Birth weight, growth indices, and seminal parameters in male offspring are resilient features to maternal pre-conceptional dietary manipulation in sheep

Gestational diet manipulation can lead to inadequate fetal nutrient supply resulting in low birth weight, limited postnatal growth, and consequently, reduced reproductive performance in the progeny. However, effects of short-term maternal pre-conceptional dietary manipulation on postnatal growth and reproductive parameters of male offspring in large animals remains unexplored. To determine these consequences, female crossbred (Polypay x Dorset) sheep were allocated to three groups (n = 33/group) of dietary manipulation for 21 days prior to mating under the following conditions: (1) control at 100 % of maintenance energy requirements (40 Kcal of metabolizable energy/kg body weight [BW]), (2) undernutrition (UN) at 50 % of Control intake, and (3) overnutrition (ON) at 200 % of maintenance energy. Singleton ram lambs (UN:9; C:12; ON:6) were monitored from birth until 8 months of age, including birth weight, weekly weights, weight gain, body mass index (BMI), and circulating testosterone. After weaning, monthly scrotal circumference and subcutaneous fat depth were measured. Semen morphology and motility were evaluated at 7 and 8 months of age. Birth weight, weight gain, and BMI at birth and weaning were not significantly different among nutritional treatments. None of the pre-conceptional diets affected body weight change from weaning until 36 weeks of age, BMI, fat depth, or scrotal circumference across the experiment. A sustained rise in plasma testosterone concentrations was detected when ram lambs were, on average, 82 days old and 37 kg. Both testosterone concentrations and scrotal circumference were positively correlated to body weight regardless of treatment group. In addition, seminal parameters did not differ among treatments, but a transient increase in plasma testosterone at 18 weeks of age was observed in ON ram lambs compared to control rams. In conclusion, birth weight, growth indices, and seminal parameters in singleton rams are resilient features in the progeny upon maternal pre-conceptional dietary manipulation in sheep.

Changes in serum testosterone and anti-Müllerian hormone concentration in bulls undergoing scrotal insulation

While changes in semen quality after heat stress are well characterized in the bull, changes in endocrine function have not been critically evaluated. It was hypothesized here that scrotal insulation results in alterations in Sertoli cell and Leydig cell function, as measured by changes in serum testosterone and anti-Müllerian hormone (AMH) concentration. Scrotal insulation bags were placed in 10 bulls for 8 d. Blood was collected on days -22 and -2, and weekly from days 5 to 96 (day 0 = first day of scrotal insulation) for measurement of serum concentration of AMH and testosterone using ELISA. The concentration of AMH decreased on day 5, followed by an increase on day 54 (P = 0.014). When AMH concentration was normalized to pre-insulation values, the percent increase in serum concentration of AMH was significant between days 26 and 54, with another peak at 75 d (P = 0.031). The serum concentration of testosterone (P = 0.0001) and the percentage of change in testosterone concentration (P < 0.0001) increased on day 5, followed by a decrease from days 33 to 96. Scrotal insulation was associated with Sertoli and Leydig cell dysfunction, as measured by serum testosterone and AMH concentration. The persistently low concentration of testosterone at the end of the study suggests a long term effect of scrotal insulation on Leydig cell function.

Effects of injectable trace minerals administered concurrently with a modified live virus vaccine on long-term protection against bovine viral diarrhea virus acute infection in dairy calves

The objective was to evaluate the effects of injectable trace minerals (ITM) concurrent with modified-live virus (MLV) vaccination on protection from bovine viral diarrhea virus (BVDV) infection in dairy calves. In a previous study (Palomares et al., 2016), thirty dairy calves received two doses of a MLV vaccine subcutaneously (SC), concurrently with ITM (n = 15) or saline (n = 15), SC. Five months later, 20 of these calves received ITM (G1, n = 10) or saline (G2, n = 10) according to their previous groups and were challenged intranasally with BVDV2. Five unvaccinated calves were also challenged with BVDV2 (G3). Blood samples were collected on days 0 (BVDV challenge), 3, 5, 6, 7, 8, 9, 11, 14, 18, 21, 32 and 61 for leukocyte count, virus isolation and BVDV serum neutralizing antibodies (SNA). Mild-moderate clinical signs were observed in G3 after BVDV challenge. Group 1 showed lower sum health score and nasal score on d5 and fecal score on d8 compared to G2. Rectal temperature and leukocyte counts were not different between G1 and G2. In contrast, G3 calves had significant leukopenia and lymphopenia from d3 to d7 (P < .05) and higher rectal temperatures on d6 to d8, compared to values on d0 (P < .05). All unvaccinated calves became viremic, while viremia was not detected in G1 or G2. Average daily gain was not different between vaccinated groups, however, only G1 calves had significantly greater (P = .04) ADG compared to non-vaccinated calves during the first 14 days post challenge. Vaccinated calves treated or not with ITM were protected from BVDV2 infection five months post-vaccination.

Effects of injectable trace minerals on humoral and cell-mediated immune responses to Bovine viral diarrhea virus, Bovine herpes virus 1 and Bovine respiratory syncytial virus following administration of a modified-live virus vaccine in dairy calves

Our objective was to evaluate the effect of an injectable trace mineral (ITM) supplement containing zinc, manganese, selenium, and copper on the humoral and cell mediated immune (CMI) responses to vaccine antigens in dairy calves receiving a modified-live viral (MLV) vaccine containing BVDV, BHV1, PI3V and BRSV. A total of 30 dairy calves (3.5 months of age) were administered a priming dose of the MLV vaccine containing BHV1, BVDV1 & 2, BRSV, PI3V, and an attenuated-live Mannheimia-Pasteurella bacterin subcutaneously (SQ). Calves were randomly assigned to 1 of 2 groups: (1) administration of ITM SQ (ITM, n=15) or (2) injection of sterile saline SQ (Control; n=15). Three weeks later, calves received a booster of the same vaccine combination SQ, and a second administration of ITM, or sterile saline, according to the treatment group. Blood samples were collected on days 0, 7, 14, 21, 28, 42, 56, and 90 post-vaccination for determination of antibody titer, viral recall antigen-induced IFN-γ production, and viral antigen-induced proliferation by peripheral blood mononuclear cells (PBMC). Administration of ITM concurrently with MLV vaccination resulted in higher antibody titers to BVDV1 on day 28 after priming vaccination compared to the control group (P=0.03). Calves treated with ITM showed an earlier enhancement in PBMC proliferation to BVDV1 following vaccination compared to the control group. Proliferation of PBMC after BVDV stimulation tended to be higher on day 14 after priming vaccination in calves treated with ITM than in the control group (P=0.08). Calves that received ITM showed higher PBMC proliferation to BRSV stimulation on day 7 after priming vaccination compared to the control group (P=0.01). Moreover, calves in the ITM group also had an enhanced production IFN-γ by PBMC after stimulation with BRSV on day 21 after priming vaccination compared to day 0 (P<0.01). In conclusion, administration of ITM concurrently with MLV vaccination in dairy calves resulted in increased antibody titer to BVDV1, and greater PBMC proliferation to BVDV1 and BRSV recall stimulation compared to the control group, suggesting that ITM might represent a promising tool to enhance the humoral and CMI responses to MLV vaccines in cattle.