 ppm DON.     

Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on feedlot beef cattle production

Two experiments were performed to evaluate the effects of bismuth subsalicylate (BSS) and calcium-ammonium nitrate (CAN) on in vitro ruminal fermentation, growth, apparent total tract digestibility of nutrients, liver mineral concentration, and carcass quality of beef cattle. In Exp. 1, four ruminally cannulated steers (520 ± 30 kg body weight [BW]) were used as donors to perform a batch culture and an in vitro organic matter digestibility (IVOMD) procedure. Treatments were arranged in a 2 × 2 factorial with factors being BSS (0 or 0.33% of substrate dry matter [DM]) and CAN (0 or 2.22% of substrate DM). In Exp. 2, 200 Angus-crossbred steers (385 ± 27 kg BW) were blocked by BW and allocated to 50 pens (4 steers/pen) in a randomized complete block design with a 2 × 2 + 1 factorial arrangement of treatments. Factors included BSS (0 or 0.33% of the diet DM) and nonprotein nitrogen (NPN) source (urea or encapsulated CAN [eCAN] included at 0.68% or 2.0% of the diet, respectively) with 0.28% ruminally available S (RAS). A low S diet was included as a positive control containing urea (0.68% of DM) and 0.14% RAS. For Exp. 1, data were analyzed using the MIXED procedure of SAS with the fixed effects of BSS, CAN, BSS × CAN, and the random effect of donor. For Exp. 2, the MIXED procedure of SAS was used for continuous variables and the GLIMMIX procedure for categorical data. For Exp. 1, no differences (P > 0.230) were observed for IVOMD. There was a tendency (P = 0.055) for an interaction regarding H₂S production. Acetate:propionate increased (P = 0.003) with the addition of CAN. In Exp. 2, there was a NPN source effect (P = 0.032) where steers consuming urea had greater carcass-adjusted final shrunk BW than those consuming eCAN. Intake of DM (P < 0.001) and carcass-adjusted average daily gain (P = 0.024) were reduced by eCAN; however, it did not affect (P = 0.650) carcass-adjusted feed efficiency. Steers consuming urea had greater (P = 0.032) hot carcass weight, and a BSS × NPN interaction (P = 0.019) was observed on calculated yield grade. Apparent absorption of S decreased (P < 0.001) with the addition of BSS. Final liver Cu concentration was reduced (P = 0.042) by 58% in cattle fed BSS, indicating that BSS may decrease Cu absorption and storage in the liver. The results observed in this experiment indicate that BSS does not have negative effects on feedlot steer performance, whereas CAN may hinder performance of steers fed finishing diets.     

不同蛋白源饲料对秦川肉牛屠宰性能及牛肉品质的影响

[目的]试验旨在研究不同蛋白源饲料对秦川肉牛日增重、屠宰性能及肉品质的影响。[方法]选择20头体重相近、健康状况良好的12月龄左右的秦川肉牛(母牛)为试验动物,随机将试验牛分为5组,各组分别饲喂5种不同精饲料。试验结束后,对照组(31%豆粕组)、试验Ⅰ组(36%菜籽粕组)和试验Ⅳ组(42%紫苏饼组)各选3头参试牛进行屠宰。[结果]试验Ⅳ组的全期总增重、平均日增重和屠宰率均显著高于对照组(P<0.05);试验Ⅳ组背最长肌中干物质和粗蛋白含量均高于其他两组,但各组间均差异不显著(P>0.05);对照组和试验Ⅰ组大理石花纹均是3级,试验Ⅳ组大理石花纹是4级。[结论]本试验条件下,精饲料中添加42%的紫苏饼能够提高肉牛日增重和屠宰率,能够提高牛肉中氨基酸的含量和粗蛋白水平。     

磷酸脲添加量对羔羊生长性能、屠宰性能和肉品质的影响

本试验旨在研究磷酸脲添加量对羔羊生长性能、屠宰性能和肉品质的影响,并对磷酸脲在肉羊生产中的安全使用剂量进行评价。试验选用80只杜寒杂交F1代平均体重(25.86±1.06)kg的公羔羊,随机分为5组,每组8个重复,每个重复2只,在精粗比为1∶1的饲粮中分别以0(对照)、0.5%、1%、2%、4%的磷酸脲替代部分豆粕类饲料。预试期为12 d,正试期为60 d。结果表明:1%组的羔羊在各时期平均日增重、宰前活重、胴体重、屠宰率均达到最高值;4%组的羔羊在各时期平均日增重、宰前活重、胴体重均极显著低于其他各组(P0.01);与对照组相比,磷酸脲添加量对肉色红度值、p H、滴水损失无显著影响(P0.05);2%组的黄度值显著高于其他各组(P0.05);在剪切力方面,1%组(5.16 kg/cm2)显著高于0.5%组(4.47 kg/cm2)、4%组(3.69 kg/cm2)和对照组(4.21 kg/cm2)(P0.05)。结果提示:磷酸脲可以作为氮磷添加剂用于肉羊饲粮中。羔羊饲粮中的磷酸脲添加量为1%时,羔羊达到最佳生长性能和屠宰性能;当磷酸脲替代比例达到4%时,极显著降低羔羊的平均日增重、胴体重,增加肌肉的亮度值;当磷酸脲替代比例为2%时,为有效安全水平,对羔羊生长性能、屠宰性能和肉品质除肌肉黄度值外无显著影响。因此,饲粮中磷酸脲适宜添加量为1%。     

2-甲基丁酸对西门塔尔牛增重、日粮养分消化和甲烷排放的影响

试验旨在研究2-甲基丁酸对西门塔尔牛日粮养分消化率、增重性能及甲烷排放的影响。选择12月龄左右、发育正常及体重相近的西门塔尔公牛36头,随机分为4组,即对照组及试验1～3组,每组9头牛,分别饲喂添加0、1.0、2.0及3.0 g/kg体重2-甲基丁酸的玉米秸秆日粮,测定日粮养分消化率、西门塔尔牛增重性能及甲烷的排放情况。试验期70 d。结果表明,试验2、3组西门塔尔牛有机物质（OM）消化率较对照组显著提高（P<0.05）;3个试验组粗蛋白质（CP）消化率均较对照组显著提高（P<0.05）,但无氮浸出物（NFE）消化率在各组间差异不显著（P>0.05）;试验2组西门塔尔牛中性洗涤纤维（NDF）消化率显著高于对照组和试验1组（P<0.05）,而其酸性洗涤纤维（ADF）消化率则显著高于其他各组（P<0.05）;试验2、3组西门塔尔牛试验期间平均日增重显著高于对照组（P<0.05）,但其在试验1组与对照组间差异不显著（P>0.05）;与对照组相比,试验2组的干物质采食量显著降低（P<0.05）,试验2、3组料重比也显著降低（P<0.05）;在日粮中添加2-甲基丁酸后,西门塔尔牛的甲烷排放呈降低趋势,试验2、3组排放的甲烷能显著低于对照组（P<0.05）。由以上结果推断,在日粮中添加2-甲基丁酸可促进西门塔尔牛的生长及对营养物质消化,同时可有效降低甲烷排放,2-甲基丁酸的适宜添加水平为2.0 g/kg体重。     

Effects of 2-methylbutyrate on Daily Gain,Dietary Nutrient Digestion and Methane Emissions in Simmental Cattle

The objective of this study was to evaluate the effects of 2-methylbutyrate on daily gain,dietary nutrient digestion and methane emissions in Simmental cattle.Thirty-six Simmental cattle (12-month-old) consuming a corn straw diet were divided randomly into four groups (control group,experimental groups 1,2 and 3) and supplemented with four levels of 2-methylbutyrate as 0,1.0,2.0 and 3.0 g/(kg·BW),respectively.Dietary nutrient digestibilities,average daily gain and methane emissions were determined.The results showed that OM digestibilities of the cattles in experimental group 2 and 3,CP digestibilities of the cattles in experimental groups 2 were significantly higher than that in control group (P<0.05).NFE digestibilities were not affected by adding 2-methylbutyrate (P>0.05).NDF digestibilities of the cattles in experimental group 2 were significantly higher than that in control group and experimental group 1 (P<0.05),while their ADF digestibility were significantly higher than that in control and other experimental groups (P<0.05).Compared with control group,the average daily gains of cattles increased significantly in experimental groups 2 and 3 (P<0.05),the dry matter intakes of cattles decreased significantly in experimental group 2 (P<0.05),and the feed gain ratio decreased significantly in experimental groups 2 and 3 (P<0.05).In addition,the methane emissions were decreased significantly in experimental groups 2 and 3 (P<0.05).The results indicated that the average daily gain,nutrient digestion could be improved,and methane emissions could be restrained by supplementing 2-methylbutyrate in Simmental beef cattle,the optimal dose of 2-methylbutyrate supplementation was 2.0 g/(kg·BW).     

Study on Supplementary Quantity of Grazing Beef Cattle in Spring in Inner Mongolia Grassland

The experiment was conducted to study the optimal supplementary feeding quantity of grazing beef cattle in spring in Inner Mongolia grassland.Seventy-five Simmental beef cattle with average weight of (281.19±17.15)kg were selected and divided into 5 groups (group A,B,C,D and E) with 15 replicates per group.Those cattle grazed optionally and supplemented with 0,0.8,1.7,2.5,3.4 kg/d concentrate,respectively,according to beef cattle weight of 0,0.3%,0.6%,0.9% and 1.2%.Pre-trial period was 15 d,the trial period was 60 d.The results showed that,with the increasing of concentrate supplementation,the daily gain of beef cattle was gradually significant increased (P < 0.05);Group D were 331.25%,130.00% and 38.00% higher than that of group A,B and C,respectively,the apparent digestibility of dry matter and crude protein were significantly higher than that of other groups (P < 0.05).The daily income of group D was 11.22 yuan and were 183.33%,102.53%,36.17%,20.52% significantly higher than that of group A,B,C and E (P < 0.05),the fattening income of group D was the highest.According to above results,the optimum adding levels was 2.5 kg/d in spring under the condition of grazing in Inner Mongolia.The higher daily gain and higher economic benefits could be obtained under the optimal supplementary feeding quantity.     

内蒙古草原放牧肉牛春季补饲量的研究

试验旨在研究内蒙古草原放牧肉牛春季最佳补饲量。选择75头体重为(281.19±17.15)kg的健康西门塔尔杂交肉牛随机分为5组(A、B、C、D、E组),每组15头牛,1头牛为1个重复。各组分别按体重的0、0.3%、0.6%、0.9%及1.2%补饲精料,依次为0、0.8、1.7、2.5及3.4 kg/d,其他放牧条件相同。预试期15 d,正试期60 d。结果表明,随着精料补饲量的增加,肉牛的平均日增重依次显著增加(P < 0.05),D组平均日增重较A、B、C组分别提高331.25%、130.00%及38.00%,日粮中干物质和粗蛋白质的表观消化率显著高于其他各组(P < 0.05);D组日均收入为11.22元,分别较A、B、C及E组显著提高了183.33%、102.53%、36.17%及20.52%(P < 0.05),育肥效益最好。综合以上结果,内蒙古草原春季放牧条件下,肉牛每天的最佳补饲量为2.5 kg,在此条件下可获得较高的日增重及较高的经济收益。     

Economic values and selection index in different Angus‐Nellore cross‐bred production systems

Bioeconomic models were developed to calculate economic values (EV) for economically important traits in beef cattle, to evaluate the impact of these traits on production profitability, to assess possible market changes with a payment system and to develop economic selection indexes for Angus cattle for two production systems. Two beef cattle production systems were simulated as follows: a cow‐calf cycle (CC) and a complete cycle (CoC). Following selection, positive changes in the EV were observed. In the CC, each 1.0% increment in weaning weight (WW), weaning rate (WR) and pregnancy rate (PR) resulted in increases in US$ 1.30, US$ 3.68 and US$ 3.55 per cow/year in profit, respectively. In the CoC, EV of US$ 1.01, US$ 1.79, US$ 1.19, US$ 1.34, US$ 6.84 and US$ 7.86 per cow/year were obtained for WW, year weight, yearling weight, final weight, WR and PR, respectively. The payment system for carcass quality showed that the scenario considering that 100% of the animals displayed uniform carcasses exhibited the highest EV and was considered optimal. Considering the sensitivity analysis, the price paid per animal was the factor that most affected the EV in both systems. The selection indexes obtained may be used in similar production systems, and the use of EV and selection indexes are important tools for any production system with positive change in profit after selection.     

Evaluation of antimicrobial use in dairy cattle,beef cattle and broilers in Japan using dosage-based indicators

The sales amount of antimicrobials intended for use in dairy cattle, beef cattle and broilers from 2008 to 2019 was evaluated for each antimicrobial class and administration route using dosage-based indicators. Our results revealed that the antimicrobial sales amount sold for use in dairy cattle in 2019 in terms of total weight of active ingredient, the number of defined daily doses (DDDs) (theoretical amount of biomass subjected to antimicrobial treatment in a year) and the number of treatment days (TDs) (theoretical number of days of treatment that an animal is subjected to in a year) calculated using Japanese DDD values (DDDjp values) was 36,751 kg, 8,261,848,000 kg·days and 15.5 days, respectively. Likewise, the antimicrobial sales amount sold for use in beef cattle and broilers in 2019 in terms of these metrics was 33,403 kg, 3,928,248,000 kg·days and 3.61 days, and 69,773 kg, 2,947,848,000 kg·days and 10.66 days, respectively. There was a considerable difference between the number of DDDs calculated using DDDjp values and that calculated using European DDD values (DDDvet values) for antimicrobial products sold for use in dairy and beef cattle. Our results also revealed that the sales amount of some antimicrobials, such as cephalosporins and quinolones represented larger proportions when calculated using dosage-based indicators than when calculated using the weight of active ingredient. Considering that Japanese veterinarians and farmers are more likely to conform to the Japanese dosage recommendations rather than the European ones, these results indicate the need for using dosage-based metrics, in particular metrics based on Japanese dosages rather than European dosages.     

Milk production increase following treatment of Dutch dairy cattle with thiabendazole

Summary

In a trial involving 542 dairy cattle on 28 farms, 276 were treated once with thiabendazole within two days of calving. The treated group showed an average increase in milk yielded over the non‐return group of 229.8 kg during the subsequent lactation.

In the treated group, total milk fat production was increased over that of the controls by 7.4 kg per cow; milk protein was increased by 6.9 kg per cow. All treatment parameter differences were highly significant at the 1% level of probability.     

影响江苏某牛场荷斯坦牛日产奶量和乳成分因素分析

[目的]探究江苏某牛场荷斯坦牛日产奶量和乳成分的影响因素。[方法]试验采集了该规模化牛场2018—2020年139 703条测定数据,并利用多因素方差模型对其进行系统的分析。[结果]不同胎次、测定季节、产犊季节、泌乳月对荷斯坦牛日产奶量、乳脂率、乳蛋白率、体细胞评分、乳尿素氮均有极显著影响(P<0.01)。产奶量与乳脂率、乳蛋白率、体细胞评分均存在极显著负相关。[结论]综上结果,在生产中,应结合胎次、季节、产犊时间、泌乳等多种因素,灵活调整牛群结构、生产规划和饲养管理,以实现提高产奶量和乳品质的目的。