ABSTRACT.- This review summarizes the status of the art of cow-calf relationships at birth and during lactation, including the physiological mechanisms throughout suckling/nursing and weaning which can impact on productive and reproductive parameters, social behaviour across the mother-offspring pairs, and the required positive cow-calf welfare approach in beef cattle. The time spent close to the calf after birth, latency to nurse, nursing time, grooming and vocalisations can be considered fair proxies of oxytocin release and maternal care during the neonatal period.

ABSTRACT.- Bovine torovirus (BToV) is an enteric pathogen that may cause diarrhea in calves and adult cattle, which could result in economic losses due to weight loss and decreased milk production. This study aimed to report the presence, the genetic characterization and the evolution of BToV in calves in Uruguay. BToV was detected in 7.9% (22/278) of fecal samples, being identified in dairy (9.2%, 22/239) but not beef (0.0%, 0/39) calves. BToV was detected in both diarrheic (14%, 6/43) and non-diarrheic (13.2%, 5/38) dairy calves.

ABSTRACT.- Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016-2017 and 2017-2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region.

ABSTRACT.- Alligator weed, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae) is an aggressive invader in waterways and pastures throughout most of the southeastern U.S.A., and California. Three insect biological control agents have provided substantial control of aquatic A. philoxeroides in the warmer parts of its range in the U.S.A. However, these insects are less effective against A. philoxeroides in riparian-terrestrial habitats.

ABSTRACT.- A comprehensive understanding of how native grasslands (rangelands) respond to chronic nutrient addition requires considering interactions with climate variability, water availability in particular, and with stocking rate management. We assessed animal production responses to phosphorus plus nitrogen fertilization sustained over a decade on a highly diverse subtropical grassland. ©2024 The Society for Range Management. Published by Elsevier Inc.

ABSTRACT.- This study aimed to evaluate the effects of different doses of equine chorionic gonadotropin (eCG; 200 and 300 IU) administered at the end of a fixed-time artificial insemination (FTAI) treatment protocol on ovulation, pregnancy, and twin rates in Bos taurus beef heifers. In addition, pregnancy losses in heifers with singleton and twin pregnancies were determined.

ABSTRACT.- Of the mycotoxicoses caused by molds contaminating grains or their byproducts, leukoencephalomalacia of horses and less frequently aflatoxicosis in cattle have been reported in South America. However, the most important group of mycotoxins in the region are those caused by fungi that infect forages and other types of plants and have regional distribution. In this group, ergotism is important, both caused by Claviceps purpurea infecting grains or by Epichloë coenophiala infecting Schedonorus arundinaceus.

ABSTRACT.- Twin lambs establish a social attachment soon after birth, which implies that they prefer to interact with each other during the suckling period. However, the role of the mother's presence in maintaining the social attachment between twins has been scarcely studied. The aims of this study were to characterize the dynamics of the distance between twin lambs during lactation until three months after weaning, and to determine the impact of the mother in this regard.

ABSTRACT.- Genetic improvement in small countries rely heavily on foreign genetics. In an importing country such as Uruguay, consideration of unknown parent groups (UPG) for foreign sires is essential. However, the use of UPG in genomic model evaluations may lead to bias in genomic estimated breeding values (GEBV). The objective of this study was to study different models including UPG or metafounders (MF) in the Uruguayan Holstein evaluation and to analyze bias, dispersion, and accuracy of GEBV predictions in BLUP and single-step genomic BLUP (ssGBLUP). © 2024, The Authors.

ABSTRACT.- Improvements in nitrogen use efficiency can be achieved through fertilizer management strategies that capitalize on nutrient synergies. However, limited research on synergies between nitrogen, sulfur, and calcium complicates understanding causal links and developing sustainable management. In this regard, the effects of different nitrogen sources on productivity and nitrogen use efficiency in Italian ryegrass (Lolium multiflorum Lam.) and pearl millet (Pennisetum glaucum (L.)), along with their impacts on forage quality and secondary production, were investigated.