Preweaning period is a critical window for rumen microbial regulation of average daily gain in Holstein heifer calves

Background Rumen bacterial groups can affect growth performance,such as average daily gain(ADG),feed intake,and efficiency.The study aimed to investigate the inter-relationship of rumen bacterial composition,rumen fermentation indicators,serum indicators,and growth performance of Holstein heifer calves with different ADG.Twelve calves were chosen from a trail with 60 calves and divided into higher ADG(HADG,high pre-and post-weaning ADG,n=6)and lower ADG(LADG,low pre-and post-weaning ADG,n=6)groups to investigate differences in bacterial composition and functions and host phenotype.Results During the preweaning period,the relative abundances of propionate producers,including g_norank_f_Butyricicoccaceae,g_Pyramidobacter,and g_norank_f_norank_o_Clostridia_vadin BB60_group,were higher in HADG calves(LDA>2,P<0.05).Enrichment of these bacteria resulted in increased levels of propionate,a gluconeogenic precursor,in preweaning HADG calves(adjusted P<0.05),which consequently raised serum glucose concentrations(adjusted P<0.05).In contrast,the relative abundances of rumen bacteria in post-weaning HADG calves did not exert this effect.Moreover,no significant differences were observed in rumen fermentation parameters and serum indices between the two groups.Conclusions The findings of this study revealed that the preweaning period is the window of opportunity for rumen bacteria to regulate the ADG of calves.

Effects of Dietary Carbohydrate Sources on Daily Weight Gain and Digestive Enzyme Activities of Juvenile Peanut Worm(Sipunculus nudus)

In the study,glucose,sucrose,dextrin,tapioca starch,potato starch,corn starch and gelatinized corn starch were selected to make the diets with same nitrogen and lipid,and Juvenile peanut worms( Sipunculus nudus) were fed with the diets came from different carbohydrate sources,effects of diets with different carbohydrate sources on daily weight gain and digestive enzyme activities of S. nudus were studied. Results showed that diets with different carbohydrate sources had significant influences on daily weight gain and digestive enzyme activities of S. nudus( P < 0. 05). Daily weight gain in gelatinized corn starch group was significantly higher than that in other groups( P < 0. 05); daily weight gain in glucose group was significantly lower than that in other groups( P < 0. 05); daily weight gain in the three ungelatinized starch groups was significantly higher than that in glucose,sucrose and dextrin groups( P < 0. 05). Analysis of digestive enzyme activities showed that dietary carbohydrate sources had significant influences on digestive enzyme activities of S. nudus( P < 0. 05). Protease activities and amylase activities of S. nudus in sucrose group were the highest,which were significantly higher than that in the other groups( P < 0. 05); lipase activities of S. nudus in glucose group were the lowest,which were significantly lower than that in other groups( P < 0. 05). In conclusion,growth-promoting effects of macromolecules carbohydrates( starch) were better than that of disaccharide( sucrose) and monosaccharide( glucose),which of gelatinized starch were better than that of ungelatinized starch.

Effect of Cumian No.1 on anti-immunity stress of chickens

2500 chickens were treated intwo households （A and B）, and divided into a test group and a contrast group in each of the households. 0.5% of ＂Cumian No.l＂ was added to the feeds of 1- to 15-day-olds of the test group and 0.2% to the feeds of 16- to 44-day-olds of the test group. The result showed that compared with the contrast group, the average weight and survival rate increased by 4.786% and 2% respectively, and FIG decreased by 9.2% in the test group in household A; the average weight and survival rate increased by 3.608% and 2% respectively, and FIG decreased by 14.9% in the test group in household B.

Effects of back fat,growth rate,and age at first mating on Yorkshire and Landrace sow longevity in China

In the present study, genetic parameters for longevity and genetic correlations with back fat （BF）, average daily gain （ADG）, and first mating age （FMA） were estimated from 19 300 Yorkshire and 18 378 Landrace sows from 12 farms derived from one breeding system. General linear models （GLM） were employed to estimate genetic correlations with heritability （h2）. Longevity was defined by six different parameters （i.e., traits） and heritability ranged from h2=0.13 to 0.16 （P〈0.05） in both swine breeds. Genetic correlations between different longevity definitions were positive and high （r=0.79 to 0.99; P〈0.05）. BF exhibited low positive genetic correlations （r=0.12 to 0.15; P〈0.05） with longevity traits identified in both pig breeds which were dependent on trait definition, whereas ADG and FMA showed weak negative genetic correlations with longevity traits. The influence of BF, ADG, and FMA on longevity traits was examined by dividing the production and reproductive traits into several numerical groups; the influence of each longevity trait was subsequently analyzed among the different groups. The results indicated BF was the best trait to improve longevity among BF, ADG, and FMA, which showed positive effects for almost all longevity traits. For Yorkshire sows, gilts with over 18 mm BF were most desirable; Landrace with 10.6-13 mm BF were suitable for longevity. ADG was not favorable for gilt selection, because the correlation between growth rate and longevity very low. For FMA, our results indicated gilts mating before 230 days exhibited a longer life span. Therefore, we suggest farmers should select for thicker back fat and mate at an earlier age to improve sow longevity.

Effects of Pleurotus eryngii Residue on Weight Gain of Chick and Duck

In the present study, Pleurotus eryngii residue was added into conventional feed of Chai chicks and meat-type ducks at different ratios to measure its effects on the production performance of chicks and ducks. The results revealed that the growth performance of chicks and ducks was the best when 20% Pleurotus eryngii residue was added into the feed. Under such condition, the daily weight gain of 8 - 11 and 12 - 15-week-old Chai chicks was increased by 6.8% and 13.5%, and that of 8 - 11 and 12 - 15-week-old ducks was increased by 11.5% and 19.3%, respectively.

Analysis of York Pigs Feeding Behavior Using Stepwise Regression and Principal Component Regression

A statistical analysis was conducted on the feeding behavior of 106 York breeding pigs.Pearson correlation analysis,principal component correlation analysis and multiple stepwise regression equation methods were applied to establish regression equations of the York breeding pigs total feed intake per time and average feed intake per time with corrected fat thickness,feed conversion rate,and corrected daily gain.The results showed that:①there were three peak feed intake periods for the pigs,and the correlation coefficient between the feed intake and the corrected fat thickness of the pigs in the 24 h period was positive or negative,that is,increasing the number of feeding times and the feed intake was not necessarily conducive to the fat thickness accumulation,but the breeding goal of fat thickness could be achieved by controlling the feeding times and feed intake;②the average feed intake of pigs in the 60-90 kg body weight stage was 30%-50%higher than that of the 30-60 kg body weight stage,but the number of feeding times decreased,the peak feeding time was more concentrated,and the feeding duration per time was 3.0 min longer,indicating that as the weight of pigs increased,the feed intake increased significantly;and③the stepwise regression equations and the principal component equations showed that the feeding behavior of York pigs in the 30-90 kg growth stage was not only affected by the feeding time within 24 h,but also by environmental factors such as temperature and humidity.The feeding behavior of York pigs is a complex process of interaction between environmental factors and animal factors.

A comparison of average daily gain,apparent digestibilities,energy balance,rumen fermentation parameters,and serum metabolites between yaks(Bos grunniens)and Qaidam cattle(Bos taurus)consuming diets differing in energy level

Yaks(Bos grunniens),indigenous to the harsh Qinghai-Tibetan Plateau,are well adapted to the severe conditions,and graze natural pasture without supplements all year round.Qaidam cattle(Bos taurus),introduced to the Qinghai-Tibetan Plateau 1,700 years ago,are raised at a lower altitude than yaks,provided with shelter at night and offered supplements in winter.Based on their different backgrounds,we hypothesized that yaks have lower energy requirements for maintenance than cattle.To test this hypothesis,we measured average daily gain(ADG),apparent digestibilities,energy balance,rumen fermentation parameters,and serum metabolites in growing yaks and cattle offered diets differing in metabolizable energy(ME)levels(6.62,8.02,9.42 and 10.80 MJ/kg),but with the same crude protein concentration.Six castrated yaks(155±5.8 kg)and 6 castrated Qaidam cattle(154±8.0 kg),all 2.5 years old,were used in 2 concurrent 4×4 Latin square designs.Neutral and acid detergent fiber digestibilities were greater(P<0.05)in yaks than in cattle,and decreased linearly(P<0.05)with increasing dietary energy level;whereas,digestibilities of dry matter,organic matter,crude protein and ether extract increased(P<0.05)linearly with increasing energy level.The ADG was greater(P<0.001)in yaks than in cattle,and increased(P<0.05)linearly with increasing energy levels.From the regressions of ADG on ME intake,the estimated ME requirement for maintenance was lower(P<0.05)in yaks than in cattle(0.43 vs.0.57 MJ/kg BW0.75).The ratios of digestible energy(DE):gross energy and ME:DE were higher(P<0.05)in yaks than in cattle,and increased(P<0.05)linearly with increasing dietary energy level.Ruminal pH decreased(P<0.05),whereas concentrations of total volatile fatty acids(VFAs)and ammonia increased(P<0.01)with increasing dietary energy level,and all were greater(P<0.05)in yaks than in cattle.Concentrations of ruminal acetate and iso-VFAs were greater(P<0.05),whereas propionate was lower(P<0.05)in yaks than in cattle;acetate decreased(P<0.001),whereas butyrate and propionate increased(P<0.001)linearly with increasing dietary energy level.Serum concentrations ofβ-hydroxybutyrate were lower(interaction,P<0.001)in yaks than in cattle fed diets of 9.42 and 10.80 MJ/kg,whereas non-esterified fatty acids were greater(interaction,P<0.01)in yaks than in cattle fed diets of 6.62 and 8.02 MJ/kg.Concentrations of serum leptin and growth hormone were greater in yaks than in cattle and serum insulin and growth hormone increased(P<0.01)linearly with increasing dietary energy level.Our hypothesis that yaks have lower energy requirements for maintenance than cattle was supported.This lower requirement confers an advantage to yaks over Qaidam cattle in consuming low energy diets during the long winter on the Qinghai-Tibetan Plateau.

Optimal Supplement Dosage of Double-Low Rapeseed Meal in Concentrated Feed of Fattening Lambs

[ Objective] To determine the optimal supplement dosage of double-low rapeseed meal in concentrated feed of fattening lambs. [ Method] A total of 120 Tibetan lambs at the age of 50 d were selected and divided randomly into four groups. The lambs in these four groups were fed with diets respectively supplemented the double-low rapeseed meal of 50,100,150 and 200 g/kg. Their diets had the same nutritional levels of energy and protein. The experimental period was 120 d. [ Result] Daily gain, feed conservation ratio and economic benefits were largely increased in the lambs fed with the diets supplemented the double-low rapeseed meal of 150 g/kg （Daily gain, P 〈 0.01 ）. However, the daily gain and feed conservation ratio were largely decreased in the lambs fed with the diets supplemented the double-low rapeseed meal of 200 g/kg. Moreover, serum levels of transaminase and thyroxine were not significantly different between the four groups. [ Conclusion] The optimal supplement dosage of the double-low rapeseed meal is 150 g/kg in fattening lambs.

Effects of Different Wind Speeds behind Windbreak Wall of Fattening Cattle Farm on Farm Environment and Performance of Beef Cattle in Zhangye District

[Objective]The paper was to study the wind-reducing effect of windbreak wall at different sheltering distances and the effects of wind speed on cattle performance.[Method]The 40 cattle with insignificant difference in initial weight were randomly distributed in four selected stalls,and were divided into two groups according to the distance between stalls and windbreak wall to measure their daily gain.According to the actual conditions and weather conditions of fattening cattle farm,the wind speed,temperature and other environmental indexes of measuring point and heat production of beef cattle were carried out field measurement and analysis.[Result]The windbreak wall in fattening cattle farm reduced the wind speed by 40%-70%within a horizontal distance of 10 times of the wall height at a height of 1.2 m.The best sheltered area behind windbreak wall was 2-4 times of the height of windbreak wall.Within the distance of 6 times of the wall height,the wind speed reduction effect was obvious and the maximum reduction rate reached 70%.With an external WCI of-15.61 and average beef cattle weight of 480 kg,the WCI of fattening cattle farm equipped with windbreak wall reached-9.00,and the heat loss reduced by each cow was 3.31 MJ/h.Meantime,due to the difference in distance from windbreak wall,the daily gain difference of beef cattle was 0.15 kg/head day,but the difference was not significant(P>0.05).

The Effect of Quantitative Feed Restriction Duration on Growth Performance and Carcass Characteristics of Broiler Chickens

The growth productivity of broilers is influenced by improving growth performance through improving body weight, average daily gain, and feed conversion rate. The objective of the study was to determine the effect of quantitative feed restriction duration on growth performance and carcass characteristics of broilers. A total of 144 day-old broiler chicks were reared in a deep litter system until slaughter at 42 days. Chicks were randomly allocated to three treatments which were replicated three times with 16 birds per replicate. The three treatments were the control (T1), one week of feed restriction (T2), and two weeks of feed restriction (T3). Birds were fed with starter, grower and finisher diets. The average daily gain (ADG), average daily feed intake (ADFI), and the feed conversion ratio (FCR) were computed for each week. Carcass weight and internal organs weights were measured. The body weight gained by the birds in T1 was similar to the birds that were restricted for a week. The treatments had a significant effect on the average daily gain in weeks 4, 5, and 6. The ADG for T2 was higher (P < 0.05) at week 5 after 1 week of restriction, than T1 and T3. The feed conversion ratio was significantly higher in T3 after 2 weeks of restriction. In T2 and T3, feed intake was significantly lower than in birds fed ad libitum at week 4 at the start of the treatment. There was no significant effect on the relative weights of heart weights, liver, gizzard, feet, and heads among the treatment groups except for intestine weight which was lower (P < 0.05) in T1 than T2 and T3. It was concluded that broilers that were restricted for one week had a positive result in growth performance. Feed restriction had minimal effect on the organ weights of broiler chickens.

Effect of Crossbreeding on Beef Production of Jersey Herd Using Fleckvieh Sires Maintained on a Pasture-Based Feeding System

Jersey bull calves and steers produce high quality meat;however, the growth rate of Jersey bull calves for veal and beef are low in comparison to other dairy breeds. This could be improved by crossbreeding with beef breeds. In the current study, the veal and beef production of Jersey and Fleckvieh × Jersey (F × J) bull calves and steers were compared. Bull calves were reared intensively for veal up to a carcass weight not exceeding 100 kg, or as steers for beef to 21 months of age. In both veal and steer production systems, the mean birth weight of F × J bull calves was higher (P < 0.001) than Jersey bull calves, i.e. 33.5 ± 1.2 kg vs. 27.9 ± 1.2 kg and (33.4 ± 0.9 kg vs. 26.9 ± 0.9 kg, respectively. The body weight of Jersey and F × J veal calves at 6 months of age differed (P < 0.01) being 163.5 ± 3.9 and 180.6 ± 4.0 kg respectively. This could be attributed to a higher (P < 0.01) average daily gain (ADG) of 0.82 ± 0.02 kg/day for F × J compared to 0.73 ± 0.02 kg/day for Jersey bull calves. Marketing age in the veal production system differed (P < 0.001) with Jersey and F×J bull calves marketed at 7.1 ± 0.1 and 6.3 ± 0.1 months of age, respectively. End live weight at 21 months of age of Jersey and F × J differed (P < 0.01) being 322.6 ± 13.4 and 441.4 ± 14.9 kg respectively. This was due to a higher (P < 0.01) average daily gain in F × J vs. Jersey steers, i.e. 0.64 ± 0.02 and 0.46 ± 0.0 kg/day, respectively. Fleckvieh × Jersey steers had a higher (P < 0.01) carcass weight at 21 months of age being 206.5 ± 8.9 kg vs. 157.9 ± 8.6 kg respectively. These results indicated the potential of improving beef production characteristics of the Jersey cattle through crossbreeding.

Optimizing the utilization of maize silage in forage blends-based rations to improve production performance and reduce methane emissions from fattening calves

This research investigated the effect of various mixtures of maize silage and ryegrass fodder on nutrient digestibility,production performance,and methane(CH4)emission of fattening calves.Twenty-four fattening calves((228±10)kg body weight(BW),(280±5)d of age)were allocated to 8 diets for 84 d,according to a randomized complete block design,and the blocks were balanced for BW,age,and sex.The diets consisted of 4 levels of maize silages,i.e.,40%(MS40),50%(MS50),60%(MS60),and 70%(MS70)in the maize silage and ryegrass fodder mixture on a dry matter(DM)basis,and each of the mixture was supplemented with either low(LC,1.0%BW)or high(HC,1.5%BW)levels of fattening concentrate.The results revealed greater(p<0.05)intakes of DM(8.35 kg/d),organic matter(OM,7.85 kg/d),and metabolizable energy(ME,12.00 Mcal/d)in calves fed with MS70-LC diet.The highest(p<0.05)digestibility(g/100 g)of DM(65.2),OM(67.3),crude protein(69.1),and neutral detergent fibre(56.3)was recorded for MS40-HC diet.The maximum(p<0.05)average daily gain(ADG,571 g/d)was recorded for diet MS70-LC.The lowest value(p<0.05)of CH4 emission was recorded in MS70-LC,MS70-HC,and MS60-HC as compared to other diets.Including 70%maize silage in the ryegrass-maize silage based diet improved ADG by 174 g/d with LC feeding.It is concluded that the optimum inclusion level of maize silage and ryegrass in the fattening ration can improve animal production performance and reduces CH4 production and concentrate requirements of fattening calves.

Growth performance of nursery and grower-finisher pigs fed diets supplemented with benzoic acid

Two experiments were conducted to investigate the efficacy of benzoic acid on the growth performance of nursery and grower-finisher pigs. A randomized complete block design was used in both experiments with the initial body weight as the blocking factor. There were 3 treatments corresponding to 3 dietary levels of benzoic acid: 0, 0.3%, and 0.5%. In experiment 1, a total of 144 PIC L1050 barrows(initial body weight 7.1 ± 0.6 kg) were used with each treatment replicated 8 times. In experiment 2, a total of 288 PIC L1050 barrows(initial body weight 36.1 ± 3.6 kg) were used with each treatment replicated 16 times.There were 6 barrows in each replicate pen for both experiments. Experiments 1 and 2 lasted 28 and 70 days, respectively. In experiment 1, average daily gain(ADG) of all growth phases increased linearly(P < 0.05) with increasing supplementation of benzoic acid, which led to a linear improvement in average body weight on d 28(P < 0.05). There was also an improvement in feed conversion ratio(FCR) of d 0 to 14(linear effect: P < 0.05) and in average daily feed intake(ADFI) of d 14 to 28 and d 0 to 28(linear effect:P < 0.01). In experiment 2, ADG during d 0 to 35 and d 35 to 70 and average body weight on d 35 improved linearly(P < 0.05) with increasing supplementation of benzoic acid. Average daily gain of d 0 to70 and average body weight on d 70 increased significantly in a both linear and quadratic manner. There was a linear improvement in FCR in all growth phases(P < 0.05). In conclusion, the dietary inclusion of benzoic acid at the supplementation levels of 0.3% and 0.5% significantly improved the growth performance of nursery and grower-finisher pigs in the current study; the nursery pigs responded to the dietary supplementation of benzoic acid up to 0.5% linearly while the grower-finisher pigs achieved the optimal ADG at the calculated supplementation level of 0.36%.

The effects of Lippia javanica dietary inclusion on growth performance,carcass characteristics and fatty acid profiles of broiler chickens

This study was conducted to determine the effect of inclusion of fever tea(Lippia javanica) leaf meal in broiler diets on growth performance, carcass characteristics and fatty acid(FA) profiles over a 42-day feeding period. One hundred and eighty, one-day-old, broiler chicks were randomly allocated to the following four treatments: 1) negative control(commercial broiler diet only [Negcontrol]); 2) positive control(commercial broiler diet + prophylactic antibiotics [Poscontrol]); 3) commercial broiler diet without prophylactic antibiotics + 5 g of L. javanica per kg of feed(Ljav5) and 4) commercial broiler diet without prophylactic antibiotics + 12 g of L. javanica per kg of feed(Ljav12). Body weights(BW) and feed intake(FI) were recorded weekly and used to calculate feed conversion ratio(FCR) and average daily weight gain(ADG). At the end of the trial(day 42),all chickens were slaughtered at a local commercial abattoir for assessment of carcass characteristics and FA profiles of meat. The broilers fed L. javanica had significantly(P < 0.05) lower FI compared with the other two groups. However,the broilers in the Poscontrol and Ljav5 treatment groups had higher(P < 0.05) ADG, lower FCR and higher slaughter weights. L. javanica inclusion had no effect on the breast weight, thigh weight, carcass weight, and dressing percentage of the broilers. Most of the n-3 FA were not affected by diets except for the docosapentaenoic, which was found to be higher(P < 0.05) in the Ljav12 treatment group and the lowest in the Negcontrol. The broilers in the Negcontrol and Poscontrol groups had higher(P < 0.05) total saturated fatty acids(SFA). On the contrary, the L. javanica fed broilers had higher(P < 0.05) total polyunsaturated fatty acids(PUFA), total n-3 FA and PUFA:SFA ratio and also had significantly lower n-6:n-3 ratios compared with the other two treatment groups. No differences were observed with regards to total monounsaturated fatty acids(MUFA) and total n-6 FA. Overall, the findings from the study showed that inclusion of L. javanica in broiler diets at 5 g/kg feed has positive influences on growth performance,carcass characteristics and FA profiles of broiler meat.