Influence of Age, Sex, and Production Class on Liver Zinc Concentration in Calves

Determination of zinc concentrations in the liver of calves and young stock is commonly requested by practitioners and nutritionists to assess whether they receive an appropriate amount of zinc in their diet. However, interpretation of liver zinc concentrations is currently based on information reported for adult cattle for which the health status was unknown and irrespective of production class, sex, and age. A retrospective study of necropsy reports was undertaken to assess the relationships between liver zinc concentrations and age, sex, and production class for calves that did not have a history compatible with zinc toxicosis or zinc deficiency. Results of a generalized least squares, polynomial regression analysis of 474 records found that zinc concentration was not affected by sex ( P = 0.29) or production class ( P = 0.50). Zinc concentration was significantly associated with linear ( P < 0.00001) and nonlinear (quadratic, P = 0.0039) functions of age ( r2 = 0.1503), where the concentration decreased from 93 mg/kg wet weight at 30 days of age to 57 mg/kg wet weight at 9 months of age, after which it began to increase. The age-specific 95% confidence limits of the mean concentration for a group of calves and the 95% prediction limits of a single concentration value for an individual animal estimated in this study suggest reconsideration of the recommended limits for liver zinc concentration in calves. As a consequence of the significant influence of age on liver zinc concentration of calves presumably not experiencing zinc toxicosis or deficiency, diagnosis of zinc imbalances based on liver zinc concentration needs to consider age as a diagnostic covariate.

Congenital chondrodystrophy of unknown origin in beef herds

Congenital chondrodystrophy of unknown origin (CCUO), often referred to as 'acorn calf disease' or congenital joint laxity and dwarfism (CJLD), has been reported in beef cattle in Canada, the United States, Europe, South Africa, New Zealand and Australia. An association of CCUO with grazing drought-affected pastures, feeding hay-only or silage-only diets or supplementation with apple pulp suggests a nutritional cause such as a mineral deficiency. This review compares published reports on CCUO in order to identify common features among outbreaks and to provide a basis for future research into the condition. A protocol for investigation of outbreaks is provided to improve the outcome of future comparisons.

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.

Bovine hereditary zinc deficiency: lethal trait A 46

Bovine hereditary zinc deficiency, also referred to as Adema disease, is an autosomal recessive disorder which results in inadequate amounts of zinc being absorbed from the gastrointestinal tract and leads to a number of clinical abnormalities. Using semen from a homozygous affected bull and obligate heterozygote cows in embryo transfer studies, 7 offspring were obtained. These included 5 affected calves and 1 heterozygous carrier; the seventh calf died within 48 hours of birth undiagnosed. One unaffected, unrelated bull calf was raised as a control. All the calves were raised and maintained under similar management conditions designed to minimize secondary complications that would obscure the clinical and biochemical observations of a zinc deficient state. The first clinical manifestation of zinc deficiency was diarrhea, followed by skin lesions, poliosis, and a decreased ability to sustain a suckle reflex. Trace mineral analysis of plasma blood samples revealed that plasma zinc concentrations of all the calves were normal at birth; however, they gradually declined in affected calves over the course of 3-8 weeks postpartum to below 0.5 ppm. Biochemical analysis of serum samples showed alkaline phosphatase activity consistently paralleled changes in the plasma zinc concentrations. The oral administration of zinc acetate caused a reversal of all clinical, biochemical, and histologic abnormalities in affected calves. The study of these affected calves allows further insight into the biological role of zinc as well as provides an animal model for the continued investigation of the human homologue acrodermatitis enteropathica.

Trace element deficiencies in cattle

Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of trace elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of trace element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a trace element deficiency.

Growth and nutrient digestion by dairy heifers fed semipurified diets

Holstein heifers, which weighed an average of 154 kg, were randomly assigned to three dietary treatments in a split plot in time design. Differences in diets were fiber source: solka floc, corn cobs, and corn silage. The major source of added protein was corn gluten meal. Total collection metabolism periods were the final 7 d of each of two 30-d periods. Several heifers had simple digestive disturbances, which appeared to be related to low ruminal pH, while consuming the solka floc diet. Average daily gains were .78, .83, and 1.02 kg/d for treatments solka floc, corn cobs, and corn silage, respectively. Gains were within the range of acceptable growth standards and were higher than reports in the literature for semipurified and purified diets. Protein in corn gluten meal appeared to be utilized efficiently by the heifers for growth. The solka floc and corn cob diets are acceptable for growing dairy heifers where a low mineral content is desired but normal growth rates need to be maintained. The solka floc diet might be improved by including a buffer to help stabilize rumen pH.

Effects of dietary zinc upon tissue zinc and percent unsaturated plasma-zinc binding capacity

Calves were fed 520 ppm zinc for 21 days, then placed on a low zinc diet (20 ppm zinc) for 35 days to determine the biological availability of zinc reserves of tissue. Concentrations of zinc in liver and kidney were elevated greatly by feeding high dietary zinc for 21 days and continued to increase with time. On the low zinc diet, the tissue burden of zinc decreased within 35 days to those comparable to calves initially fed low zinc. Likewise, both zinc in plasma and percent capacity of unsaturated plasma for binding zinc were near negative controls 21 days after removal of calves from high zinc diets. Tissue stores of zinc will not maintain adequate zinc in blood for extended periods, and hence, they probably will not sustain optimal feed intakes and growth rates of calves on low-intakes of zinc.

Acrodermatitis enteropathica

Acrodermatisis enteropathical has had a remarkable hist orical course beginning only 35 years ago, first passing through a period of empiric management with the 8-hydroxyquinoline drugs and culminating with the discovery of a biochemical effect in zinc absorption. This accomplishment has not only resulted in the cure of a serious and often fatal disease, but has opened the way to an understanding of the vital role played by the trace element zinc in many previously unrecognized areas of human physiology.

Effect of high amounts of dietary zinc and age upon tissue zinc in young chicks

Weight gains of younger broiler chicks were not reduced by up to 2400 p.p.m. added zinc fed to four weeks of age. Tissue zinc was not changed significantly by 600 or 1200 p.p.m. supplemental dietary zinc, but at 2400 p.p.m. added zinc, blood, kidney, and liver zinc were significantly elevated (P less than 0.05). In the heart, zinc was not affected by the added dietary zinc but increased over time with all diets. Unlike the calf and weanling pig, the metabolism of zinc in the young chick does not appear to change appreciably with increasing maturity. Thus, the homeostatic control mechanisms of the young chick are effective for up to 1200 p.p.m. dietary zinc, but are partially overcome by 2400 p.p.m. added dietary zinc.

Intracellular distribution of zinc and zinc-65 in calves receiving high but nontoxic amounts of zinc

The zinc homeostatic control breakdown in cattle fed a high but nontoxic amount of zinc was investigated. Liver copper was decreased by the 600 ppm added dietary zinc indicating altered copper metabolism. However, duodenal copper, liver and duodenal iron and manganese were not affected. Zinc-65 in blood was reduced 90% by the high dietary zinc 48 h following oral zinc-65 dosing. The 600 ppm supplemental zinc increased zinc by 500% in liver, 20 times in pancreas and kidney, and 100% in the duodenum. The increased liver and duodenal zinc was confined largely to the soluble cell fraction. This concentrating of excess tissue zinc in the soluble fraction may be an adaptive mechanism which detoxifies large quantities of zinc and prevents disruption of normal cellular activity.