Precise calving monitoring is essential for minimizing the effects of dystocia in cows and calves. We conducted two studies in healthy cows that compared seven clinical signs (broad pelvic ligaments relaxation, vaginal secretion, udder hyperplasia, udder edema, teat filling, tail relaxation, and vulva edema) alone and in combination in order to predict the time of parturition. The relaxation of...

Genetic and phenotypic (co)variances for mature equivalent yield of 4% FCM and calving interval were simultaneously estimated by REML for grade Holstein cows in first and second parity. Data were 305d mature equivalent lactation records and calving dates for 299,441 daughters of 2489 AI sires first calving from 1970 to 1985 in California, New York, or Texas. Data were divided into three time pe...

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 main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (BW), gestation length (GL) and calving difficulty (CD) in first-parity Iranian Holstein dairy cattle. The data included 29,950 calving records collected during 1995 to 2014 by the Animal Breeding and Improvement Center of Iran. A threshold-linear sire-maternal grandsire model was ...

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...

Objective. To compare four different dry cow treatments (DCT) and establish their effectiveness in reducing intramammary infections (IIM). Materials and methods. DCTs included systemic tylosin (12g) alone or accompanied by cefapirine intramammary infusions and or an internal teat sealant. A total number of 278 cows at the end of lactation period were randomly assigned to one of 4 dry cow treatm...

Data from 528 male and 645 female progeny of 63 sires were used to estimate genetic correlations between female and male reproductive traits. Data were from two Hereford herds involved in a long-term selection program of the North Carolina Agricultural Experiment Service. Testicular measurements of circumference, diameter, length and volume were obtained on bulls at 205 and 365 d. Testicular gr...

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...

A reproductively efficient beef cow herd is fundamental to meeting the protein and specifically, red meat demand of an ever increasing global population. However, attaining a high level of reproductive efficiency is underpinned by producers being cognisant of and achieving many key targets throughout the production cycle and requires significant technical competency. The lifetime productivity o...