Effect of dietary niacin supplementation on phlorhizin and 1,3-butanediol-induced ketonemia and hypoglycemia in steers

1,3-Butanediol and phlorhizin were used to induce ketonemia and hypoglycemia in steers. Oral administration of butanediol increased blood beta-hydroxybutyrate (BHB) and plasma nonesterified fatty acids (NEFA) and decreased serum glucose. Subcutaneous injections of phlorhizin, given in addition to butanediol orally, further increased NEFA and BHB concentrations and decreased glucose. Dietary niacin supplementation of steers given phlorhizin and butanediol caused serum glucose concentration to increase and blood BHB and plasma NEFA concentrations to decrease.     

Diurnal variation and the effect of feed restriction on plasma and milk metabolites in TMR-fed dairy cows

The objective was to study the diurnal variation in metabolites in plasma and milk of dairy cows fed total mixed rations (TMR) with a low-energy (LE) or high-energy content (HE) expected to give a minor and a major diurnal variation, respectively. Further, the purpose was to quantify and compare the responses in plasma and milk parameters when cows changed from ad libitum to restrictive feeding. Eight multiparous, early-lactating Danish Holstein cows were used in a cross-over design with two consecutive 14-day periods. Blood and milk samples were collected hourly on day 11 of each period and on days 12-14 of each period, the cows were fed restrictively (65% of ad libitum dry-matter intake). The concentration of beta-hydroxybutyrate (BHB) in plasma was significantly higher in the evening for cows fed the HE TMR, than for cows fed the LE TMR. There was a significant diurnal variation in BHB in milk, with the highest concentrations between milkings and the lowest concentrations at milking. Non-esterified fatty acids (NEFA) in plasma showed significant diurnal variation that was caused by high concentrations in the morning. Plasma glucose did not show any diurnal variation. It has been argued that feeding a TMR removes diurnal changes related to feeding, which is contrary to earlier diurnal studies where concentrates have been fed twice daily. Feed restriction increased (P < 0.001) NEFA and BHB in plasma by 121 and 90%, respectively, while the glucose concentration decreased (P < 0.001) by 19%. Milk concentrations of BHB, citrate and fat increased (P < 0.001) by 163, 11 and 26%, respectively, because of feed restriction, while there were no changes in milk protein and lactose. The relatively high increase in BHB during feed restriction suggests that BHB is more advantageous as a milk indicator of metabolic status in dairy cows than citrate and fat.     

Evaluation of estimated genetic merit for carcass weight in beef cattle: Blood metabolites, carcass measurements, carcass composition and selected non-carcass components

In Ireland, a new beef genetic index has been developed. Growth rate is expressed as expected progeny difference for carcass weight (EPD_CWT) and is estimated on an across-breed basis. Cross-breeding of dairy cows with both Aberdeen Angus and Belgian Blue beef sires is widely practised. The objective of this study was to compare blood metabolites, slaughter traits and carcass composition of progeny from Holstein–Friesian dairy cows and Aberdeen Angus (AA), Belgian Blue (BB), Friesian (FR) and Holstein (HO) sires. The AA and BB sires were selected, within breed, to be of either high (H) or low (L) estimated genetic merit for carcass weight. A total of 170 male progeny from spring-calving cows and 42 sires (10 AA, 13 BB, 7 FR and 12 HO) were artificially reared indoors and managed together until the end of their second grazing season when they were assigned to either a Light (560 kg) or Heavy (620 kg) slaughter weight. Blood metabolite concentrations were measured six times throughout life and feed intake was recorded during the first and second winter. Carcass measurements and selected non-carcass components were recorded after slaughter and the right side of each carcass was dissected into lean, fat and bone. Differences in blood metabolite concentrations amongst genetic groups were negligible although there were some effects of the prevailing level of nutrition. M. longissimus area scaled for carcass weight was 0.220, 0.221, 0.260, 0.255, 0.212 and 0.208 (SE 0.004) cm²/kg for AAH, AAL, BBH, BBL, FR and HO, respectively. Carcass measurements scaled for carcass weight were greater for L, AA, HO and the dairy strains than for H, BB, FR and the beef breeds, respectively. There was no effect of estimated genetic merit for carcass weight on carcass composition. Statistically significant interactions between genetic merit and beef breed existed for some traits with the genetic merit effect largely evident for AA only. BB and the beef breeds had more lean, less fat and more high value lean in the carcass than AA and the dairy strains, respectively. It is concluded that genetic group had little effect on blood metabolite concentrations but there were some feeding level effects. Estimated genetic merit for carcass weight affected carcass weight, m. longissimus area and carcass measurements scaled for carcass weight but the effects were confined to AA. There were large effects of beef breed and dairy strain on carcass composition.     

Phenotypic and genetic variation in body weight,food intake and energy utilisation in Hereford cattle I. Performance test results

From body weight, food intake and carcass composition data on 542 Hereford bull calves, measuredfrom 200 to 400 days, several traits relating to the efficiency of beef cattle production were derived and analysed. Traits included body weight at various ages, weight gain, predicted carcass lean content, lean growth rate, food intake, food conversion ratio, lean food conversion ratio, food intake in relation to metabolic body weight, energy required for protein and fat deposition, and predicted maintenance expenditure.Maintenance expenditure and the costs of fat and protein deposition were calculated by two means,firstly from allometric equations describing fat and protein accretion, and secondly from a multiple regression of food intake on weight gain and predicted carcass lean content. The two methods gave different mean values, but the correlations between traits calculated by the two methods were almost all 1.00. Exponents for metabolic body weight derived from the two methods were 0.738 and 0.758, respectively.Genetic parameters were calculated using multivariate Restricted Maximum Likelihood techniques.Body weight, carcass composition and traits combining these measurements were moderately to strongly inherited whereas traits related to food intake and efficiency were weakly to moderately inherited. Energy used to deposit fat and lean was more strongly inherited than predicted maintenance expenditure, and these traits were genetically almost uncorrelated. Maintenance energy expenditure showed no genetic relationship with predicted carcass lean content. Efficiency and predicted maintenance expenditure were favourably correlated.     

Correlated response to selection for litter size in pigs: II. Carcass,meat, and fat quality traits

Data on a pig line selected for litter size (H) and a control line (C) were used to estimate the correlated responses to litter size in carcass, meat, and fat quality traits. The differences between the genetic means of animals from line H and line C were used to estimate correlated responses. No differences were found between the two lines in carcass measurements except backfat depth, which was higher (P < 0.05) in line H (0.69 +/- 0.28 mm). This led to a decrease (P < 0.05) in predicted carcass lean content (-6.0 +/- 2.7 g/kg). Differences in joint weight distribution between lines were primarily due to belly weight, which was higher (P < 0.05) in line H (6.3 +/- 1.2 g/kg). There were no important changes in meat quality traits. Chemical composition of semimembranosus muscle (SM) and subcutaneous backfat (SB) differed between lines only for DM in SB, which was higher (P < 0.05) in line H (15.1 +/- 7.1 mg/g), and for the fatty acid composition of intramuscular fat. The fatty acid profile in line H showed a lower (P < 0.01) proportion of polyunsaturated fatty acids (-14.7 +/- 4.8 mg/g FA), particularly with regard to the content of linoleic acid (-12.5 +/- 3.9 mg/g FA). It is concluded that selection for litter size reduced the lean content in the carcass but the proportion of high-priced cuts and meat quality traits were not affected. However, selection may lead to changes in the composition of intramuscular fat lipids towards a lower content of polyunsaturated fatty acids. The observed correlated effects can be interpreted assuming that selected pigs are more mature at the same weight, though the underlying genetic and physiologic processes that cause them are unknown. The results of this experiment indicate that the metabolic pathways taking part in fat metabolism should be considered first.     

Polymorphisms in genes of the somatotrophic axis are independently associated with milk production, udder health, survival and animal size in Holstein-Friesian dairy cattle

The somatotrophic axis consisting of pituitary-derived growth hormone and circulating insulin-like growth factor 1 has been well established as key regulators of animal health, metabolism, lactation, fertility, body composition and growth rate. The aim of this study was to simultaneously quantify the associations between SNPs in candidate genes of the somatotrophic axis (i.e., IGF-1, GH1 and GHR) with performance traits in Holstein-Friesian (HF) dairy cattle. Both novel SNPs identified previously by this group alongside other published SNPs within these genes were analysed for associations with performance in dairy cattle. Multiple regression analyses regressing genetic merit of up to 848 HF sires on novel SNPs (n = 76) and published SNPs (n = 33) were undertaken using weighted animal mixed linear models. Twenty-three SNPs were significantly associated with at least one of 18 traits analysed and involved in milk production, udder health, fertility and growth. Eight traits including milk fat composition, carcass conformation, stature, chest width, body depth, rump width, carcass and cull cow weight were independently associated with SNPs in two genes. Furthermore, for several traits including milk fat yield, somatic cell count, survival and carcass fat, SNPs in all three genes were independently associated with performance. Milk fat yield and carcass fat showed the highest number of independent associations across all three genes with five SNPs associated with both traits. The cumulative effects of the favourable alleles of all five SNPs across GH1, GHR and IGF-1 result in an increase of 5.9 kg and 28.6 units of milk fat and carcass fat, respectively. Cow survival was associated with a single SNP in each of the three genes with a cumulative allele effect of 1.5%. Independent effects of polymorphisms in GH1, GHR and IGF-1 reinforce the central role of the somatotrophic axis on animal development and performance.     

松辽黑猪IGF-Ⅰ基因外显子4多态性及与部分生产性能的关系

以IGF-Ⅰ基因作为松辽黑猪生长和胴体性状的候选基因，采用PCR-SSCP方法检测30头松辽黑猪IGF-Ⅰ基因外显子4(179 bp)的多态性，对该基因的不同基因型与生长和胴体性状的关系进行分析。结果表明，IGF-Ⅰ基因的2个等位基因和3种基因型在松辽黑猪中均有不同频率的分布，遗传多态性较高; IGF-Ⅰ不同基因型对断奶后日增重有显著影响，AA型显著高于AB型和BB型(P<0.01)。AA型猪的瘦肉率显著低于AB型和BB型(P<0.01)，而AA型猪的平均背膘厚显著高于AB型和BB型(P<0.01)，对其它性状的影响差异不显著。因此，IGF-Ⅰ基因的遗传分析结果说明该基因对松辽黑猪的平均日增重、瘦肉率和平均背膘厚等3个性状有显著的遗传影响，可以初步推断IGF-Ⅰ基因可能是影响猪生长和胴体性状的一个主效基因或是一个与影响猪生长和胴体性状的QTL连锁的基因。     

Evaluation of purebred and crossbred rabbits for carcass merit

Two hundred twenty-six fryers representing four breed types, New Zealand White (NZW) and Californian (CAL) purebreds, CAL x NZW (CxN), and Flemish Giant (FG) terminal crossbreds (the latter group including FG x CAL, FG x CHA [CHA = Champagne D'Argent], and 1/2FG x 1/4CAL x 1/4CHA), were appraised for carcass merit. Evaluation criteria included the following: preslaughter and carcass weights; pelt, visceral, giblet, abdominal fat, and dressing percentages; percentages of carcass in loin, forequarter, and hindquarter primal cuts; and weight of lean in loin and ratio of lean to bone weight in loin cut. The least squares model consisted of breed type (B), season of birth (S), and gender (G) as fixed effects, B x G and S x G interactions, litter within B and S as a random variable, and random residual. Breed type influenced (P less than .10) all traits except giblet and forequarter cut percentages. Season of birth significantly influenced all all traits except percentage of loin cut. Gender of rabbit affected (P less than .05) only the percentage of forequarter cut. A B x G interaction was observed (P less than .05) for pelt and visceral percentages. The NZW control purebreds were generally inferior (P less than .05) to the three other breed types for carcass yield and cutability traits. Purebreds were lighter for preslaughter, carcass, and loin lean cut weights and lower for loin lean-to-bone ratio than were CxN crossbreds (P less than .05). The FG crossbreds had heavier preslaughter and carcass weights and a lower abdominal fat percentage (P less than .01) than NZW, CAL and CxN. Results of this study provide corroborative evidence in support of terminal crossbreeding using CAL sires with NZW dams and FG purebred or crossbred sires with CAL and CHA purebred or crossbred dams to improve carcass merit.     

Whole-genome QTL scan for ultrasound and carcass merit traits in beef cattle using Bayesian shrinkage method

Fine mapping of quantitative trait loci (QTL) for 16 ultrasound measurements and carcass merit traits that were collected from 418 hybrid steers was conducted using 1207 SNP markers covering the entire genome. These SNP markers were evaluated using a Bayesian shrinkage estimation method and the empirical critical significant thresholds (α = 0.05 and α = 0.01) were determined by permutation based on 3500 permuted datasets for each trait to control the genome-wide type I error rates. The analyses identified a total of 105 QTLs (p < 0.05) for seven ultrasound measure traits including ultrasound backfat, ultrasound marbling and ultrasound ribeye area and 113 QTLs for seven carcass merit traits of carcass weight, grade fat, average backfat, ribeye area, lean meat yield, marbling and yield grade. Proportion of phenotypic variance accounted for by a single QTL ranged from 0.06% for mean ultrasound backfat to 4.83% for carcass marbling (CMAR) score, while proportion of the phenotypic variance accounted for by all significant (p < 0.05) QTL identified for a single trait ranged from 4.54% for carcass weight to 23.87% for CMAR.     

产前运动对围产期奶牛生理代谢指标的影响

本试验旨在研究产前运动对围产期奶牛生理代谢指标的影响，为围产期奶牛健康管理提供科学指导和理论依据。试验选取年龄相似，体况评分、胎次和预产期相近的经产荷斯坦奶牛24头，随机分为试验组（TRT组）和对照组（CON组），每组12头，统一饲养管理。于预产期前21 d开始，TRT组奶牛每日09：00和16：00以<3 km/h的速度运动1 h，每头奶牛每日总运动量为（4.0±0.2） km/d；CON组自由活动。分别在预产期前21、7 d、分娩当天及产后7、30 d （分别记为－21、－7、0、+7和+30 d），于晨饲前采集血液，测定血浆中非酯化脂肪酸（NEFA）、β-羟基丁酸（BHBA）、葡萄糖（GLU）、甘油三酯（TG）、胆固醇（CHOL）、肌酐（CREA）及尿素（UREA）浓度。结果显示，试验期间，TRT组血浆NEFA、BHBA浓度与CON组相比均呈下降趋势（0.05<P<0.1），－7 d时TRT组NEFA浓度显著低于CON组（P<0.05）；TRT组血浆GLU浓度变化较CON组平稳，在＋30 d极显著高于CON组（P<0.01）；两组血浆TG浓度均在分娩当天急剧下降，产前血浆TG浓度均极显著高于分娩后各时间点（P<0.01），＋30 d时TRT组极显著高于CON组（P<0.01）；血浆UREA、CREA浓度在两组间无显著差异（P>0.05）。综上，以<3 km/h的速度进行运动（4.0 km/d±0.2 km/d），可有效降低围产期奶牛血浆NEFA和BHBA浓度，缓解能量负平衡（NEB）压力。     

Genetic associations of prolificacy with performance, carcass, meat quality, and leg conformation traits in the Finnish Landrace and Large White pig populations

The objective of this study was to estimate genetic associations of prolificacy traits with other traits under selection in the Finnish Landrace and Large White populations. The prolificacy traits evaluated were total number of piglets born, number of stillborn piglets, piglet mortality during suckling, age at first farrowing, and first farrowing interval. Genetic correlations were estimated with two performance traits (ADG and feed:gain ratio), with two carcass traits (lean percent and fat percent), with four meat quality traits (pH and L* values in longissimus dorsi and semimembranosus muscles), and with two leg conformation traits (overall leg action and buck-kneed forelegs). The data contained prolificacy information on 12,525 and 10,511 sows in the Finnish litter recording scheme and station testing records on 10,372 and 9,838 pigs in Landrace and Large White breeds, respectively. The genetic correlations were estimated by the restricted maximum likelihood method. The most substantial correlations were found between age at first farrowing and lean percent (0.19 in Landrace and 0.27 in Large White), and fat percent (-0.26 in Landrace and -0.18 in Large White), and between number of stillborn piglets and ADG (-0.38 in Landrace and -0.25 in Large White) and feed:gain (0.27 in Landrace and 0.12 in Large White). The correlations are indicative of the benefits of superior growth for piglets already at birth. Similarly, the correlations indicate that age at first farrowing is increasing owing to selection for carcass lean content. There was also clear favorable correlation between performance traits and piglet mortality from birth to weaning in Large White (r(g) was -0.43 between piglet mortality and ADG, and 0.42 between piglet mortality and feed:gain), but not in Landrace (corresponding correlations were 0.26 and -0.22). There was a general tendency that prolificacy traits were favorably correlated with performance traits, and unfavorably with carcass lean and fat percents, whereas there were no clear associations between prolificacy and meat quality or leg conformation. In conclusion, accuracy of estimated breeding values may be improved by accounting for genetic associations between prolificacy, carcass, and performance traits in a multitrait analysis.     

Effects of dietary soy isoflavones on growth, carcass traits, and meat quality in growing-finishing pigs

Two experiments were conducted to determine the effect of soy isoflavones on growth, meat quality, and carcass traits of growing-finishing pigs. In Exp. 1, 36 barrows (initial and final BW, 26 and 113 kg, respectively) were used and each treatment was replicated four times with three pigs each. The dietary treatments were 1) corn-soybean meal (C-SBM), 2) corn-soy protein concentrate (low isoflavones, C-SPC), or 3) C-SPC + isoflavones (isoflavone levels equal to those in C-SBM). Daily gain and ADFI were increased (P < 0.10) in pigs fed the C-SPC relative to pigs fed the C-SPC + isoflavone diet in the late finishing period; otherwise, growth performance was not affected (P > 0.10) by diet. Longissimus muscle area, 10th-rib fat depth, percentage muscling (National Pork Producers Council), 24-h pH and temperature, color, firmness-wetness, marbling, drip loss, and CIE L*, a*, and b* color values were not affected (P > 0.10) by diet. Dressing percentage, carcass length, weight and percentage of fat-free lean in ham and carcass, lean gain per day, lean:fat, and ham weight were increased (P < 0.10), and ham fat and percentage fat in ham and carcass were decreased (P < 0.10) in pigs fed the C-SPC + isoflavone diet compared with pigs fed the C-SPC diet. Pigs fed the C-SPC + isoflavone diet had similar (P > 0.10) carcass traits as pigs fed the C-SBM diet, except carcass length, percentage ham lean and thaw loss were greater (P < 0.10), and total ham fat was less (P < 0.10) in pigs fed the C-SPC + isoflavone diet. In Exp. 2, 60 gilts (initial and final BW, 31 and 116 kg, respectively) were used, and each treatment was replicated five times with four pigs per replicate. The treatments were 1) C-SBM, 2) C-SBM + isoflavone levels two times those in C-SBM, and 3) C-SBM + isoflavone levels five times those in C-SBM. Daily feed intake was linearly decreased (P < 0.10) in the growing phase and increased (P < 0.10) in the late finishing phases as isoflavone levels increased; otherwise, growth performance was not affected (P > 0.10) by diet. Diet did not affect (P > 0.10) carcass traits; however, CIE a* and b* color scores and drip loss were decreased (P < 0.06) as isoflavone levels increased. Soy isoflavones decreased fat and increased lean in barrows when fed within the dietary concentrations found in typical C-SBM diets but not when fed to gilts at concentrations above those present in C-SBM diets.     

Endocrine characteristics of late pregnant hyperketonaemic ewes and their reproductive performance following the induction of ovarian cyclicity out of the breeding season

Ketosis was diagnosed in a flock of Merino ewes that conceived from synchronised oestrus in the early autumn period. On day 140 of pregnancy the ewes were sampled for determination of betaOH-butyrate (BHB), AST, glucose, non-esterified fatty acids (NEFA), total cholesterol (TCH), insulin, T4, T3, cortisol, IGF-1 and leptin. The results were evaluated according to the number of fetuses born some days later and the presence of hyperketonaemia (BHB: > or = 1.60 mmol/l). In May, about 3 months after lambing, cyclic ovarian function was induced (Cronolone + eCG), and the ewes were inseminated artificially (AI) 48 h after the removal of gestagen-containing sponge. At the time of AI and 10 days later blood samples were collected again to check the plasma levels of the same constituents as previously (in samples taken at AI), and to monitor the ovarian response by assaying progesterone (in both samples). On day 140 of gestation significantly lower BHB levels were detected in dams with single (n = 41) than in those with twin (n = 57) pregnancies. Hyperketonaemia was found only in ewes bearing twins (n = 27). These animals had higher NEFA and cortisol, and lower TCH, insulin, IGF-1, leptin and T3 levels than their normoketonaemic twin-bearing flock-mates, and those with single pregnancy. The blood glucose concentrations varied within a wide range, and the means of groups did not exhibit any significant differences. The formerly hyperketonaemic individuals were characterised by lower leptin level 3 months after lambing, and they showed a poorer response to the cycle-induction procedure than the others. The non-responders had lower IGF-1 and leptin levels than those ovulated after this treatment. It was concluded that the subclinical form of ovine ketosis is characterised by complex endocrine alterations, reflecting an obvious form of negative energy balance. If attempts to induce cyclic ovarian function outside the breeding season are made soon after lambing, the ovarian response and fertility of these ewes may also be depressed.     

Genetic correlations between live yearling bull and steer carcass traits adjusted to different slaughter end points. 1. Carcass lean percentage

We studied genetic relationships between age-constant live yearling beef bull growth and ultrasound traits and steer carcass traits with dissected steer carcass lean percentage adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant end points. Three measures of steer carcass lean percentage were used. Blue Tag lean percentage (BTLean) was predicted from HCW, fat depth, and LM area measurements. Ruler lean percentage (RulerLean) was predicted from carcass fat depth and LM depth and width measurements. Dissected lean percentage (DissLean) was based on dissection of the 10-11-12th rib section. Both BTLean (h2 = 0.30 to 0.44) and DissLean (h2 = 0.34 to 0.39) were more heritable than RulerLean (h2 = 0.05 to 0.14) at all end points. Genetic correlations among DissLean and RulerLean (rg = 0.61 to 0.70), DissLean and BTLean (rg = 0.56 to 0.72), and BTLean and RulerLean (rg = 0.59 to 0.90) indicated that these traits were not genetically identical. Adjusting Diss-Lean to different end points changed the magnitude, but generally not the direction, of genetic correlations with indicator traits. Ultrasound scan-age-constant live yearling bull lean percentage estimates were heritable (h2 = 0.26 to 0.42) and genetically correlated with each other (rg = 0.68 to 0.99) but had greater correlations with DissLean at slaughter age (rg = 0.24 to 0.48) and HCW (rg = 0.16 to 0.40) end points than at fat depth (rg = -0.08 to 0.13) and marbling score (rg = 0.02 to 0.11) end points. Scan-age-constant yearling bull ultrasound fat depth also had stronger correlations with DissLean at slaughter age (rg = -0.34) and HCW (rg = -0.25) than at fat depth (rg = -0.02) and marbling score (rg = -0.03) end points. Yearling bull scan-age-constant ultrasound LM area was positively correlated with DissLean at all endpoints (rg = 0.11 to 0.23). Genetic correlations between yearling bull LM method 1 width (rg = 0.38 to 0.56) and method 2 depth (rg = -0.17 to -0.38) measurements with DissLean suggested that LM shape may be a valuable addition to genetic improvement programs for carcass lean percentage at slaughter age, HCW, and fat depth constant end points. At all end points, steer carcass fat depth (rg = -0.60 to -0.64) and LM area (rg = 0.48 to 0.59) had stronger associations with DissLean than did corresponding live yearling bull measurements. Improved methods that combine live ultrasound and carcass traits would be beneficial for evaluating carcass lean percentage at fat depth or marbling score end points.     

Effects of betaine on growth, carcass characteristics, pork quality, and plasma metabolites of finishing pigs

An experiment was conducted to determine the effect of dietary betaine (0, 0.125, 0.250, or 0.500%) on growth, carcass traits, pork quality, plasma metabolites, and tissue betaine concentrations of cross-bred finishing pigs. Four replications of three pigs (two barrows and one gilt) each were used for each treatment. The basal diet contained 0.85 (69 to 88 kg BW) or 0.65% Lys (88 to 115 kg BW). Overall ADG and gain:feed were not affected (P > 0.10) by betaine, but overall ADFI was decreased (quadratic, P < 0.05; 0 vs betaine, P < 0.01) by betaine; pigs fed 0.250% betaine had the lowest ADFI. Loin muscle area, average back-fat, dressing percentage, percentage lean, total fat, lean:fat, and leaf fat weight were not affected (P > 0.10) by betaine. Tenth-rib backfat thickness was decreased (quadratic, P < 0.05; 0 vs betaine, P < 0.05); pigs fed 0.250% betaine had the lowest 10th-rib backfat thickness. Carcass length was increased (linear, P < 0.05; 0 vs betaine, P < 0.10) as the level of betaine was increased. Fat-free lean, lean gain per day, ham weight, ham fat-free lean, and ham percentage lean were increased (quadratic, P < 0.10), but percentage fat, total ham fat, percentage ham fat, and butt-fat thickness were decreased (quadratic, P < 0.10); these traits were respectively highest or lowest in pigs fed 0.250% betaine. Thaw loss and 24-h pH were increased (quadratic, P < 0.10; 0 vs betaine, P < 0.05) and cook loss was decreased (linear, P < 0.05) in pigs fed betaine. The CIE L* value for the biceps femoris was decreased (quadratic, P < 0.10; 0 vs betaine, P < 0.10); pigs fed 0.250% betaine had the lowest CIE L* value. Subjective color, firmness-wetness, marbling, percentage moisture and bound water of the loin muscle, and shear force were not affected (P > 0.10) by betaine. Betaine was not detectable (< 0.07 mg/g) in the loin muscle of pigs fed 0% betaine, but betaine was detectable and relatively constant in pigs fed 0.125, 0.250, or 0.500% betaine (0.22, 0.17, and 0.21 mg/g, respectively). Plasma urea N, total protein, albumin, triglycerides, and HDL cholesterol concentrations were not affected (P > 0.10). Plasma total cholesterol (linear, P < 0.10) and NEFA (quadratic, P < 0.10) were increased in pigs fed betaine. Betaine improved carcass traits when provided at 0.250% of the diet and improved some aspects of pork quality.     

Effect of short-term fasting on plasma concentrations of leptin and other hormones and metabolites in dairy cattle

We determined the effects of short-term fasting and refeeding on temporal changes in plasma concentrations of leptin, insulin, insulin-like growth factor- 1 (IGF-1), growth hormone (GH), glucose, and nonesterified fatty acids (NEFA), in early lactating cows, non-lactating pregnant cows, and postpubertal heifers. In experiment 1, Holstein cows in early lactation were either fed ad libitum (Control, n=5) or feed deprived for 48 h (Fasted, n=6). Plasma leptin, insulin, and glucose concentrations rapidly declined (P<0.05) within 6h, and IGF-1 by 12h, but all these variables sharply returned to control levels (P>0.10) within 2h of refeeding. Plasma NEFA and GH concentrations were elevated (P<0.05) by 4 and 36 h of fasting and returned to control levels (P>0.10) by 8 and 24h after refeeding, respectively. In experiment 2, four ruminally cannulated pregnant non-lactating Holstein cows were used in a cross-over design and were fasted for 48 h (Fasted) or fasted with partial evacuation of rumen contents (Fasted-Evac). The plasma variables measured did not differ (P>0.10) between Fasted and Fasted-Evac cows. Plasma leptin, insulin, and IGF-1 concentrations were reduced by 10, 6, and 24h of fasting, respectively, in Fasted-Evac cows; and these variables were reduced by 24h in Fasted cows (P<0.05). Plasma glucose levels were reduced (P<0.05) by 48 h of fasting in both groups of fasted animals. Plasma NEFA and GH levels were increased (P<0.05) by 12 and 48 h of fasting, respectively. In experiment 3, postpubertal Holstein heifers were either fed ad libitum (Control, n=4) or feed deprived for 72 h (Fasted, n=5). Concentrations of leptin, insulin, IGF-1, and glucose in plasma were reduced (P<0.05) by 24, 10, 24, and 48 h of fasting, respectively. Plasma NEFA concentrations increased (P<0.05) by 4h, of fasting while GH levels were not significantly (P>0.10) affected by fasting. Collectively, our data provide evidence that plasma leptin concentrations are reduced with short-term fasting and rebound on refeeding in dairy cattle with the response dependent on the physiological state of the animals. Compared to the rapid induction of hypoleptinemia with fasting of early lactation cows, the fasting-induced hypoleptinemia was delayed in non-lactating cows and postpubertal heifers.     

Effect of colostrum intake on plasma glucose, non-esterified fatty acid and glucoregulatory hormone patterns in the neonatal pig

The effect of colostrum on endocrine and metabolic factors affecting glucose homeostasis was evaluated in 60 neonatal pigs that were fasted, fed (nursed ad libitum) or limit-fed colostrum (25% ad libitum, 4-hr interval feeding). Plasma acquired at birth (t0), and after 10, 20 and 30 hr (t10, t20 and t30, respectively) was analyzed for glucose, non-esterified fatty acids (NEFA), and the glucoregulatory hormones--insulin, glucagon, cortisol, growth hormone and catecholamines. The concentration of glucose and NEFA was similar among treatment groups at birth and increased in proportion to the quantity of colostrum consumed. Pigs fed ad libitum achieved and maintained a higher (greater than or equal to 40%; P less than .01) glucose concentration when compared to fasted neonates. Limit-fed counterparts also achieved and maintained higher levels, with glucose concentration being approximately 20% higher throughout (P less than .05). Fed pigs maintained NEFA concentrations which were approximately 2.5-fold to 4-fold greater than that of fasted pigs (P less than .05). Likewise, limit-fed pigs tended (P = .19) to have elevated NEFA concentrations and a lower (P less than .05) insulin:glucagon molar ratio. An inverse relationship was observed between colostrum intake and plasma concentrations of cortisol and growth hormone. Concentrations of epinephrine and norepinephrine tended (P greater than .10) to be elevated in fed pigs, relative to those of fasted counterparts. Provision of even limited quantities of colostrum is therefore beneficial to the glucoregulatory response in newborn pigs.     

Effect of heat stress on adipokines and some blood metabolites in goats from Jordan

To date and to the best of our knowledge, there have been no available data on the interaction between heat stress (HS) and secretion of adipokines and some blood metabolites in Baladi goats from Jordan. Therefore, this study aimed at evaluating the changes in leptin, adiponectin, non‐ester fatty acid (NEFA) and beta‐hydroxybutyrate (BHB) concentrations in Baladi goats under HS conditions in Jordan. Six goats were exposed to direct solar radiation versus six goats exposed to shade regimen. Blood samples were collected and serum concentrations of leptin, adiponectin, NEFA and BHB were measured. Ambient temperature, relative humidity (RH) and body weight (BW) were recorded. Results indicated that leptin and adiponectin concentrations were significantly increased under HS. The concentration of NEFA was significantly increased under HS at the 7th and 14th days of the experiment, while mean total concentration of NEFA was not significantly affected by HS. Neither weekly nor mean total concentrations of BHB were significantly affected by HS during the experimental period. In conclusion, HS is associated with changes in leptin and adiponectin concentrations in Baladi goats. Heat‐stressed goats were able to keep their blood NEFA and BHB concentrations similar to those of thermo‐neutral goats.     

不同体重商品猪胴体性能肉质性状及其相关程度研究

研究测定了92～109 kg体重阶段31头杂交商品猪的胴体品质和肉质特性，以分析商品猪胴体、肌肉品质随体重的变化规律及其相关程度，为确定适宜上市屠宰体重提供依据。结果表明，商品猪在92～95 kg阶段屠宰瘦肉率最高为61.17％，分别比其它3组提高4.83％（P>0.05）、11.83％（P<0.05）和8.84％（P<0.05）；在107～109 kg阶段屠宰肉品质〖JP2〗优良，肌肉pH 6.07，肉色和大理石纹评分较高分别为3.13和 3.33，肌内脂肪含量较高为3.89％，肌肉失水率较低为18.91％。胴体和肉质性状间相关程度有强有弱，相关系数有正有负。相同性状间有较强的正相关，相反性状间有较强的负相关。综合分析试验结果认为，注重产肉量强调胴体瘦肉率时可选择在92～95 kg阶段屠宰；注重肉品质时可选择107～109 kg阶段屠宰；若二者兼顾则选择95~98 kg阶段屠宰较为合适。     

大约克猪背最长肌肌糖原含量与胴体品质及肉质相关分析

为分析大约克猪肌糖原含量与胴体品质及肉质的相关关系,将18头体重35 kg左右的大约克猪在相同条件下饲养,体重达100 kg时屠宰,测定肌糖原、胴体品质及肉质。结果表明,肌糖原含量与胴体品质及肉质性状间相关程度有强有弱,相关系数有正有负。肌糖原含量与部分胴体性状相关性显著,与瘦肉率显著正相关,相关系数为0.524（P〈0.05）;与脂肪率显著负相关,相关系数为-0.520（P〈0.05）。肌糖原含量与部分肉质性状相关性显著,如与pH1显著正相关,相关系数为0.613（P〈0.05）,与其他肉质性状相关较弱。肌糖原含量与背最长肌甘氨酸和亚油酸含量极显著正相关,相关系数分别为0.598（P〈0.01）和0.621（P〈0.01）。