Effects of two levels of dietary selenium (se) on reproductive performance and blood Se status of mature gestating and lactating sows were evaluated over one reproductive cycle. Four groups of six Duroc sows were fed basal corn-soybean meal (SBM) or corn-SBM-tankage diets each with or without .1 ppm supplemental Se. The basal diets contained .1 ppm natural Se. Changes from the 28th day of gesta...

The objectives of this study were to estimate the heritability of milk urea nitrogen (MUN) concentration and describe the genetic relationship between MUN and reproductive performance and between MUN and diseases in Holsteins. Dairy Records Management Systems (Raleigh, NC) provided lactation data. The Danish Agricultural Advisory Center provided breeding value estimates for diseases. Infrared (...

The experiment was conducted to test the hypothesis that supplementing diets of lactating first parity sows with a mixture of carbohydrases (CS) improves lactation performance and second parity reproductive performance. The CS used in this study contained 7 units/g of α-1,6-galactosidase, 22 units/g of β-1,4-mannanase, β-1,4-mannosidase and trace amounts of other enzymes. Twenty primiparous sow...

A cooperative study using 215 sows during two parities (349 litters) was conducted at six stations to determine the effect of raw soybeans in gestation and lactation diets on sow and litter performance. Sows were bred and allotted to fortified corn diets containing either soybean meal (control) or raw soybeans. A corn-soybean meal-soybean oil diet, isocaloric to the raw soybean diet, was includ...

Daily milk yield over the course of the lactation follows a curvilinear pattern, so a suitable function is required to model this curve. In this study, 7 functions (Wood, Wilmink, Ali and Schaeffer, cubic splines, and 3 Legendre polynomials) were used to model the lactation curve at the phenotypic level, using both daily observations and data from commonly used recording schemes. The number of ...

In this study the effects of supplemental crystalline niacin on sow reproduction and sow and litter performance were evaluated using 240 litters produced by 67 sows. A basal 12.80% CP corn-soybean meal-oat diet was supplemented with 0 or 33 mg of crystalline niacin/kg during gestation and lactation. The sows were grouped to equalize initial BW and parity among the two treatment groups. Each sow...

Sixteen Friesian cows were used in Expt 1 to measure the effect of substituting urea-N with fishmeal-N either in early lactation (Part 1) or in mid-lactation (Part 2). In Part 1 (days 15-84 of lactation) the major N constituent of the concentrate was urea (U), urea-N: fishmeal-N in the ratio 2:1 (UF) or 1:2 (FU), or fishmeal (F). In Part 2 (days 84-175 of lactation) only urea (UM) and fishmeal ...

Endocrine disruptors, chemicals that disturb the actions of endogenous hormones, have been implicated in birth defects associated with hormone-dependent development. Phytoestrogens are a class of endocrine disruptors found in plants. In the current study we examined the effects of exposure at various perinatal time periods to genistein, a soy phytoestrogen, on reproductive development and learn...

The objective of this study was to produce anti-idiotypic antibodies with bovine somatotropin (bST)-like activity by active immunization of lactating cows and to determine their effects on milk yield. Several monoclonal antibodies against bST were evaluated for their interaction with bST in a rat growth bioassay. Two bST-agonist monoclonal antibodies (1 and 2), and two bST-antagonist monoclonal...