Effect of repeated HPA axis stimulation on hair cortisol concentration, growth, and behavior in preweaned dairy cattle.

The study objective was to investigate the effect of repeated hypothalamic-pituitary-adrenal (HPA) axis stimulation using synthetic adrenocorticotropic hormone (ACTH) intramuscular injections on hair cortisol concentration, growth, and behavior in preweaned dairy calves. Twenty-seven Holstein calves were assigned to nine triads (based on sex and birth order) and randomly assigned to 1 of 3 treatments: 1) control (CON; 2 mL saline weekly); 2) moderate (MOD; alternating Cosyntropin [2 mcg/kg body weight (BW)] and saline weekly); or 3) frequent (FREQ; Cosyntropin [2 mcg/kg BW] weekly). Calves received their first injection on study day 0 (7±1 d of age). Hair was collected from the tail switch between days -5 and -3 (baseline), 21, and 49 and analyzed for cortisol concentration. To verify the endogenous cortisol release by Cosyntropin during the treatment period, saliva was collected on days 0, 14, 28, and 42 before injection and every 15 min for 2 h after injection for analysis of salivary cortisol concentration. Calves were fitted with accelerometers to continuously monitor lying time, number of lying bouts, and lying bout duration throughout the study. Growth measures (BW, hip height, hip width) were recorded weekly. Data were analyzed using repeated measures ANOVA (SAS, Version 9.4), and models included the fixed effects of treatment, time (min or study day), and interaction between treatment and time. Temperature humidity index was included as a continuous covariate in all models. We observed a treatment × min interaction (P < 0.0001), whereby salivary cortisol concentration was lower in CON calves compared to MOD and FREQ calves 15 to 120 min post injection. While hair cortisol concentration was not influenced by treatment, concentration decreased from day 21 (1.28±0.03 ng/mL) to 49 (0.93±0.03 ng/mL). Average body weight was similar across treatments (CON [59.4±1.09 kg], MOD [58.6±0.98 kg], and FREQ [57.6±0.96 kg]; P=0.50). There was no evidence to suggest a difference in average daily lying time (CON [18.5±0.23 h/d], MOD [18.6±0.23 h/d], and FREQ [18.5±0.23 h/d]; P=0.99). These results suggest that repeated HPA axis stimulation through Cosyntropin administration increased salivary cortisol concentration, but did not influence hair cortisol concentration, growth, or behavior in preweaned dairy calves.

Complete or partial loss of the Y chromosome in an unselected cohort of 865 non-vasectomized, azoospermic men.

BACKGROUND: Structural abnormalities as well as minor variations of the Y chromosome may cause disorders of sex differentiation or, more frequently, azoospermia. This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions in the azoospermia factor region (AZF) to complete loss of the Y chromosome in azoospermic men. RESULTS: Eleven of 865 azoospermic men (1.3%) collected from 1997 to 2022 were found to have a karyotype including a 45,X cell line. Two had a pure 45,X karyotype and nine had a 45,X/46,XY mosaic karyotype. The AZF region, or part of it, was deleted in eight of the nine men with a structural abnormal Y-chromosome. Seven men had a karyotype with a structural abnormal Y chromosome in a non-mosaic form. In addition, Y chromosome microdeletions were found in 34 men with a structural normal Y chromosome. No congenital malformations were detected by echocardiography and ultrasonography of the kidneys of the 11 men with a 45,X mosaic or non-mosaic cell line. CONCLUSIONS: In men with azoospermia, Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% (53/865). Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions.

RéSUMé: CONTEXTE: Des anomalies structurelles ainsi que des variations mineures du chromosome Y peuvent provoquer des troubles de la différenciation sexuelle ou, plus fréquemment, une azoospermie. Cette étude visait à déterminer la prévalence de la perte de matériel chromosomique Y dans le spectre allant de petites microdélétions dans la région du facteur d'azoospermie (AZF) à la perte complète du chromosome Y chez les hommes azoospermiques. RéSULTATS: Onze des 865 hommes azoospermiques (1,3 %), collectés entre 1997 et 2022, présentaient un caryotype comprenant une lignée cellulaire 45,X. Deux avaient un caryotype pur 45,X et neuf avaient un caryotype mosaïque 45,X/46,XY. La région AZF, ou une partie de celle-ci, était absente chez huit des neuf hommes présentant un chromosome Y anormal sur le plan structurel. Sept hommes présentaient un caryotype avec un chromosome Y structurellement anormal sous une forme non mosaïque. De plus, des microdélétions du chromosome Y ont été trouvées chez 34 hommes présentant un chromosome Y de structure normale. Aucune malformation congénitale n'a été détectée par échocardiographie et échographie des reins des 11 hommes porteurs d'une lignée cellulaire 45,X mosaïque ou non mosaïque. CONCLUSIONS: Chez les hommes qui ont une azoospermie, une perte du chromosome Y, allant de petites microdélétions à une perte complète du chromosome Y, a été observée chez 6,1 % (53/865). Les microdélétions partielles de la région AZFb peuvent donner un phénotype testiculaire plus doux que les microdélétions complètes de l'AZFb.

Housing and management characteristics of calf automated feeding systems in the Upper Midwest of the United States.

Automated milk feeders are used by dairy producers to manage preweaned calves in group housing, but little is known about how these feeding systems are being used in the United States. To better understand how US dairy producers are operating these systems, this study investigated characteristics of barn design, environment, and management practices on 38 farms in the Upper Midwest of the United States via a questionnaire and on-farm measurements. Farms using automated feeders ranged in size from 7 to 300 calves on site. Natural ventilation was used on 50% of the farms, followed by barns with mechanical ventilation (39.5%), tunnel ventilation (7.9%), or outdoor facilities (sheltered plastic domes; 2.6%). Calves were kept in groups of 17.6 ± 9.8 animals (range: 5.9 to 60.5) with an average space allowance of 4.6 ± 2.0 m2/animal (range: 1.6 to 11.9). Calves on these farms received 3.7 ± 0.75 L (range: 2 to 6) of colostrum, but 22% of the tested calves had serum total protein values lower than 5.0 g/dL. Calves had an initial daily allowance of 5.4 ± 2.1 L (range: 3 to 15 L) of milk or milk replacer, rising to a peak amount of 8.3 ± 2.0 L (range: 5 to 15 L) over 18 ± 11.4 d (range: 0 to 44 d). Milk replacer was fed to calves on 68.4% of the farms compared with whole milk supplemented with nutrient balancer on 23.7% and whole milk alone on 7.9% of the farms. Calves were completely weaned at 56.8 ± 9.0 d of age (range: 40 to 85.5) and 52.1 ± 7.5 d (range: 40 to 79) since introduction into the group pen with the feeder. Notably, bacterial contamination of milk was common; the median coliform count was 10,430 cfu/mL (interquartile range: 233,111; range: 45 to 28,517,000) and standard plate count was 2,566,867 cfu/mL (interquartile range: 15,860,194; range 6,668 to 82,825,000) for samples collected from the feeder tube end (or feeder hose). Some areas of deficiency might be of concern as they might be influencing the success of using automated calf feeding systems. In particular, a better understanding of the dynamics of pathogen load is needed in both the group pen area and in the automated feeder unit itself, as these reservoirs represent significant risk to calf health and welfare.

Mortality and health treatment rates of dairy calves in automated milk feeding systems in the Upper Midwest of the United States.

Automated calf feeding systems are increasing in use across the United States, yet information regarding health and mortality outcomes of animals in these systems is limited. The objective of this study was to investigate the relationship between farm management practices, housing, and environmental factors with mortality and health treatment rates of preweaned dairy calves housed in groups with automated feeding systems. Farm records were collected for health treatments and mortality on 26 farms in the Upper Midwest of the United States. Relationships between factors of interest and mortality or treatment rate were calculated using a correlation analysis. Overall median annual mortality rate was 2.6 (interquartile range = 3.6; range = 0.24-13.4%), and 57% of farms reported mortality rates below 3%/yr. Farms that disinfected the navels of newborn calves had lower mortality rate (mean = 3.0%; standard error = 0.8; 78% of farms) than farms that did not disinfect (mean = 7.3%; standard error = 1.6; 22% of farms). Farm size (number of cows on site) was negatively associated [correlation coefficient (r) = -0.53], whereas the age range in calf groups was positively associated (r = 0.58) with mortality rate. Average serum total protein concentration tended to be negatively associated with annual mortality rate (r = -0.39; median = 5.4; range = 5.0-6.4 g/dL). Health treatment rate was positively associated with coliform bacterial count in feeder tube milk samples [r = 0.45; mean ± standard deviation (SD) = 6.45 ± 4.50 ln(cfu/mL)] and the age of calves at grouping (r = 0.50; mean ± SD = 5.1 ± 3.6 d). A positive trend was detected for coliform bacterial count of feeder mixing tank milk samples [r = 0.37; mean ± SD = 3.2 ± 6.4 ln(cfu/mL)] and calf age at weaning (r = 0.37, mean ± SD = 57.4 ± 9.6 d). Seasonal patterns indicated that winter was the season of highest treatment rate. Taken together, these results indicate that, although automated feeding systems can achieve mortality rates below the US average, improvements are needed in fundamental calf care practices, such as colostrum management and preventing bacterial contamination of the liquid diet and the calf environment.

Factors associated with dairy calf health in automated feeding systems in the Upper Midwest United States.

Automated calf feeding systems are becoming more common on US dairy farms. The objective of this study was to evaluate calf health in these systems and to identify risk factors associated with adverse health outcomes on farms in the Upper Midwest United States. Over an 18-mo period on bimonthly farm visits to 38 farms, calves (n = 10,179) were scored for attitude, ear, eye, and nasal health, as well as evidence of diarrhea (hide dirtiness score of perianal region, underside of the tail, and tailhead). For all health score categories, a score of 0 represented an apparently healthy animal. Rectal temperatures were taken in calves scoring a ≥2 in any category, and those with a temperature >39.4°C were categorized as having a fever (n = 550). Associations were determined between farm-level variables and health scores to identify risk factors for higher (worse) scores. All health outcomes were associated with season of measurement, with fall and winter seasons increasing the odds of a high health score or detected fever. High bacterial counts measured in the milk or milk replacer were associated with increased odds for higher attitude and ear scores, and higher odds for calves having a detected fever. Higher peak milk allowance (L/d) was associated with lower hide dirtiness score, whereas a longer period of time (d) to reach peak milk allowance was associated with increased odds of higher scores for attitude, ear, eye, and hide dirtiness, as well as fever. Higher fat content in milk was associated with increased odds of high eye score. Less space per calf (m2/calf) was associated with higher ear and eye scores, whereas larger group sizes were associated with increased odds of higher nasal score and decreased odds of higher hide dirtiness score. Rectangular pen shape was associated with decreased odds of higher eye score. Absence of a positive pressure ventilation tube was associated with increased odds of having a calf detected with a fever. Based on these results, we hypothesize that these factors could be managed to improve health outcomes for dairy calves on automated feeding systems.