Eighty eight Friesian cows and heifers were fed one of four complete diets based on maize silage and containing increasing levels of grain (from 0 to 500 g DM/kg diet DM), in two trials. Days from calving to first observed oestrus and to conception were recorded as were yields of milk and milk fat and live weight changes during early lactation. In the second trial, complete lactation data were ...

It is known that at the moment of delivery immediate lost of conceptus (main site of glucose disposal in late pregnancy) is not able to disturb glucose homeostasis in early lactating mothers. However, the mechanism by which this adaptation takes place in early lactation is still unknown. Most studies concerning insulin sensitivity in lactating rats were carried out at 11-13 days postpartum and ...

The aim of this study was to evaluate the effects of balancing low protein diets for methionine and lysine on performance of early lactation Holstein cows under hot environmental temperature. Twenty one multiparous Holstein cows in early lactation were allocated to three experimental rations including, 1) High protein ration with 17.5% CP, 2) Medium protein ration with 16% CP and 12 g/d rumen p...

Milk samples were collected in early lactation (8–14 days milk; DIM) and late (199–326 from 11 cows to assess the differences bovine milk fatty acid (FA) triacylglycerol (TAG) composition, FA positional distribution TAG structure, solid fat content (SFC). Cows that negative energy balance, mobilised C16:0, C18:0, C18:1cis9 their body stores, increasing concentrations of these fat. These high C1...

The study was conducted on 20 Holstein X Sahiwal cross bred dairy cows, with an average milk production of 2,752±113.79 liters in 284±5.75 days during a single lactation, that were divided in to two groups of 10 animals. We investigated the oxidative stress and antioxidant status during the transition period in dairy cows. In this study, plasma level of MDA was considered as an indicator of lip...

Studies examining hormones throughout pregnancy and lactation in women have been limited to single, or a few repeated, short-term measures of endocrine activity. Furthermore, potential differences in chronic hormonal changes across pregnancy/lactation between first-time and experienced mothers are not well understood, especially as they relate to infant development. Hormone concentrations in ha...

Increased genetic selection and capacity for milk production in dairy cows has been associated with a decline in fertility. Following parturition, nutritional requirements increase rapidly with milk production and the resulting negative energy balance (NEBAL) extends for 8–10 weeks of early lactation. NEBAL delays the timing of first ovulation through attenuation of LH pulse frequency and low l...

The changes in the activities of a number of enzymes, representing various metabolic activities, in pyridine nucleotides, in levels of deoxyriboand ribonucleic acid, and in numbers of nuclei in mammary glands removed from rats at various stages of pregnancy and lactation have been documented. The onset of lactation is accompanied by a rapid 3to 4-fold increase in numbers of nuclei and in DNA le...

OBJECTIVES Widespread use of heavy metal lead (Pb) for various commercial purposes has resulted in the environmental contamination caused by this metal. The studies have shown a definite relationship between low level lead exposure during early brain development and deficit in children's cognitive functions. This study investigated the passive avoidance learning and spatial learning in male rat...

We investigated the effect of the amount of body condition loss in the dry period and early lactation in 42 high-yielding Holstein-Friesian cows on milk yield and the share of fatty acids in milk fat. Energy reserves were estimated based on the body condition scoring (BCS) and backfat thickness (BFT). Milk yield and milk composition were determined over 305-d lactation. From d 6 to 60 of lactat...