Nutrient needs increase during pregnancy and lactation to support fetal growth and milk synthesis, respectively. Physiological adjustments that are made to meet those needs alter the fraction of ingested nutrient retained, or the bioavailability. Using stable isotopes as tracers, we measured calcium, zinc and selenium homeostasis in women during reproduction. The physiological response, and the...

From an evolutionary perspective, the high basal metabolic rate (BMR) of homeotherms is hypothesised to be a by-product of natural selection for effective parental care. We estimated daily milk output during two consecutive lactation bouts in mice divergently selected for high/low BMR and applied a cross-fostered design to control for potential differences in the between-line suckling abilities...

The goals of a dairy replacement management program are to rear heifers at a low economic and environmental cost without compromising future lactation performance. To meet these objectives, increased sophistication dairy heifer nutrition programs may be required. Research evaluating more sophisticated dairy heifer nutrition programs however does not always result in a relevant field application...

pregnancy to late lactation, whereas cytochrome oxidase remained constant. No change in the distribution of these enzymes or of protein was found at the three stages of the lactation cycle studied. 3. In mammary gland succinate-neotetrazolium reductase increased rapidly over parturition and throughout lactation; cytochrome oxidase showed a smaller increase during lactation. These increases were...

Photoperiodic manipulation has dramatic physiological and production effects in dairy cows. During lactation, exposure to long day photoperiod (LDPP) increases milk yield and circulating IGF-I and prolactin (PRL) concentrations. Conversely, cows housed under a short day photoperiod (SDPP) during the dry period produce more milk in the subsequent lactation than cows exposed to LDPP or natural ph...

Thirty-six lactating Alpine does were used to determine effects of stage of lactation and level of feed intake on energy utilization. Twelve does were assigned to measurement periods in early, mid, and late lactation (wk 5, 13, and 27, respectively). For 6 does of each group, after ad libitum consumption of a 60% concentrate diet, feed intake was restricted to near the metabolizable energy (ME)...

The aim of the present study was to compare the occurrence and duration of clinical mastitis in different seasons, stages of lactation period and parities in a Holstein dairy farm in Iran. A retrospective epidemiological survey from April 2005 to March 2008 was conducted on 884 clinical mastitis cases of 7437 lactations. Data of each case including calendar-date of mastitis onset, days in milk ...

Some dairy farmers opt to omit one milking, either incidentally or weekly, without changing other milking times. This practice entails an extended milking interval of 24h (24h-MI), which is associated with a decrease in milk yield. This decrease varies among cows and could be partly due to factors such as stage of lactation and milk yield level. The aim of this study was to describe the average...

Oligosaccharides (OS) from bovine milk are a class of bioactive molecules that are receiving increasing commercial attention for their potential health benefits. In the present work we measured, comprehensively and systematically, free milk OS in the colostrum of 7 Holstein-Friesian cows during the first 3 d of lactation in 12-h intervals by HPLC-chip/time-of-flight mass spectrometry to determi...