Therapeutic management of copper deficiency in buffalo heifers: Impact on immune function

To evaluate the magnitude of copper deficiency in Northern India and to examine the various haematobiochemicals, enzymes, vitamins and immune functions affected by copper deficiency, and to identify the parameters which can be of diagnostic importance in copper deficiency, a survey was conducted in 12 districts of Northern India. Significant deficiency of copper was observed in soil, fodder and serum samples of buffalo heifers. Fifty hypocuperaemic buffalo heifers were selected from these areas and were randomly divided into two groups, A and B. The heifers in group A were provided with mineral mixture containing copper sulphate and in group B without copper sulphate. Significant (p < 0.01) improvement in serum ceruloplasmin level was observed within 30 days of treatment, while significant (p < 0.01) improvement in monoamine oxidase and liver cytochrome oxidase was observed at the 60th day of treatment in group A animals. Significant improvement was observed in T₃ and T₄, in the animals of group A within 60 days of treatment. The values of vitamin A and E showed significant (p < 0.01) improvement within 30 days of treatment. The phagocytic activity of neutrophils against Candida albicans significantly (p < 0.01) improved in group A within 60 days of treatment. Similarly, significant improvement in superoxide dismutase activity in red blood cells was observed at the 30th day, and in total leukocytes and whole blood at the 60th day in group A animals. Significant improvement in liver copper level was observed at the 30th day of treatment, while in group B the liver copper was significantly (p < 0.01) depleted at the 60th day of experimentation. Additional copper supplementation improved growth performance significantly in group A.     

Therapeutic Efficacy of Zinc Sulphate Used in Clustered Model Treatment in Alleviating Zinc Deficiency in Cattle and Its Effect on Hormones,Vitamins and Production Parameters

A survey was conducted in 10 districts of northern India. Significant deficiency of zinc was observed in soil, fodders and (cattle) serum samples. The animals showed typical signs of zinc deficiency, namely stiff gait, swelling of hocks and knees, subcutaneous fluid accumulation, rough coat, etc. of variable intensity. A clustered model therapeutic trial was conducted and zinc-deficient cattle were divided into three groups. Group A was provided with mineral mixture containing zinc sulphate. Group B was given mineral mixture without zinc sulphate and group C was given no mineral mixture. Significant improvement (p < 0.01) was observed in the haemoglobin (Hb), total white blood cells (WBC) and total erythrocyte count (TEC) levels at the 7th day of treatment in the animals of group A. Significant improvement in enzyme serum alkaline phosphatase (SAP) was observed in group A animals at the 7th day, while improvement in asparatate aminotransferase (AST), alanine aminotransferase (ALT) and ceruloplasmin (Cp) was observed after 21 days of treatment. Regarding hormones, significant improvement was observed in thyroxine (T₃) and triiodothyronine (T₄), oestrogen and progesterone in group A animals within 14 days of treatment. The values of vitamin A showed a highly significant (p < 0.01) improvement within 7 days of treatment in group A animals and that of vitamin E on the 21 st day of treatment. The milk yield of lactating cattle and body weight of growing calves in group A showed highly significant (p < 0.01) increases at about 14 and 30 days, respectively. It is concluded that zinc sulphate supplementation is highly effective in alleviating zinc deficiency and improving various biochemical and production parameters in cattle. The clustered model treatment provides a better indicator of the most limiting element under field conditions where simultaneous deficiency of various minerals is prevalent.     

The effect of beta-carotene on thyroxine and cholesterol levels in pregnant heifers before and after parturition

Thyroxine (T4) and cholesterol concentrations and their dynamic changes and differences were studied in 20 pregnant heifers 10 days before calving until 56 days after calving. Ten control heifers were fed the feed ration for pregnant heifers according to Czechoslovak Standard CSN 46 7070. The feed ration given to another ten (experimental) heifers was fortified with 300 mg of synthetic beta-carotene per head/day within the period of five months before insemination, during pregnancy and till the 56th day after parturition. As suggested by the regression function of straight line, no obvious differences were recorded in the dynamic changes of T4 before parturition and during the first days after parturition. T4 concentrations had a generally descending tendency in both groups, the lowest values being recorded in the 48th hour in the experimental group and the 24th hour in the control. A marked increase of T4 concentrations with the values significantly higher in the control group than in the experimental group was observed between the 21st and 35th day after calving. A medium increase of cholesterol concentrations was found in the heifers given rations fortified with beta-carotene. No significant differences in cholesterol concentrations were observed between the two groups, except in the 72nd hour and the seventh day. Significant T4: cholesterol correlations were recorded in the experimental animals in the first and second hours, on the 42nd day (P less than 0.05), and in the 72nd hour (P less than 0.001); in the control group these observations were made the seventh day before calving and in the sixth hour and on the 14th, 21st and 56th days (P less than 0.05) after calving. It is inferred from the results that beta-carotene interferes with the activity of the thyroid gland and the production of its hormones, and that the increases or decreases of the activity of this gland, caused by beta-carotene, influence the metabolism of cholesterol in the body.     

Effects of growth hormone-releasing factor on growth hormone response, growth and feed conversion efficiency in buffalo heifers (Bubalus bubalis)

The aim of this study was to determine the benefits of growth hormone-releasing factor (GRF) on growth and feed conversion efficiency (FCE) in buffaloes. Twelve Murrah buffalo heifers (Bubalus bubalis) of mean age 24.8 months and mean body weight 302.4kg were divided into two groups (treatment and control) with six animals in each group. The buffaloes were given intravenous injections of bovine GRF (bGRF) at a dose rate of 10microg/100kg body weight or an equal volume of saline at 15-day intervals for a period of 9 months. Plasma growth hormone (GH) responses to bGRF challenge were measured in blood samples collected at 90-day intervals on days 1, 90, 180 and 270 and samples were taken at -60, -30, 0, +10, +20, +30, +60, +120 and +180min relative to bGRF injection. Blood samples were also collected weekly by jugular venepuncture for the quantification of plasma GH. The average growth rate (AGR) and FCE of all animals were recorded at 15-day intervals. Plasma GH concentrations increased (P=0.001) steadily following bGRF challenge, peaking 10-20min after challenge and declining to baseline by 180min. In the treatment group, there were no significant differences (P>0.05) in either the peak heights of the GH response or the area under the curve (AUC) of the GH response after bGRF challenge on any of the four occasions of intensive bleeding. There were overall increases in plasma GH concentrations (P<0.01), AGR (P<0.01) and FCE (P=0.05) in the treatment group compared with the control animals. The study showed that GH responsiveness to administration of bGRF at 15-day intervals over 9 months of treatment remained unchanged in buffalo heifers. Exogenous bGRF treatment for a long period can therefore enhance GH release leading to higher growth rates and better feed conversion efficiency in buffalo heifers.     

中药对鸡实验性汞中毒临床症状和病变的影响

通过观察中药对实验性汞中毒鸡病变的影响,为中药治疗汞中毒提供基础资料。将试验鸡(脱温鸡苗72只)随机分为3组,每组24只,分别为空白对照组,阳性对照组和中药治疗组。试验动物于第20、40、60天时,处死试验鸡,观察脏器指数,取肝、脾和肾制作组织切片,观察病变。试验结果表明,中药在60日龄时,明显缓解鸡汞中毒临床症状;阳性对照组第20天脏器指数明显高于空白对照组(P0.05),阳性对照组第40和第60天增加更为显著(P0.01);与阳性对照组比较,中药治疗第40天各脏器指数显著下降(P0.05),第60天下降极显著(P0.01);中药能缓解汞中毒鸡组织病变。由此推断中药可缓解汞中毒鸡组织器官损伤。     

Impact of trace mineral source on beef replacement heifer growth,reproductive development,and biomarkers of maternal recognition of pregnancy and embryo survival

Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Beef heifers (n = 129) were randomly assigned to one of two treatments. From weaning through breeding, all heifers were individually fed a basal diet supplemented with cobalt (Co), copper (Cu), manganese (Mn), and zinc (Zn) either from organic sources (COMP; Cu, Mn, and Zn amino acid complexes and Co glucoheptonate; Availa-4, Zinpro Corporation, Eden Prairie, MN) or inorganic sources (INORG; Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z, Micronutrients, Indianapolis, IN) and Co as CoSO₄. Blood samples and a reproductive tract score (RTS) were collected to determine pubertal status. All animals were synchronized and artificially inseminated. Pregnancy status was determined by lymphocyte gene expression, circulating concentrations of pregnancy-associated glycoproteins (PAGs), and by transrectal ultrasonography after artificial insemination. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a tendency (P = 0.13) for decreased embryonic loss among COMP heifers (27 ± 6%) compared to INORG heifers (38 ± 6%). There was a treatment by pregnancy status by time interaction (P < 0.01) on circulating PAG concentrations with PAG concentrations tending (P = 0.08) to be greater on day 25 among heifers in the COMP treatment compared to heifers in the INORG group. In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase circulating PAG concentrations and embryo survival.     

A Possible Association between Dietary Intake of Copper,Zinc and Phosphate and Delayed Puberty in Heifers in Sudan

Zinc and copper deficiencies have been reported in heifers of various breeds at four different locations in Sudan. These were Kuku (5 km north of Khartoum), Seleit (20 km northwest of Khartoum), Medani (180 km south of Khartoum) and El Obeid (600 km west of Khartoum). Phosphorus deficiency was only observed in the serum of heifers at El Obeid. The heifers at all locations showed delayed puberty, stunted growth and infertility. The heifers of the local breeds at El Obeid only attained puberty by 1530 days of age compared with 840 days for the pure Friesian heifers at Seleit. The crossbred animals at Kuku and Medani attained puberty at 1440 and 1020 days of age, respectively. The marginal or low zinc and copper contents in pasture, soil or animal feed may have been predisposing factors for the observed deficiencies and might have been responsible for the delayed age of puberty.     

Efficacy of intravaginal progesterone administration as an additional treatment on two types of timed AI protocols in a commercial herd of Holstein heifers

Reproductive performance of two types of timed artificial insemination (TAI) protocols with or without intravaginal progesterone insert (CIDR) was investigated in a commercial herd of Holstein heifers. A total of seventy-four heifers with 14.4 months of age were allocated to two groups; Ovsynch (n=44) and estradiol benzoate (EB) used Heatsynch (EB-Heatsynch, n=30), and each group was additionally divided into two subgroups with CIDR insertion from day 0 to 7 (n=36) and without CIDR group (n=38). Blood was collected for progesterone (P4) analysis and ovarian finding was monitored with ultrasonography. Heifers in CIDR-treated group resulted in higher pregnancy rate as compared to No-CIDR-treated group (63.9% vs 21.1%, P<0.01). Heifers with functional corpus luteum (CL) on day 0 resulted in significantly higher pregnancy rate in CIDR-treated group than No-CIDR-treated group (day 0: 67.9% vs 13.0%, P<0.01). CIDR insertion suppressed the intermediate ovulation during the first 7 days and the period from the second GnRH or EB administration to TAI as compared to No-CIDR-treated group (first 7 days: 33.3% vs. 52.6%; P<0.05, before TAI: 11.1% vs. 37.0%; P<0.05). In conclusion, the selected TAI protocols with CIDR provided acceptable pregnancy rate and contributed to the economical improvement by shortening the average age of first calving approximately for 2.5 months as compared to the previous management without TAI protocols.     

健胃中药与木醋液对育肥猪血液指标的影响

选择45头体况良好60日龄左右杜长大三元杂交健康仔猪,分为3组,每组设3个重复,每组重复5头。各组添加药物成分,检测其血液指标的变化。A组添加0．5％中药制剂,B组添加0．5％木醋液,C组添加0．5％中药＋木醋液（1：1）。试验结果表明,淋巴细胞A、B、C3组之间差异极显著（P〈0．01）;谷草转氨酶、谷丙转氨酶A、C与B组之间差异极显著（P〈0．01）,总蛋白、白蛋白、球蛋白A组、C组与B组之间差异极显著（P〈0．01）,甘油三酯、总胆固醇B组与A组、C组之间差异极显著（P〈0．01）,这说明A、C两组在提高动物机体对营养物质消化吸收和代谢率、提高育肥猪免疫力方面优于B组,而B组在降低胆固醇和甘油三酯方面好于A、C两组。     

Intake of heavy metals (lead, cadmium, zinc) originating from colored paints and their incorporation into organs and tissues of heifers

In a feeding trial the effect of heavy metals as lead, cadmium and zinc originating from colour paints was investigated. The study included 30 early pregnant heifers subdivided in five groups with six animals each with an average body weight of 419 kgs. During the testing period the trial was carried out in a three factorial fashion with two time sections: section one--mineral supplementation and lead preexposure; section two--Exposure to heavy metal containing colour paint pigments. The investigation led to the following results: A short time uptake of daily 10 g lead containing colour paint (i.e. 22-24 mg Pb/per animal and day) did not cause any change of general health and normal behavior of the respective animals. A storage of lead in the body tissue could be observed by way of a hint. An additional prestress with lead (145-158 mg Pb/animal/day over a period of 84 days did not influence the general health of the animals significantly. Both the fodder uptake and the body weight gain was inconspecious. A storage of lead could be traced in the skeleton, kidney and liver and--on a reduced level--also in the muscle. Only the content of lead in the kidney exceeded the maxmium tolerated value (> 1.0 mg/kg) of the German Meat Hygiene regulation. A mineral deficient feeding regimen (especially lack of calcium) enhance an increased storage of lead in the tissues (skeleton).     

不同剂量的蛋氨酸铜对肉鸡肝脏病理组织结构和粪便铜含量的影响

选择1日龄健康AA肉仔鸡120只,随机分成4组。使用蛋氨酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个高铜试验组分别为:110mg/kg、220mg/kg和330mg/kg,试验至60日龄结束。于第12,36,60日龄在各组内随机采血,测定血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活性;测量60日龄各组肝脏和粪便的铜含量并观察肝脏组织病理变化。结果显示:①血清ALT和AST活性均在正常范围内,没有异常升高;②110mg/kg和220mg/kg组的肝脏组织中铜含量比对照组有所升高,但是差异不显著(P>0.05),而330mg/kg组则极显著高于其他3个试验组(P<0.01);110mg/kg,220mg/kg和330mg/kg组的粪便中铜含量均极显著高于对照组(P<0.01);③330mg/kg组的肝脏组织大部分细胞中度变性,其他各组病理变化不明显。试验结果表明,日粮中蛋氨酸铜浓度达到330mg/kg时,肝脏内的铜蓄积量会迅速增多且对肝脏造成较大的损伤,粪便中的铜含量随着日粮中铜含量的增加而迅速增多,可能对环境造成不利影响。     

Effect of feeding Lagerstroemia speciosa and conventional fodder based rations on nutrient utilization,ruminal metabolites and body weight gain in mithun (Bos frontalis)

The aim of the present study was to evaluate the effect of feeding green fodder, rice straw and concentrate‐based total mixed rations (TMR) on dry matter (DM) intake (DMI), nutrient utilization, rumen fermentation patterns and body weight (BW) gain (BWG) in mithun (Bos frontalis) calves. In a randomized block design, male mithun calves (n = 18, 8–10 months of age, 121 ± 2 kg BW) were randomly divided into three experimental equal groups (six animals in each group) and fed isonitrogenous TMRs ad libitum for 120 days. The TMR₁ contained 30% Napier grass and 30% rice straw, TMR₂ contained 60% rice straw and TMR₃ contained 30% tree leaves (Lagerstroemia speciosa) and 30% rice straw (DM basis). All the TMRs contained 40% concentrate mixture (DM basis). The results indicated that the BWG, DMI and feed conversion efficiency were significantly (p < 0.01) increased with the inclusion of green fodder in TMRs. The apparent digestibility of DM, crude protein, ether extract, crude fibre and nitrogen free extract were also improved significantly (p < 0.01) with the inclusion of green fodder in TMRs. The higher concentration of total nitrogen and total volatile fatty acid in rumen liquor, but low ruminal pH were evident in animals fed green fodder supplemented TMRs. An increased (p < 0.01) molar proportion of acetic acid was evident in animals fed rice straw‐based TMR. In contrast, the molar proportion of propionic and butyric acids were significantly (p < 0.01) higher in animals fed green fodder supplemented TMRs. On the basis of higher DMI and higher daily BWG, it is concluded that Napier grass and L. speciosa tree leaves may be incorporated upto 30% (DM basis) in TMR of growing mithuns for feeding in complete confinement system.     

Phagocytic activity of blood leukocytes and level of serum immunoglobulins and albumin after parenteral administration of zinc during vaccination against trichophytosis in calves

The study dealt with the evaluation of the contents of the total serum immunoglobulins (CS-Ig), serum albumin, and with the phagocytic activity of blood leucocytes in trichophytosis-affected calves (aged 4 months), in dependence on the doses (revaccination) of the live avirulent vaccine against trichophytosis (the calf group R) and its administration with a zinc based-injection preparation (calf group ZnR). In calf group ZnR (5 mg Zn.kg-1 l. w.) there was a potentiating effect on the percentual proportion of potential blood phagocytes (compared with data before administration: P less than 0.01 on the first day, P less than 0.05 on the third, eighth and thirtieth day; in comparison with the group of calves R: P less than 0.01 during a 24h experiment) and on the percentage of phagocytic cells (compared with data before administration: P less than 0.05 the first and 30th day; compared with calf group R: P less than 0.05 in a 24h experiment. No effect on the index of phagocytic activity was observed. In both groups positive statistical significance was stated in the level of CS-Ig, as compared with the value before administration (on the 8th, 15th, 30th and 60th day of investigation, P less than 0.05, resp. 0.01), but there was no significance when the groups were compared with each other. Significant increase was stated in serum immunoglobulin concentration on the 15th day of examination within each group of calves. Its concentration in calf group ZnR was lower at the beginning of the experiment and at the end of the experiment it was almost exactly the same as in calf group R.     

Intramuscular Selenium Administration in Selenium-Deficient Cattle

Nine recently weaned Hereford heifers were randomly assigned to a control group (n = 3) or a treatment group (n = 6). The animals were selenium (Se) deficient (mean ± SD blood Se concentration = 0.024 ± 0.012 μg/mL). They were maintained on a selenium-deficient diet, and on day 0 of the study the treatment group was given 0.05 mg Se/kg body weight intramuscularly, while the control group received a placebo. The Se concentration of blood, serum, and urine as well as the glutathione peroxidase (GSH-Px) activity of blood and serum was measured over an 84-day period. Peak blood Se and serum Se concentrations (mean ± SD) in the treatment group occurred at 5 hours postinjection and were 0.131 ± 0.028 μg/mL and 0.154 ± 0.027 μg/mL, respectively. The mean blood Se concentration of the treatment group was greater (P < .05) than that of the control group for the first 28 days after injection. The mean serum Se concentration of the treatment group was greater (P < .05) than that of the control group for all times after injection, except for day 56. The mean (±SD) blood GSH-Px activity of the treatment group (12.0 ± 2.3 mU/min/mg hemoglobin) was increased (P < .05) over the control group (2.0 ± 1.4 mU/min/ mg hemoglobin) by day 28 and continued to be greater (P < .05) throughout the 84 day postinjection period. The blood GSH-Px activity and the blood Se concentrations in the treatment group heifers did not reach concentrations considered indicative of Se adequacy (30 mU/min/mg hemoglobin and 0.10 μg/mL, respectively) except briefly, at 5 hours postinjection when the blood Se concentration of the treatment group was 0.131 ± 0.028 μg/mL. The mean serum GSH-Px activity of the treatment group did not differ at any time from that of the control group (P≥ .17). The mean (±SD) fractional excretion (FE) of Se, as an estimate of Se excretion, was greater (P < .05) in the treatment group heifers (n = 5; 6.2 ± 2.5%) than in the control heifers (n = 3; 1.3 ± 0.6%) at 24 hours postinjection. The mean (±SD) weight gain, from day 0 to day 84, for the treatment group heifers was 63.0 ± 18.1 kg and the mean weight gain for the control group heifers was 53.1 ± 7.3 kg at 84 days postinjection and there was no difference between the groups (P < .39). Conclusions drawn from this study include: 1) the increase in blood GSH-Px activity occurs approximately 28 days after Se injection given to Se-deficient heifers, 2) a single label dose of injectable Se does not result in blood Se concentrations or blood GSH-Px activity normally considered to be adequate, 3) the label dose of injectable Se, although therapeutically beneficial for nutritional myodegeneration (NMD), does not seem to be a desired method for long-term Se supplementation of cattle consuming a Se-deficient diet, and 4) blood Se is a better predictor of Se status than serum Se. (Journal of Veterinary Internal Medicine 1993; 7:342–348. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the acute phase response to a provocative immune challenge

The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (T_a) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in 4 temperature-controlled environmental chambers. Initially, T_a in the 4 chambers was cycling at thermoneutrality (TN; 18.5°C–23.5°C) for a 1-wk adjustment period, followed by an increase in 2 of the 4 chambers to cycling heat stress (HS; 24°C–38°C) for 2 wk. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), sickness behavior scores (SBSs) were recorded, and blood samples were collected at 0.5-h intervals from −2 to 8 h and again at 24 h relative to LPS challenge at 0 h. Serum was isolated and stored at −80°C until analyzed for cortisol and cytokine concentrations. A breed by T_a interaction (P < 0.001) was observed for RT such that the post-LPS average RT in RO heifers housed at TN was lower than the RT of all other treatment groups (P < 0.001), whereas ANG heifers housed at HS had greater post-LPS average RT than all other treatment groups (P < 0.001). In response to LPS, HS increased SBS after LPS in RO heifers compared to RO heifers housed at TN (P < 0.001), whereas HS decreased SBS after LPS in ANG heifers compared to ANG heifers housed at TN (P = 0.014). The cortisol response to LPS was greater in TN than in HS heifers (P < 0.01) and was also greater in RO than in ANG heifers (P = 0.03). A breed by T_a interaction (P < 0.01) was observed for tumor necrosis factor-α (TNF-α) concentration such that HS increased post-LPS serum concentrations of TNF-α in ANG heifers compared to ANG heifers housed at TN (P = 0.041), whereas HS decreased post-LPS concentrations of TNF-α in RO heifers compared to RO heifers housed at TN (P = 0.008). A tendency (P < 0.06) was observed for a breed by T_a interaction for IL-6 concentrations such that RO heifers had greater post-LPS concentrations of IL-6 than ANG heifers when housed at HS (P = 0.020). A breed by T_a interaction was observed for interferon-γ (IFN-γ; P < 0.01) concentrations such that HS decreased post-LPS concentrations of IFN-γ in ANG heifers compared to ANG heifers housed at TN (P < 0.001), and HS increased post-LPS concentrations of IFN-γ in RO heifers compared to RO heifers housed at TN (P = 0.017). These data indicate differences in the acute phase response between the heat-tolerant RO and heat-sensitive ANG heifers under different T_a which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds.     

The effect of age, weight and the breed of heifer on the concentration of thyroxine during insemination

We determined the thyroxine (T4) concentration in 63 heifers on 0th (day of insemination), 6th and 21st day after first and in repeat-breeder cows after second and third insemination in relation with the breed, age and weight of animals. The examination was carried out with a feed ration balanced according to the Czechoslovak State Standard CSN 46 7070, with all-the-year-round housing, with keeping the uniform time of insemination (8.00--9.00 a. m.) as well as the time of blood sampling (10.00--12.00 a. m.). The animals were inseminated from August to November. The average T4 concentrations, with a successful insemination, fluctuated on 0th day after first, second and third insemination at levels of 56.15 +/- 13.6; 84.6 +/- 10.66 and 89.75 +/- 13.62 nmol X l-1 of serum. As the results show, the lowest T4 concentrations (P less than 0.001; P less than 0.001) on 0th day were recorded in animals becoming pregnant in first insemination. The comparison with non-pregnant animals did not show any statistically significant difference in T4 concentrations. On 0th day of the second insemination, the T4 concentrations in pregnant animals were higher (P less than 0.01) as compared with non-pregnant. On 6th and 21st day after successful first insemination the T4 content increased significantly (P less than 0.001). After second and third successful insemination we recorded in T4 concentrations a moderate decrease on 6th day (P less than 0.01 for third insemination), with insignificant increase on 21st day.(ABSTRACT TRUNCATED AT 250 WORDS)     

不同粗饲料水平和补充脂肪对奶水牛采食量和泌乳性能的影响研究

本试验选用30头第一泌乳中期的奶水牛，分为5组(1个对照组和4个试验组)，每组6头。分别饲喂不同水平的高粗料和补充脂肪日粮。结果表明：①奶水牛喂75％粗饲料日粮，减重约2.5kg；奶水牛喂65％粗饲料，高脂肪（7.5%）和中等脂肪（5.0%）日粮，分别增重3和6 kg。体重比较有极显著差异（P<0.01)。②粗饲料水平和脂肪水平对干物质采食量有极显著影响（P< 0.01)。奶水牛喂75％粗饲料与65%粗饲料日粮比较，有较低的干物质采食量(19.7与21.3 kg/d)。奶水牛喂试验日粮，干物质采食量变化相似。③奶水牛喂对照和试验日粮，日均产奶量分别为8.5和8.2 kg，喂高粗料（75%）和高脂肪（7.5%）产奶较少（分别为8.1、8.2、8.25和8.35 kg/d)。在所有试验和对照日粮每千克干物质产奶量差异极显著(P<0.01)。对所有日粮，干物质采食量随时间推移而下降。     

硫辛酸对黄羽肉鸡生长性能、抗氧化能力和免疫功能的影响

本试验旨在研究饲粮中添加硫辛酸对黄羽肉鸡生长性能、抗氧化能力和免疫功能的影响。将 ６０只 ２１日龄体重相近的黄羽肉鸡随机分为 ２组,即对照组和硫辛酸组,每组 ５个重复,每个重复 ６只鸡。对照组饲喂基础饲粮,硫辛酸组饲喂在基础饲粮中添加 ３００ｍｇ／ｋｇ硫辛酸的试验饲粮,试验期 ３０ｄ。结果表明,硫辛酸对黄羽肉鸡的生长性能无显著影响（Ｐ＞０．０５）;在试验第 １５天时,硫辛酸可以显著提高黄羽肉鸡血清总超氧化物歧化酶活性（Ｐ＜０．０５）、降低一氧化氮含量（Ｐ＜０．０５）,促进脾脏的发育（Ｐ＜０．０５）,提高血清免疫球蛋白 Ｇ含量（Ｐ＜０．０１）;在试验第 ３０天时,硫辛酸可以显著降低黄羽肉鸡血清丙二醛含量（Ｐ＜０．０５）、提高抑制羟自由基的能力（Ｐ＜０．０１）,提高由伴刀豆球蛋白 Ａ和脂多糖刺激的外周血淋巴细胞转化率以及血清免疫球蛋白 Ｇ含量（Ｐ＜０．０５）。由本试验可知,饲粮中添加 ３００ｍｇ／ｋｇ硫辛酸可以在一定程度上提高肉鸡抗氧化能力,增强其免疫功能。     

Effects of supplement type on performance, reproductive, and physiological responses of Brahman-crossbred females

Two experiments were conducted to compare the performance and physiological responses of forage-fed beef females supplemented with either a molasses-based (ML) or a citrus pulp-based (CT) supplement. In Exp. 1, BW gain, reproductive performance, and concentrations of blood urea N (BUN), plasma glucose, insulin, IGF-I, and progesterone (P4) were assessed in 60 Brahman x Angus heifers supplemented 3 times weekly with either ML or CT. Supplement intakes were formulated to be isocaloric and isonitrogenous. Reproductive performance was not affected by treatments, but mean BW gain was greater (P < 0.01) for heifers fed CT than for those fed ML (0.40 vs. 0.30 kg/d). Mean plasma concentrations of glucose, insulin, and IGF-I were greater (P < 0.05) for heifers fed CT, whereas BUN was greater (P < 0.05) for heifers fed ML. Mean plasma P4 concentration did not differ between treatments, but both groups had lower plasma P4 concentrations during days that supplements were offered (P < 0.01). In Exp. 2, forage DMI and concentrations of BUN, plasma glucose, insulin, IGF-I, and P4 were assessed in 24 Brahman x British mature cows supplemented with the same treatments described in Exp. 1. Overall forage DMI did not differ between treatments, but a day effect and a treatment x day interaction were detected (P < 0.05). Both groups consumed less forage during the days on which the supplements were offered (P < 0.01), and forage DMI for cows fed CT was less (P < 0.05) than for cows fed ML during those days. No differences were detected in any blood or plasma measurement. In addition, no differences in concentrations of P4 were detected between CT- and ML-fed cows. We concluded that CT-supplemented heifers had greater BW gain compared with ML-supplemented heifers, but no differences in reproductive performance were observed. We also observed that CT-supplemented cows had a greater variability in forage DMI compared with ML-supplemented cows.     

A theory of beef production

Groups of maiden heifers (105 dairy and 119 beef) were treated twice with an 11-day-interval between injections of Cloprostenol (0.5 mg/i.m.), and were then inseminated at 72 h and 96 h after the second injection. The pregnancy rate (PR) was 39% in both types of heifers. Significant PR differences between groups of heifers were largely due to differences in the proportion of non-cycling (anoestrus) animals within each group. Excluding these animals from the analyses increased PR's to the set-time inseminations by over 11%.

An alternative treatment regime was used in a second series of trials. Entire bulls fitted with chin-ball mating harnesses were run with groups of heifers. Those heifers served in the first 11-day-period were subsequently injected with 0.5 mg of Cloprostenol 6 days later and inseminated 72 h and 96 h after treatment. The second sub-group of heifers served in the second 11-day-period received the same injection-insemination sequence. Unmated heifers were examined at the same time as the second sub-group was injected. The PR among the 90 treated dairy heifers (from a total of 102 animals) was 69%, and 58% in 163 treated beef heifers. Almost all of the heifers not served by bulls in the pretreatment period were subsequently found to be anoestrus, pregnant to a previous (unrecorded) mating, or abnormal (freemartin).

The use of oestrus synchronisation in maiden heifers can facilitate the use of AB with associated advantages through genetic improvement. The additional advantages in aspects of herd management, particularly in the reduction in the time-span of conventional AB programmes, may be its greatest use. In either case, the pretreatment identification, and the exclusion of heifers which cannot be successfully synchronised, will be important in obtaining satisfactory results.