Relationship between Body Composition and Reproduction in Heifers

Carcass and reproductive data including scan weight, ribeye area, rump fat, 12-13th rib fat and percentage intramuscular fat and reproductive tract scores (RTS) at 344 days were collected on 180 1998-born and 70 1999-born Angus heifers to determine the relationship between these traits. 1998-born heifers with higher RTS tended to be heavier and have more rump fat at 405 days (P \u3c .05). Heavier heifers and heifers with more rump fat had higher RTS when adjusted to 395 days (P \u3c .05). 1999-born heifers showed a similar pattern, with heavier heifers having higher RTS (P \u3c .05). Rump fat was not as significant for 1999-born heifers compared with 1998-born heifers. Heavier heifers with more rump fat are more likely to have more mature reproductive tracts at breeding

Detection of asymptomatic renal infection in abattoir slaughtered cattle in southeastern Georgia, United States

Objectives: Leptospirosis is one of the most widespread zoonotic infectious diseases affecting humans and animals. Several animal species, including cattle, can act as potential asymptomatic carriers facilitating zoonotic transmission of Leptospira . This study was conducted to assess the occurrence of asymptomatic renal Leptospira carriers among cattle slaughtered in southeastern Georgia, United States. Methods: A battery of diagnostic tests, including dark field microscopy, direct fluorescent antibody staining, polymerase chain reaction, and culture, were performed on a set of bovine kidneys (n = 37) collected from an abattoir in southeastern Georgia, United States. Virulence of a field isolate obtained from this study was tested in a hamster experimental model. Results: Motile spirochete-like structures were observed by dark field microscopy in 23 (59%) out of 37 kidney samples tested. In all, 29 samples (78%) were positive by direct fluorescent antibody staining. Only 11 (29.7%) samples by polymerase chain reaction and 3 (8.1%) by culture were positive for Leptospira sp. The isolates obtained by culture were confirmed as Leptospira borgpetersenii . Hamsters experimentally infected with one of the Leptospira field isolates obtained from this study did not show clinical signs but developed renal infection with interstitial nephritis and tubular necrosis. Conclusions: This study confirms that asymptomatic Leptospira renal infection is present among cattle in the region. Our findings underscore the need for future studies to assess the potential environmental contamination and transmission to humans in contact with infected cattle