Consequences of gene editing of on thermotolerance, growth, and male reproduction in cattle.

Global warming is a major challenge to the sustainable and humane production of food because of the increased risk of livestock to heat stress. Here, the example of the prolactin receptor () gene is used to demonstrate how gene editing can increase the resistance of cattle to heat stress by the introduction of mutations conferring thermotolerance. Several cattle populations in South and Central America possess natural mutations in that result in affected animals having short hair and being thermotolerant.

Influence of proportion of Brahman genetics on productivity of Brahman-Angus cows at weaning.

This study evaluated the association between the proportion of Brahman genetics and productivity of Brahman-Angus cows at weaning using a 31-yr dataset containing 6,312 cows and 5,405 pregnancies. Cows were contemporaneously reared and enrolled in yearly breeding seasons under subtropical conditions of North-Central Florida. They were evenly distributed in six-breed groups (G) according to the proportion of Brahman genetics: G0% to 19%, G21% to 34%, G38% (Brangus), G41% to 59%, G63% to 78%, and G81% to 100%.

Reproductive response of crossbred Bos taurus × Bos indicus cows to biostimulation by pre-pubertal and pubertal teasers.

Although the beneficial effect of biostimulation on reproduction has been reported, the influence of selectivity and social factors on the response to biostimulation has not received sufficient research attention in both Bos indicus and Bos indicus influenced cattle. Furthermore, 'green and cheap' strategies to improve cattle reproduction are currently in demand while Bos indicus influenced cattle with inferior reproductive performance, and farmers with economic limitations are common in tropical zones. Hence, to assess the reproductive response of crossbred taurus × indicus cows to biostimulation by pre-pubertal (PPM) or pubertal (PM) teasers males, two trials of 2 years each were conducted.

Effects of the SLICK1 mutation in PRLR on regulation of core body temperature and global gene expression in liver in cattle.

The SLICK1 mutation in bovine PRLR (c.1382del; rs517047387) is a deletion mutation resulting in a protein with a truncated intracellular domain. Cattle carrying at least one allele have a phenotype characterized by a short hair coat (slick phenotype) and increased resistance to heat stress.

Choline acts during preimplantation development of the bovine embryo to program postnatal growth and alter muscle DNA methylation.

The preimplantation period of embryonic development can be a key window for programming of postnatal development because extensive epigenetic remodeling occurs during this time. It was hypothesized that modification of one-carbon metabolism of the bovine embryo by addition of the methyl-donor choline to culture medium would change postnatal phenotype through epigenetic modification. Embryos produced in vitro were cultured with 1.

Genome-wide scan reveals important additive and non-additive genetic effects associated with resistance to Haemonchus contortus in Florida Native sheep.

Florida Native sheep is among the sheep breeds best adapted to humid and hot climatic conditions such as those of Florida, USA, and have shown a superior ability to regulate nematode burdens. This is one of the oldest sheep breeds in North America and is an endangered species. To ensure genetic diversity and long-term survival of the breed, protection of the current genetic stock is critical and conservation efforts are required to promote its breeding and production.

Effect of season and genotype on values for bull semen variables under tropical conditions.

To assess the effects of season and genotype on fresh semen quality for freezing and subsequent use for AI, 32 healthy, mature (>4 to <6 years old) and habituated bulls (Bos indicus n = 14, Bos taurus n = 5, Crossbred taurus x indicus n = 6, and tropically adapted Bos taurus composites n = 7) were evaluated at a Venezuelan AI center for 12 months in which four distinct seasons (Hot-dry, Transition, Hot-humid, Cool-rainy) occur. Ejaculates were collected weekly from Bos taurus (n = 260), Bos indicus (n = 669), tropically adapted Bos taurus composites (n = 389), and crossbred Bos taurus x Bos indicus (n = 340) bulls. Routine AI Center assessments were conducted i.

About the inconvenience of handling mixed-breed herds; aspects of social behavior as a potential source of stress and economic losses.

The objective of this study was to assess aspects of the social behavior of a mixed-breed herd of beef cows as a potential source for stress and economic losses. Angus (AN; N = 10), Brahman (BR; N = 10), and Senepol (SE; N = 10) cows were assigned to two groups (N = 15 each containing equal breed numbers) on separate pastures. Agonistic interactions (win/loss) during feeding were recorded daily for 45 days.

Association study reveals Th17, Treg, and Th2 loci related to resistance to Haemonchus contortus in Florida Native sheep1.

The aim of this study was to identify for the first time single nucleotide polymorphisms (SNPs) associated with Haemonchus contortus resistance in Florida Native sheep, using a targeted sequencing approach. One hundred and fifty-three lambs were evaluated in this study. At the start of the trial, phenotypic records for fecal egg count (FEC), FAMACHA score, body condition score (BCS), and weight were recorded and deworming of sheep with levamisole (18 mg/kg of body weight) was performed.

Systemic humoral immunity in beef bulls following therapeutic vaccination against Tritrichomonas foetus.

The utility of therapeutic vaccination of bulls against Tritrichomonas foetus has been advocated in previous studies, but anecdotal reports suggest this practice does not clear infections and may additionally confound diagnostic testing by reducing parasite burdens below detectable limits. The objective of this study was to characterize the systemic humoral immune response to therapeutic vaccination in T. foetus-infected bulls over a period of four months using an indirect ELISA and to compare the dynamics of this response to culture and PCR results to establish the existence of a relationship (or lack thereof) between immunization and infection status.

Lymphatic fluid for the detection of Mycobacterium avium subsp. paratuberculosis in cows by PCR, compared to fecal sampling and detection of antibodies in blood and milk.

Johne's disease (JD), caused by Mycobacterium avium subsp. paratuberculosis (MAP), can cause considerable economic losses in affected herds. Early diagnosis of JD is hampered by the chronic nature of the disease with a slow subclincal progression.

Association between ecological factors and the presence of Rhipicephalus (Boophilus) microplus larvae in Puerto Rico.

A prevalence study was conducted to survey tick larvae populations in Puerto Rico (PR), compare the number of infested sites with Rhipicephalus (Boophilus) microplus larvae between the wet and dry season, and assess the associations of ecologic factors on the presence of R. microplus larvae. Ninety-six sites were selected using a GIS-based sampling method.

The collection of lymphatic fluid from the bovine udder and its use for the detection of Mycobacterium avium subsp. paratuberculosis in the cow.

The objective of the current study was to evaluate the feasibility of lymph collection from the bovine udder and to investigate if the lymphatic fluid might be of diagnostic value in cows infected with Mycobacterium avium subsp. paratuberculosis (MAP), the etiologic agent of paratuberculosis. Lymph fluid collection was attempted from 58 cows, and the reactions of the cows as well as the level of difficulty of the procedure were recorded in 56 animals.

Diagnostic accuracy of methods for detecting Anaplasma marginale infection in lactating dairy cattle of Puerto Rico.

Bovine anaplasmosis (BA) is a hemoparasitic disease of great importance in cattle within the tropical and subtropical regions of the world. Control programs for BA require accurate diagnostic assays but validation can be challenging because the true disease status of all animals is frequently not known with certainty. The objective of this study was to estimate the accuracy of assays for detection of Anaplasma marginale infection in lactating dairy cattle of Puerto Rico using Bayesian methods without a perfect reference test.

Candidate gene polymorphisms (BoIFNG, TLR4, SLC11A1) as risk factors for paratuberculosis infection in cattle.

Paratuberculosis (Johne's disease) imposes a significant problem to the world dairy and beef industries and today is considered a potential zoonosis. The disease is caused by Mycobacterium avium subsp. paratuberculosis and is characterized by progressive weight loss and profuse diarrhoea.

Risk haplotype analysis for bovine paratuberculosis.

Paratuberculosis (Johne's disease), caused by Mycobacterium avium subsp. paratuberculosis, is an important disease for bovines, although its genetic basis is poorly understood. In this study, three candidate genes were typed to study the associations between single nucleotide polymorphisms (SNPs) and paratuberculosis susceptibility (measured in a 1 or 0 form) at the haplotype level.

Association between CARD15/NOD2 gene polymorphisms and paratuberculosis infection in cattle.

Paratuberculosis represents a major problem in farmed ruminants and at the present is considered a potential zoonosis. The disease is caused by Mycobacterium avium subsp. paratuberculosis, and susceptibility to infection is suspected to have a genetic component.

Tritrichomonas foetus.

Tritrichomonas foetus is a venereal disease of cattle that has a clear pattern of adverse reproductive sequela in the affected female, with a carrier state in the bull in which he shows no outward signs. Given sexual rest and symptomatic treatment, the female returns to reproductive viability. In contrast, the male remains infective and is a risk to other female contacts.

Assessing performance of cow-calf operations using epidemiology.

This article examines the epidemiologic tools available to the cow-calf beef veterinarian (and cattle producer) to assess the performance of the beef cow herd and to examine ways in which these tools may be used.

Epidemiology of Tritrichomonas foetus in beef bull populations in Florida.

The objectives of this study were to estimate the prevalence of herd and individual bull infection with Tritrichomonas foetus in a survey of beef bulls in the state of Florida and to perform an epidemiological investigation of risk factors for the disease. Bulls were tested for T. foetus colonization by a single preputial scraping and culture.

Environmental, genetic and social factors affecting the expression of estrus in beef cows.

Genetic, social and environmental factors affecting behavioral estrus were evaluated in Angus (n = 10), Brahman (n = 10) and Senepol (n = 10) cows during a PGF2alpha synchronized estrus and subsequent spontaneous estrus. Cows were equally stratified by breed to two groups of 15. Both groups were pre-synchronized with a modified two-injection PGF2alpha protocol.