In a replicated 4 x 4 Latin square design with 4-wk periods, we used 12 multiparous Holstein cows averaging 83 d postpartum to compare corn distillers grains (CDG) versus a blend (BLEND) of other protein sources with CDG (fish meal and soybean meal), and to determine the effectiveness of ruminally protected lysine and methionine (RPLM) in improving the utilization of CDG as a protein supplement...

Supplementing cows with fat can have several beneficial effects. It usually increases the energy density of the diet as starch or fiber is replaced with fatty acids. If milk production is increased, then feed efficiency may be improved. Less heat may be produced in the rumen during digestion of fat-supplemented diets as fatty acids are not digested in the rumen. Less heat produced during digest...

The aim of this study was to evaluate the nutrient digestibility, ruminal fermentation and microbial protein synthesis of mid-lactating cows fed high dietary levels of monensin. Twelve Holstein cows were distributed into four 3 × 3 latin squares and assigned to the following treatments: control (CON), monensin 24 (M24, addition of 24 mg monensin/kg diet DM) and monensin 48 (M48, addition of 48 ...

BACKGROUND: Dairy cows undergo physiological changes during pregnancy and lactation and cardiovascular system may alter during these periods. OBJECTIVES: Understanding the physiological effects of production periods of dairy cows on heart electrical activities can aid to better monitoring the cardiovascular system in these animals. METHODS: Five multiparous Holstein dairy cows were studied from...

One critical determinant of fertility is the establishment and maintenance of pregnancy after insemination or embryo transfer. Pregnancy success is low in lactating dairy cows. Reduced fertility of the dairy female is only expressed in the lactational state but the magnitude of depression of fertility is not related to milk yield. Pregnancy failure occurs throughout gestation with the greatest ...

Introduction The large proportion of CP in alfalfa silage (AS) that is present as NPN substantially reduces the efficiency of protein utilization by lactating dairy cows (Nagel and Broderick, 1992). Red clover silage (RCS) typically has a much lower content of NPN than AS (Albrecht and Muck, 1991). In a previous feeding study (Broderick and Sterrenburg, 1996 USDFRC Res. Sum.), we found that DMI...

treatments the cows were randomly assigned to two groups. One group of cows (n= 281) was fed 0.5 mg of melengestrol acetate (MGA) per head per day for ten days while the other group of cows (n= 257) served as controls. All cows were bled for progesterone concentrations at the beginning of the MGA feeding (d -21), before the SMB treatment, and at the time of artificial insemination (AI). Twenty-...

An experiment was conducted in order to assess the effect of level of RDP:UDP ratio and level of feeding concentrate on milk yield, milk composition and nutrient utilization in lactating crossbred cattle. Twenty four medium producing (~10 kg/d, 45 to 135 days postpartum) lactating crossbred cows were divided into four groups of six animals each in a 2×2 factorial completely randomized design. T...

An experiment was conducted in vitro to determine whether the addition of saponin-containing Yucca schidigera or Quillaja saponaria reduces methane production without impairing ruminal fermentation or fiber digestion. A slightly lower dose of saponin was then fed to lactating dairy cows to evaluate effects on ruminal fermentation, methane production, total-tract nutrient digestibility, and milk...