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1.
【目的】 研究发酵中药对蛋鸡生长性能、抗体水平和肠道微生物菌群的影响。【方法】 选用1日龄科宝蛋鸡84只,预饲至13日龄,于14日龄进行正式试验,将雏鸡随机分为7组,每组单笼饲养,每笼12只,分别为空白对照组（A组）,复方中药组（B组）,发酵中药低剂量组（C组）、中剂量组（D组）、高剂量组（E组）,发酵菌液组（F组）,对照药物黄芪多糖组（G组）。试验期间记录每日给料量与剩料量,于试验第1（14日龄）、14（28日龄）、28（42日龄）天清晨空腹称重,计算各阶段平均日增重、平均日采食量及料重比。于试验第7、14、21、28天每组鸡翅下静脉采血,用于抗体效价的检测。试验结束后对A、B、D、F、G组鸡进行剖检,每组取5只鸡的盲肠内容物进行高通量测序分析。【结果】 试验第1~14天,D、E组平均日采食量均极显著高于A、F、G组（P<0.01）,D、E组平均日增重极显著或显著高于A、F组（P<0.01;P<0.05）;F、G组料重比均极显著低于其他各组（P<0.01）。试验第15~28天,C、E组平均日采食量均显著高于B、F组（P<0.05）,B组平均日增重极显著高于其他各组（P<0.01）,E组显著高于A组（P<0.05）;B组料重比极显著低于其他各组（P<0.01）,D、E、F、G组料重比均极显著低于A组（P<0.01）。试验第7天,各组鸡血清抗体效价均无显著差异（P>0.05）;试验第14天,E组抗体水平均显著高于A、F、G组（P<0.05）;试验第21和28天,E组抗体水平显著高于A组（P<0.05）。D组Chao1和Observed species指数最高,但与其他组间无显著性差异（P>0.05）。在门水平上,D和G组盲肠中拟杆菌门相对丰度均显著高于A组（P<0.05）;在属水平上,D组盲肠中拟杆菌属相对丰度均显著高于A组（P<0.05）。【结论】 发酵中药可以提高鸡的生长性能和抗体水平,对肠道菌群有明显的调控作用。  相似文献   

2.
Parturition was induced in 12 dairy heifers with prostaglandin (PG) F2 alpha about 2 weeks before the expected time of calving. Eight animals gave birth after two injections (group 1), three animals needed more than two injections (group 2) and one animal (cow no. 740) required one injection. All animals in groups 1 and 2 had retained foetal membranes and the time needed to induce parturition was 59 +/- 7 and 149 +/- 10 h, respectively. As cow no. 740 did not have retained foetal membranes and calved 24 h after one PGF2 alpha injection, it was excluded from the results. Udder distension and relaxation of the pelvic ligaments could predict the calving to within 12 h. Furthermore, the pre-calving drop of body temperature could predict the time of parturition to within 16 h. The total white blood cells and polymorphonuclear cells were at their highest values on the day preceding parturition whereas mononuclear cells had a tendency to increase 3 days after calving. Increased levels of haemoglobin were found at the time of parturition, whereas, plasma-calcium levels significantly decreased after parturition (P < 0.001). Progesterone levels markedly decreased after the first PGF2 alpha injection and reached 2 nmol/l at the time of parturition. Plasma levels of oestradiol-17 beta reached the peak at the time of parturition, whereas, the highest levels of the PGF2 alpha metabolite and cortisol were recorded 16 h after calving.  相似文献   

3.
Ten multiparous crossbred local Zebu cows were randomly divided into two nutritional groups (A and B) to determine the effect of urea-molasses-mineral block supplementation on body weight gain, milk production, and onset of ovarian cyclicity after calving. Both groups had farm rations daily, but the supplemented group (B) was provided with an additional diet daily of 250 g urea-molasses-mineral block. The cows in group A required 80-120 days (98.0 +/- 6.7 days) until peak milk progesterone concentrations and 60-80 days (72.0 +/- 3.8 days) were required for group B (p<0.05). Group B needed a shorter period for expression of standing estrus (91-101 days; mean 96.2 +/- 2.3 days) than group A [130-153 (141.6 +/- 4.6) days; p<0.01]. For groups A and B, body weight gain was 8.4 +/- 3.4 kg and 18.4 +/- 3.2 kg, respectively (p<0.01). The average milk production of groups A and B were 3.3 +/- 1.0 and 4.8 +/- 1.6 L/day, respectively (p>0.05). There was linear improvement in milk yield from Day 60 postpartum up to Day 90 of lactation in group B (supplemented). However, in group A, milk production decreased starting on Day 40 after parturition.  相似文献   

4.
AIM: To identify some production and reproductive effects of calving induction in seasonally calving herds. METHODS: Forty seasonally calving herds entered on the DairyMAN management information system and whose milk yield and reproductive data were recorded, including pregnancy diagnosis results, were included in the study. Cows with an induced parturition were compared with normally calving contemporaries that had the same lactation number and calved at the same time. RESULTS: Milk yield was 1.2 +/- 0.2 litres/cow/day less over the entire lactation for cows induced to calve, with the greatest difference being 2.5 +/- 0.4 litres/cow/day measured in early lactation. The effects on milkfat and protein yield were similar, with 0.04 +/- 0.01 kg/cow/day less milkfat (p < 0.0001) and 0.03 +/- 0.01 kg/cow/day less protein (p < 0.0001). A higher milkfat percentage (+ 0.09 +/- 0.04 %) (p < 0.0001) and protein percentage (+ 0.10 +/- 0.02%) (p < 0.0001) for cows that were induced to calve reduced the effect of a lower milk yield on milkfat and protein production. The first service conception rate for cows induced to calve was 54.4 +/- 3.3%, which was significantly less (p = 0.03) than for cows that calved normally (59.5 +/- 3.3%). Cows induced to calve had a pregnancy rate at the end of mating of 91.4 +/- 2.1%, which was also significantly less (p <0.0001) than for cows that calved normally (93.6 +/- 1.7%). The 21-day submission rates were not significantly different between groups. CONCLUSIONS: This study indicates that, under some New Zealand management conditions, the induction of calving is associated with reduced daily milk yield and inferior reproductive performance.  相似文献   

5.
A study with the objectives of estimating breed differences, heterosis and recombination effects as well as heritabilities (h2) and repeatabilities (r2) for age at first calving (AFC), calving interval (CI), days open (DO) and number of services per conception (SPC) was conducted using reproduction records collected from 1496 cows comprising purebred Boran (B), Friesian (F), crosses of Friesian and Jersey (J) with Boran breeds. The crossbred cow groups included four F × B crosses [1/2F:1/2B(F1), 1/2F:1/2B(F2), 5/8F:3/8B and 3/4F:1/4B], three J × B crosses [1/2J:1/2B(F1), 1/2J:1/2B(F2) and 3/4J:1/4B] and one three‐breed cross (1/4F:1/4J:1/2B). The crossbreeding parameters were estimated using a repeatability animal model for CI, DO and SPC, and a unitrait animal model for AFC. The overall least‐squares means estimated were: 38.3 ± 0.26 months, 435 ± 4 days, 145 ± 10 days and 1.58 ± 0.03 (number) for AFC, CI, DO and SPC, respectively. The breed additive effects of F and J were only significant (p < 0.01) for AFC. Relative to B, both F and J additive contributions for AFC were ?5.4 ± 0.5 and ?5.5 ± 1.9 months, respectively. Crossing the B with F and J breeds also resulted in significant heterosis (p < 0.05) ranging from 10 to 21% in all traits. The estimated recombination loss was only significant for AFC (2.8 ± 1.0 months) for F × B crosses. Heritability estimates were high for AFC (0.44 ± 0.05) and low for CI (0.08 ± 0.03), DO (0.04 ± 0.03) and SPC (0.08 ± 0.02). The corresponding estimates for the repeatability (r2) were 0.14 ± 0.02 and 0.14 ± 0.02 for CI and DO, respectively. The permanent environmental effect for SPC was zero. These findings show that breed differences between F or J and B, and the individual cow variations are low for reproductive traits studied, except for AFC. Heterotic effects seem to be the major genetic causes for the improved reproductive performances in both the F × B and J × B crossbred cows.  相似文献   

6.
Plasma progesterone, oestradiol, 13,14-dihydro, 15-keto, prostaglandin F2 alpha (PGFM) and luteinising hormone were measured in daily samples from eight dairy cows for 15 days before and after spontaneous calving, and compared to patterns obtained from 15 cows during and after induction of parturition with dexamethasone +/- prostaglandin. The average (+/- sd) length of pregnancy in the control cows was 285 +/- 3.04 days compared to 264 +/- 7.4 days in the induced group. Only nine cows required prostaglandin on day 11 after dexamethasone, which resulted in all nine calving 1.7 +/- 0.3 days later. Eight of the 15 treated cows retained the fetal membranes; however, the calving to first heat interval for all treated cows was 46.7 +/- 10 days (range 30 to 66 days) and calving to conception 52.4 +/- 17 days (range 30 to 85 days) compared to 42.1 +/- 15 days (range 28 to 64 days) and 76.5 +/- 24 days (range 54 to 115 days) respectively for the eight cows which calved without induction. The pre-partum hormone profiles were similar in all cows. Hormone profiles in the post partum period were also similar in all cows, irrespective of previous history. Baseline values for progesterone and oestradiol were not reached until 4.6 +/- 1.7 days and 2.75 +/- 0.7 days post partum respectively, whereas PGFM values increased for two or three days, reaching baseline levels 8.87 +/- 2.10 days later. Five cows had secondary peaks of PGFM on days 5,6 and 7. Luteinising hormone values increased steadily after calving in all cows.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Studies were conducted to examine the temporal changes in phenobarbital pharmacokinetics during chronic dosing in dogs. Ten dogs were allotted into 2 groups, administered a single oral dose, rested for 35 days, and then given the drug for 90 consecutive days. After single administration of 5.5 mg/kg of body weight or 15 mg/kg, the total body clearance (Clt/F) was 5.58 +/- 1.89 ml/h/kg and 7.28 +/- 1.07 ml/h/kg, respectively. The half-lives (t1/2) for the 2 groups were 88.7 +/- 19.6 hours for the 5.5-mg/kg dose and 99.6 +/- 22.6 hours for the 15-mg/kg dose. Significant differences in Clt/F or t1/2 were not observed between the 2 groups. Multiple-dosing regimens (5.5 mg/kg/day or 11 mg/kg/day) were initiated in the same dogs for 90 days. The Clt/F was significantly (P less than 0.05) greater on days 30, 60, and 90 than the single dose for both groups. After the last dose on day 90, several blood samples were obtained to determine phenobarbital t1/2. On day 90, the t1/2 was significantly (P less than 0.05) shorter and the Clt/F was significantly greater than single-dose values. The Clt/F and t1/2 were 10.2 +/- 1.7 ml/h/kg and 47.3 +/- 10.7 hours for the group given the low dose and 15.6 +/- 2.5 ml/h/kg and 31.1 +/- 4.4 hours for the group given the high dose, respectively. Both Clt/F and t1/2 were significantly (P less than 0.05) different between the 2 groups on day 90.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
The relationship between placental retention, progesterone and pregnancy-specific protein B (bPSPB) was determined in 60 calving Holstein cows. The cows were divided into two groups with placental retention (WPR, n = 16) and no placental retention (NPR, n = 44). Every 4 days, until 60 days post-partum, blood samples were taken and the uteri were checked using ultrasonographv. The puerperal characteristics of NPR and WPR were as follows: mean days of abnormal vaginal discharge: 20.2+/-5 versus 35.6+/-7 (P < 0.01); mean intervals to uterine involution: 21.4+/-3.7 versus 27.6+/-7.6 days (P < 0.01); rate of endometritis: 25 versus 100% (P < 0.01). The mean numbers of oestrus cycles per cow were 1.75+/-0.5 versus 0.85-/+0.9 (P < 0.05) and the mean durations of the first oestrus cycle were 18+/-3.5 versus 16+/-2.1 days (P > 0.05). The mean intervals to first ovulation were 21.5+/-8.4 versus 35+/-19 days (P < 0.01). bPSPB blood concentrations were higher in the WPR group at calving with 955+/-170 versus 750+/-205 ng/ml (P < 0.01) and also during the first 32 days post-partum with 173.68+/-47.3 versus 131.0+/-29.2 ng/ml (P < 0.01). The mean bPSPB half-life was similar in the two groups: 6.9+/-2.5 versus 6.5+/-2.1 days (P > 0.05). In conclusion, it was found that placental retention was associated with a higher rate of endometritis, a lower number of cycles, longer interval to first post-partum ovulation and higher concentration of bPSPB at calving and during the post-partum period. The positive relationship between bPSPB concentrations and calf birth weight and their association with post-partum pathological events may be useful in monitoring animals presenting high concentrations at calving.  相似文献   

9.
Interleukin-2 and interleukin-12 have been used independently to successfully treat the induced and the spontaneous tumours in animals. This trial was done to determine if a combination of IL-2 and IL-12 in the treatment of spontaneous bovine ocular squamous cell carcinomas (BOSCC) would be more successful than IL-2 or IL-12 therapy by themselves. For this trial, we selected 25 BOSCC tumours seen on Holstein Fresian cows in Beatrice, Zimbabwe. The cows were randomly assigned to a treatment group of 5 days of IL-2 (200,000 U/day), 5 days of IL-12 (0.5 microg/day) or 5 days of IL-2 (200,000 U/day) and IL-12 (0.5 microg/day). At 20 months after treatment, the IL-2 therapy group had 63% complete regressions; the combination group had 38% complete regressions, which were significantly higher than the IL-12 group, which had 0% complete regressions at 20 months, despite having 29% complete regressions at 6 months. These results show that IL-2 therapy by itself and in combination with IL-12 is more successful than IL-12 by itself. However, combination therapy does not improve the outcome in comparison to IL-2 as a single therapy. It also proves that IL-2 is consistently successful in the therapy of BOSCC with over 60% complete regression, which corresponds to a number of other studies we have done on IL-2 therapy of BOSCC [Rutten, V.P.M.G., Klein, W.R., De Jong, W.A., Misdorp, W., Den Otter, W., Steerenberg, P.A., De Jong, W.H., Ruitenberg, E.J., 1989. Local interleukin-2 therapy in bovine ocular squamous cell carcinoma. A pilot study. Cancer Immunol. Immunother. 30, 165--169; Stewart, R.J.E., Hill, F.W.G., Masztalerz, A., Jacobs, J.J.L., Koten, J.W., Den Otter, W., 2003. Local low dose interleukin-2 therapy of bovine ocular squamous cell carcinomas in cattle in Zimbabwe, submitted for publication; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H.M., Rutten, V.P.M.G., Ruitenberg, E.J., 1993. Low doses of interleukin-2 can cure large bovine ocular squamous cell carcinoma. Anticancer Res. 13, 2453-2455; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H., Rhode, C., Stewart, R., Faber, J.A., Ruitenberg, E.J., 1995. Therapy of bovine ocular squamous cell carcinoma with local doses of interleukin-2: 67% complete regressions after 20 months of follow-up. Cancer Immunol. Immunother. 41, 10-14].  相似文献   

10.
A total of 2230 yak cows (5-13 years of age) in two populations with different milking systems were investigated. One population had a system of milking once a day (MOD), and the other population twice a day (MTD). The average milk yield of MOD cows was 0.7 +/- 0.2 kg/day within a milking period of 109 +/- 9 days. This compared with an average of 1.24 +/- 0.3 kg/day in 127 +/- 6 days in MTD yaks (p < 0.01). The cows showed a calving rate of 71% under the MOD system and 51.4% under the MTD system. Three farms with a total of 104 MTD cows between six and 12 years of age were used to provide three different feeding groups. The groups were fed with, or without oat hay or highland barley straw in amounts of 1-1.5 kg/head/day from December to April. The three farms were designated as Farm I, Farm II, and Farm III. Farm I had 41 cows with body weight of 230 +/- 67 kg each for grazing with no supplement (GNS). Farm II had 30 animals with body weight of 216 +/- 28 kg each for grazing + oat hay (GOH). Farm III had 33 animals body weight of 221 +/- 34 kg each for grazing + highland barely straw (GBS). The calving rates of the cows in GOH and GBS were 23 and 19% higher, respectively, than GNS cows (p < 0.01), and the highest rate reached 76.7% in GOH. The live weight loss of the cows in GNS was considerably higher (p < 0.01) than in the two other groups. Ten GOH cows and 12 GNS cows were used to collect milk samples for measuring the progesterone concentration using RIA kits provided by IAEA/FAO: Milk was sampled every five days from calving until 90 days postpartum. In the unsupplemented group, milk progesterone (P4) levels suggested that cows had started cyclic ovarian activity by 40 days postpartum, whereas only 25% had been observed in estrus. In the supplemented group, 80% of cows had started cyclic ovarian activity by the same time and 70% had been seen in estrus. Two types of cyclic activity in terms of progesterone changed were found. With Type I (normal), 50 and 80% of cows from GNS and GOH, respectively, had cyclic changes of P4 in milk at 40 days postpartum. With Type II, the P4 levels in the milk remained 0.89 ng/ml until 90 days postpartum. A total of 46 grazing cows between five and 13 years of age (body weight 214 +/- 68 kg) was used to collect blood samples to measure concentrations of nutrient of metabolites at two weeks pre-calving and at two weeks, two months and four months postcalving, respectively. The concentrations of nutrient metabolites [albumin, globulin, urea, beta-hydroxybutyrate (BHB) and inorganic phosphorus] suggested general underfeeding of energy and protein in the winter/late pregnancy period with some recovery in lactation. Energy constraints appeared again as the summer progressed. No dietary phosphate deficiency was found. BHB and albumin testing on serum yaks could be a useful tool to identify poor nutritional status during the winter and so illustrate the need for supplementation.  相似文献   

11.
Blood samples were taken thrice a week for 2 weeks from 33 pregnant cows in 9 groups, 1 month apart. In addition, blood samples were collected twice daily 1 week from 8 cows before parturition. Plasma progesterone and total oestrogens were quantified by validated radioimmunoassays and total corticosteroids by a competitive protein binding technique. During the 1st 3 month of pregnancy, no remarkable changes were observed from the 3 hormones studied. From the 4th month on, concentrations of progesterone and total corticosteroids decreased significantly (P less than 0.05) and remained fairly constant until the 9th month. Values of total oestrogens increased significantly (P less than 0.05) from the 4th to 6th months and stayed unchanged afterwards. Progesterone levels in periparturient cows decreased linearly (P less than 0.01) during 3 days preceding delivery. Concentrations of total oestrogens rose sharply from day -5 and peaked at calving. Values of total corticosteroids increased dramatically on the 6th day and 24 hours before parturition. The results obtained suggest that in contrast to studies cited earlier plasma corticosteroids could play a key role for triggering parturition in cows.  相似文献   

12.
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.  相似文献   

13.
In three series of experiments the variations of lactic acid and glucose concentrations were investigated in pregnant sows, crossbreds of the Large White and Landrace breeds, and in their foetuses on the 104th and 113th day of pregnancy, then in farrowing sows of the same breed and their piglets at delivery (birth) and till the 10th day after birth. In nonpregnant sows the value of lactacidaemia is 1.60 +/- 0.08 mmol per 1. In the first twenty days of pregnancy it increases to 2.50 +/- 0.95 mmol per 1 (p less than 0.05). In the following days of pregnancy until the 81st to 100th day the value ranges from 1.5 to 1.7 mmol per 1. In the last twenty days of pregnancy it increases slightly to 2.10 +/- 0.25 mmol per 1. On the 104th and 113th day the values of lactacidaemia in foetuses in vena and arteria umbilicalis make 7.40 +/- 0.41 and 6.80 +/- 0.37, or 8.50 +/- 0.43 and 8.16 +/- 0.21 mmol per 1, respectively. Glucosaemia values are decreasing in pregnant sows in the first forty days, in the following period of pregnancy they are increasing and on the 101st to 120th day of pregnancy they make 5.39 +/- 0.26 mmol per 1. The foetus to dam ratio lactic acid concentrations is 2.3 and 2.1, respectively, on the 104th and 113th days. Lactacidaemia is highest in farrowing sows (3.15 +/- 0.19 mmol per 1), then there is a statistically significant decrease in the value of this characteristic, and on the day after delivery it makes 2.38 +/- 0.66 mmol per 1.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
The effect of 2 types of feeding on the involution of the genital tract and on the fertility was studied in 79 Finnish dairy cows on a research farm. The cows were fed twice a day with home-produced feed in accordance with the Finnish feeding standard. The cows were divided according to the type of feed into a hay-urea group and a silage group. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The time required for the complete involution of uterus and cervix was recorded. The cows in the silage group had a significantly longer time in uterine involution, a lower fertility rate at first insemination and a longer interval from calving to conception than those in the hay-urea group. The pregnancy rate in the first insemination was in the hay-urea group 91% and in the silage group 57%. The interval between calving and the first insemination was shorter in the hay-urea group than in the silage group: 71.4 +/- 10.6 and 74.0 +/- 10.3 days, respectively. The interval between calving and conception was in the hay-urea group significantly (p less than 0.01) shorter than in the silage group; 74.8 +/- 15.1 and 89.5 +/- 24.4 days, respectively.  相似文献   

15.
The Piedmontese breed has a high frequency of double-muscling. Animals tested in this breed are homozygous for a guanine to adenine transition in exon 3 (C313Y) of the myostatin (MSTN) gene. This transition seems to be responsible for the double-muscling phenotype. The objective of this study was to compare effects of alternative MSTN genotypes on proportion of assisted calving and weights at birth, weaning, and 1 yr of age. Reciprocal backcross and F2 calves out of Piedmontese-Angus (PA) and Piedmontese-Hereford (PH) dams born in 1995 (n = 82), 1996 (n = 75), and 1997 (n = 144) were evaluated for birth (BWT, kg), adjusted weaning (W200, kg), and yearling (W365, kg) weights and calving difficulty expressed as a proportion of assisted calving (CD). The number of copies of C313Y was assessed in each calf. Data were analyzed with a model that included effects of year, sex, subclasses of proportion Piedmontese (.25, .5, .75) by number of C313Y copies (0 = +/+, 1 = mh/+, 2 = mh/mh), and age of dam as covariate. For BWT, heterozygous mh/+ animals were 3.2 +/- .8 kg heavier than +/+ animals. Homozygous mh/mh animals increased .19 +/- .06 in proportion of CD compared with mh/+ animals. Differences between homozygous animals (mh/mh - +/+) were 5.2 +/- 1 kg for BWT and .21 +/- .06 for CD. Heterozygous mh/+ animals were 9.1 +/- 4 kg heavier at W200 than homozygous +/+ animals. Homozygous +/+ and heterozygous animals were 20 +/- 8 and 24.5 +/- 8 kg, respectively, heavier at W365 than mh/mh animals. Differences between mh/+ and the mean of mh/mh and +/+ genotypes for W200 and W365 were 8.8 +/- 3 and 18 +/- 5 kg, respectively, suggesting dominance effects on postnatal growth. Production of heterozygous animals, to take advantage of the positive impact of one copy of C313Y on carcass traits, may be a viable option when the value of increased retail product yield is greater than the increased cost associated with calving difficulty.  相似文献   

16.
AIMS: To assess the efficacy of a feed supplement designed to reduce the dietary availability of calcium when fed during the last 2-3 weeks of pregnancy, on the incidence of postparturient hypocalcaemia (milk fever) and on milksolids (MS) production in pasture-fed dairy cows in early lactation. METHODS: In Experiment 1, late-pregnant Holstein/Friesian cows, 4-10 years old, grazing pasture, were either fed the supplement (1 kg/cow/day) for 2-4 weeks prior to calving (n=11) or no supplement (n=10). Plasma calcium concentrations were measured immediately before and after a 20 h fast intended to induce hypocalcaemia at the end of this period, 1-7 days before the cows calved. In Experiment 2, mixed-breed dairy cows, 3-10 years old in 7 commercial dairy herds were fed the same supplement (1 kg/cow/day) for 1-3 weeks immediately prior to calving (n=565) or no supplement (n=614), and incidences of clinical milk fever and MS production at 6-9 weeks post calving were compared between groups. RESULTS: In Experiment 1, plasma calcium concentrations were higher (p=0.01) in supplemented than in non-supplemented cows after fasting, indicating reduced susceptibility to fasting-induced hypocalcaemia. In Experiment 2, the incidence of milk fever was lower (6.4% vs 17.1%, p=0.001) and MS production was higher (p=0.01) in supplemented than in non-supplemented cows. CONCLUSIONS: These preliminary results demonstrate that feeding a supplement designed to reduce dietary calcium availability for 2-4 weeks immediately prior to calving reduced the susceptibility of cows to fasting-induced hypocalcaemia, reduced the incidence of clinical milk fever and increased MS production in early lactation. CLINICAL RELEVANCE: The concept and product reported here have potential to provide dairy farmers with a practical means to prevent hypocalcaemia and improve milk production during early lactation.  相似文献   

17.
An experiment was conducted to investigate the temporal relationship of peripheral estrone (E1) concentration to changes in the size of the pelvic opening preceding and immediately following parturition. Twenty-six multiparous beef cows were observed from approximately 50 d prepartum to 7 d postpartum. Blood samples were collected at 7 d intervals preceding calving and at 1, 3 and 7 d following for E1 quantitation. Estimates of pelvic opening area were made at the time of blood sampling. Peripheral E1 concentrations were elevated beginning at approximately 25 d prepartum. Dams bearing male fetuses had greater (P less than 0.01) concentrations of E1 than did dams with female fetuses. Calf birth weight was correlated (r = 0.44, P less than 0.01) with E1 levels from 10 d prepartum through parturition. Postpartum pelvic area was greater for cows giving birth to male calves, with no significant differences for calf birth weights by sex. Correlations were observed between E1 concentration, and pelvic area measured from 50 d prepartum to 7 d postpartum (r = 0.26, P less than 0.01), 10 d prepartum to calving (r = 0.42, P less than 0.01), and from calving to 7 d postpartum (r = 0.33, P less than 0.01). Percentage increase in E1 concentration from 50 d prepartum to calving was significantly correlated (r = 0.75, P less than 0.01) to percentage pelvic area increase over the same period. A correlation also exists between maternal E1 concentrations and fetal sex and pelvic area. In summary, the increased estrogen concentrations in cows with male calves may facilitate pelvic spread, resulting in a larger pelvic opening.  相似文献   

18.
Performance of finishing pigs in hoop structures or confinement during winter and summer was evaluated in Iowa. Hoops are large, tent-like shelters with cornstalks or straw for bedding. During summer and winter seasons for 3 yr (1998 to 2001), six trials were conducted using three hoop barns (designed for 150 pigs per pen, one pen per hoop) or a mechanically ventilated confinement barn with slatted floors (designed for 22 pigs per pen, six pens in the barn). A total of 3,518 pigs started the trials. Summer trials were June through October, and winter trials were December through April. Target stocking density was 1.11 m2/pig in hoops and 0.74 m2/pig in confinement. Identical corn-based diets were fed ad libitum from 16 to 118 kg for 127 d. Pigs were scanned before harvest for backfat and loin muscle area. When seasons were merged (season x housing interaction, P > or = 0.05), hoop-fed pigs had more backfat (21.8 +/- 0.3 vs 20.8 +/- 0.2 mm; P < 0.001), smaller loin muscle area (41.3 +/- 0.3 vs 43.0 +/- 0.2 cm2; P < 0.001), less lean percentage (51.1 +/- 0.2 vs 52.1 +/- 0.1%; P < 0.001), and less yield (74.9 vs 75.8 +/- 0.1%; P < 0.001) than confinement-fed pigs. When season x housing type interactions were observed (P < 0.004), summer hoop-fed pigs had greater ADG (834 +/- 5 vs 802 +/- 3 g/d; P < 0.001), required fewer days to 113 kg (174.9 +/- 0.9 vs 178.5 +/- 0.6 d; P < 0.01), had similar ADFI (2.40 +/- 0.03 vs 2.35 +/- 0.02 kg/d, as-fed basis) and gain:feed (G:F; 348 +/- 4 vs 342 +/- 3 g/kg) compared with confinement-fed pigs. Lean gain/day and efficiency of lean gain did not differ between housing systems. During winter, hoop-fed pigs had similar ADG (794 +/- 5 vs 801 +/- 3 g/ d), required more days to 113 kg (176.7 +/- 0.9 vs 172.9 +/- 0.6 d; P < 0.01), had greater ADFI (2.54 +/- 0.03 vs 2.35 +/- 0.02; P < 0.001), less G:F (313 +/- 4 vs 341 +/- 3; P < 0.001), less lean gain/day (312 +/- 2 vs 322 +/- 1 g/d; P < 0.01), and less efficiency of lean gain (130 +/- 2 vs 144 +/- 1 g lean gain/kg feed; P < 0.01) than confinement-fed pigs. Percentage of mortalities and culls did not differ between housing systems. During summer, there was a trend for fewer light pigs at marketing (< 100 kg) from hoops (0.8 vs 1.7%; P = 0.10). During winter, there were more light pigs at marketing from hoops (3.9 vs 1.3%; P = 0.01) than from confinement. Bedding use in hoops was 92 and 122 kg/pig for summer and winter, respectively. Performance of finishing pigs in bedded hoop structures depends in part on thermal environment.  相似文献   

19.
The objective of this work was to compare breed types with increasing percentage of Bos taurus on cow/calf energy requirements and preweaning efficiency. Forty mature, lactating, nonpregnant cows [10 Nellore (NL), 10 Canchim x Nellore (CN), 10 Angus x Nellore (AN), and 10 Simmental x Nellore (SN)] were randomized in blocks by calving date. Calves from cross-bred cows were sired by Canchim bulls (5/8 Charolais + 3/8 Zebu), whereas calves from NL cows were sired by Nellore bulls. Cows were individually fed a pelleted diet with 50% hay (alfalfa and coastcross) and 50% concentrate from calving to weaning (20 to 180 d post-partum). Estimated diet ME content was 2.24 Mcal/kg of DM. Individual cow DMI was adjusted every 14 d to keep shrunk BW and BCS constant. Shrunk BW and BCS were 430 +/- 12 kg and 4.7 +/- 0.09 for NL, 449 +/- 10 kg and 4.8 +/- 0.09 for CN, 496 +/- 10 kg and 5.0 +/- 0.09 for AN, and 507 +/- 12 kg and 5.1 +/- 0.09 for SN. At 40 d calves were allowed ad libitum access to the same diet. Milk yield was recorded using a weigh-suckle-weigh technique. Increasing B. taurus percentage had a linear effect (P < 0.01) on ME intake (MEI) of cow/calf pairs: 21.9 +/- 0.38 for Nellore, 23.6 +/- 0.35 for 31.5% B. taurus (CN), and 25.6 +/- 0.27 Mcal/d for 50% B. taurus (AN and SN). Bos taurus percentage was also positively associated with milk production. Nellore calves had lower (P < 0.05) weaning weight (kg) than crossbreds: 167 +/- 12 vs. 206 +/- 10 for 3/4 Canchim 1/4 Nellore (3/4C), 220 +/- 11 for 1/2 Canchim 1/4 Angus 1/4 Nellore (1/4A) and 228 +/- 11 for 1/2 Canchim 1/4 Simmental 1/4 Nellore (1/4S). Calf body composition was estimated at weaning using the 9-10-11th-rib section. Retained energy (Mcal) was greater (P < 0.05) in 1/4A (384 +/- 19.9) than in Nellore (298 +/- 21.6) and 3/4C calves (312 +/- 19.8), and was intermediate in 1/4S calves (333 +/- 21.6). Cow/calf energetic efficiency (kcal deposited/Mcal of MEI by the pair) was greater (P < 0.05) for AN (103 +/- 5.3) than NL (84.9 +/- 5.9), CN (83 +/- 5.3), and SN pairs (83.5 +/- 6.1). Difference (P < 0.05) between Continental and British crosses was shown in linear contrasts; SN pairs had greater MEI and lower retained energy than AN. Increasing the B. taurus percentage increased inputs as well as outputs. However, a relatively greater increase in outputs resulted in significantly greater preweaning efficiency. Purebred Nellore had lower ME requirements; however, in an environment without nutritional constraints, crossbreeding improved preweaning biological efficiency.  相似文献   

20.
Previously published reports have indicated that postpartum anovulatory intervals can be markedly reduced and rebreeding performance enhanced in Bos taurus cows by eliminating nighttime suckling. We sought to confirm this hypothesis by examining the effects of day, nighttime, and ad libitum suckling on suckling behavior of calves, duration of the postpartum anovulatory interval, and pregnancy rates in 45 fall-calving Brahman x Hereford (F1) cows. Beginning on d 9 to 12 postpartum, calves were removed from lactating cows from 0700 to 1900 (Night-Suckled, n = 15) or from 1900 to 0700 (Day-Suckled, n = 15), or remained with their dams continuously (Ad Libitum-Suckled, n = 15). Cows in each group were maintained with fertile Angus bulls from d 10 postpartum until the first normal luteal phase or 100 d postpartum, whichever occurred first. Cows were observed for estrous behavior twice daily, and jugular blood samples were collected twice weekly for the determination of serum progesterone concentration. Mean number of suckling episodes per 24 h was greater (P < .0001) for the Ad Libitum-Suckled group than either Night- or Day-Suckled groups (5.9+/-.42 vs 3.8+/-.14, and 3.9+/-.32, respectively). Hourly analysis of suckling episodes in the Ad Libitum group indicated that they were not skewed toward a particular period, with suckling occurring at a periodicity of 4 to 6 h. Intervals to the first rise in progesterone > or = 1 ng/mL (32+/-2.5, 32+/-4.5, and 31+/-1.7 d, respectively), first normal luteal phase (38+/-3.1, 38+/-3.8, and 37+/-2.5 d, respectively), and first estrus (43+/-3.5, 40+/-3.9, and 36+/-1.1 d, respectively) did not differ (P > .05) among the three groups. Similarly, cumulative pregnancy rates within 100 d after calving did not differ (P > .05). These results in Bos indicus x Bos taurus (F1) cattle do not support the previous conclusions in Bos taurus that eliminating nighttime suckling reduces the postpartum anovulatory interval.  相似文献   

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