A field study using different technologies to detect calving at a large-scale hungarian dairy farm

The objective of this study was to investigate three different calving detection systems in order to assess and compare their efficiency. The study was conducted at a large-scale dairy farm involving 54 Holstein-Friesian dairy cows and heifers. Animals were fitted with multiple devices: a rumination measuring device (Ruminact^® (RA)), an intravaginal thermometer (Vel’Phone^® (VP)) and a tail movement sensor (Moocall^® (MC)) 5 to 7 days before expected calving and were removed after parturition. RA detects rumination time (RT) and calculates it in 2-hr intervals. VP detects a decrease in vaginal temperature that might indicate calving within 48 hr and the drop in temperature resulting from the expulsion of the device at calving (EXP message). MC detected increased tail movements and if they persisted for one hour, 1HA message was sent. If they continued during the subsequent hour, then 2HA message was sent. Messages sent by MC within 4 hr before calving (C4) were selected retrospectively as true positives for the prediction of calving, using the significant changes in RT as a baseline. All other messages were categorized as false positive. The mean value of RT decreased in a non-significant manner between interval −22 and −4 before calving. Significant decrease of RT was detectable between the two intervals of −4 and −2 before calving (24.7 ± 18.6 min/2 hr and 14.0 ± 13.0 min/2 hr, respectively). There was no significant difference between RT of primiparous and multiparous animals. EXP messages were accurate (positive predictive value 100%) indicators of the onset of calving. We received on average 12.7 ± 15.2 messages/animal (11.0 ± 10.1 and 16.6 ± 22.2 for cows and heifers, respectively). Positive predictive value was 12.6%. The number of false-positive messages was significantly higher in heifers. All three automatic systems could be used in a large-scale farm environment.     

Remote monitoring system as a tool for calving management in Mediterranean Buffalo heifers (Bubalus bubalis)

Buffalo breeding is common in Southern Italy. Dystocia compromises dam's and newborn health and welfare. Difficult parturition could be solved through prompt calving assistance, even if the identification of the beginning of delivery is challenging. Herein, we aimed to evaluate a remote calving alarm system in 15 Mediterranean buffalo heifers. An intravaginal probe was placed close to the external cervical os once premonitory signs of delivery were observed. No vaginal discharge nor signs of discomfort were notified in the days following the insertion of the probe. Heifers calved from 48 to 72 hr after the alarm was activated. The system correctly warned the farm personnel at the beginning of stage II of parturition, except for 2 cases. In the former, the intravaginal probe was expelled but the poor carrier network coverage negatively affected phone's signal quality; in the latter, recurrent vaginal prolapse was responsible for non-retention of the probe. Overall median expulsive phase was 68 ± 8 min, while the expulsion of a female calf took 54 ± 22.0 min and 90 ± 34.0 min in males, with significant difference (p =.02). Deliveries were homogeneously distributed across a 24-hr interval. No retention of foetal membranes nor metritis was identified at postpartum clinical examination. The calving alarm system used in this work was well tolerated in buffalo heifers. The introduction of smart technology in buffalo farming could contribute to the overall farm net return by reducing calf losses, especially for calves born from sexed-sorted semen, and by increasing animal welfare through quick resolution of dystocia. Further studies will be necessary to evaluate the net return in buffalo farms which will implement a remote calving alarm system on a wider population.     

Growth of foetal bones and metabolic profile during gestation in primiparous ewes and multiparous ewes

Primiparous ewes and multiparous ewes show physiological differences during pregnancy, which can have an impact on the development of their offspring. The objective of this study was to compare the changes in the metabolic profile and in the size of some foetal bones throughout gestation between primiparous and multiparous ewes. Twelve primiparous (PM) ewes and 14 multiparous (MT) ewes were used. According to the dates of lambing, two groups of ewes were formed: Group 1 (G1, n = 6 PM and n = 7 MT) and Group 2 (G2, n = 6 PM and n = 7 MT). The body weight, body condition score, metabolic and foetal morphometric parameters were determined from before conception until the end of gestation. After lambing, the body weight and survival rate during the first 72 hr of life of lambs, as well as the maternal behaviour score were recorded. The PM ewes were lighter (p < .01) and had a greater mobilization of body reserves during gestation, mainly evidenced by a greater serum concentration of NEFAs and lower serum concentration of total proteins (p < .05) compared with the MT ewes. The parity did not affect the foetal morphometric variables. The lambs of MT ewes were heavier at parturition (p = .002) and tended to have a greater survival rate than those lambs of PM ewes (p = .09). In conclusion, PM ewes and MT ewes differ in their metabolic profile throughout the gestation. However, in the present study, we did not find parity differences in the dimensions of foetal bones during growth in gestation.     

Acupuncture prevents the postpartum reduction in matrix metalloproteinase type‐2 immunoexpression,tissue concentration and enzyme activity in bovine caruncles

The objectives of this study were to determine the effects of acupuncture in dairy cows (Bos taurus) on caruncular matrix metalloproteinase type‐2 (MMP2) at 0, 2 and 4 hr after calving. Acupuncture (n = 6) was applied at 0 and 2 hr after calving to 6 points that relax the cervix and stimulate uterine contractions. Controls (n = 9) were kept in a stanchion for 15 min without acupuncture. All of the cows in the study delivered their placenta in <4 hr. Formalin‐fixed caruncles were paraffin‐embedded and subjected to routine immunohistochemistry to determine MMP2 expression, which was scored by a single observer. Flash frozen caruncles were homogenized, and protein concentration was determined. MMP2 concentrations were calculated using commercial bovine ELISAs. MMP2 enzyme activity was determined using zymography. The mean value for each time point for each cow was used to calculate the mean ± SEM for each treatment group. MMP2 was predominantly localized to the epithelial and subepithelial stromal cells of the caruncles in both treatment groups. MMP2 immunoexpression was lower 4 hr after calving in the control cows (p = 0.012) but not in the acupuncture treated cows indicating that acupuncture treatment maintained MMP expression. MMP2 tissue concentration was lower 2 hr after calving in the control cows (p = 0.048) but not in the acupuncture treated cows. MMP2 enzyme activity decreased from 0 to 2 hr after calving in control cows (p = 0.046) but not in acupuncture treated cows. This study provides physiologic evidence for the effects of acupuncture on the bovine reproductive tract and substantiates the use of this treatment in cases of placental retention.     

Effect of estradiol cypionate and GnRH treatment on plasma estradiol‐17β concentrations,synchronization of ovulation and on pregnancy rates in suckled beef cows treated with FTAI‐based protocols

Two experiments were conducted to evaluate the effect of different ovulation inducers on E‐17β plasma concentrations, synchronized ovulations and pregnancy rates. In Experiment 1, cows received a progesterone intravaginal device (PID) with 1 g of progesterone (P4) plus 2 mg of estradiol benzoate (EB) (day 0). At PID removal (day 8), cows received 0.150 mg of D‐cloprostenol and were randomly assigned to four treatment groups (n = 10/treatment): Group ECP: 1 mg of estradiol cypionate at PID removal, Group EB: 1 mg of EB 24 hr after PID removal, Group GnRH: 10 μg of GnRH 48 hr after PID removal, Group ECP‐GnRH: 1 mg of ECP at PID removal plus 10 μg of GnRH 48 hr later. Ultrasonographic examinations were performed to detect the dominant follicle and ovulation. GnRH‐treated cows ovulated later (p < .05) compared to ECP‐ and ECP+GnRH‐treated cows. There were effects of treatment, time and their interaction on E‐17β concentrations (p < .05). ECP treatment affected plasma E‐17β concentration, which increased earlier and decreased later compared to treatments without ECP. In Experiment 2, cows received (i) ECP: n = 126; (ii) EB: n = 126; (iii) GnRH: n = 136; (iv) ECP+GnRH: n = 139; FTAI was performed 48–50 hr after PID removal. Pregnancy rates did not differ among ovulation inducers (p > .05; ECP: 54.0%, 68/126; EB: 49.2%, 62/126; GnRH: 40.4%, 55/136; ECP+GnRH: 43.9%, 61/139). In conclusion, ECP administration (ECP and ECP+GnRH treatments) affected E‐17β concentrations, determining its earlier increase and later decrease compared to treatments without ECP (EB and GnRH treatments). ECP+GnRH‐treated cows achieved the best distribution of ovulations without affecting pregnancy rates.     

Reproductive performance of immobilized cryopreserved bovine semen used for timed artificial insemination

The SpermVital^® technology comprises embedding of spermatozoa within an alginate gel to facilitate release of sperm cells over a prolonged period in utero after AI. The aim of this study was to examine whether the survival time of spermatozoa is extended when applying this immobilization technology in combination with cryopreservation. Sperm cell survival (acrosome and plasma membrane integrity) was studied in vitro for 48 hr at physiological temperature. One dose of SpermVital^® (SV) semen was compared with single doses of Biladyl^® (B) processed semen as well as double doses of B (B double). B double was obtained by adding a second B dose the following day, thereby mimicking double AI. Furthermore, reproductive performance applying single early timed AI (TAI) with SV following oestrus synchronization was studied in a field trial. Double insemination (TAI on two consecutive days) with B semen served as control. Number of acrosome‐intact live sperm cells decreased over time in vitro for all treatments (p < .05). There was no difference between SV sperm cell survival and B double after 24 hr (p > .05). However, after 48 hr, SV sperm cell survival was higher than B double (p < .05). Moreover, multivariate analysis showed that the outcome of single early TAI with SV was not significantly different from B double (p > .05). Likelihood of pregnancy and calving in the heifer group was higher than in the cow group (p < .05). These results imply that spermatozoa immobilized in alginate gel have prolonged survival.     

Feed and water deprivation has a negative but transient effect on the rumen kinetics of Bos indicus steers

The effects on rumen kinetics after feed and water had been deprived for 72 hr were studied using four fistulated Bos indicus steers. The animals were assigned in a 2 × 4 crossover design with two treatments: feed and water ad libitum (control) and no feed and water for 72 hr (deprived) with four steers per treatment over two time periods. Feed and water deprivation caused decreases in the numbers of cellulolytic bacteria (1.4 vs. 0.4 cfu × 10⁶/ml; p = .001), live (23.7 vs. 0.8 × 10⁹/ml; p = .001), dead (12.7 vs. 0.5 × 10⁹/ml; p = .001) and total bacterial counts (36.4 vs. 1.4 × 10⁹/ml; p = .001) at day 0, compared with the control treatment. However, the deprived group had greater numbers of cellulolytic bacteria (2.7 vs. 50.1 cfu × 10⁶/ml; p = .001), live (18.3 vs. 42.2 × 10⁹/ml; p = .001), dead (6. 5 vs. 19.1 × 10⁹/ml; p = .001) and total bacterial counts (24.8 vs. 61.3 × 10⁹/ml; p = .001) from rumen fluid on day 4, compared with the control treatment. The numbers of protozoa in rumen fluid from the deprived group were less than (551.2 vs. 2.4 × 10³/ml; p = .001) the control group on day 0. However, the deprived treatment had fewer protozoa in rumen fluid than the control treatment on day 4 (p = .001) and day 9 (p = .001). Volatile fatty acids and in vitro gas production as functional measurements of rumen fluid followed the same trend as the bacterial and protozoa populations. These results indicate that feed and water deprivation would have a negative but transient effect on the rumen kinetics of Bos indicus steers.     

Pregnancy and offspring sex ratio following insemination with SexedULTRA and conventional semen in cows in a commercial beef operation

Pregnancy rate per AI (PR/AI) and breeding season pregnancy rates between insemination with sexed semen (SS; at 18 hr after the onset of oestrus) and conventional semen (CS; at 12 hr after the onset of oestrus,) and offspring gender ratio between two groups were compared. Angus cross cows (n = 686, during 2019 and 2020 breeding seasons) were oestrus-synchronized using Select-Synch + CIDR protocol and were observed thrice daily for oestrus until 72 hr after PGF2α administration. Cows expressed oestrus (n = 513) were inseminated with either SS (n = 246; SexedULTRA 4M™; y chromosome-bearing sperm) or CS (n = 267). Cows (n = 173) that failed to express oestrus at 72 hr after PGF2α received 100 μg of GnRH and CS insemination concomitantly. Two weeks later, cows were penned with natural service sires (bull:cow ratio 1:25) for 45 days. Pregnancy was diagnosed 30 days after bull removal. Calves' gender was determined at birth. For cows that expressed oestrus, PR/AI did not differ (p > .1) between SS (65.0%) and CS (66.7%) groups. The overall PR/AI differed (p < .05) between SS (65.0%) and CS (56.4%) groups. The natural service PR differed (p < .001) but breeding season PR (p > .05) did not differ between SS vs. CS groups. Bull:heifer gender ratio following AI was 88:12 and 52:48 for SS and CS groups, respectively, with an overall 66:34 ratio. Bull:heifer gender ratio for the two breeding seasons was 79:21 and 52:48 for SS and CS groups, respectively, with an overall 62:38 ratio. In conclusion, the fertility of SS insemination at 18 hr after onset of oestrus was 97% of CS insemination at 12 hr after onset of oestrus. Though breeding season pregnancy did not differ between SS and groups, preferred calf gender was 25 percentage points greater for SS over CS application. The gender accuracy was 88%.     

Lactoferrin concentration and expression in New Zealand cows milked once or twice a day

This study evaluated the concentration and expression of lactoferrin (LF) in cows selected for once a day (OAD) milking compared to twice a day (TAD) milking. Milk samples were collected from the Massey University TAD and OAD herds. Milk traits and expression of LF and insulin‐like growth factor 1 (IGF‐1) were analyzed with a general linear model that included the fixed effects of milking frequency, lactation number, interaction between milking frequency and lactation number, and as covariates proportion of F, heterosis F × J and deviation from the herd median calving date. Cows milked OAD produced milk with higher (p < .01) concentrations of protein and lactose than TAD milked cows. Compared to TAD cows, cows milked OAD had higher expression of the LF gene (1.40 vs. 1.29 folds, p = .03) and the IGF‐1 gene (1.69 vs. 1.48 folds, p = .007). The correlation between the expression of LF gene and the concentration of LF in milk was strong (r = .66 p < .001), but the correlation between the expression of the IGF‐1 gene and LF concentration was stronger (r = .94, p < .001). These results suggest that milking frequency affects the milk composition and expression of milk composition genes at early lactation.     

Repeated pregnant mare serum gonadotropin‐mediated oestrous synchronization alters gene expression in the ovaries and reduces reproductive performance in dairy goats

This study aimed to elucidate the effects of repeated pregnant mare serum gonadotropin (PMSG) treatment for oestrous synchronization (ES) on ovarian gene expression and reproductive parameters in Xinong Saanen dairy goats, the dominant breed of dairy goat in China. The experiment was carried out at the Research Station of Northwest A&F University (NWAFU), China (34°16′N, 108°4′E). Forty‐one does were randomly assigned to groups receiving ES treatments thrice every fortnight (3‐PMSG group; n = 19), or ES treatment only once simultaneously with the third ES treatment in the 3‐PMSG group (1‐PMSG group; n = 22) during middle of the breeding season from late July (14 hr light) until late September (12 hr light). ES treatment was performed via intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300 mg progesterone (P4), followed by 300 IU PMSG injections 48 hr before CIDR withdrawal. Oestrus was monitored using vasectomized bucks. Ovaries of three goats in oestrus from both groups were harvested for morphological examination and RNA sequencing (RNA‐Seq). Then, all the oestrous goats in the 1‐PMSG (n = 21) and 3‐PMSG (n = 11) groups were artificially inseminated twice. The 3‐PMSG group showed reduced oestrous rate (57.89%), pregnancy rate (31.58%) and litter size (1.17) compared, respectively, with 95.45%, 68.18% and 1.67 for 1‐PMSG group (p < 0.05). However, no differences were found in the ovarian morphology between the 1‐PMSG and 3‐PMSG groups (p > 0.05). RNA‐Seq revealed 114 differentially expressed genes (DEGs) in the ovaries of the 3‐PMSG group, among which GCG, FSTL3, TET3 and AQP3 were deemed novel and promising candidate genes for regulating fertility. The present study indicates that the three‐time PMSG treatment dysregulated several ovarian genes, thereby reducing reproductive performance.     

A low protein maternal diet during gestation has negative effects on male fertility markers in rats – A Systematic Review and Meta-analysis

Research indicates that some adult diseases including reproductive pathologies are programmed in utero during foetal development. In particular, maternal low dietary protein, during the most critical developmental periods of male foetal development, may have a detrimental impact on male fertility through direct and epigenetic mechanisms. The aim of our study was to evaluate the impact of a gestational low protein diet on fertility markers in male offspring in rats through a systematic review and meta-analysis. A systematic search using PubMed, and EMBASE databases was performed and two investigators independently screened the 1,703 prospective articles. Eleven articles met the eligibility criteria. Outcome measures were pooled using random-effects models and expressed as mean differences (MDs) at 95% CIs for each study. The results reveal significant reduction in testis weight (MD (mean difference) −0.08 g; −0.12, −0.42; p = .0001), epididymal sperm count (MD −35.34 × 10⁶ cells; −52.15, −18.53; p = .0001), number of Sertoli cells (MD −7.27 × 10⁶ (−13.92, −0.62; p = .03), testosterone (T) concentration (MD −0.29 ng/ml; −0.48, −0.09; p = .004) and luteinising hormone (LH) concentration (MD of −0.24 ng/ml; −0.45, 0.04; p = .02) in comparison with controls. In contrast, follicle-stimulating hormone (FSH) concentration (MD of 0.07 ng/ml; −0.16, 0.29; p = .56) was not significantly different from controls. We conclude that low gestational dietary protein maternal intake potentially negatively impacts fertility in male progeny later in life. The mechanisms of action responsible for these phenomena remain unclear.     

Supplemented stallion seminal plasma can improve impaired motility due to the dilution effect in chilled Asian elephant sperm

The dilution effect and effect of restoring seminal plasma (SP) proportion in diluted semen were determined in chilled Asian elephant sperm. Semen was collected from eight males, and samples with ≥30% motile sperm were used in the study. Tris‐glucose‐egg yolk extender (TE) was used for cooled storage at 4°C for 48 hr. In experiment 1 (n = 18), semen was diluted to 1:1, 1:3, 1:7 and 1:15 with TE (volume per volume). There were no significant changes in sperm viability and sperm with normal acrosome integrity among dilutions, but sperm motility and motility velocities were greater (p < .05) in the 1:1 dilution than those of the 1:7 and 1:15 dilutions at 48 hr of storage. In experiment 2, supplemented SP was derived from elephants and stallions. In experiment 2.1, diluted semen (1:7 dilution) was restored with SP to obtain a 1:2 proportion (n = 8). Sperm motility, viability and sperm with normal acrosome integrity were similar among treatments, but motility velocities were greater (p < .05) with stallion SP at 48 hr of storage. In experiment 2.2, diluted semen (1:15 dilution) was restored with SP to obtain a 1:3 proportion (n = 10). Sperm viability and sperm with normal acrosome integrity were similar among treatments at 48 hr of storage. However, sperm motility and motility velocities were greater (p < .05) with stallion SP than those of others. In conclusion, elephant sperm motility was affected by a dilution effect and restoration of SP proportion with stallion SP, but not with elephant SP, could improve motility in chilled highly diluted sperm.     

Factors influencing pre-ovulatory follicle diameter and weaning-to-ovulation interval in spontaneously ovulating sows in tropical environment

Follicle development and timing of ovulation are indicators of the reproductive performance of sows. The present study aimed to determine factors influencing pre-ovulatory follicle diameter and weaning-to-ovulation interval (WOI) in spontaneously ovulating sows in tropical climates with special emphasis on breed, parity and backfat thickness at weaning. In total, 80 sows were included in the study. Follicle development was determined by using transrectal real-time B-mode ultrasonography every 6 hr after standing oestrus. Weaning-to-oestrous interval (WEI), oestrous-to-ovulation interval (EOI), WOI and the diameter of graafian follicles were investigated in relation to breed, parity number (1, 2–3 and 4–7) and backfat thickness (low, moderate and high) of sows. Overall, WEI, EOI, WOI and the pre-ovulatory follicle diameter were 92.5 ± 21.6 hr, 64.3 ± 19.3 hr, 156.3 ± 29.1 hr and 10.3 ± 2.0 mm, respectively. Pre-ovulatory follicle size was smaller in primiparous sows compared with sows of greater parity, 4–7 (9.7 ± 0.51 and 11.7 ± 0.52 mm, respectively, p < .05). Weaning-to-ovulation interval was positively correlated with WEI (r = 0.75, p < .001) and EOI (r = 0.66, p < .001), but negatively correlated with size of the graafian follicle (r = –0.34, p < .01). Sows with a shorter WEI had a larger pre-ovulatory follicle diameter (at 64 hr after oestrus) (r = –0.37, p < .01). Sows with low backfat thickness had a WOI 23.4 hr longer than those with moderate backfat thickness (p < .05) and 17.6 hr longer than sows with a high backfat thickness (p = .140). The follicle diameter in primiparous sows with high backfat thickness (11.7 ± 1.1 mm) was higher than in those with low (8.9 ± 0.7 mm, p < .05) or moderate (8.6 ± 0.8, p < .05) backfat thickness. In conclusion, factors influencing follicle diameter and WOI in sows included parity number and backfat thickness at weaning. The impact of backfat thickness on follicle diameter, WEI and WOI was most pronounced in primiparous sows.     

The impact of cross‐breeding Egyptian and Italian buffalo on reproductive and productive performance under a subtropical environment

The aim of this study was to investigate the reproductive and productive performance of pure Egyptian (PE) buffaloes and their crosses with Italian buffaloes. In this study, 2969 dairy buffaloes were used (1599 PE; 615 F₁ crosses, 50% PE and 50% Italian buffaloes; and 755 backcross [BC], 75% PE and 25% Italian buffaloes). When compared to PE, the BC and F₁ had a significantly lower incidence of calving difficulty (odds ratio [OR] = 0.18, p < .0001 and .34, p < .0001, respectively) in conjunction with a lesser incidence of stillbirth (OR = 0.06, p < .0001 and 0.43, p < .0001, respectively). Backcross buffaloes were also noted to have a lower rate of not conceived after first insemination (OR = 0.74, p < .0001) in comparison with PE. The cross F₁ buffaloes were superior in terms of productive traits, whereas PE buffaloes were best in most of the reproductive traits (days of non‐pregnant p = .001, service per conception p < .0001 and calf weight p = .01). Although the study results appeared to indicate towards a contrary association between milk production and reproductive traits, BC was similar to F₁ in terms of production and similar to PE in terms of reproductive traits. Thus, the farmers should be encouraged to breed BC animals in their herds for enhancing milk yield to meet with the market demands.     

Resynchronization of ovulation with new and reused intravaginal progesterone‐releasing devices without previous pregnancy diagnosis in Bos taurus indicus cows subjected to timed‐artificial insemination

The study aimed to evaluate pregnancy per artificial insemination (P/AI) of cows subjected to synchronization and resynchronization in ovulation protocols using intravaginal progesterone‐releasing insert (P4) before pregnancy diagnosis (PD) and the relationship of PR with the diameter of preovulatory follicles (ØPOF) before TAI. Cows (n = 378) were distributed into two groups: a resynchronization group with new devices (GRN; n = 185) and resynchronization group with used devices (GRU; n = 193). On Day 0, both groups received a new P4 and estradiol benzoate (EB). On D8, P4 removal + D‐cloprostenol + eCG + estradiol cypionate (EC) was done. On d10, TAI was conducted. On d32, cows were resynchronized and divided into two groups, GRN (n = 185) and GRU (n = 193). The GRN group received a new P4 + EB, and the GRU group received a used P4 + EB. On d40, the P4 was removed + PD. The non‐pregnant cows received D‐cloprostenol + eCG + EC. US was done again on d42 to determine ØPOF before the second TAI. The P/AI of the GRN and GRU groups after synchronization were 56.2% and 57.0% (p = 0.87), respectively, and those after resynchronization were 58.0% and 37.3% (p < 0.008), respectively. The P/AI of the GRN and GRU groups observed after TAI (synchronization + resynchronization) were 81.6% and 73.1%, respectively (p = 0.047). No difference (p = 0.067) in ØPOF between the pregnant and non‐pregnant cows in the GRN was found, whereas the GRU group showed a significant difference (p = 0.003). Resynchronization protocols optimized the P/AI in both groups. New intravaginal devices resulted in greater P/AI and P/AI accumulation in resynchronization as compared with the GRU; the ØPOF was related with P/AI.     

Effects of heat stress on reproductive efficiency in Holstein dairy cattle in the North African arid region

This work aims to study the relationship between variations of the Temperature-Humidity Index (THI) and the parameters of reproduction especially the first conception rate (FCR) and to determine the threshold THI value where cows’ fertility rate dropped in 12 Holstein dairy herds raised in the arid climatic conditions of Tunisia. THI values were calculated over 22 years (1996–2018), and the mean monthly temperature and relative humidity data were obtained from the Meteorological Institute of Tunisia. A total of 20,396 individual records (Insemination and calving dates) were extracted from the Livestock and Pasturing Office (OEP, Tunisia) with regard to the highest THI before breeding, on the breeding day, and after breeding. Statistical analysis was performed using the GLM procedure of SAS software. Results point to the fact that a summer heat stress exists in southeast Tunisia and lasts for 4 months starting from June until September with THI values fluctuating between 73 ± 2.38 and 79 ± 3.01 exceeding, therefore, THI threshold of 72. Increased THI from ≤70 to ≥80 units was associated with drops in conception rate (CR) and fertility rate (FR) of 49% and 45% giving a correlation with the THI of (r = −.72, p < .05) and (r = −.74, p < .05), respectively. When cows were inseminated on extremely hot days (THI ≥ 80) preceded by cooler temperatures, pregnancy by service (P/AI) was 7% points higher than for other cows that were exposed to high temperatures before breeding. The average number of insemination was higher (p < .05) from THI ≤ 70 (2.01) compared to THI ≥ 80 (3.41). Cows calving during an absence of heat stress (THI ≤ 70) have the shortest average calving intervals (CI: 420 ± 15.1 days). Contrastly, calving in the condition of heat stress (THI ≥ 80) has the longest CI (487 ± 12.8 days). For each point increase in the THI value above 67, there is a decrease in the first conception rate by 1.39%. In this particular arid environment, high-yielding Holstein cows’ breeding success is strongly affected by heat stress that takes place just before or after breeding.     

Influence of mastitis metritis agalactia (MMA) on bone and fat metabolism

Mastitis metritis agalactia (MMA) is a common disease in post-partum sows and has a negative effect on sows’ longevity as well as on sows’ and piglets’ health. MMA leads to an inflammatory state. The aim was to investigate the impact of MMA on bone and fat metabolism. The hypothesis was that it is possible to predict MMA by measuring ketone bodies and bone markers. Blood samples from 175 sows were taken within 72 hr after farrowing. Serum was analysed for 25-hydroxyvitamin D (25-(OH)-D), serum crosslaps (CTX-I), osteocalcin (OC), alkaline phosphatase (ALP), calcium (Ca), magnesium (Mg), phosphorus (P), parathyroid hormone (PTH), triglycerides (TG), beta-hydroxybutyric acid (BHB), tumour necrosis factor-alpha (TNF-α) and haptoglobin. Spontaneous urine was collected, and pH value was measured in addition to Ca and P. A proximate analysis of the sows’ diets was performed. Age, litter size, body condition score (BCS) and clinical signs of MMA were recorded for each sow. A multivariable logistic regression was undertaken with disease status (MMA or healthy) as the dependent variable. Significance was accepted at p < .05. MMA sows had a poorer BCS (p < .001) in relation to healthy sows. Age and number of piglets did not differ. MMA sows showed increased serum CTX-I (p = .004) and decreased serum OC (p < .001). Concentrations of P (p = .007), activity of ALP (p = .002) and BHB (p = .019) as well as TNF-α (p < .001) and haptoglobin (p = .048) concentrations were increased in MMA sows. No difference in urinary pH value between MMA and healthy sows was found. Our results are in accordance with the known fact that sows are in an extreme catabolic state peripartum. Bone metabolism in MMA sows is much more negatively affected than in healthy sows post-partum, due to inflammatory processes shown by higher concentrations of pro-inflammatory cytokines.     

Nutritional parameters in the blood of dams during late gestation and immediately after calving,in the umbilical vein at calving,and in the blood of calves immediately following birth in Holstein heifers pregnant with either Holstein or beef breed fetuses

Dairy cattle management lacks consideration of fetal breed, the effect of which on fetal growth and nutrition are unclear. We investigated blood parameters in 12 late-pregnant Holstein heifers with similar (Holstein, n = 5) or different (Japanese Black [n = 4] or F1 cross [n = 3]; Holstein × Japanese Black) fetus breeds and in their umbilical cords and calves. Samples were obtained from dams 1 week before calving (−1 week) and immediately after calving, from the umbilical vein at calving, and from calves immediately after birth. Dams with beef fetuses had higher serum glucose levels (−1 week; p < .05) than those with Holstein fetuses. Plasma total amino acid, total essential amino acid, total nonessential amino acid, and other amino acid concentrations were lower in the umbilical veins of dams with calves of the beef breeds than in those of the Holstein breeds (p < .05). Furthermore, serum glucose and plasma amino acid levels were lower in the beef calves than in the Holstein calves (p < .05). Overall, nutrient supply from dams to beef fetuses was lower than that to Holstein fetuses. Our findings may facilitate feeding management of dairy cattle pregnant with beef breeds for appropriate fetal growth and nutrition.     

Dynamics of sperm DNA fragmentation in raw boar semen and fertility

The aims were to evaluate sperm DNA fragmentation (SDF) in boars through the dispersion of their chromatin in raw semen samples, quantifying the extent of SDF, and to assess dynamic aspects of sperm DNA damage after incubation to obtain the rate of sperm DNA fragmentation (rSDF) under thermal conditions similar to the uterus (37°C) over a period of up to 24 hr and to correlate the reproductive outcome of the sows with the SDF of the boars at ejaculation. The study was performed on a pig‐breeding farm in southern Uruguay. Sixty‐one ejaculates from five of the most frequently used hybrid boars were evaluated. Semen was collected weekly from each of the boars, using the gloved‐hand technique and discarding the jelly‐like fraction of the ejaculate. Fresh semen was kept in a water bath at 37°C and protected from light, and was thereafter processed with Sperm‐Sus‐Halomax^® to evaluate SDF. The smears for time 0 (T0) were made on farm, and thereafter smears were made at the laboratory at 4 hr of obtaining the semen (T4), then every 2 hr (T6, T8, T10, T12) and a final fixation at 24 hr (T24). Differences in SDF were observed among exposure times for all boars (p < .05), but not between T10 and T12 (p = .7751) nor T4 and T24 (p = .9113). In none of the T24 samples, sperm heads could be seen with chromatin dispersion halos. Furthermore, there were differences among boars when comparing sperm rSDF (p < .05). Farrowing rate was not affected by SDF at T0 (r = .38, p = .75), nor was litter size (r = .16, p = .70). With the present experimental conditions, we have not been able to show a relationship between sperm DNA fragmentation at ejaculation and reproductive performance. However, this could be a result of the low number of ejaculates and boars used.     

Activity of selected glycosidases and availability of their substrates in bovine placenta during pregnancy and parturition with and without retained foetal membranes

The activity of glycosidases is crucial for the function and biological activity of proteins conjugated with sugar moieties, which play an important role in adhesion of cells during attachment and detachment of the foetal membranes. The aim of study was to describe the ability of bovine placental tissues to break down O-glycosidic bonds in different glycoproteins by the determination of activity of β-galactosidase, α-l-fucosidase, β-N-acetyl-hexosaminidase and sialidase in early–mid-pregnancy as well as at parturition with released and retained foetal membranes. Moreover, the availability of substrates for these glycosidases in placental homogenates was evaluated. Placental samples were collected from pregnant (2–4 months) cows in slaughterhouse (n = 8) as well as during Caesarean section and divided into released foetal membranes (n = 8) and retained foetal membranes (n = 8). Tissue homogenates were subjected to spectrofluorimetric and spectrophotometric determinations of enzyme activities as well as electrophoretic separations. Enzyme activities expressed changes within examined time with significant (p < .05) differences between pregnancy and physiological parturition in β-N-acetyl-hexosaminidase and α-l-fucosidase in foetal part of placenta while in maternal part only in the latter one. Decreasing tendency in enzyme activity was noticed in foetal part of retained samples in comparison with released ones with significant (p < .05) differences in α-l-fucosidase activity. The analysis of staining of sugar moieties attached to selected proteins depicted availability of sugar molecules in examined tissues, but their patterns differed between samples. In conclusion, sugar moieties in conjugated proteins express changes in the course of pregnancy which is reflected by the alterations in activities of placental glycosidases.