The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]glucose i.v. infusion in lactating dairy cows. Sample enrichments were analysed by gas chromatography/mass spectrometry. Linearity (enriched solutions) and specificity (enriched plasma) were good: for enrichments ranging between 1.6 and 6.3 mol% excess, the slopes were about 1 and the ordinates at th...

The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows milk fever, ketosis, retained placenta (RP), and displacement of the abomasum occur within the first two wk of lactation. In addition to metabolic disease, the majority of infectious disease experienced by the dairy cow, especially...

considering different fertility traits 411 cows from 73 farms used for economic analyses. from these, 202 lactating cows were selected for evaluating the fertility status. pre-tested data sheets were used to record the socioeconomic status of the farms including their assets, cost and return and productive and reproductive performance of the dairy cows. targets were set considering the situatio...

this experiment was conducted to investigate the effect of feeding frequency and oil supplementation to the diet on performance and feeding behavior of lactating dairy cows. twenty four lactating holstein cows, 12 primiparous, (bw= 626±58 kg and dim= 195±44 day) and 12 multiparous, (bw= 617±25 kg and dim= 207±39 day) were randomly assigned to four diets contained 2.5 percent supplemental oil or...

Twenty multiparous Holstein cows in midlactation grazed pastures of 4 forage mixtures in a 12-wk study repeated during 2 grazing seasons to determine if forage mixture complexity affected intake and productivity of lactating dairy cows. The forage mixtures were 1) orchardgrass plus white clover [2 species (SP)]; 2) orchardgrass, white clover, and chicory (3SP); 3) orchardgrass, tall fescue, per...

Nutritional grouping is a herd management strategy that provides different diets to different groups of lactating cows to better fulfill their nutrient requirements. Hence, it can be beneficial by saving feed costs, improving productivity, improving herd health, and decreasing nutrient emissions to the environment (Cabrera and Kalantari, 2016). Total mixed rations have become an industry standa...

Both clinical and subclinical deficiency of calcium and magnesium may cause problems in dairy cows. Clinical hypocalcaemia most commonly occurs at calving and onset of lactation and is associated with milk fever, while clinical hypomagnesaemia occurs under certain dietary conditions. Factors affecting the calcium and magnesium status in dairy cows were examined in this thesis. The effect of die...

Objectives were to compare circulating progesterone (P4) profile and pregnancies per AI (P/AI) of two commercial intravaginal P4 devices (PRID-Delta(®) vs CIDR(®)). In Experiment 1, ovariectomized dairy cows (PRID-Delta, n=6 vs CIDR, n=6) were sampled throughout 7 days to measure circulating P4. In Experiment 2 (PRID-Delta, n=399 vs CIDR, n=375), cows were assigned to treatments, as follows: D0...

The objective of this study was to investigate the effects of concentrations of forages and dried distillers grains with solubles (DDGS) on production of lactating dairy cows. Twelve Holstein cows were assigned randomly to replicated 4 × 4 Latin squares in a 2 × 2 factorial arrangement of treatments. Diets were formulated containing low forage (LF; 41% of diet DM) or high forage (HF; 60% of die...

The daily challenge of getting cows pregnant is nothing new to any dairy producer. What is new is the variety of approaches that researchers are taking to understand the mechanisms underlying this problem and propose effective solutions to it. Our applied reproductive research program is focused on controlling ovarian physiology to optimize fertility of lactating dairy cows. Our goal is to deve...