Primiparous beef cows produced in 3 calving systems were used in a 2-yr study with a completely random design to measure milk yield throughout a 190-d lactation (2002, n = 20; 2003, n = 24 per calving system). Calving occurred in late winter (average calving date = February 4 +/- 2 d), early spring (average calving date = March 30 +/- 2 d), and late spring (average calving date = May 26 +/- 1 d...

assessing the effects of monensin on economic factors of milk (percents of protein and fat), and quality of milk fat during early lactation. thirteen multiparous holstein cows were blocked into a control and a treatment group from 3 weeks prepartum to 45 days postpartum according the number of their calving. the groups received similar diets. the treatment group received monensin added to grain...

The objective of this research was to estimate the genetic parameters of body condition score (BCS) in the first 3 lactations in Canadian Holstein dairy cattle using a multiple-lactation random regression animal model. Field staff from Valacta milk recording agency (Sainte-Anne-de-Bellevue, QC, Canada) collected BCS from Québec herds several times throughout each lactation. Approximately 32,000...

The aim of the study is to determine whether low doses of "endocrine disrupting chemicals" (EDCs) affect the development and proliferative activity of the mammary glands (MGs). Adult parous/nulliparous female Sprague-Dawley (SD) rats were treated from post-natal day (PND) 1 until PND 180 with diethylphthalate (DEP), methylparaben (MPB), triclosan (TCS) and a mixture at doses comparable to human...

In mammalian physiology, lactation follows pregnancy, and disruption of this physiology is associated with adverse health outcomes for mother and child. Although lactation is the physiologic norm, cultural norms for infant feeding have changed dramatically over the past century. Breastfeeding initiation fell from 70% in the early 1900s to 22% in 1972. In the past 40 years, rates have risen subs...

Normal physiological values of different blood parameters for various animals are influenced by a number of factors such as age, sex, breed, season, altitude, climatic conditions, nutrition and life habits of the species [4,6,9,19]. It has been reported that the significant differences (p < 0.001) in glucose, total lipid, cholesterol, total protein, uric acid and calcium levels were found betwe...

The objective of the present study was to estimate the genetic parameters for test-day milk yields (TDMY) in the first and second lactations using random regression models (RRM) in order to contribute to the application of these models in genetic evaluation of milk yield in Gyr cattle. A total of 53,328 TDMY records from 7118 lactations of 5853 Gyr cows were analyzed. The model included the dir...