percentages and yields of fat, crude protein (cp), true protein (tp) and non-protein nitrogen (npn) wereassessed in milk of four groups of holstein cows, at early, mid and late lactation (days in milk 20-70, 71-110, 111-150 and 151-210), on a diet rich in concentrates during a hot summer. four milk samples were taken from individual cows at 10-day intervals. milk fat percentages were close to b...

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...

Plasmatic concentrations of von Willebrand Factor (vWF) increase during pregnancy in humans and dogs; however the mechanism of such increase is still not well defined. The aims of this study were: (i) to evaluate changes in vWF concentration during pregnancy and during the subsequent oestrous cycle in bitches affected and unaffected by von Willebrand Disease (vWD); (ii) to correlate the vWF lev...

Mammary transcriptome analyses across the lactation cycle and transgenic animal studies have identified candidate genes for mammogenesis, lactogenesis and involution; however, there is a lack of information on pathways that contribute to lactation performance. Previously we have shown significant differences in lactation performance, mammary gland histology, and gene expression profiles during ...

The study examined microRNA (miRNA) expression and regulatory patterns during an entire bovine lactation cycle. Total RNA from milk fat samples collected at the lactogenesis (LAC, day1 [D1] and D7), galactopoiesis (GAL, D30, D70, D130, D170 and D230) and involution (INV, D290 and when milk production dropped to 5 kg/day) stages from 9 cows was used for miRNA sequencing. A total of 475 known and...

Fasting is associated with a series of physiological responses that protect body tissues from degradation by efficiently using expendable energy reserves while sparing protein. Lactation requires the mobilization of maternal nutrients for milk synthesis. The rare life history trait of fasting simultaneous with lactation results in the conflicting demands of provisioning offspring while meeting ...

Choice of a male or female social contact was studied in intact female rats in a runway-choice apparatus during estrous cycle, pregnancy, and lactation. The male was chosen significantly more often during proestrus/estrus than during the diestrous days of the cycle. During pregnancy this preference in choice declined only to reappear gradually during the lactation period. The shifts in the leve...

A nutritionally-regulated compensatory growth regimen imposed during a growing period from prepuberty to gestation can significantly affect mammary development and subsequent lactation performance. The objectives of this study were as follows: 1) to determine whether a compensatory nutrition regimen enhances lactation potential for the first and second lactation cycles and 2) to determine the e...

The modern dairy cow has been selected over generations for high milk production, with many successful dairy operations averaging over 13,500 kg of milk per lactation cycle per cow. This amount of nutrient output in the form of milk components puts a tremendous amount of pressure on the metabolism of the dairy cow, especially during early lactation. In fact, it is common to all mammals, includi...