Incidence of palmar process fractures of the distal phalanx and association with front hoof conformation in foals.

REASONS FOR PERFORMING STUDY: Recent studies indicate a high prevalence of fractures of the palmar processes (PP) of the distal phalanx in foals. However, information on the prevalence of such fractures in different breeds and the effect of predisposing factors, such as hoof conformation, is limited. OBJECTIVES: To examine the prevalence of distal phalanx PP fractures in foals and report the relationship of distal limb and hoof conformation with the prevalence of fracture. STUDY DESIGN: Longitudinal study. METHODS: Front hooves of 19 Thoroughbred, Quarter Horse and Arabian foals were examined. Digital radiographic and photographic images of the distal aspect of the forelimbs were taken at ∼2.5 month intervals. Five radiographic projections of each limb were as follows: lateromedial; horizontal beam dorsopalmar; dorso60°proximal-palmarodistal oblique; dorso60°proximo45°lateral-palmarodistomedial oblique; and dorso60°proximo45°medial-palmarodistolateral oblique. The relationship between measurements and the prevalence of fractures was assessed by 3-way ANOVA. RESULTS: Fractures were found in 74% (n = 14) of the foals during the study period. The prevalences of lateral PP and medial PP fractures were not significantly different. Several hoof measurements were associated with PP fractures. Longer dorsal length of the distal phalanx was associated with medial PP fractures, while smaller lateral angle and shorter lateral palmar length were associated with a higher prevalence of lateral PP fractures. CONCLUSIONS: This study revealed a high prevalence of PP fractures in young foals, particularly in Thoroughbred foals. The hoof conformation may be one of the contributory factors to PP fractures in foals.

Late gestational hyperprolactinemia accelerates mammary epithelial cell differentiation that leads to increased milk yield.

The growth rate of piglets is limited by sow milk yield, which reflects the extent of epithelial growth and differentiation in the mammary glands (MG) during pregnancy. Prolactin (PRL) promotes both the growth and differentiation of the mammary epithelium, where the lactational success of pigs is absolutely dependent on PRL exposure during late gestation. We hypothesized that inducing hyperprolactinemia in primiparous gilts during late gestation by administering the dopamine antagonist domperidone (DOM) would increase MG epithelial cell proliferation and differentiation, subsequent milk yield, and piglet growth. A total of 19 Yorkshire-Hampshire gilts were assigned to receive either no treatment (CON, n = 9) or DOM (n = 10) twice daily from gestation d 90 to 110. Serial blood sampling during the treatment period and subsequent lactation confirmed that plasma PRL concentrations were increased in DOM gilts on gestation d 91 and 96 (P < 0.001). Piglets reared by DOM-treated gilts gained 21% more BW during lactation than controls (P = 0.03) because of increased milk production by these same gilts on d 14 (24%, P = 0.02) and 21 (32%, P < 0.001) of lactation. Milk composition did not differ between the 2 groups on d 1 or 20 of lactation. Alveolar volume within the MG of DOM-treated gilts was increased during the treatment period (P < 0.001), whereas epithelial proliferation was unaffected by treatment. Exposure to DOM during late gestation augmented the postpartum increase in mRNA expression within the MG for ß-casein (P < 0.03), acetyl CoA carboxylase-α (P < 0.01), lipoprotein lipase (P < 0.06), α-lactalbumin (P < 0.08), and glucose transporter 1 (P < 0.06). These findings demonstrate that late gestational hyperprolactinemia enhances lactogenesis within the porcine MG and increases milk production in the subsequent lactation.

Technical note: A vacuum-assisted approach for biopsying the mammary glands of various species.

Biopsy of the mammary glands is a technique used in both research and clinical diagnosis. A vacuum-assisted approach that enables the collection of tissue from the mammary glands of various species is described, along with methods for biopsying cows and pigs. The procedure involves tissue penetration via blunt dissection with a sharpened trocar. Tissue cores are excised and collected via the vacuum-assisted handpiece followed by a saline lavage and wound closure. This approach yields tissue cores of approximately 100 mg, is well suited for use in various species, and affords the potential to reduce postoperative complications.