This study evaluated the impact of the presence of diseases within the first 21 days in milk (DIM) in dairy cows on metabolic status after the voluntary waiting period (VWP), conception at first service, infectious disease seroconversion, and the association between metabolic status at first artificial insemination (AI) and conception at first service. Cows were classified as sick (n = 48) or healthy (n = 75) based on diseases within 21 DIM. Blood samples were obtained at first AI (D0), pregnancy diagnosis (D30), and pregnancy confirmation (D60) after the first AI. Samples were analyzed for glucose, cholesterol, aspartate aminotransferase, alanine aminotransferase, non-esterified fatty acids (NEFA), and insulin-like growth factor 1 (IGF-1) using a linear mixed model for repeated measures. An Energetic Metabolic Index (EMI) at AI was calculated, integrating cholesterol, NEFA, and glucose. Logistic regression models were used to predict EMI, conception at first service, and seroconversion to Leptospira spp. and Bovine Viral Diarrhea Virus (BVDV). The presence of diseases did not affect the metabolic status after the VWP (P > 0.05); however, changes in blood metabolites by day were observed (P < 0.001). EMI was not associated with the presence of diseases (P = 0.13). EMI, IGF-1 concentration, and the presence of diseases were significant predictors of conception at first service (P ≤ 0.05). Sick cows were 37 times more likely to seroconvert to BVDV at D60 (P = 0.001). EMI at AI may serve as a valuable biological marker for predicting fertility. Simple summary: This study identifies the association between the presence of diseases within the first 21 days in milk in dairy cows and metabolic status after the voluntary waiting period, conception at first service, and the effect of metabolic status at first artificial insemination on conception. Integrating multiple metabolites into an Energetic Metabolic Index (EMI) may improve the prediction of fertility outcomes by better capturing complex metabolic responses than relying on insufficient single metabolite analyses. EMI and the presence of diseases were significant predictors of conception at first service. The EMI may serve as a potential biological marker for predicting fertility.

We hypothesized that suckling restriction with nose plates (NPs) during an 8-day progesterone, estradiol, and eCG-based synchronization protocol increases fertility. On Day -9, body condition score (BCS; 1–5 scale) and the presence of corpus luteum (CL) were assessed in 502 Hereford cows (35–80 d postpartum), which were randomly assigned to the NP (n = 266) or control group (n = 236). The synchronization protocol consisted of inserting a 0.5 g progesterone intravaginal device (IVD) and administering estradiol benzoate (2.0 mg) on Day -9, followed by IVD removal and the administration of 0.5 mg estradiol cypionate and 400 IU eCG on Day -1. In the NP group, NPs were fitted to calves on Day -9 and removed on Day -1. Cows were exposed to bull mating from Day 0 to 87. On Day -9, approximately 60

We evaluated the effects of a synthetic eCG-like glycoprotein on dominant follicle (DF) size and growth, ovulation rate (OR), corpus luteum (CL) size, and plasma progesterone concentrations in primiparous suckled Angus cows synchronized with a 5-d Co-Synch protocol, with or without postpartum protein supplementation. Thirty-two primiparous cows (BCS = 3.7 ± 0.2 [1-9 scale]; days postpartum = 20 ± 3.7) were randomly allocated to one of two dietary treatments for 82 days (from Day -47 to Day 35; Day 0 was the TAI day). The supplemented group (SUP) received ad libitum native grass hay (CP, 8.9 %; IVDMD, 52.4 %; ME, 1.7 Mcal/Kg) plus 2 kg of 28 % CP supplement per animal daily. The non-supplemented group (NSUP) received ad libitum native grass hay. On Day -8, all cows received a progesterone intravaginal device (1.0 g; IVD) and 100 μg GnRH. On Day -3, cows received 500 μg cloprostenol, IVDs were removed, and cows from each nutritional treatment were assigned randomly to eCG-like (400 IU eCG-like glycoprotein; Fixplan-R®, Syntex, Argentina) or Control group (no eCG-like). On Day -2, all cows received a second dose of 500 μg cloprostenol. On Day 0 (72 h post-IVD removal), cows received 100 μg GnRH and were inseminated. Cow BW on Days -47, -8, and 35 was analyzed using repeated measures in PROC MIXED, with day as the repeated effect. Dominant follicle size on Day -3 and 0, DF growth, CL size on Day 8, and progesterone concentrations on Day 8 were analyzed using PROC MIXED. Ovulation rate (evaluated on Day 8) was analyzed with PROC GLIMMIX using a binary distribution and logit link function. In all models, fixed effects included nutritional treatment (SUP vs. NSUP), hormonal treatment (eCG-like vs. Control), and their interaction, while pen was included as a random effect. There was an interaction between nutritional treatment and days (P = 0.01) on BW. On Day -47, BW was similar between nutritional treatments (331.4 and 329.8 ± 3.6 Kg for NSUP and SUP, respectively; P = 0.74). However, on Day 35, cows in the SUP group had greater BW than those in the NSUP group (316.1 and 329.4 ± 3.6 Kg for NSUP and SUP, respectively; P = 0.01). All cows were without a CL at the beginning of the ovulation synchronization protocol. Nutritional treatment did not affect (P > 0.1) follicular and luteal characteristics. Treatment with synthetic eCG-like glycoprotein increased (P ≤ 0.05) DF size on Day 0, DF growth rate, OR, CL size on Day 8, and progesterone concentrations on Day 8 (Table 1). These findings indicate that eCG-like glycoprotein improved follicular and luteal characteristics, regardless of nutritional treatment.

Introduction:Metabolic alkalosis induced by prepartum diet cations impairs Ca homeostasis in the periparturient cow. Adding anions to prepartum diets reduces blood pH improving periparturient Ca homeostasis. Urine pH generally reflects blood pH and is practical to measure on farm. The degree to which urine should be acidified to increase periparturient blood Ca concentration is not well defined. Materials and methods:Prepartum urine pH and periparturient blood Ca concentrations determined in 660 multiparous Holstein cows from 9 studies were analyzed. Least Square Means of the lowest blood Ca concentration (Ca nadir) observed in cows within 6 urine pH categories (≤ 5.75, 5.76 to 6.25, 6.26 to 6.75, 6.76 to 7.25, 7.26 to 7.75, and ≥ 7.76) were determined. Data were analyzed across all 660 cows and then by parity. Results:Across all cows, the Ca nadir was lowest and the incidence of cows with Ca nadir < 2.00 mM, indicative of subclinical hypocalcemia (SCH), was greatest when urine pH was ≥ 7.76. Mean Ca nadir increased in all cows with urine pH < 7.75. There was no significant difference in Ca nadir or % of cows with SCH when prepartum urine pH was < 7.75. This was also the case for 2nd and 3rd parity cows. However, in ≥ 4th parity cows, those with urine pH between 6.26 and 6.75 had significantly higher Ca nadir than cows with urine pH above 7.25 or below 5.75. Calcium nadir and blood Ca concentrations at 2 days in milk (DIM) were highly correlated (r = + 0.58), and blood Ca concentrations at 2 and 4 DIM were moderately correlated (r = + 0.43). Blood Ca concentration at 4 DIM was weakly associated with Ca nadir (r = + 0.30). Discussion:These analyses support acidification of cows to achieve prepartum urine pH below 7.75 to increase blood Ca nadir for 2nd and 3rd parity cows. For ≥ 4th parity cows, the highest blood Ca nadir was observed with urine pH below 7.25 and above 5.75. For ≥ 4th parity cows, urine pH below 5.75 was associated with significantly lower blood Ca nadir.

The objective of the present study was to evaluate the effects of a synthetic eCG-like glycoprotein treatment, body condition score changes, and postpartum nutritional supplementation on follicular and luteal characteristics and pregnancy rates in suckled beef cows synchronized with a 7-d Co-Synch protocol. In Experiment I, 1218 suckled cows received a progesterone intravaginal device (1.0 g; IVD) and 100 μg GnRH on Day -10. On Day -3, IVDs were removed, and cows received 0.5 mg sodium cloprostenol and were randomly assigned to receive either 400 IU eCG-like glycoprotein (eCG-like; n = 602) or no eCG-like glycoprotein (Control; n = 616). On Day 0, 100 μg GnRH was given concurrently with TAI. Body condition score (BCS) was recorded on Day -10 and 35, and its change was calculated. Corpus luteum (CL) presence was evaluated on Day -10, and pregnancy (P/TAI) on Day 35. In cows without CL, eCG-like increased estrus expression rate (EER; 58.2 vs. 45.3 %; P = 0.01). In cows that lost BCS, eCG-like increased P/TAI (47.2 vs. 32.1 %; P = 0.01). In Experiment II, 72 cows, 21 d postpartum, were assigned to supplemented (SUP; 4 kg of corn daily) or non-supplemented (NSUP) diets for 80 days. Cows were subjected to the same synchronization protocol and eCG-like glycoprotein treatment described in Exp. I. Nutritional SUP increased (P ≤ 0.05) body weight and BCS. Dominant follicle (DF) growth tended to be greater in eCG-like group than Control (1.2 vs. 0.7 ± 0.3 mm/d; P = 0.08), while the SUP group exhibited greater ovulation rate and CL area compared with NSUP (P ≤ 0.03). The eCG-like treatment increased EER in cows without CL and P/TAI in those losing BCS. Although eCG-like tended to improve DF growth, no interaction was observed between nutritional and eCG-like treatment on follicular and luteal characteristics.

This study determined the effects of administering a glycoprotein with equine chorionic gonadotropin (eCG)-like activity (eCG-like) on corpus luteum (CL) area, serum progesterone concentrations, incidence of multiple ovulations (MOV), estrus expression rate (EER), and pregnancy to timed AI (P/TAI) in Angus cattle synchronized with a 5-d Co-Synch protocol. On Day -8, cattle were body condition scored (BCS), and received a 1.0 g progesterone intravaginal device (IVD) and 100 μg GnRH. On Day -3, the IVDs were removed and 500 μg cloprostenol was administered intramuscularly (i.m.). Cattle were randomly assigned into one of two groups: eCG-like (heifers, n = 232, primiparous, n = 148, and multiparous cows = 485; 300 IU (heifers) and 400 IU (cows) eCG-like i.m. on Day -3), or Control (heifers, n = 240, primiparous, n = 151, and multiparous cows, n = 478; no eCG-like). On Day -2, cattle received a second dose of 500 μg cloprostenol, and on Day 0, 100 μg GnRH was given concurrently with TAI. Estrus expression rate was assessed by observing the tail paint rubbed off in a subset of heifers (n = 372) and all cows on Day 0. Transrectal ultrasonography was used to evaluate the presence of CL on Day -8 and to diagnose P/TAI on Day 30-35. In a subset of cattle (heifers = 194 and multiparous cows = 87), CL area, serum progesterone concentrations, and incidence of MOV were evaluated on Day 7. Heifers, primiparous, and multiparous cows were analyzed separately. Treatment with eCG-like did not affect (P > 0.1) EER in heifers. Estrus expression rate was increased (P ≤ 0.03) in primiparous (68.9 % vs 45.0 %) and multiparous (75.5 % vs. 68.8 %) cows treated with eCG-like compared with Controls. Pregnancy/TAI was increased (P < 0.01) in heifers (65.2 % vs 48.3 %) and primiparous cows (48.3 % vs. 35.1 %) treated with eCG-like than Controls. In multiparous cows with a BCS ≤ 4 P/TAI was increased (P = 0.03) in the eCG-like group (47.7 %) than the Control group (34.8 %) but was similar (P > 0.1) between treatment groups in multiparous cows with a BCS ≥ 4.5. The eCG-like treatment increased (P < 0.05) CL area in heifers and multiparous cows and tended (P = 0.10) to elevate serum progesterone concentrations only in heifers. However, it did not affect (P > 0.1) the incidence of MOV in heifers and multiparous cows. Glycoprotein eCG-like administration increased fertility in heifers and primiparous cows, but in multiparous the effect of eCG-like on fertility was associated with BCS.

The economic evaluation of mastitis control is challenging. The objective of this study was to perform the economic evaluation of mastitis control, under different intervention scenarios, quantifying the total cost of mastitis caused by S. aureus in Holstein cows in Argentina. A model was set for a dairy herd of Holstein cows endemically infected with S. aureus. A basic mastitis control plan including proper milking procedures, milking machine test, dry cow therapy, and treatment for clinical mastitis, was compared against other more complex and costly interventions, such as segregation and culling of chronically infected cows. Sensitivity analysis was performed by modifying the intramammary infection transition probabilities, economic parameters, and efficacy of treatment strategies. The basic mastitis control plan showed a median total cost of USD88.6/cow per year, which was close to the infected cows culling scenarios outputs. However, the segregation scenario was the most efficient, in which the total cost was reduced by about 50%. Such cost was more sensitive to probabilities and efficacy than the economic parameters. The model is flexible and can be customized by producers and veterinarians according to different control and herd settings.

The objective of this study was to compare the late embryo mortality (LEM) rate (losses approximately between 32 and 53 days of gestation) and Pregnancy Specific Protein B (PSPB) and progesterone (P4) concentrations on day 32 post AI in Holstein cows bred with either Holstein or Limousine semen. A sample size of 1082 cows per group diagnosed pregnant between 28- and 35-days post breeding was calculated. The study consisted of evaluating LEM (%) in a cohort of Holstein cows bred with Holstein semen (HO × HO) or Limousine semen (HO × LM), to compare pregnancy loss from 28 to 35 days post breeding to 50-57 days post breeding. A logistic regression model to compare embryo losses was developed considering as main explanatory variable the cohort (HO × HO embryo vs. HO × LM embryo), correcting by lactation number, breeding season, days to breeding and AI technician. HO × HO embryos had greater LEM (15.16%) than HO × LM embryos (9.79%). Cows bred in summertime had higher LEM (15.23%) than cows bred in no-summertime (9.88%). There were no differences among AI technicians. Within summertime there was no difference in LEM (%) between groups within each lactation number; yet, within no-summertime, LEM (%) was higher in HO × HO than HO × LM within each lactation number. Pregnancy SPB optical densities were significantly greater in the HO × HO than in the HO × LM (p = .023) group; yet, the concentration of P4 was not different between groups (p > .05).

Spermatogenesis and sperm maturation take place in the testes and epididymis, respectively. These complex physiological processes are regulated by multiple genes, which have not been studied in the stallion. In this study, Illumina sequencing was used to analyze the transcriptomes of the testes, head, body and tail of the epididymis from three reproductively normal stallions. The mRNA was extracted and the libraries were generated using Next Generation Sequencing (NGS). The expression patterns of differentially expressed genes (DEGs) in the testes and epididymis were determined by bioinformatics analysis. Gene Ontology (GO) enrichment analysis of DEGs was implemented and gene length bias was corrected. Differentially expressed genes were compared between the different segments of the epididymis and the testis (control tissue). GO-terms with adjusted p < 0.05 were considered significantly enriched. Among the four libraries, 18,732 genes were identified. Of those, 6,574 genes (39.1%) were tissue-specific. The distribution of tissue-specific genes was 14.2 % in the testes, 2.2 % in the epididymal head, 1.1 % in the epididymal body, and 1.4 % in the epididymal tail. Compared with testicular tissue, there were 13,349 DEGs (5,595 up-regulated and 7,754 down-regulated) in the epidydimal head, 14,207 DEGs (5,884 up-regulated and 8,323 down-regulated) in the epididymal body, and 14,822 DEGs (5,842 up-regulated and 8,980 down regulated) in the epididymal tail. In the epididymal head,the main downregulated terms were male gamete generation (224 DEGs), spermatogenesis (224 DEGs), organelle fission (264 DEGs), sexual reproduction (343 DEGs) and nuclear division (233 DEGs). The main upregulated terms were associated with the ribosome (322 DEGs), lymphocyte activation (226 DEGs), and cytosolic part (104 DEGs). In the epididymal body, the most significantly downregulated terms were male gamete generation (232 DEGs), spermatogenesis (232 DEGs), sexual reproduction (358 DEGs), cilium morphogenesis (151 DEGs) and cilium (235 DEGs). The most significantly upregulated terms were lysosome (150 DEGs), lytic vacuole (150 DEGs), positive regulation of locomotion (197 DEGs), cytosolic ribosome (71 DEGs), vacuole (182 DEGs). In the epididymal tail, the most significantly downregulated terms were male gamete generation (239 DEGs), spermatogenesis (193 DEGs), cilium (253 DEGs), ciliary part (186 DEGs), cilium morphogenesis (158 DEGs). The most significantly upregulated terms were associated with the ribosome (438 DEGs) and cytosolic part (109 DEGs). In summary, we found decreased expression of genes involved in gamete production, and increased expression of genes involved in protein synthesis, immunity and sperm transport in different segments of the epididymis. These findings provide genome-wide mRNA expression profiles for the horse epididymis and testes, providing a biological basis for future research on stallion fertility.

This study evaluated the effect of administering a glycoprotein with equine chorionic gonadotropin like activity produced by recombinant DNA technology (eCG-like) associated with a 7-d Co-Synch protocol on estrus rate (ER) and pregnancy per timed AI (P/TAI). A total of 1,344 suckled Angus cows (primiparous, n = 381; multiparous, n = 963) from 11 herds were scanned at initiation of synchronization protocol by transrectal ultrasonography and the presence of corpus luteum (CL) and uterine tone was used to classify them by cycling. On day -10, cows received 100 μg GnRH analogue and a progesterone intravaginal device (IVD; 1.0g progesterone) for 7 days. At IVD removal, cows were administered 500 μg of cloprostenol and randomly assigned to receive 400 IU of eCG-like glycoprotein (Syntex S.A., Argentina, PCT/EP2019/073277; eCG-like, n = 665) or to remain as untreated (Control, n = 679). Also on day -3, paint was applied on the sacrum to the tail head of each cow. Finally, 100 μg GnRH analog were injected concurrently with TAI on Day 0 (66h after IVD removal) and the ER was evaluated by the degree of paint loss. Pregnancy to TAI was determined on day 30 by transrectal ultrasonography when an embryo and fluid were detected in the uterus. Body condition score (BCS; scale = 1-9) was evaluated on days -10 and 30. Optimal BCS was considered ≥ 5 and BCS balance between days -10 and 30 was classified as negative (lost BCS) or positive (maintained or gained BCS). The associations among treatment, parity, cyclicity at initiation of protocol, optimal BCS on day -10, and their interactions and ER and P/TAI were analyzed by GLIMMIX (SAS 9.3). Estrus expression and BCS balance were also included as effects in the model of pregnancy per TAI. The effect of herd was included as a random effect. The model specifications included an option to retrieve the mean, SEM, and an adjustment for multiple comparisons (Tukey-Kramer). The percentage of acyclic cows was 31.3%. The ER in cyclic cows was 64.9% and the eCG-like treatment increased ER only in anestrus cows (55.8 vs. 44.3%; Treatment x cyclicity interaction; P = 0.03). The percentage of cows with negative BCS balance was 27.2%. The P/TAI in cows with positive BCS balance was 48.4% and the eCG-like treatment increased P/TAI only in cows with negative BCS balance (44.7% vs. 30.5%; Treatment x BCS balance interaction; P = 0.01). In conclusion, the addition of a recombinant eCG-like glycoprotein to a 7-day Co-Synch protocol increased estrus expression in anestrus Angus cows and P/TAI in those with negative body condition score balance. However, this addition did not influence the estrus expression in cycling cows or on P/TAI in those with positive BCS balance.

The objective was to compare pregnancy rates (PR) on day 30 and pregnancy loss between days 30 and 60 (PL) after timed artificial insemination (TAI; day 0) using 2 synchronization protocols, and plasma progesterone on day 18 in suckled beef cows. Angus cows were randomly assigned to either 7-d progesterone CoSynch (7-d P + GnRH) or 8-d progesterone + estradiol (8-d P + ES) synchronization protocols for TAI. On day -10, cows in the 7-d P + GnRH treatment group (n=574) received a progesterone-releasing intravaginal device (PIVD) and GnRH, on day -3 the PIVD was removed and cows received cloprostenol. On day 0 (64 h after PIVD removal), cows received GnRH and were subjected to TAI. On Day -10, cows in the 8-d P + ES treatment group (n=574) received a PIVD and estradiol benzoate, on Day -2 the PIVD was removed, and cows received cloprostenol and estradiol cypionate. On day 0 (48 h after PIVD removal), cows were subjected to TAI. The TAI pregnancy rates for each treatment were determined on day 30 and day 60. In a subset of cows [n=81, (7-d P + GnRH, n=41; 8-d P + ES, n=40)], serum progesterone concentration was evaluated on day 18. The PR (7-d P + GnRH=48.9%; 8-d P + ES=45.6%) and PL (7-d P + GnRH=3.6%; 8-d P + ES=4.6%) did not differ (P≥0.28) between treatment groups. In a subset of cows, serum progesterone concentration on day 18 did not differ (P=0.67) between treatment groups but tended to be less (P=0.07) in cows that had PL compared with cows that had no PL. In conclusion, there was no difference in PR and PL between suckled beef cows using 7-d CoSynch or 8-d estradiol-based protocols for synchronization of ovulation and TAI.

Two experiments were conducted to compare, follicle diameter (FD) on Day -1, corpus luteum (CL) area on Day 7, progesterone (P4) concentration on Day 7 and 18, pregnancy per timed artificial insemination (TAI) on Day 30, and pregnancy loss (PL) between Days 30 and 60 after TAI (TAI, Day 0) using two different synchronization protocols. In Experiment 1, Angus cows (n = 1148) were randomly assigned to either 7-d progesterone CO-Synch (7-d CO-Synch) or 8-d progesterone + estradiol (8-d P + ES) synchronization protocols for TAI. On Day -10, cows in the 7-d CO-Synch treatment group (n = 574) received a progesterone-releasing intravaginal device (PIVD; 0.5 g P4) and GnRH (0.105 mg), on Day -3 the PIVD was removed and cows received cloprostenol (0.150 mg), then, on Day 0 (64 h after PIVD removal), cows received GnRH (0.105 mg) and were TAI. On Day -10, cows in the 8-d P + ES treatment group (n = 574) received a PIVD (0.5 g P4) and estradiol benzoate (2.0 mg), on Day -2 the PIVD was removed, and cows received cloprostenol (0.150 mg) and estradiol cypionate (0.5 mg), then, on Day 0 (48 h after PIVD removal), cows were TAI. Pregnancy per TAI was determined on Days 30 and 60. In a subset of cows (7-d CO-Synch, n = 41; 8-d P + ES, n = 40), serum P4 concentration was evaluated on Day 18. In Experiment 2, anestrus (n = 34) and cyclic (n = 34) suckled beef cows were selected and submitted at random on Day -10, to either 7-d CO-Synch or 8-d P + ES treatment groups. Follicle diameter on Day -1, CL area, and serum P4 concentration on Day 7 were determined. In Experiment 1, pregnancy per TAI on Day 30 did not differ (7-d CO-Synch = 48.9%; 8-d P + ES = 45.6%) between treatments but it was greater for cows with BCS >= 5 (P < 0.01). Pregnancy loss between Days 30 and 60 did not differ between treatment groups but tended to be greater in cows with BCS <5.0 (P < 0.1). In a subset of cows, serum P4 concentration on Day 18 did not differ between treatment groups but tended to be lower (P < 0.1) in cows that had PL between Days 30 and 60 compared to cows that had no PL. In Experiment 2, FD tended to be greater (P < 0.1) and CL area was greater (P = 0.05) in anestrus cows from 7-d CO-Synch treatment. In cyclic cows, the treatment did not affect the FD or CL area. In conclusion, there was no difference in pregnancy per TAI on Day 30 and PL between Days 30 and 60 between cows using 7-d CO-Synch + PIVD or 8-d estradiol-based + PIVD protocols for estrus synchronization and TAI.(c) 2023 Elsevier Inc. All rights reserved.

Abstract The objective of this short communication was to discuss two field case investigations to determine the usefulness of a milk‐line sampling device to detect bacteria either coming from a group of cows suffering from mastitis or from the milking line potentially contaminated with environmental bacteria. In Case 1, the in‐line sampling device was able to detect certain segments of the milk‐line contaminated with environmental bacteria, but not coming from the cows. In Case 2, 19 out of 25 pooled in‐line samples were in agreement with at least one of the individual sampled cows shedding either Staphylococcus or Streptococcus spp. or both, which accounted for 76% accordance between both methods. The in‐line system, although not perfect, provided a reliable method to detect individual cows shedding mastitis‐causing organisms. In conclusion, the milk‐line sampling device system was able to help identify foodborne pathogens. Regular monitoring of the microbial quality of milk through a milk‐line sampling device is recommended for groups of cows within the dairy herd to detect potential mastitis‐causing microorganisms. Furthermore, the sampling device was an effective tool to screen the efficacy of cleaning and disinfecting mechanisms of the milk lines to identify and control potential foodborne pathogens that are collected in the bulk tank.

The stress associated with training may reduce reproductive efficiency in Criollo stallions. The objective of this study was to compare semen quality and hormone concentrations in Criollo stallions under training or under regular field conditions. Criollo breed stallions (n = 18) were evaluated during the spring. The exercise group (n = 9) performed 1 hour of exercise per day and participated in competitions during the experimental period. The control group (n = 9) neither performed exercise nor participated in competitions. Serum and semen samples were obtained every 15 days (two separate ejaculates an hour apart). Sperm motility, velocity, and morphology were evaluated with a phase-contrast microscope and concentration by a hemocytometer. Diff-Quik stain was used to identify polymorphonuclear cells, and the degree of chromatin condensation was evaluated with the toluidine blue stain. The sperm survival test was performed at a room temperature of 22°C. Semen evaluation was performed in raw samples and in samples diluted in a skim milk and glucose-based extender. Cortisol, testosterone, and estradiol were measured using radioimmunoassay. There was no effect of exercise on testosterone and estradiol concentrations (P = .28 and P = .97, respectively). However, in the exercise group, cortisol concentration was higher after exercise (P = .004). There was an effect of exercise on the following semen parameters: gel-free volume (P < .001), sperm motility (P < .0001), total number of sperm (P = .0001), normal sperm morphology (P < .0001), and total number of morphologically normal and motile sperm (P < .001). No effect of exercise was found in the following semen parameters: color, pH, and sperm concentration. This study showed that exercise had a negative impact on seminal quality; nevertheless, semen parameters were within the normal ranges established for the equine species.

The use of anionic salts to prevent milk fever in dairy cattle has been an effective nutritional strategy; however, the degree of acidification that determines the most acceptable productive responses and well-being of the cow is still a controversial topic. The objective of this study was to assess urine pH in prepartum Holstein cows fed anionic diets and determine its association with plasma total Ca, Mg, P, β-hydroxyl-butyrate (BHB) concentrations at parturition and the occurrence of peripartum disorders. This investigation consisted of 2 studies. Study 1 was conducted on a grazing dairy. Between February and May 2019, 60 prepartum multiparous cows were tested for urine pH and plasma metabolite concentration at parturition. Total Ca, P, Mg and BHB at day 1 in milk (DIM) were assessed and statistically analyzed by ANOVA (models for polynomial regression). Study 2 was conducted on a drylot dairy farm. Between July 2018 and January 2019, 203 cows were evaluated for urine pH and followed-up for 30 DIM to obtain the incidence of dystocia, stillbirths, milk fever, retained fetal membranes, metritis, clinical mastitis and ketosis. Cows were categorized based on their last urine pH as group 1: pH > 7.0 (n = 135); group 2: pH between 6.0 and 7.0 (n = 46) and group 3: pH < 6.0 (n = 22). A logistic regression model for each health event was conducted considering urine pH group as the main effect. Urine sample was collected at 2.71 ± 2.84 days before parturition. In study 1, there was a quadratic effect of urine pH on total Ca. Total Ca concentration was higher between urine pH 6.0 and 7.0, while decreasing below pH 6.0 and above pH 7.0. There was a trend (P = 0.11) for a quadratic effect of urine pH on the concentration of plasma BHB at parturition. β-Hydroxyl-butyrate was lower approximately between urine pH 6.5 and 7.5. In study 2, the odds for a stillborn in cows with urine pH < 6.0 was 2.39 (95% CI = 1.06–5.40) times the odds for a stillborn in cows with urine pH ≥ 7.0. There was no association between urine pH and the other diseases. In conclusion, cows with prepartum urine pH < 6.0 and >7.0 had lower concentration of plasma total Ca and tended to have a higher concentration of BHB. Cows with urine pH < 6.0 had a higher incidence of stillbirths than cows with urine pH > 7.0.

This study was conducted to compare efficacy of treatments with EB or GnRH and different quantities of exogenous progesterone (P4) for synchronization of time of ovulation on follicular growth and pregnancy in lactating dairy cows. In Experiment 1, 40 cows were treated with EB or GnRH and 1.9 or 3.0 g of P4 via progesterone-containing intravaginal devices (IVPD; D0), two doses of PGF2α on D7, GnRH on D9, and TAI on D10. In Experiment 2, 1,440 cows were treated with EB or GnRH and 1 g IVPD on D0, cloprostenol, eCG and EB on D7. Cows in estrus by 48 h were AIDE, and non-estrous cows were administered GnRH and TAI 60 h after IVPD removal. Non-estrous cows were AIDE 72 h after IVPD removal. In Experiment 1, P4 was greater on D7 for cows treated with GnRH than those treated with EB. The dominant follicle was larger for cows treated with GnRH than those treated with EB. In Experiment 2, for estrous cows, pregnancy per AI was greater in cows AI at 48 h compared to 60 h after IVPD removal for cows treated with GnRH, and greater with AI at 60 h after IVPD removal compared to 48 h in EB-treated cows. In non-estrous cows, there was no effect on pregnancy. In conclusion, treatment with GnRH compared with EB resulted in increased P4 regardless of amount of exogenous P4, and there were differential proportions of estrous cows pregnant depending on time of AI after IVPD removal.

Folliculogenesis and ovulation are regulated by gonadotrophins and other factors such as Insulin like growth factor 1 (IGF1) and leptin. In various species the presence of IGF1 receptor (IGF1R) and leptin receptor (ObR) has been detected in the ovary, but not in the alpaca. Thus, the aim of the present study was to evaluate the presence of these receptors in this tissue and analyze if the presence of these receptors in the ovary is related to the presence of a corpus luteum (CL) and if abundances, as determined by immunostaining intensity vary with follicle size. The IGF1R and ObR were identified in primary and secondary follicles, granulosa and theca interna cells of tertiary follicles and in CL. There were greater abundances of IGF1R in granulosa cells of tertiary follicles of ovaries without compared with those with CL. In both groups, the immunostaining of granulosa cells was greater than in theca interna cells. The abundance of ObR was greater in primary and secondary follicles, and theca interna cells of tertiary follicles in ovaries with than those without CL. Immunostaining of granulosa cells was greater than theca interna cells only in ovaries without CL. There were no differences in the abundance of ObR and IGF1R between primary and secondary follicles and granulosa cells of tertiary follicles, neither in ovaries with or without CL. The abundance of IGF1R was not correlated with abundance of ObR neither in ovaries with or without CL. These results indicate a possible role for IGF and leptin in ovarian function. Furthermore, these receptors could be regulated by ovarian steroid hormones because abundance of these receptors in ovaries varies depending on whether there is a CL present in the ovary.

Context Ketosis in grazing cattle has been sparsely studied. A large commercial grazing dairy in southern Chile, representative of a significant proportion of the systems in the country, was used in this case study. Aims The study had three objectives: (i) to establish a cut-off for β-hydroxybutyrate (BHB) concentration for subclinical ketosis (SCK), and use this to measure the proportion of cows with SCK at 7 days postpartum in spring- and autumn-calving cows; (ii) to describe the relationship of SCK and other periparturient diseases and fertility; and (iii) to compare milk yield of healthy cows and those affected by SCK in a dairy herd with autumn and spring parturitions under grazing conditions in southern Chile. Methods During 2016, 234 cows with autumn parturitions and 632 cows with spring parturitions (n = 866) were assessed for blood BHB at 7 days postpartum. A receiver operating characteristic analysis for a BHB cut-off value was completed. Models were developed for disease occurrence, culling risk, conception risk and pregnancy rate, considering SCK as the main explanatory variable. Key results In total, 810 cows were used for the final analysis. The frequency of cows with SCK, based on the cut-off value obtained (BHB ≥1.1 mmol/L), was 22.2% at 7 days postpartum. The risk of SCK was higher (P < 0.0001) in cows calving in spring (27.0%) than in autumn (10.3%), and in multiparous (24.6%) than primiparous cows (15.1%). The seasonal difference in proportion of cows with SCK was parity-dependent, because the frequency of SCK in multiparous cows was higher (P < 0.0005) in spring (32.0%) than autumn (10.1%), whereas SCK in primiparous cows showed no significant (P = 0.41) difference between spring (15.4%) and autumn (12.5%). Milk production up to 100 days-in-milk was greater (P = 0.002) in cows with SCK (3394 kg) than without SCK (3015 kg). Disease occurrence was higher (P < 0.0001) in cows with SCK and in multiparous cows (P < 0.0001). There was no difference in conception risk at first service (P = 0.62) or in overall pregnancy rate (P = 0.90) between cows with and without SCK. Conclusions Multiparous cows calving in spring had the highest risk of SCK (BHB ≥1.1 mmol/L). SCK was associated with higher milk yield and greater occurrence of other diseases, but not with reproductive performance. Implications Grazing herds have challenges with SCK that may require different management strategies depending on the calving season and the parity of the animals.

The objective was to compare pregnancy per AI and follicular dynamic in suckled Bos taurus beef cows treated with either a 7-day progesterone + estradiol-based protocol or a 5-day progesterone CoSynch protocol for timed artificial insemination (TAI) during four breeding seasons. We hypothesized that estrous cycle status, days postpartum (DPP), fat depth and plasma progesterone concentration differentially modify the effect of treatments. Every year, 9 days before initiation of each breeding season, cows were randomly assigned to one of two groups. Cows in the 7-d P + E group (n = 428) received a progesterone intravaginal device (DIB) and estradiol benzoate on Day -9. On Day -2 the device was removed, and cows received cloprostenol and estradiol cypionate. Forty-eight hours later (Day 0) cows received TAI. Cows in the 5-d P + CoS group (n = 428) received a DIB, and GnRH on Day -8. On Day -3, the device was removed, and cows received cloprostenol. A second dose of cloprostenol was given on Day -2. Cows received GnRH and TAI 72 h after device removal (Day 0). On Day -9, estrous cycle status was determined. In a subset of cows (n = 79) the size of the dominant follicle was determined between Days -2 and 0. In another subset of cows (n = 340), DPP, fat depth (mm) and plasma progesterone concentration (ng/mL) were evaluated on Day -9. Pregnancy per AI was determined 30 d after TAI. Pregnancy per AI was greater for cows in the 5-d P + CoS group than for cows in the 7-d P + E group (50.9% vs. 41.3%, P = 0.01) and was also greater in cyclic than in anestrus cows (543% vs. 33.2%, P < 0.0001). There was also a significant effect of breeding season (P = 0.0002) and sire (P = 0.03), and an interaction between treatment group and breeding season (P = 0.03). The dominant follicle was larger (P < 0.0001) in cows in the 5-d P + CoS group than the 7-d P + E group (10.7 +/- 0.29 mm vs. 9.0 +/- 0.28 mm). Pregnancy per AI was greater in cows with >= 55 DPP (47.0% vs. 29.6%, P = 0.001), fat depth >= 0.50 mm (44.7% vs. 29.7%), and with plasma progesterone concentration >= 1 ng/mL (47.2% vs. 28.7%, P = 0.01). In cows with plasma progesterone >= 1 ng/mL on Day -9, pregnancy per AI was greater in the 5-d P + CoS group (60.5%) than in the 7-d P + E group (34.9%), but there was no difference between treatment groups in cows with plasma progesterone < 1 ng/mL (P = 0.07). In conclusion, the 5-d P + CoS protocol resulted in greater size of the dominant follicle and pregnancy per AI in suckled Bos taurus beef cows subjected to TAI. (C) 2019 Published by Elsevier Inc.