One hundred sixteen spring-calving Polled Hereford x Angus cows were milked using milking machines after receiving 20 IU of oxytocin. Sires of the cows had been divergently selected on yearling weight (YW) and total maternal (MAT) EPD to form four groups: high YW, high MAT EPD; high YW, low MAT EPD; low YW, high MAT EPD; and low YW, low MAT EPD. Average milk production after 12-h calf separatio...

Background: The Osteopontin (OPN) is a highly phosphorylated glycoprotein in numbers of bovine tissues and milk. OPN has been reported to be associated with milk production in cattle. Objective: The genotype and allelic frequencies for OPN and its association with milk production will be evaluated in Iranian Holstein Bulls.   Materials and Methods: Bulls DNA (100) was isolated. Oligo was used f...

On a short-term basis, the efficiency of nutrient use for milk production is primarily dependent on the milk production level. As milk yield increases, a lower proportion of total feed intake is used for maintenance (a non-productive requirement that is more or less constant) of the cow. A cow producing 12 kg/d of milk is using about 50% of available nutrients for milk synthesis, whereas the co...

We investigated the effects of omitting one or two milkings weekly on milk yield and milk composition in dairy sheep. Ninety Spanish Assaf ewes were allocated to three experimental treatments: T0 (no milking omission; 14 milkings/week), T1 (omission of one evening milking per week; 13 milkings/week) and T2 (omission of two evening milkings per week; 12 milkings/week). The experiment was extende...

Although the chemical, physical, and nutritional properties of bovine milk have been extensively studied, only a few studies have attempted to characterize milk-synthesizing genes using RNA-seq data. RNA-seq data was collected from 21 Holstein samples, along with group information about milk production ability; milk yield; and protein, fat, and solid contents. Meta-analysis was employed in orde...

Some production parameters of seropositive cows (age, first calving age, 305 day mature equivalent last milk yield production, lifetime mature equivalent milk yield production, lifetime total milk production, lifetime total milking period, lifetime monthly milk production, lifetime daily milk production, lifetime total days of milking, number of inseminations per pregnancy (for last pregnancy),...

A common perception is that pasture-based, low-input dairy systems characteristic of the 1940s were more conducive to environmental stewardship than modern milk production systems. The objective of this study was to compare the environmental impact of modern (2007) US dairy production with historical production practices as exemplified by the US dairy system in 1944. A deterministic model based...

the aim of this study was to estimate genetic parameters of age at first calving and its relationship with productive traits of holstein dairy cows. a total of 24491 first lactation records (2x 305d) which were collected from 1995 to 2009 were used. the general linear model (glm) procedure was applied to determine effective factors on studied traits. herd-year-season (hys) and age at first calv...

T h e high cost of milk proteins limits the profits of veal production. The situation is made worse by an increasing demand for beef. For this reason the rearing of calves for veal production is expected to decline to one-third within the next 10 years. One method of solving some of these problems would be the partial or total replacement of milk proteins with suitable substitutes. This course ...