Some physiological effects of shading dairy cattle

Mycotoxin Effects in Dairy Cattle

Mycotixin Effects in Dairy Cattle

• Molds are filamentous (fuzzy or dusty appearing) fungi that occur in many feedstuffs, including roughages and concentrates. • Molds can infect dairy cattle, especially during stressful periods when they are immune suppressed, causing a disease referred to as mycosis. • A wide range of different molds produce poisons called mycotoxins that affect animals when they consume contaminated feeds. •...

Physiological and practical effects of progesterone on reproduction in dairy cattle.

The discovery of progesterone (P4) and elucidation of the mechanisms of P4 action have an important place in the history of endocrinology and reproduction. Circulating P4 concentration is determined by a balance between P4 production, primarily by the corpus luteum (CL), and P4 metabolism, primarily by the liver. The volume of luteal tissue and number and function of large luteal cells are prim...

Physiological Mechanisms Leading to Reproductive Decline in Dairy Cattle

Dairy cattle are inseminated and pregnancy is established during lactation. Therefore, lactation and the reestablishment of pregnancy must overlap. Unfortunately, recent changes in the genetics, productivity, and management of dairy cows have led to a decline in reproductive efficiency. Reproductive decline in dairy cows began in the mid-1980’s and may be continuing on modern dairy farms (Lucy,...

Photoperiodic effects on dairy cattle: a review.

Since the initial report in 1978 of galactopoietic effects of a photoperiod of 16 h of light:8 h of darkness, numerous studies have confirmed long-day stimulation of milk yield. The endocrine factor(s) responsible for increased milk yield, however, has eluded identification. Recent studies suggest that insulin-like growth factor-I (IGF-I) may mediate the galactopoietic response to long day phot...