This study was carried out to investigate the relationship between early lactation curve parameters andcalving interval in Holstein cows of Iran. In order to describe the lactation curve, the incomplete gammafunction was fitted to 5,754,428 test-day milk records corresponding to 766,108 lactations on 315,634 cowsin 2,448 herds. Cows with higher milk yield during early lactation had shorter calv...

The aim of this study was using Bayesian approach via Gibbs sampling (GS) for estimating genetic parameters of production, reproduction and health traits in Iranian Holstein cows. Data consisted of 320666 first- lactation records of Holstein cows from 7696 sires and 260302 dams collected by the animal breeding center of Iran from year 1991 to 2010. (Co) variance components were estimated using ...

The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) o...

Objective of this study was to determine the effects of varying dietary cation-anion differences (DCAD) in prepartum period on milk fever, subclinical hypocalcemia and negative energy balance in dairy cows of Urmia, Iran. Ninety nine Holstein cows assigned to three groups (n=33) were fed diets with DCAD of -24 (anionic), +80 (cationic) and +230 (cationic) mEq/Kg dry matter for 3 weeks before ex...

Body condition score (BCS), energy content (EC), cumulative effective energy balance (CEEB), and blood serum concentrations of glucose, beta-hydroxybutyrate (BHBA), and nonesterified fatty acids (NEFA) were measured throughout first lactation in 497 Holstein cows raised on a large commercial farm in northern Greece. All these traits are considered to be indicators of a cow's energy balance. An ...

The objectives of this study were to determine the effect of the dry cow management system (pasture or confined) on: (1) lying behaviour and activity; (2) feeding and heat stress behaviours; (3) intramammary infections, postpartum. Non-lactating Holstein cows were assigned to either deep-bedded, sand freestalls ( n = 14) or pasture ( n = 14) using rolling enrollment. At dry-off, cows were equip...

This study was designed to investigate the alteration in serum haptoglobin (Hp) concentration in dystocia affected cows in comparison to those having normal parturition. Thirty cows included in this study, seventeen with normal parturition and thirteen with difficult parturition (dystocia). Blood samples, from cows that having normal parturition, were collected every three days during the last ...

In spite of the difficulties in delivering PUFA to ruminants, studies have generally indicated that the PUFA of the omega-6 (linoleic acid) and omega-3 [α-linolenic acid; eicosapentaenoic (EPA), C20:5 omega-3; docosahexaenoic (DHA), C22:6 omega-3] families are the most beneficial to improving reproduction in cows. The objectives were to determine if a diet enriched in α-linolenic acid (omega-3)...

According to the most recent National Animal Health Monitoring System for dairy cattle (National Animal Health Monitoring System, 2008), leading causes of morbidity in dairy cattle are clinical mastitis, lameness, infertility, retained placenta, milk fever, reproductive problems, and displaced abomasum. Of cows removed from herds, about 53% leave for one or more of the above reasons. Additional...

At 50 d prior to predicted calving, 37 multiparous Angus cows were grouped by sire of mating, age and weight of cow and placed on either a high energy (HE, n = 19) diet or a moderate energy (ME, n = 18) diet. Objectives were to determine the effect of prepartum nutrition on: prepartum serum concentrations of estrone (E1), estrone sulfate (E1SO4) and progesterone (P4); pre- and postpartum cow bo...