Joan M. Ballam

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To determine the accuracy of a pregnancy-associated glycoprotein (PAG) ELISA in identifying pregnancy status 27 d after timed artificial insemination (TAI), blood samples were collected from lactating Holstein cows (n = 1,079) 27 d after their first, second, and third postpartum TAI services. Pregnancy diagnosis by transrectal ultrasonography (TU) was(More)
Dry periods of 40 to 60 d have been an industry standard because dry periods <40 d have resulted in reduced milk yields in the subsequent lactation by 10 to 30%. However, recent research has demonstrated no production losses for cows given a 30-d dry period. The current study evaluated milk production effects of shortened or omitted dry periods for cows at(More)
The effects of age, breed, and diet on fecal chemistry, enzyme activity, and bacterial populations of dogs were studied. Eighteen dogs from two age groups (young: 2.5 ± 0.5 years, old: 10.9 ±0.7 years) and three different breeds (German shepherds, miniature schnauzers, and English setters) were rotated through a Latin Square design such that every dog was(More)
OBJECTIVE To evaluate the effects of 25% diet restriction on life span of dogs and on markers of aging. DESIGN Paired feeding study. ANIMALS 48 Labrador Retrievers. PROCEDURES Dogs were paired, and 1 dog in each pair was fed 25% less food than its pair-mate from 8 weeks of age until death. Serum biochemical analyses were performed, body condition was(More)
OBJECTIVE To determine prevalence of radiographic evidence of osteoarthritis in 4 diarthrodial joints of dogs with restricted feed intake, compared with dogs without restricted feed intake. DESIGN Paired feeding study. ANIMALS 48 Labrador Retrievers. PROCEDURE Dogs in litters from 7 dams and 2 sires were paired by sex and weight within litters and(More)
While aging studies employing a cross-sectional design have been informative in documenting many age-related alterations in immune function between different age cohorts within a population, longitudinal studies are invaluable for verifying changes at the level of the individual and for defining the precise periods of life during which particular changes(More)
A trend in food labeling is to make claims related to agricultural management, and this is occurring with dairy labels. A survey study was conducted to compare retail milk for quality (antibiotics and bacterial counts), nutritional value (fat, protein, and solids-not-fat), and hormonal composition (somatotropin, insulin-like growth factor-1 [IGF-1],(More)
The objective of this study was to determine the effects of altering dry period length in multiparous dairy cows (n = 341) on milk production for a full lactation (294 d). The study used 3 commercial herds in the western United States. Cows producing greater than 8,400 kg of mature-equivalent milk were assigned to treatments 60 d before their due dates. The(More)
The objective of this study was to compare 2 strategies for resynchronization of ovulation based on nonpregnant diagnoses using transrectal ultrasonography or a pregnancy-associated glycoprotein (PAG) ELISA. Lactating Holstein cows (n = 1,038) were submitted for first postpartum timed artificial insemination (TAI) using a Presynch + Ovsynch protocol. After(More)
Immune function was assessed in a group of 47 Labrador Retrievers, ranging in age from 0.8 to 11.5 years, in order to establish baseline data on canine immunosenescence. Natural killer cell activity, lymphocyte subset distributions, antibody production, and mitogen-induced lymphoproliferative responses, all of which have been demonstrated to undergo(More)