This paper discusses when to start and stop breeding cows in their lactation. First, a review of the literature on the optimal voluntary waiting period (when to start breeding cows) shows that there is not much consensus on how long the economically optimal voluntary waiting period is. Secondly, the paper then describes a computer program that calculates the insemination value (IN$) for cows in...

protection of the mammary gland against mastitis-causing pathogens is mediated by many factors in thegland and blood circulation. the professional phagocytic cells of bovine udder, polymorphonuclearneutrophils (pmn) and macrophages, comprise the first line of defense against invading mastitis pathogens.most researchers now accept that the pmn is a key factor in the cows’ defense against intrama...

A growing concern of the dairy industry is to increase dairy cattle wellbeing in anticipation of a demand from the general public of welfare-certified dairy products. Lameness is one of the most important welfare issues of high producing dairy cows in North America (Vermunt, 2007). It is a debilitating condition that challenges sustainability of production systems used in North America because ...

Oocyte fertilization rates in bovines following artificial insemination or natural mating are generally good (~90%). Curiously, only about one third of these pregnancies remain until 30 days post-AI in dairy cows. Thus, most pregnancies are lost between fertilization and early embryonic growth. Although classical pathways describing that lower progesterone post-AI is the main culprit to these e...

Ketosis is an important metabolic disease of high milk-producing cows. There are significant changes in many metabolite and hormonal concentrations in metabolic diseases. This study was carried out to assess the concentrations calcium (Ca), selenium (Se), total antioxidant (TAOC), insulin, free triiodothyronine (fT3) and free thyroxine (fT4) in cows with subclinical and clinical ketosis. This s...

Gastrointestinal nematodes (GIN) infection can impair milk production (MP) in dairy cows. To investigate whether MP would be optimized by spring targeted-selective anthelmintic treatment in grazing cows, we assessed (1) the effect on MP of an anthelmintic treatment applied 1.5 to 2 months after turn-out, and (2) herd and individual indicators associated with the post-treatment MP response. A ra...

background: cardiovascular system is a very importantorgan that plays a vital role in tissue function. in farm animals,the growth and high milk production depends on function ofcardiovascular system. objectives: cardiovascular health inhigh and low-yielding dairy cows was investigated. methods:fifty 4-year-old high- yielding holstein dairy cows and fifty 4-year-old low- yielding holstein dairy ...

Background: There are accumulating evidences showing the role of adiponectin, a newly discovered adipocytokine secreted from adipose tissue, in the regulation of the ovarian function in dairy cows. The objective of the present study was to evaluate the pattern of serum adiponectin concentration during a normal estrous cycle in the postpartum dairy cows. Materials and Methods: Coccygeal vein blo...

Pten is a tumor suppressor gene regulating many cellular processes, including growth, adhesion, and apoptosis. In the aim of investigating the role of Pten during mammary gland development and lactation of dairy cows, we analyzed Pten expression levels in the mammary glands of dairy cows by using western blotting, immunohistochemistry, and quantitative polymerase chain reaction (qPCR) assays. D...