The effect of concentrate level and concentrate composition on the performance of growing dairy heifers reared and finished for beef production

Abstract

The objectives of the study with growing dairy heifers were to determine the effects on animal performance of (1) concentrate level and (2) the concentrate composition in the grass silage-based diet. Animals (30 heifers) were randomly assigned to three feeding treatments: (1) low level (1.75 kg dry matter (DM)/d) of rolled barley (LB); (2) low level (1.75 kg DM/d) of commercial pelleted concentrate (LC); and (3) medium level (3.5 kg DM/d) of commercial pelleted concentrate (MC). All animals were also offered grass silage and hay. The commercial concentrate contained more crude protein than barley grain (135 g/kg DM vs. 205 g/kg DM). The data were analysed using analysis of variance and differences between the treatments were tested by orthogonal contrasts: LC vs. MC and LB vs. LC. The growth of the heifers increased and carcass conformation improved with increasing concentrate level. Commercial concentrate did not improve animal performance compared with barley grain.     

饲料油菜FTMR的羔羊强度育肥效果研究

为研究饲料油菜发酵全混合日粮(FTMR)的羔羊强度育肥效果,本试验选取2.5月龄的湖羊40只,随机分为2组,每组20只,公母各半。试验组饲喂以油菜为主原料配制的FTMR日粮,对照组饲喂以青贮玉米为主原料配制的TMR日粮。预试期15d后称初试体重,正式期90d,每15d称重,记录采食量,计算平均日增重。结果表明:湖羊母羊采食量、体重和日增重在两种日粮间无显著差异(P>0.05);而试验组公羊采食量显著高于对照组(P<0.05),75d后体重和日增重都显著高于对照组(P<0.05)。根据日增重、采食量、饲料成本、活羊价格计算育肥收益,油菜FTMR日粮育肥湖羊公羊和母羊的收益都高于对照组。因此,饲料油菜FTMR日粮用于羔羊强度育肥效果较好。     

全混合日粮压块饲料育肥肉牛试验研究

分别采用玉米秸秆、稻草秸秆与精料设计全混合日粮,配制压缩块状饲料进行肉牛育肥及屠宰测定试验,研究秸秆与精料分开的传统饲养模式与压块饲料饲喂肉牛对肉牛育肥效果的影响。结果,分别饲喂玉米、稻草秸秆与精料全混合日粮压块饲料的两试验组(Ⅰ和Ⅱ)育肥牛平均日增重分别为1259．26±161．11 g和1259．26±82．82 g,而对照组分别采用传统的精粗料分开不补喂/补喂蛋白补充料育肥牛平均日增重分别为506．17±228．48 g和318．93±119．80 g,各试验组与对照组牛之间平均日增重差异均达到极显著水平(P＜0．01);试验组Ⅰ和Ⅱ、Ⅲ和Ⅳ(对照)间平均日增重均无明显差异(P＞0．05),表明以玉米秸秆或稻草秸秆与精料补充料等复合配制而成的全混日粮压块饲料,育肥肉牛效果较秸秆与精料分开的传统饲养模式饲喂内牛育肥效果更为好。     

全混合日粮饲喂技术应用于肉牛育肥的研究

本研究旨在分析全混合日粮饲喂技术与传统的精粗分饲对育肥肉牛增重效果、产肉性能及经济效益的影响。采用完全随机单位组设计方法,选择体重(455±10)kg、年龄相近的西门塔尔杂交品种育肥牛14头,随机分为2组,分别为精粗分饲组(对照组)与全混合日粮组(试验组),两组只是在饲喂方式的不同,其余饲养管理条件均一致,试验期153 d。结果表明:(1)头均日增重对照组(968.2±86.84)g,试验组(1 078.5±40.04)g,提高了11.4%,差异达到显著水平(P<0.05);(2)屠宰率、净肉率、胴体产肉率、肉骨比值、眼肌面积、失水率与不同等级分割肉占净肉重的比例等,两组均存在差异,但未达到显著水平(P>0.05);(3)累计增重利润试验组比对照组多243.4元。结果表明在肉牛产业化生产中,应用推广全混合日粮饲喂技术,替代传统的精粗分饲,效果更好。     

Ensiling characteristics of total mixed ration prepared with local feed resources in Mozambique and their effects on nutrition value and milk production in Jersey dairy cattle

To effectively utilize total mixed ration (TMR) prepared with locally available feed resources, we studied the nutritional value and milk production in Jersey dairy cattle fed a local general diet (LGD) and fermented TMR in Mozambique. Ten head of Jersey dairy cattle with 337 ± 19.8 kg body weight, aged 3–4 years in mid location were used in this study. The LGD diet was designed following the general feeding method of local smallholding farms; it contained native grass, Napier grass, wheat bran, and mineral–vitamin mix. Fermented TMR was prepared using Napier grass, corn bran, wheat bran, formula feed, and mineral–vitamin mix. Fermented TMR was preserved as good quality, with a relatively low pH and high lactic acid content. Compared to LGD, fermented TMR significantly improved the dry matter intake and digestibility in dairy cattle. Milk yield was significantly higher in dairy cattle fed with TMR than in those fed with LGD, by 3.75 L/d; milk quality was not significantly different between treatments. The results confirmed that LGD had a low dry matter intake and milk yield, and fermented TMR prepared with local feed resources can attain good quality and improve milk yield in dairy cattle in Mozambique.     

Effects of forage ensiling and ration fermentation on total mixed ration pH,ruminal fermentation and performance of growing Holstein‐Zebu cross steers

Our objective was to determine the effect of forage ensiling and ration fermentation on total mixed ration pH, ruminal fermentation and animal performance. Thirty Holstein‐Zebu cross steers were allotted to feeding treatments for 188 days in a randomized complete block design including: fresh grass‐total mixed ration (GTMR; pH 4.7), grass silage‐TMR (STMR; pH 4.0) and fermented‐TMR (FTMR; pH 3.5). Average daily gain for STMR was greatest during the first 3 months period; however, that for FTMR tended to be greater than GTMR during the second 3 months period (P < 0.10). During the second period dry matter intake for STMR was the greatest (P < 0.01), but feed conversion ratio (P < 0.01) and cost per gain (P < 0.01) were the least for FTMR. Protein digestibility tended (P < 0.10) to be greater for FTMR than STMR and fat digestibility was greater (P < 0.05) for GTMR and FTMR than STMR. FTMR had less (P < 0.01) ruminal NH₃‐N content than STMR. Total volatile fatty acids post‐feeding was greatest for GTMR (P < 0.01). Ruminal proportions of acetic and butyric acids were greater for FTMR than GTMR (P < 0.05); in contrast, propionic acid was greater for GTMR (P < 0.05). Utilizing silage or total ration fermentation did not negatively impact on ruminal pH. STMR and FTMRs can be used to maintain performance of growing crossbred Holstein steers.     

Relationship between body measurements,metabolic hormones,metabolites and residual feed intake in performancetested pedigree beef bulls

The objective of this study was to examine the relationship between easily measured, potential physiological and physical indicators of feed efficiency including metabolic hormones, metabolites, ultrasonic muscle and fat measures with performance and efficiency traits in performance tested pedigree beef bulls (n = 302; initial bodyweight 493 (SD = 64) kg). Animals were offered a high energy concentrate ad libitum plus 1.5 kg fresh weight grass hay daily and individual feed intake was measured for 70 days. Blood samples were collected by coccygeal venipuncture at the start and end of the performance test period and analysed for plasma concentrations of IGF-I, insulin, leptin and various metabolites. Similarly, ultrasonic muscle and fat depths were measured at the start and end of the test period. Residual feed intake (RFI) was computed for each animal as the residuals from a multiple regression model regressing dry matter intake (DMI) on average daily gain (ADG) and mid-test BW^0.75 (MWT). Overall ADG, DMI, feed:gain (F:G) and RFI were 1.91 (SD = 0.29), 10.10 (SD = 1.31), 5.37 (SD = 0.84) and 0.00 (SD = 0.78), respectively. Residual feed intake was strongly correlated with DMI (r = 0.67) and moderately correlated with F:G (r = 0.40). Moderate positive correlations ranging from 0.3 to 0.6 were estimated between ultrasonic measures of final fat and muscle depth and their respective gains over the test period with DMI, ADG and RFI. There was no evidence of a strong association between any of the plasma analytes measured and RFI at either sampling times. However, end of test insulin was negatively correlated (r = − 0.14) with RFI. Final IGF-I concentration was negatively associated with DMI (r = − 0.14) and F:G (r = − 0.15). End of test circulating leptin concentration was positively correlated with DMI (r = 0.14) and F:G (r = 0.15). Plasma glucose concentration at the end of test was negatively related to DMI (r = − 0.21) and F:G (r = − 0.21). A positive relationship was observed between end of test plasma urea concentration and DMI (r = 0.30). Overall, the correlation coefficient estimates between the potential blood markers and measures of intake, performance and efficiency were weak and generally not different from zero. This suggests that it is unlikely that measurement of these metabolic indicators, per se, will be useful in the early identification of feed efficient animals.     

Performance of free suckling dairy calves in an automatic milking system and their behaviour at weaning

Abstract

The performance of dairy calves allowed to suckle freely (FS) until eight weeks of age in a cubicle system with automatic milking was compared to automatic teat-feeding with low milk (LM) or high milk (HM) substitute allowances. Weight gain and feed intake of FS (n = 13), LM (n = 23) and HM (n = 22) calves were recorded until two weeks after abrupt weaning, and their behaviour was studied during weaning. FS calves had higher weight gain, but much lower solid feed intake until weaning, than LM and HM calves and their advantage in weight remained throughout the study despite very low post-weaning gain. During the first 24 hours after weaning, FS calves displayed more behavioural signs of stress. However, at 72 hours after weaning, behaviour was similar for all treatments. Methods to stimulate solid feed intake before weaning need to be developed to draw advantage of the FS system.     

全混合日粮对奶牛产乳性能的影响

试验选用了12头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为试验组和对照组,研究全混合日粮对奶牛产乳性能的影响。试验结果表明,试验组4％标准乳产量比对照组提高1 24kg,差异显著(P<0．05),乳脂率及乳脂、乳糖和乳固形物含量也分别比对照组显著提高11．60％、17．50％、13．21％和9．86％(P<0.05)。     

Assessing the accuracy of modelling weight gain of cattle using feed efficiency data

Different methods of estimating weight gain were compared for accuracy and utility, using the amount of error variation from fitting the residual feed intake (RFI) model. Data were collected on 1481 cattle of temperate and tropically adapted breeds, feedlot-finished for the domestic (liveweight 400 kg), Korean (520 kg), or Japanese (steers only; 600 kg) markets. Cattle were tested in 36 groups over 4 years. The aim was to estimate weight gain over the period feed intake was measured, which was at least 49 days and averaged 63 days, including time for animals to adapt to the automatic feeding system. The different estimates were derived from linear and quadratic regressions of weight over time fitted to: F1) all weighings in the feedlot and F2) all weighings in the feedlot excluding atypical records in the first few weeks following feedlot entry. More complex linear and quadratic models were also fitted to weighings when feed intake was being measured, using the amount of feed eaten on the day of weighing, and previous days, to adjust for gut fill. Finally, a random regression model including general trends in the growth of each animal and short term measurement error was fitted to dataset F2 to estimate weight gain for the period feed intake was measured.The RFI equation: feed intake=intercept(s)+β_w*mean(weight^0.73)+β_g*weight gain+error (i.e. RFI) was fitted using the different weight gain estimates. Based on mean squared errors from fitting this equation, longer measurement periods generally resulted in more accurate estimates of weight gain. The increased accuracy from using all weight measurements in the feedlot outweighed the loss from not measuring over the desired time interval—i.e. the period for which feed intake was measured.     

Genetic parameters for dry matter, energy and protein intake, and their relationships with performance and carcass traits in Japanese Black cattle

Genetic parameters for feed intake and performance traits of 514 bulls and carcass traits of 22 099 of their progeny, and the relationships of measures of feed intake with performance and carcass traits were estimated. Feed intake traits were dry matter intake (DMI), concentrate intake (CONI), roughage intake, ratio of roughage intake to DMI, metabolizable energy intake (MEI) and digestible crude protein intake (DCPI). Performance traits included daily gain, metabolic weight, live weight at the end of test, dry matter conversion ratio and residual feed intake. Progeny carcass traits were carcass weight, percentage of meat yield, rib eye area (REA), subcutaneous fat, marbling score, meat colour (MCS), fat colour (FCS) and meat quality grade. All the feed intake and performance traits were moderately heritable. The heritabilities for REA and MCS were moderate, and that for FCS was low, while those for the other carcass traits were high. Selection against DMI, CONI and DCPI would reduce excessive intake of feed, but would have undesirable effects on growth and most of the carcass traits. Selection against MEI would lead to improvements in feed efficiency and growth traits. Selection against DCPI would also improve feed efficiency; however, responses in growth traits would decrease. Results indicate that selection against MEI might be better than any other measures of feed intake to improve feed efficiency with simultaneous improvement in growth and most of the carcass traits.     

TMR日粮不同颗粒大小对奶牛采食行为的影响

试验选择6头体况良好,产奶天数(DIM)接近的荷斯坦奶牛,采用3×3重复拉丁方设计,通过给奶牛饲喂由不同颗粒片段大小(长切割L,短切割S,中等水平M)的玉米青贮组成的TMR日粮来研究其对奶牛采食、反刍行为等的影响。结果表明:降低日粮颗粒片段大小,奶牛的干物质采食量(DMI)、中性洗涤纤维采食量(NDFI)及酸性洗涤纤维采食量(ADFI)均下降,但各处理组间差异不显著(P>0.05);物理有效中性洗涤纤维采食量(peNDFI)也下降,L组与S组间差异显著(P<0.05);降低日粮颗粒大小,奶牛的采食时间、反刍时间及总咀嚼时间下降,L组与S组间奶牛的采食和反刍时间差异显著(P<0.05);奶牛的总咀嚼时间L组与M组、M组与S组间差异显著(P<0.05),而L组和S组间差异极显著(P<0.01)。试验表明,改变日粮颗粒大小对奶牛的DMI等影响不显著,对奶牛的咀嚼活动则有显著的影响。     

Simultaneous Bayesian estimation of genetic parameters for curves of weight,feed intake,and residual feed intake in beef cattle

Rates of gain and feed efficiency are important traits in most breeding programs for growing farm animals. The rate of gain (GAIN) is usually expressed over a certain age period and feed efficiency is often expressed as residual feed intake (RFI), defined as observed feed intake (FI) minus expected feed intake based on live weight (WGT) and GAIN. However, the basic traits recorded are always WGT and FI and other traits are derived from these basic records. The aim of this study was to develop a procedure for simultaneous analysis of the basic records and then derive linear traits related to feed efficiency without retorting to any approximation. A bivariate longitudinal random regression model was employed on 13,791 individual longitudinal records of WGT and FI from 2,827 bulls of six different beef breeds tested for their own performance in the period from 7 to 13 mo of age. Genetic and permanent environmental covariance functions for curves of WGT and FI were estimated using Gibbs sampling. Genetic and permanent covariance functions for curves of GAIN were estimated from the first derivative of the function for WGT and finally the covariance functions were extended to curves for RFI, based on the conditional distribution of FI given WGT and GAIN. Furthermore, the covariance functions were extended to include GAIN and RFI defined over different periods of the performance test. These periods included the whole test period as normally used when predicting breeding values for GAIN and RFI for beef bulls. Based on the presented method, breeding values and genetic parameters for derived traits such as GAIN and RFI defined longitudinally or integrated over (parts of) of the test period can be obtained from a joint analysis of the basic records. The resulting covariance functions for WGT, FI, GAIN, and RFI are usually singular but the method presented here does not suffer from the estimation problems associated with defining these traits individually before the genetic analysis. All the results are thus estimated simultaneously, and the set of parameters is consistent.     

Evaluation of total mixed ration silage with brewers grains for dairy buffalo in Tarai,Nepal

To investigate the effects of total mixed ration (TMR) silage, which contained brewers grain and rice straw as a substitute for conventional concentrate on feed intake and milk production in middle‐to‐late lactation buffaloes, four multiparous Murrah buffaloes were assigned to a 3 × 3 Latin square design experiment. The TMR silage, which had higher neutral and acid detergent fiber contents and digestibility than concentrate (P < 0.05) and similar crude protein (CP) and total digestible nutrient (TDN) contents with concentrate were used for the lactation experiment. The treatments were control (CTL) fed concentrate at 0.6% of body weight (BW), and T1 and T2 fed the TMR silage at 0.6 and 1.2% of BW on a dry matter (DM) basis, respectively, with rice straw ad libitum. Daily intakes of DM, CP and TDN, and BW change were higher in T2 than in CTL and T1 (P < 0.05). Although milk composition did not differ among the treatments, milk yield (MY) was higher in T2 (P < 0.05). There were no significant differences in MY/DM intake and MY/TDN intake among the treatments. The increase of BW and MY in middle‐to‐late lactation buffaloes might have been due to high TDN intake from supplementary TMR silage.     

A simulation model for predicting the voluntary feed intake of a growing pig

Abstract

The main goal of this simulator is to predict voluntary feed intake based on the effects of temperature and stocking density. The model indicates the limiting factors relative to diet (protein, energy or ash), housing environmental conditions and stocking density. The concepts of compensatory protein growth, correction of lipid growth, the desired feed intake to meet energy, protein and ash requirements, and influences of stocking density, genotype and sex are also introduced in this model. This study draws a flow chart and steps to predict feed intake of a growing pig to make it clear how the model works. The model simulates the outcomes of feed intake, energy and protein requirements for maintenance, the energy cost for cold thermogenesis, and protein and lipid retention on a daily basis until slaughter weight. This model was also validated by comparison with published experiments.     

Diet change from a system combining total mixed ration and pasture to confinement system (total mixed ration) on milk production and composition,blood biochemistry and behavior of dairy cows

This study aimed to determine if a diet change from a mixed system to a confinement system affects the milk production and composition, behavior and blood biochemistry of dairy cows. Cows were assigned randomly to one of the two treatments: cows fed with TMR (total‐mixed‐ration) (confined) throughout the period group fed TMR (GTMR, n = 15) and cows that changed their diet from pasture plus TMR to exclusive TMR at 70 ± 14 DIM (GCHD, n = 15). GTMR cows produced more milk and greater lactose and protein yield before the change of diet than GCHD cows (p ≤ .01), but these differences disappeared after the change. GCHD cows decreased the frequency of rumination and lying from before to after the change (p ≤ .03), but in GTMR cows no changes were observed. After diet change, GCHD cows had lower frequency of rumination and lying than GTMR cows (p ≤ .02). Before the change, GCHD cows had greater NEFA (non esterified fatty acids) concentrations than GTMR cows (p = .002). Abrupt change from a mixed system to a confined system was favorable on blood biochemical and milk variables of dairy cows. However, in relation to behavior, the cows expressed difficulties to adapt quickly to the abrupt change of system.     

Theoretical turnover rate of the rumen liquid fraction in dairy cows and its relationship to feed intake,rumen fermentation,and milk production

Ruminant animals are able to convert plant materials (grain and the human‐indigestible portion of carbohydrates) to milk and meat. In this conversion, most of the plant materials are digested by rumen fermentation and are changed to short‐chain fatty acids, microbial cells, and methane, which is released into the atmosphere. The relationships among feed, rumen fermentation, and milk production are poorly understood. Here we report a novel indicator of characteristics of rumen fermentation, theoretical turnover rate (TTOR) of the rumen liquid fraction. The TTOR was calculated from the presumed rumen volume (PRV) which is estimated by dividing the methane yield by the methane concentration of rumen fluid. The formula for the TTOR is: TTOR = PRV/body weight^0.75. Our present analyses confirm that the TTOR as an indicator is capable of connecting feed, rumen fermentation, and milk production, because dry matter intake/TTOR showed a strong correlation with milk yield/TTOR. In addition, the TTOR may be related to ruminal pH, as we observed that the ruminal pH decreased as the TTOR increased. We propose that the TTOR is a factor characterizing rumen fermentation and a good indicator of the productivity of ruminants and dysbiosis of the rumen microbiome.     

全混合日粮中添加牛至精油对泌乳期荷斯坦奶牛生产性能和蹄病发生率的影响

本研究旨在探讨向全混合日粮(TMR)中添加牛至精油对日粮温度、荷斯坦奶牛干物质采食量、产奶量和蹄病发生率的影响。选择72头健康荷斯坦奶牛,根据生产性能、泌乳天数和胎次相近原则进行配对试验设计分为试验组[产奶量(29.88±8.55)kg·d-1,TMR中添加牛至精油]和对照组[产奶量(29.15±7.07)kg·d-1,TMR中未添加牛至精油],每组36头牛。试验组奶牛按每天每头0.028 kg添加牛至精油。结果表明,在6月份17:00,7月份13:00、17:00,8月份13:00、17:00试验组TMR日粮温度升高幅度显著低于对照组(P0.05);5月份试验组奶牛干物质采食量显著高于对照组(P0.05),6、7、8月份极显著高于对照组(P0.01);6、7、8、9月份试验组产奶量极显著高于对照组(P0.01)。因此,牛至精油可降低TMR温度、改善适口性、提高新鲜度;同时还可增加奶牛干物质采食量及产奶量,尤其当奶牛处于北方夏季高温天气下,这一效果尤为显著。     

不同的粗饲料搭配对TMR饲料发酵品质的影响

利用玉米Zea mays秸秆(对照)、玉米秸秆+沙打旺Astragalus adsurgens+紫花苜蓿Medicago sativa、玉米秸秆+无芒雀麦Bromus inermis+垂穗披碱草Elymus nutans、玉米秸秆+华北驼绒藜Ceratoidesarborescens+尖叶胡枝子Lespedeza hedysaroides、玉米秸秆+紫花苜蓿+垂穗披碱草、玉米秸秆+紫花苜蓿+华北驼绒藜、玉米秸秆+无芒雀麦+华北驼绒藜制成TMR粗饲料,配以玉米面、胡麻饼、麸皮、高效钙磷多维骨粉分别制成TMR饲料,并对不同的TMR饲料发酵后的pH值、有机酸、营养成分等进行分析比较。结果表明,各粗饲料搭配组与对照组相比均能显著降低TMR发酵饲料的pH值、中性洗涤纤维,且显著增加粗蛋白含量,钙、磷含量变化则不明显,不同粗饲料搭配而成的TMR饲料均改善了发酵品质,获得了优良的TMR发酵饲料。     

Comparison of supplementary concentrate levels with grass silage, separate or total mixed ration feeding, and duration of finishing in beef steers

Winter finishing of beef cattle is expensive so feed costs per kg carcass gain must be minimised. The objectives of this study with finishing beef steers were (1) to determine the production responses to varying levels of supplementary concentrates with grass silage, (2) to compare the effects of feeding silage and concentrates separately or as a total mixed ration (TMR), and (3) to compare short (S) and long (L) finishing periods. A total of 117 finishing steers were blocked on weight and assigned to 13 groups of 9 animals each comprising a pre-experimental slaughter group and 12 finishing groups arranged in a 6 (feeding treatments) × 2 (durations of finishing) factorial experiment. The 6 feeding treatments were: (1) silage only offered ad libitum (SO), (2) SO plus a low level of concentrates offered separately (LS), (3) SO plus a low level of concentrates offered as a TMR (LM), (4) SO plus a high level of concentrates offered separately (HS), (5) SO plus a high level of concentrates offered as a TMR (HM), and (6) concentrates ad libitum plus restricted silage (AL). Target low and high concentrate levels were proportionately 0.375 and 0.750 of daily dry matter (DM) intake, respectively. S and L finishing periods were 105 and 175 days, respectively. Silage DM intake decreased (P < 0.001) and total DM intake increased (P < 0.001) with increasing concentrate level. Maximum DM intake occurred at the high concentrate level but maximum net energy intake occurred on ad libitum concentrates. Live weight gains for SO, LS, LM, HS, HM and AL were 212, 900, 929, 1111, 1089 and 1207 (S.E. 46.2) g/day, respectively. Corresponding carcass weight gains were 119, 506, 540, 662, 633 and 746 (S.E. 25.4) g/day. Kill-out proportion, carcass conformation score and all measures of fatness increased significantly with increasing concentrate level. Feeding a TMR increased silage intake at the low concentrate level but otherwise had no effect on overall animal performance or carcass traits. Extending the finishing period reduced (P < 0.001) daily live weight gain, but the associated reduction in carcass weight gain was not statistically significant. It is concluded that the response to supplementary concentrates decreased with increasing level, there was no animal production advantage to a TMR over separate feeding of the dietary constituents, and extending the duration of the finishing period reduced mean daily live weight gain and increased fatness.