Influence of postfast dietary crude protein and phosphorus content on nitrogen, phosphorus, calcium, and magnesium repletion in sheep.

An experiment was conducted to determine the influence of postfast dietary CP and P concentration on the repletion of N, P, Ca, and Mg lost during a 3-d fast in sheep. Four Suffolk wether lambs averaging 35 kg were used in a 4 x 4 Latin square design. Lambs were fed a control diet (700 g/d; as-fed basis) for 14 d and were then deprived of feed and water for 3 d. Lambs were then fed one of four isoenergetic realimentation diets: 1) low CP/low P, 2) low CP/high P, 3) high CP/high P, and 4) high CP/very high P. Realimentation N and Mg intakes were 9.8 and 1.1 g/d for lambs fed the low-CP diet and 18.1 and 1.7 g/d for lambs fed the high-CP diets, respectively. Realimentation P intakes were 1.40, 2.36, 2.66, and 3.82 g/d for lambs fed Diets 1, 2, 3, and 4, respectively. Nitrogen, P, Ca, and Mg apparent digestibility and balance and serum urea N, free fatty acids, P, Ca, Mg, and alkaline phosphatase were determined during the prefast, fast, and realimentation periods. Lambs fed the high-CP diets had higher (P less than .05) N and P digestibility and balance than lambs fed the low-CP diet. Increasing the dietary P content did not affect (P greater than .15) P balance or digestibility. In general, the realimentation diet fed did not affect (P greater than .15) serum concentrations of free fatty acids, alkaline phosphatase, inorganic P, Ca, or Mg.     

黑龙江省7个不同地区养殖场肉牛血液钙、磷和镁浓度的比较分析

通过黑龙江省7个不同地区肉牛养殖场血液钙(Ca)、磷(P)和镁(Mg)浓度的检测比较,来判断这7个肉牛养殖场肉牛钙磷代谢的情况,为肉牛养殖场预防钙磷代谢障碍疾病提供理论依据。选择黑龙江省大庆、双鸭山、九三、牡丹江市7个不同地区不同饲养方式的肉牛养殖场作为调查点,分别记为A组(双鸭山放牧加舍饲)、B组(双鸭山全舍饲)、C组(大庆全舍饲)、D组(九三放牧)、E组(大庆放牧加舍饲)、F组(大庆放牧加舍饲)、G组(牡丹江全舍饲),并对7个不同地区养殖场血中Ca、Mg和P的浓度及游离脂肪酸(NEFA)、葡萄糖(GLU)、β-羟丁酸(BHBA)进行比较分析,综合判定7个肉牛养殖场Ca、P代谢的状况。结果显示:7个调查点65头肉牛血浆中Ca、P和Mg浓度均在正常范围内,各地区间血Ca浓度差异不显著,P浓度有差异性,其中C、G组极显著高于A组(P<0.01);C、G组极显著高于B组(P<0.01);C组极显著高于D、E、F组(P<0.01);G组极显著高于D组(P<0.01);G组极显著高于E组(P<0.01);G组极显著高于F组(P<0.01),能量指标NEFA B组显著高于D组(P<0.05),其他各组间无差异性。GLU各组间存在差异其中A组显著高于E组(P<0.05);B组显著高于A、D组(P<0.05),极显著高于E、F、G组(P<0.01);C组极显著高于A、D、E、F、G组(P<0.01);D组显著高于E组(P<0.05);F组显著高于E组(P<0.05),BHBA有组间差异,C、D、E组极显著高于A组(P<0.01)、F组显著高于A组(P<0.05);C组显著高于B组(P<0.05);D、E组极显著高于B组(P<0.01);C组极显著高于G组(P<0.01);D组极显著高于F、G组(P<0.01);E组极显著高于F、G组(P<0.01)。各组间在血磷、NEFA、GLU、BHBA方面存在差异,与各组间的饲养方式,饲料精粗比及饲养环境有关。结果表明,黑龙江省大庆、双鸭山、九三、牡丹江市7个不同地区肉牛养殖场没有发生钙磷代谢障碍性疾病,但也要预防营养代谢疾病的发生。     

A review of calcium, phosphorus and magnesium metabolism in the horse

Mineral metabolism in the equine is a complex process involving absorption sites and interactions between the minerals themselves and other compounds. Factors such as the digestibility of the minerals and the extent of the interactions all play an important role in the mineral amounts required in the diet.Inadequate levels of minerals in the diet can lead to physiological maladies such as HNS and Ricketts. A knowledge and understanding of mineral metabolism is essential to the success of equine management.     

Factors affecting skim milk progesterone assay results.

Five studies were performed to determine factors affecting progesterone concentration in skim milk. Results of the first study indicated that progesterone concentration was higher in skim milk of samples kept 16 hours in an ice bath (0 C) than of those left at room temperature (21 C). In the second study, this temperature effect was found to be reversible, with skim milk progesterone concentration increasing when whole milk samples were cooled prior to centrifugation. In the third study, [3H]-labeled progesterone was used to determine the relationship between fat content of foremilk (the first milk obtained from the teats), midmilk (milk obtained midway through milking), and strippings (milk obtained immediately after milking machines have been removed) samples and temperature (4 C and 21 C) on the percentage of progesterone in the skim milk fraction. The relationship between percentage of butterfat and percentage of progesterone in skim milk was linear when the log of these variables was used for calculations. In the fourth study, assayable progesterone in the skim milk fraction of foremilk, midmilk, and strippings was affected by temperature. In the fifth study, a multiple-regression procedure was used to determine the amount of variation in percentage of radioactive progesterone in the skim milk fraction. Independent variables (whole milk butterfat and temperature of incubation [1, 3, 13, 22, 37, and 50 C]) and the natural log of each variable, were entered into a stepwise multiple-regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum concentrations of calcium, phosphorus, magnesium and calciotropic hormones in donkeys

OBJECTIVE: To provide reference values for serum biochemical variables that are used for evaluation of mineral metabolism in donkeys and compare values with those in horses. ANIMALS: 18 donkeys and 18 horses. PROCEDURES: Total calcium (tCa), total magnesium (tMg), and inorganic phosphorus (P) concentrations were measured in serum samples via spectrophotometry. Ionized calcium (iCa) and magnesium (iMg) concentrations were quantified with selective electrodes. By use of a micropartition system, tCa and tMg were fractionated to separate protein-bound (pCa, pMg) and ultrafiltrable fractions. Complexed calcium (cCa) and magnesium (cMg) concentrations were calculated by substracting ionized fractions from ultrafiltrable fractions. Parathyroid hormone (PTH) and calcitriol (CTR) concentrations were measured via radioimmunoassay. RESULTS: Serum tCa concentration in donkeys (3.37 +/- 0.21 mmol/L) was composed of pCa (1.59 +/- 0.21 mmol/L [47.0 +/- 4.2%]), iCa (1.69 +/- 0.04 mmol/L [50.4 +/- 3.0%]), and cCa (0.09 +/- 0.08 mmol/L [2.6 +/- 2.9%]). Serum tMg concentration (1.00 +/- 0.08 mmol/L) was fractioned in pMg (0.23 +/- 0.08 mmol/L [23.4 +/- 8.1%]), iMg (0.59 +/- 0.04 mmol/L [58.8 +/- 5.1%]), and cMg (0.18 +/- 0.08 mmol/L [17.8 +/- 7.2%]). Serum concentrations of P (1.14 +/- 0.30 mmol/L), PTH (20.4 +/- 21.2 pg/mL), and CTR (13.4 +/- 5.9 pg/mL) were determined. CONCLUSIONS AND CLINICAL RELEVANCE: Serum variables of mineral metabolism in donkeys were within reference ranges for horses. However, when compared with horses, donkeys had higher iCa, cMg, and CTR and lower pMg and PTH concentrations.     

Contribution of breed, cow weight, and milk yield to the traits of heifers and cows in four beef breeding systems.

Measurements were taken on 216 cows with 469 calvings for weight at weaning, condition at weaning, milk yield, milk fat percentage, milk lactose percentage, milk protein percentage, dry period feed intake, lactation period feed intake, total feed intake, first-service pregnancy rate, pregnancy rate, and days to pregnancy. Measurements were also taken on 183 heifers for first-service pregnancy rate, days to pregnancy, and age at first calving. The data spanned the years 1980 to 1988; animals belonged to one of four breeding systems: Hereford, small rotation (Angus, Gelbvieh, Pinzgauer, Tarentaise), large rotation (Charolais, Maine Anjou, Simmental), and Angus-large rotation (cows with Angus sires and large-rotation dams). Maine Anjou-sired cows had lower annual feed intake and Charolais-sired heifers lower first-service pregnancy rate than the other large-rotation breeds. Gelbvieh-sired cows had lower milk lactose and protein percentages than the other small-rotation breeds. Within breeding system neither cow weight nor milk yield were significantly associated with reproductive traits of cows. No differences among breeding systems in associations between feed intakes and weights or milk yields were detected.     

Effect of level of beef cow milk production on pre- and postweaning calf growth

Three groups of beef cows that were similar in growth and mature size, but different in genetic potential for level of milk provided to their calves, were studied. A procedure for fitting grafted polynomials based on calf suckling data was used to estimate the total amount of milk produced by each cow during 205-d lactations. Estimated 205-d milk production of the high milk group exceeded that of the medium and low milk groups by 186 and 561 kg, respectively. Differences in milk production of the three groups tended to increase as dams got older. The pooled, within milk-group correlation between calf gain to 205 d and milk intake was .60. Calves suckling dams with low milk production relied earlier and to a greater extent on alternative food sources of lower nutritional value than milk. Calves suckling high milk-group dams had 16.9 kg greater 205-d weaning weight than those suckling low milk-group dams, solely because of differences in maternal environment. Calves from the high milk group maintained 63% of the advantage over those in the low milk group in 205-d weight through a fairly rapid postweaning growth period to slaughter.     

钙磷同补治疗乳牛产后瘫痪效果分析

采用单补钙法及钙磷同补法对乳牛产后瘫痪进行治疗比较试验。结果表明:单补钙疗法治愈率为62.5%,钙磷同补法治愈率为87.5%。经t检验,单补钙疗法与钙磷同补疗法间存在极显著差异(P0.01)。     

Effects of biological type of beef steers on vitamin D, calcium, and phosphorus status

Feedlot steers (n = 36) from three biological types (Bos indicus, Bos taurus-Continental, and Bos taurus-English) were used to determine the Ca, P, and vitamin D3 status of feedlot cattle. The USDA yield and quality grade traits were measured at slaughter, and the concentrations of vitamin D3 (VITD) and the metabolites 25-hydroxyvitamin D3 (25-OH D) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2 D) were determined in LM, liver, kidney, and plasma. Plasma and muscle Ca and P concentrations also were determined. Biological type of cattle affected a number of carcass traits. Carcasses from Bos taurus-English cattle had more marbling, resulting in higher quality grades (P < 0.05). Carcasses from Bos taurus-Continental cattle had lower calculated yield grades (P < 0.05) than did carcasses from cattle in the other biological types. In general, differences in carcass traits resulting from biological type were consistent with other reports. Plasma and LM Ca and P concentrations were not affected (P = 0.06) by biological type of cattle, indicating that Ca and P homeostasis is a conserved trait across the different types of cattle. Plasma VITD and 25-OH D concentrations were not affected (P = 0.41) by biological type, whereas plasma 1,25-(OH)2 D concentration was lower (P < 0.05) in Bos taurus-English cattle than in Bos taurus-Continental and Bos indicus cattle. Liver VITD and 25-OH D were not affected by biological type (P = 0.76), but liver 1,25-(OH)2 D concentration was greater (P < 0.05) in Bos indicus cattle than in Bos taurus-Continental cattle. Kidney vitamin D metabolite concentrations were not affected by biological type of cattle (P = 0.21). Muscle VITD concentration was greater (P < 0.05) in Bos taurus-English cattle than in the other two biological types, and muscle 25-OH D concentrations were greater (P < 0.05) in Bos taurus-English cattle than in Bos indicus cattle. Muscle 1,25-(OH)2 D concentration was less (P < 0.05) in the Bos taurus-Continental cattle than in the other two biological types. Cooking eliminated vitamin D metabolite differences among the biological types. Our results suggest that Bos indicus cattle had greater 1,25-(OH)2 D (the biologically active form) in tissues, and greater 1,25-(OH)2 D plasma concentrations than Bos taurus cattle. Thus, the need for VITD supplementation and optimal levels of Ca and P in feedlot diets might differ between Bos indicus and Bos taurus cattle.     

Influence of dietary carboxymethylcellulose on the apparent absorption of calcium, magnesium and phosphorus in rats

Introduction   Dietary pectin vs cellulose has been shown to enhance apparent magnesium absorption in rats (unpublished data). This observation supports that of V ahouny et al. (1987), indicating that pectin feeding produced a more positive balance of magnesium in young, growing rats than did cellulose feeding. Pectin is a soluble, viscous and readily fermentable non-starch polysaccharide, but is not digested by animal enzymes. Pectin feeding raises the viscosity of small intestinal digesta in rats (J udd and T ruswell 1985). The increase in magnesium absorption seen after pectin feeding could relate to its fermentation, which may lower the pH of the small intestinal digesta, which in turn raises the solubility of minerals, rendering them more available for absorption. Both dietary lactulose and lactose, which are not digestible but highly fermentable, lower the pH of small intestinal digesta and increase mineral absorption in rats (H eijnen et al. 1993). The influence of viscosity per se on mineral absorption is unknown. In contrast to the above-mentioned mechanism, the observed stimulatory effect of pectin feeding on magnesium absorption (unpublished data) could relate to viscosity of small intestinal contents. To provide clues as to this possibility, the model compound carboxymethylcellulose (CMC) may be used. This compound is not digested by animal enzymes, is non-fermentable, but is highly viscous and has been shown to raise the viscosity of small intestinal contents in broiler chickens (S mits et al. 1997). Thus we fed rats on diets with different levels of CMC to study the influence of digesta viscosity on apparent absorption of calcium, magnesium and phosphorus.     

影响奶牛产奶量的主要因素浅析

品质优良的奶牛是在优质饲料的供应下、在科学的饲养管理条件下、在健康无疾病和舒适的生活环境中实现的。各国对于高产奶牛的定义有所差异,以饲养和营养水平较高的美国为例,高产奶牛是指305d产奶量超过11000kg的奶牛。根据我国目前的饲养水平,由于饲养管理及饲料组成的影响,年产奶量超过8000kg即可算高产奶牛。1遗传因素不同品种、个体和体重均影响奶牛产奶量。每头奶牛的产奶量若年递增大约2%￣3%,那其中来自于遗传因素为33%￣40%,其余的60%￣67%来自于饲养和管理。同一品种内的不同个体,其产奶量和乳脂率也有差异。体重大的个体其产奶量…