Understanding spatiotemporal variability in prey accessibility is important for disentangling predator-prey interactions and is relevant to management interventions to reduce predation. Recently, caribou (Rangifer tarandus) in Newfoundland declined by 66%, with calf predation by black bears (Ursus americanus) implicated as a major proximate mechanism of the decline. Most predation occurs when c...

The search for ways to select for improved beef cow efficiency has become the holy grail of the beef cattle seedstock industry. Increases in beef production have often been possible due to enhancements in the reproduction indexes (e.g. calving frequency, age at first calving, calving interval), nutrition concepts (e.g. strategic supplementation, type of forage as well as quantity and quality), ...

A 4-yr study using 217 cows/yr (3/4 Red Angus, 1/4 Simmental) evaluated effects of calving date and wintering system on cow and calf performance from birth to harvest. Cows were assigned to 1 of 5 treatments: 1) March (Mar) calving cows wintered on native range, 2) Mar calving cows wintered on corn residue, 3) June (Jun) calving cows wintered on native range, 4) Jun calving cows wintered on cor...

Calving records collected between 2000 and 2008 at the Gudmundsen Sandhills Laboratory, Whitman, NE, were used to determine the effect of estrous synchronization on calving distribution and the impact of time of calving on carcass characteristics. Calves born between 2000 and 2006 resulted from non-synchronized 60 d breeding seasons between 1999 and 2005 (n = 2075). Calves born in 2007 and 2008...

At many marine-terminating glaciers, the breakup of mélange, a floating aggregation of sea ice and icebergs, has been accompanied by an increase in iceberg calving and ice mass loss. Previous studies have argued that mélange may suppress calving by exerting a buttressing force directly on the glacier terminus. In this study, I adapt a discrete element model to explicitly simulate mélange as a c...

The effectiveness of dexamethasone and prostaglandin in combination for induction and synchronization of parturition in cattle was evaluated in 100 pregnant Angus, Hereford, Charolais and Simmental cows. Cows were distributed equally by breed, day of gestation and cow age to one of three treatments: 1) Control, 2) Dexamethasone (25 mg) plus prostaglandin F(2alpha) (25 mg) or 3) Dexamethasone (2...

This study compared the effects of two levels of crude protein (CP) supplementation during a close-up dry period on the productive performance, nitrogen balance, and blood profiles of Holstein cows. Eighteen cows (8 primigravid and 10 multiparous), 21 days prior to calving, were divided into four groups and fed a diet containing a low (11.5 to 12.7% CP) or high (14.1 to 15.3% CP) level of prote...

ABSTARCT The objective of this study was to analyze the effects of factors affecting reproductive traits in the Holstein population of the Isfahan dairy farms for subsequent compilation of the model for genetic evaluation as well as for herd management practice. A data set containing 99012 records were analyzed by a linear model with fixed effects of year , herd ,season, parity of dam, calving ...

The main reason for calving replacement heifers early is economics. Economic assessments (2) have demonstrated that heifer rearing cost increases $50.00 to $60.00 each month calving is delayed. In addition, older calving ages result in the need for more heifers for herd replacement. These classic concepts are presented in Table 1. Conceptually, as calving age is reduced there is a linear reduct...