不同生理状态对荷斯坦奶牛钙、磷表观消化率的影响

本试验研究了不同生理状态下荷斯坦牛Ca、P表现消化率的变化规律.结果表明:生长期内不同生长阶段对奶牛Ca、P表观消化率影响显著(P<0.05),12月龄和24月龄奶牛Ca表观消化率显著高于18月龄(P<0.05);12月龄和24月龄奶牛P表现消化率极显著高于18月龄(P<0.01);泌乳2月与干奶期奶牛Ca、P表观消化...     

Influence of footing surface on mounting and other sexual behaviors of estrual Holstein cows

Seven ovariectomized Holstein cows, treated sequentially with progesterone and estradiol benzoate to induce estrus, were used to determine whether cows showed a preference for mounting and displaying other sexual behaviors toward estrual or nonestrual cows tied on dirt or concrete surfaces. Preference tests were conducted in a test area that consisted of equal-sized concrete and dirt surfaces; two cows, designated A and B, were tied on the two surfaces, one on either side. Cows A and B were treated so that on each of four test days both were estrual, only A was estrual, only B was estrual or neither A nor B were estrual. On each test day, five estrual test cows were introduced individually into the test area for two 30-min test periods. During the first test period, tied cow A was on concrete and tied cow B was on dirt, but during the second test period, their positions were switched. Test cows were able to move freely from surface to surface and to interact with tied cow A or B. Estrual test cows spent 21.6 +/- 1.4 min of each 30-min test period on dirt, regardless of the estrual status of the cow tied on concrete or dirt. Mounting activity was 3- to 15-fold greater on dirt than on concrete when there was an estrual cow tied on dirt, regardless of the estrual status of the cow on concrete. Mounting activity was fourfold greater on concrete than on dirt when there was a tied estrual cow on concrete and a tied nonestrual cow on dirt.(ABSTRACT TRUNCATED AT 250 WORDS)     

日粮添加碳酸氢钠对荷斯坦奶牛生产性能的影响

选择体重、胎次、泌乳期、乳脂率和产奶量基本一致的健康无病的中国荷斯坦奶牛30头,随机分成3组,分别为试验组Ⅰ,Ⅱ和对照组。试验组Ⅰ,Ⅱ奶牛日粮每日每头分别添加130、150g碳酸氢钠,对照组奶牛日粮每日每头分别添加110g碳酸氢钠,试验期28d。结果表明,试验组Ⅰ干物质采食量、粪便pH比对照组高1.41%、0.20(P0.05),非脂乳固体比对照组低0.4(P0.05);试验组Ⅱ干物质采食量、产奶量、4%标准乳、粪便pH分别比对照组高2.04%、2.01%、2.68%、0.42(P0.05),乳脂率高0.13%(P0.05),乳蛋白、非乳脂固体分别低0.36%、0.51%(P0.05)。另外,碳酸氢钠的增加使得牛乳中体细胞数显著降低,且与乳脂肪呈显著负相关(P0.05),而与乳蛋白质呈显著正相关(P0.05)。由此可知,在每头奶牛日粮中添加150g碳酸氢钠的范围内,随着日粮中碳酸氢钠的增加,能显著改善荷斯坦奶牛的生产性能,有效预防奶牛瘤胃酸中毒。     

不同生理状态乳牛卵巢卵母细胞基因的差异表达

为了研究不同生理状态下的卵巢卵母细胞基因的表达情况，采集乳牛的卵巢，分离了卵母细胞，以单个卵母细胞的mRNA作为模板，用设计的随机引物和锚定引物，采用一步法RT-PCR扩增了卵母细胞基因。经聚丙烯酰胺凝胶电泳检测，发现有功能黄体和无黄体卵巢卵母细胞基因的电泳条带之间无明显差异，对一条明显差异条带进行回收、纯化，将纯化的PCR产物连接到T载体，阳性克隆经鉴定后，进行测序和同源性比较。结果显示，与体外培养的牛早期胚胎的一条序列具有很高的同源性。     

Effects of heat stress during pregnancy on postpartum reproductive changes in Holstein cows

Effects of heat stress during the last third of gestation on reproductive changes postpartum were studied in Holstein cows. Cows and heifers 160 to 190 d of gestation were assigned in June 1978 to shade (n = seven cows and two heifers) or no shade (n = eight cows and two heifers) management treatments. After parturition, all cows (n = 19) were moved to the milking herd and managed uniformly. On the day of calving and on each Monday, Wednesday and Friday thereafter until d 50 postpartum, jugular blood samples were collected. Beginning approximately 7 d postpartum, the reproductive tract of each cow was examined rectally after collection of blood samples. Estrus was monitored twice daily and cows were inseminated after d 45 postpartum. Prepartum heat stress increased 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) concentrations postpartum and increased the rate of uterine involution. Regardless of prepartum treatment, progesterone concentrations indicated that luteal phases had begun by d 12.4 +/- 1.3 postpartum, which was about 3 d before PGFM was basal. The first luteal phase lasted only 10.7 +/- .9 d. First estrus was not detected until d 32.3 +/- 4.8 postpartum. The previously gravid uterine horn had a negative effect on ovarian volume, diameter of the largest follicle and percentage of ovaries with a corpus luteum. However, prepartum heat stress attenuated this effect. This study indicates that heat stress prepartum had residual effects on postpartum reproductive changes, and that the previously gravid uterine horn exerted some control, which was attenuated by heat stress, over ovarian recrudescense. Even though heat stress prepartum affected sensitive measures of postpartum reproductive function, it did not alter days to first estrus, days open (102.3 +/- 13.1) or services/conception (2.5 +/- .3).     

The relationships between environmental parameters in livestock pen and physiological parameters of Holstein dairy cows

There has been an increase in temperature and the incidence of extreme weather events, such as heat wave, due to global warming, which has promoted the incidence of livestock diseases. Therefore, it is important to examine the effect of changes in environmental parameters on livestock performance. The aim of this study was to examine the relationship between ambient environmental conditions in livestock pen and the physiological parameters of Holstein dairy cows. The results showed that there was a decrease in the red blood cell counts, hemoglobin concentrations, and mean corpuscular hemoglobin concentration of the cows with increasing pen temperature, wet bulb globe temperature (WBGT), and temperature humidity index (THI). Additionally, high daily variation in temperature caused a decrease in the serum albumin levels of the cows. Moreover, the lowest serum calcium, inorganic phosphorus, and magnesium concentrations were observed in November, and were negatively correlated with the 24-hr temperature, WBGT, and THI range of the pen prior to sampling. Multiple regression analysis showed a positive correlation between serum cortisol concentration and 24-hr WBGT range of the pen prior to samplings and packed cell volume. However, serum cortisol and total protein concentrations were negatively correlated. Overall, the findings of the study suggest that large variation in temperature induced stress in the cows, which could be overcome by increased water consumption and improved protein digestion and absorption by the animals, and the addition of minerals, such as calcium to the diet.     

膨化全脂大豆对荷斯坦奶牛产奶性能的影响

选择出生日期、胎次、产奶量和体重相近的16头健康荷斯坦奶牛,随机分成4组(对照组、试验1组、试验2组、试验3组),每组4头。对照组饲喂基础日粮,试验组在基础日粮中分别依次添加0.5、1.5 kg和2.5 kg的膨化全脂大豆,预试期12 d,正试期60 d,研究不同膨化水平全脂大豆对产奶性能的影响。结果表明:试验1组、2组和3组的产奶量和标准乳产量均显著高于对照组(P<0.05),试验组间差异不显著;乳脂率试验1组、2组显著高于对照组(P<0.05),试验3组和对照组差异不显著(P>0.05);乳蛋白率试验2组、3组显著高于对照组(P<0.05),对照组和试验1组差异不显著(P>0.05);而对乳中非脂固形物的影响,4个组间均差异不显著(P>0.05)。综合考虑在奶牛日粮干物质中添加1.5 kg的膨化全脂大豆对提高产奶量和乳品质是最有利的。     

外源性金属硫蛋白对中国荷斯坦奶牛产能性能和内分泌的影响

选取24头泌乳奶牛,随机分成A、B、C和D,4组,分别按剂量0.0(对照),6.0,12.0和16.0 mg/头静脉注射金属硫蛋白(MT),以探讨外源性MT对奶牛产能性能和内分泌的影响.结果表明,B组1～30 d、C组1～45 d的标准产奶量显著高于A组,C组乳脂率在31～45 d较A组有显著改善;B组INS含量30 ...     

Effects of clinical mastitis on reproductive and milk performance of Holstein cows in Morocco

The aim of this study was to determine the influence of clinical mastitis and time of first mastitis occurrence on reproductive and milk performance of Holstein cows. Data were collected in a dairy farm from 2008 to 2012 on 1725 cows, among which 464 cows with mastitis. To determine the influence of clinical mastitis on reproductive and milk performance, models included fixed effects of parity, calving season, calving year, and group (cows with and with no mastitis). To determine the effect of time of 1st mastitis occurrence on reproductive performance, the mastitic cows group was further reclassified into three groups: prior to 60 days, between 60 and 90 days and greater than 90 days postpartum. For milk performance, the mastitic cows group was divided into two groups: before and after peak milk yield. Clinical mastitis had significant effects on calving to first AI interval, milk yield, and fat yield, but a non-significant effect on days open, number of inseminations per conception, and milk fat percentage. Mastitic cows had a calving to first AI interval 6.1 days longer and 549.6 kg milk and 20.4 kg fat per 305 days of lactation lower than those with no mastitis. Time of 1st mastitis occurrence did not have any significant effect on reproductive performance. Further, milk and fat yields of cows diseased before peak milk yield were 506 kg and 23.9 kg, respectively, lower than those of cows affected after peak milk yield. Extra attention needs to be paid to mastitis during the early postpartum period.

     

对当前中国荷斯坦牛育种工作的建议

改革开放以来,我国奶牛养殖业得到了突飞猛进的发展。2003年我国奶牛存栏数已达到893.2万头,牛奶总产达到1746.3万t,人均占有牛奶量达到12kg,取得了可喜的成绩。但是,成年母牛平均单产仅有3200余kg,同国际奶牛业发达国家平均9000～10000kg相比较,差距很大,仅是人家的三分之一左     

复合益生菌制剂对奶牛泌乳性能及乳品质的影响

为研究复合益生菌制剂对奶牛泌乳性能及乳品质的影响,试验选取45头泌乳期相近的荷斯坦奶牛,随机分为3组,对照组、试验1组、试验2组,每组3个重复,每个重复5头。对照组饲喂基础日粮,试验1、2组分别在基础日粮中添加1%、2%的复合益生菌制剂,试验期为60d。结果表明:试验2组在第10、30、60天奶牛产奶量较对照组分别提高2.28%、0.62%、9.08%(P<0.05),试验1组在第10、60天较对照组分别提高4.6%、8.9%(P<0.05);第30天时,试验1、2组乳中总固形物含量较对照组均显著性提高(P<0.05),乳糖率、乳蛋白率、乳脂率之间差异不显著(P>0.05);第60天时,与对照组相比,试验1、2组乳中乳糖率分别提高了4.41%、7.02%(P<0.05),乳蛋白率提高了4.16%、9.97%(P<0.05),总固形物含量提高了2.44%、3.02%(P<0.05),乳脂率含量之间差异不显著(P>0.05)。综上,日粮中添加复合益生菌制剂可有效提高奶牛产奶量及乳品质,且添加2%复方益生菌制剂效果更优。     

不同程度热应激对泌乳中期奶牛产奶量和乳成分的影响

选取36头临床健康、头胎、泌乳中期奶牛,通过实时监控外界温湿度指数,结合奶牛呼吸、心率、肛温等生理指标,确定奶牛热应激状态,并测定奶牛产奶量和乳成分。结果,与无热应激相比,中度热应激使奶牛日均产奶量降低16.33%,轻度热应激对此影响不明显。中度热应激奶牛乳脂率较轻度热应激显著降低,但与无热应激组相比差别不显著。轻度热应激使奶牛乳蛋白水平极显著降低,但随热应激程度加深,乳蛋白水平有升高趋势。试验结果表明:不同程度热应激对泌乳中期奶牛产奶量和乳成分有不同影响。     

Effects of feed deprivation on behavioral reactivity and physiological status in Holstein cattle

The present study evaluated whether feed deprivation can increase reactivity to stressful events, such as those that can occur at slaughter. Therefore, effects of 30 h of feed deprivation on behavior, including reactions to psychological stressors, and physiological status in cattle were determined. Sixteen Holstein cows (Exp. 1) and 32 Holstein heifers (Exp. 2) were either fed (FE) or 30-h feed deprived (FD). Throughout the first day of feed deprivation and during evening feed distribution to control animals, FD heifers and cows were more active than controls (P < 0.05). In Exp. 1, during a feeding test, in response to a sudden air blast arising from the bucket from which the cow was feeding, FD cows showed a longer latency to return to feed (P = 0.0002), spent less time in the bucket air blast zone (P = 0.008) and less time motionless (P = 0.03), and tended to withdraw over a longer distance (P = 0.07) than FE cows. In Exp. 2, during a reactivity test, FD heifers spent more (P = 0.0001) time motionless in response to social isolation than FE heifers. In Exp. 2, one-half of the FE and FD heifers were subjected to an additional physical and psychological stressor just before the reactivity test by driving them for 5 min through a labyrinth. Within heifers subjected to the additional stressor, FD heifers were less accepting of being detained (P = 0.05) and stroked (P = 0.003) by a familiar stockperson in a corner of the test arena. Compared with FE animals, FD heifers and FD cows had greater plasma cortisol concentrations (P < 0.05). Feed-deprived cows also had reduced β-hydroxybutyrate concentrations (P = 0.02) compared with FE cows. Thus, in cattle, FD influenced some of the classical indicators of energy metabolism and exacerbated reactivity to sudden events. In addition, when additional stressors were applied, FD cattle were more reluctant to accept handling. Results indicate that a multifactorial origin of stressors during the slaughter period may synergistically increase psychological stress of cattle.     

Comparison of crossbred cows containing various proportions of Brahman in spring- or fall-calving systems: IV. Effects of genotype x environment interaction on lifetime productivity of young cows.

Lifetime productivity of young (2 to 6-yr-old) crossbred cows containing various proportions (0, 1/4, or 1/2) of Braham breeding was evaluated using 188 spring-calving and 154 fall-calving cows. Cows were mated to Limousin sires to produce 1983 through 1986 calf crops. The 1987 calf crops were produced using Limousin and Salers sires. Significant (P less than .10) genotype (crossbred cow group) x environment (season of calving) interactions were found for age at first calf and lifetime calving percentage and mature cow weight. Within the spring calving group, no differences were found between crossbred groups for age at first calf or lifetime calving percentage. However, within the fall-calving group, 0 and 1/2 Braham cows from Angus dams calved earlier than did those from Hereford dams. Age at first calf also tended to increase as proportion of Brahman increased in the fall-calving group. Within the fall-calving group, lifetime calving percentage for 0 and 1/2 Brahman cows from Hereford dams was lower than for those from Angus dams. The opposite was true for the 1/4 Braham crosses. In general, as the proportion of Brahman breeding increased, productivity, measured as weight per calf or weight weaned per year, increased; however, age at first calving increased also as proportion of Brahman increased. All spring-calving groups calved earlier in life (P less than .05) than their respective fall-calving counterparts and with the exception of the 0 Brahman groups, which were similar, spring-calving groups produced a higher (P less than .05) percentage of calves than did the fall groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of high environmental temperatures on physiological and nutritional status of prepubertal Holstein heifers

A series of studies were carried out to determine the effects of increasing environmental temperature (20 to 28 to 33 °C) at a constant (60%) relative humidity on the physiological responses, energy and nitrogen balance of prepubertal Holstein heifers (n = 4, initial body weight = 198 ± 3 kg). The relatively high environmental temperatures of 28 and 33 °C increased rectal temperature by 0.2 and 1.2 °C and increased respiration by 23 and 58 breaths per min, respectively. At 28 °C, dry matter intake was similar to that at 20 °C, whereas at 33 °C dry matter intake was lower (P < 0.10) by about 9%. However, the dry matter digestibility was higher (P < 0.05) at 33 °C than at 20 °C, hence the thermal treatments did not affect daily weight gain. At 33 °C blood urea nitrogen increased whereas hematocrit and plasma glucose concentrations decreased. At 33 °C energy and nitrogen intake were lower (P < 0.10), while energy and nitrogen digestibility were higher at 33 °C than at 20 °C. Urinary nitrogen was elevated at 33 °C resulting in lower nitrogen retention. Although, energy retention as fat did not differ (P > 0.10) among the treatments, energy retention as protein was lower (P < 0.05) at 33 °C than at 20 °C or 28 °C. These results confirmed that the effects of environmental temperature on prepubertal heifers were severe above 28 °C.     

季节与放牧牛反刍行为的关系

对放牧牛反刍行为特性进行了观察,结果表明:日反刍行为的季节间差异是气候、草地状况和放牧制度共同影响的结果。在日出晚归的放牧管理制度下,反刍行为主要在夜间进行。季节对夜间反刍行为参数的影响,本质上是牧草品质和数量的差异带来的影响。     

添加保护性脂肪或豆油对奶牛纤维素瘤胃降解率和表观消化率的影响

选用3头装有永久性瘤胃瘘管和十二指肠瘘管的荷斯坦奶牛,分别在4个阶段饲喂日粮(I基础日粮+棕榈油脂肪粉400g/d)、日粮I(I基础日粮+棕榈油脂肪酸钙400g/d)、日粮II(I基础日粮+豆油400g/d)和日粮Ⅳ(基础日粮)4种日粮,研究了棕榈油脂肪粉、棕榈油脂肪酸钙、豆油对纤维素瘤胃降解率和表观消化率的影响。结果表明:各试验组有降低日粮NDF、ADF、CF瘤胃降解率的趋势,添加豆油组72hNDF、CF瘤胃降解率与对照组差异极显著(P<0.01),除个别时间点外添加棕榈油脂肪粉组NDF、ADF、CF瘤胃降解率与对照组差异不显著(P>0.05);添加棕榈油脂肪粉组、棕榈油脂肪酸钙组日粮DM、NDF、ADF、CF表观消化率与对照组差异不显著。     

复合饲料添加剂对荷斯坦奶牛生产性能及血清生化指标的影响

文章旨在探究复合型饲料添加剂对荷斯坦奶牛生产性能、血清生化指标的影响.采取单因素试验设计,将18头身体健康、体况相近的泌乳中期荷斯坦奶牛随机分为2组,分别为对照组、试验组(添加复合型饲料200?g/d),其中每组设置3个重复,每个重复3头牛,整个试验周期为30?d.于试验期第15和30天采集奶牛乳样及空腹血样,用于测定...     

复方中草药添加剂对荷斯坦奶牛免疫和泌乳性能的影响

试验旨在研究自制的复方中草药添加剂对泌乳奶牛免疫机能与泌乳性能的影响。试验采用4×4拉丁方设计。选择4头胎次、泌乳天数、体重均相近的健康荷斯坦奶牛,分为4组,其中A组为对照组,饲喂基础饲粮,B、C、D组分别在基础饲粮中添加30、50和80 g/d复方中草药。试验分4期进行,每期28 d(预试期7 d,正试期14 d,排空期7 d)。结果显示:1)添加复方中草药显著增加了白细胞数、嗜中性细胞百分比及血小板数(P<0.05);但对血液生化指标无显著影响(P>0.05)。2)添加复方中草药显著降低了丙二醛(MDA)含量(P<0.05);与对照组相比,添加30 g/d复方中草药显著增加了血清免疫球蛋白M(IgM)及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活力(P<0.05)。3)复方中草药添加剂可以增加血清生长激素(GH)和催乳素(PRL)含量,且添加30 g/d时显著增加(P<0.05)。4)与对照组相比,日粮添加30、50和80 g/d可以使产奶量分别增加10.18%、6.79%和5.19%,但是对产奶量、乳成分及体细胞数的影响均不显著(P>0.05)。试验结果表明,复方中草药添加剂可以调节奶牛机体免疫性能和提高抗氧化能力,且每头牛添加30 g/d时效果最佳。但其对奶牛泌乳性能无显著影响。     

Dietary grain source and oil supplement: Feeding behavior and lactational performance of Holstein cows

Effects of grain source and dietary oil supplement on dry matter intake (DMI), feeding, chewing behavior, and production performance of lactating dairy cows were evaluated using eight multiparous Holstein cows (77±22.1 days in milk; mean±SD) in a duplicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Experimental diets contained either ground barley or ground corn supplemented with either fish oil or soybean oil at 2% of dietary dry matter (DM). Geometric mean particle size of dietary treatments was 4.1 mm. Dry matter intake tended (P=0.09) to be greater for barley- vs. corn-based diets (23.2 vs. 22.3 kg/d), but was reduced for the fish oil compared to soybean oil supplemented diets (21.1 vs. 24.3 kg/d; P<0.001). This reduction in DMI was attributed to smaller meal size (1.24 vs. 1.55 kg of DM; P=0.004) and slower eating rate (0.082 vs. 0.098 kg of DM/min; P<0.001) for fish oil compared to soybean oil supplemented diets. Main treatment effects interacted (P=0.005) for DMI of particles retained on 19 mm sieve but not for sorting index. Eating rate (0.090 kg of DM/min) was similar between barley- and corn-based diets, however, rumination time was greater for barley- compared to corn-based diets as result of longer rumination bout duration (32.5 vs. 28.5 min/bout; P=0.01). Barley- compared to corn-based diets increased total chewing time by 71 min (709 vs. 638 min) for cows fed fish oil, but not for cows fed soybean oil. Grain source did not affect milk yield or milk composition. Compared to soybean oil, fish oil negatively affected milk yield (40.4 vs. 43.4 kg/d; P=0.01), and thereby, both milk fat (0.91 vs. 1.26 kg/d; P<0.001) and protein (1.23 vs. 1.33 kg/d; P=0.007) production. However, feed efficiency (milk yield/DMI) was greater in fish oil compared to soybean oil supplemented diets (1.94 vs. 1.80; P=0.003). Results indicated that grain source and oil supplement can interact to affect feeding and chewing behavior, but not lactational performance of lactating cows.