Impact of postpartum health disorders on metabolic status and reproductive performance of lactating dairy cows.

An extended calving interval (CInt) by extending the voluntary waiting period (VWP) could be associated with altered metabolism in dairy cows. The aim of this study was first to evaluate the effects of VWP on metabolism and body condition during the first 305 d after the first calving in the experiment (calving 1), around the end of the VWP, and during pregnancy (280 d before calving 2). Second, the effects of the VWP on metabolism were determined from 2 wk before until 6 wk after calving 2. Third, individual cow characteristics were used to predict milk production and body condition of cows after different VWP. Holstein-Friesian cows (N = 154, 41 primiparous [PP], 113 multiparous [MP]) were blocked for parity, milk production, and lactation persistency, randomly assigned to a VWP of 50, 125, or 200 d (VWP50, VWP125, or VWP200) and followed from calving 1 until 6 wk after calving 2. In the first 6 wk after calving 1 and from 2 wk before until 6 wk after calving 2, weekly plasma samples were analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate, glucose, insulin, and insulin-like growth factor 1 (IGF-1). From wk 7 after calving 1 until 2 wk before calving 2, insulin and IGF-1 were analyzed every 2 wk. Fat- and protein-corrected milk (FPCM) and body weight (BW) gain were measured weekly. Cows were divided in two parity classes based on calving 1 (PP and MP) and remained in these classes after calving 2. During pregnancy, MP cows in VWP200 had greater plasma insulin and IGF-1 concentration and lower FPCM compared with MP cows in VWP125 (insulin: 18.5 vs. 13.9 µU/mL, CI 13.0-19.7, P < 0.01; IGF-1: 198.5 vs. 175.3 ng/mL ± 5.3, P = 0.04; FPCM: 22.6 vs. 30.0 kg/d ± 0.8, P < 0.01) or VWP50 (insulin: 15.8 µU/mL, P < 0.01; IGF-1: 178.2 ng/mL, P < 0.01; FPCM: 26.6 kg/d, P < 0.01) and had a greater daily BW gain compared with cows in VWP50 (3.6 vs. 2.5 kg/d ± 0.2; P < 0.01). After calving 2, MP cows in VWP200 had greater plasma NEFA concentration (0.41 mmol/liter) compared with MP cows in VWP125 (0.30 mmol/liter, P = 0.04) or VWP50 (0.26 mmol/liter, P < 0.01). For PP cows, the VWP did not affect FPCM or body condition during the first lactation in the experiment, or metabolism after calving 2. Independent of the VWP, higher milk production and lower body condition before insemination were associated with higher milk production and lower body condition at the end of the lactation. Variation in these characteristics among cows could call for an individual approach for an extended VWP.

The objectives of this observational study were to determine the optimal progesteronemia threshold for defining anovulation at 50 days in milk (DIM) in dairy cows and to identify risk factors for this condition.A total of 3,776 cows from 100 Holstein dairy herds were enrolled in this cow-level study.During farm visits, cows were bled at 1-14DIM to quantify ketonemia and glycemia, examined at 30-43 DIM to diagnose purulent vaginal discharge, cytological endometritis, and leukocyte esterase endometritis, and were bled at a 14d interval to quantify progesteronemia.Multiple progesteronemia thresholds were tested to identify the one providing the highest sum of sensitivity and specificity to predict the pregnancy status at first service.The optimal threshold found for defining anovulation at 50DIM was ≤0.90 ng/mL.The final model for risk factors included parity group, season of calving, cytological endometritis, hyperketonemia, hypoglycemia, and the two-way interaction term of hyperketonemia and hypoglycemia.Overall, these results suggest that a progesteronemia threshold of ≤0.9ng/mL could be used to define anovulation at 50 days in milk in dairy cows.

Extending the duration of the voluntary waiting period from 60 to 88 days in cows that received timed artificial insemination after the Double-Ovsynch protocol affected the reproductive performance, herd exit dynamics, and lactation performance of dairy cows

The purpose of this study was to determine the link between insulin-like growth factor 1 (IGF-1), progesterone (PROG), non-esterified fatty acids (NEFAs), β-hydroxybutyrate (BHB), and glucose (GLU) and pregnancy probability after the first artificial insemination (AI) and during the first 100 days in milk (DIM), during the critical transition period. We determined levels of serum IGF-1, PROG, NEFA, BHB, and GLU in Holstein dairy cows via ELISA, using blood samples collected 7 days before parturition (DAP) until 21 days postparturition (DPP). The group was split into cows diagnosed pregnant at 100 DIM (PREG) and those that did not conceive at 100 and 150 DIM (NPREG). Serum IGF-1 and PROG median levels at 7 DAP were significantly higher in PREG vs. NPREG (p = 0.029), the only statistically significant differences across the subgroups. At 7 DAP, IGF-1 levels within the initial group showed a strong negative correlation with PROG (r = -0.693; p = 0.006), while for the PREG subgroup, the IGF-1 levels exhibited a very strong positive correlation with GLU (r = 0.860; p = 0.011) and NEFA (r = 0.872; p = 0.013). IGF-1 and PROG levels detected at 7 DAP may be useful to predict pregnancy at 100 DIM. The positive correlation of NEFA and GLU levels during the transition period demonstrates that the initial group is not in NEB; thus, the NEFA level was not a decisive factor for reproduction success.

Simple SummaryEnhancing the concentration of individual fatty acids (FA) in milk has been, for a long time, a major aim for researchers because certain FAs are linked with several health benefits in humans as well as improving the processing quality of milk products. It is well documented that diet, management regime, and extent of biohydrogenation in the rumen are critical in determining the composition of FA in the milk of dairy cows. This study investigated the effects of including chicory into the traditional feeding regime of ryegrass/white clover, and time of its allocation on milk production, rumen fermentation, and FA composition of milk and rumen digesta of dairy cows. Our findings show that allocation of mature chicory herbage to dairy cows at 50% of their ration modified rumen fermentation and improved both milk yield and the FA profile of the milk. Allocating chicory herbage during the afternoon is a useful strategy that can translate to improved milk production and quality. These findings reflect not just the feasibility of including chicory as part of a feeding regime, but also the role of chicory in rumen fermentation and biohydrogenation.The goals of the current study were to investigate the effects of including chicory (Cichorium intybus L.) into the traditional feeding regime of ryegrass/white clover (Lolium perenne L./Trifolium repens L.), and time of its allocation on milk production, rumen fermentation, and FA composition of milk and rumen digesta of dairy cows. Nine groups of four cows were allocated one of three replicated feeding regimes: (1) ryegrass/white clover only (RGWC), (2) ryegrass/white clover + morning allocation of chicory (CHAM), and (3) ryegrass/white clover + afternoon allocation of chicory (CHPM). One cow per group had a rumen cannulae fitted. Treatment did not affect total grazing time or estimated dry matter intake, but cows ruminated more when fed RGWC than chicory. Allocating chicory in the afternoon elevated milk production compared with RGWC and CHAM. Milk from cows grazing chicory contained greater concentrations of polyunsaturated FA (PUFA) such as C18:3 c9, 12, 15 and C18:2 c9, 12 than those on RGWC. As with milk, rumen digesta concentration of PUFA increased when cows grazed on chicory rather than RGWC, which corresponded with lower concentrations of intermediate vaccenic and biohydrogenation end-product stearic acid for cows grazing on chicory. Mean ruminal pH was lower for cows offered chicory than those on RGWC, reflecting greater rumen concentrations of volatile fatty acids (VFA) for cows fed chicory. Allocating chicory during the afternoon is a useful strategy that can translate to improved milk production. The lower rumen pH, lower concentration of vaccenic and stearic acids, and elevated concentration of PUFA in the rumen of cows fed chicory suggest reduced biohydrogenation and may explain the elevated concentration of PUFA in the milk of cows fed chicory compared with those fed RGWC.

Supplemental feeding with glycerol or propylene glycol of dairy cows in early lactation—Effects on metabolic status, body condition, and milk yield

Extending the voluntary waiting period (VWP) for insemination in dairy cows is of interest as a strategy to reduce the frequency of calving events and inseminate at a moment with fewer fertility problems. Little is known about the calves born from dams with a different VWP followed by a different calving interval (CInt). The objective of the current study was to identify the effect of dam's CInt on body condition, metabolic status, and milk production of their offspring from birth until 100 DIM of the offspring's first lactation. Holstein-Friesian dairy cows (n = 154, 41 primiparous, 113 multiparous) were blocked according to parity, milk yield, and SCC and randomly assigned to a VWP of 50, 125, or 200 d. Female calves (n = 62) from cows with different CInt were monitored from birth until their first calving event as heifer. Certain dams were not successfully inseminated soon after the planned VWP, resulting in differences between the intended VWP and the actual CInt. Calves were regrouped according to their dam's actual CInt (CInt_1: 324-408 d; CInt_2: 409-468 d; CInt_3: 469-586 d). The dam's CInt did not affect calf birth weight. From birth to weaning, the calves born to dams in CInt_1 had a higher plasma nonesterified fatty acids (NEFA) concentration (0.34 mmol/L; CI: 0.30, 0.37) than CInt_2 (0.28 mmol/L; CI: 0.26, 0.31) and CInt_3 (0.26 mmol/L; CI: 0.24, 0.29) calves. Calves born to dams with a shorter CInt (CInt_1) had greater IgG and IgM against keyhole limpet hemocyanin (KLH) than CInt_3 (IgG: 6.05 ± 0.30 vs. 4.64 ± 0.30; IgM: 6.45 ± 0.17 vs. 5.89 ± 0.16, respectively; mean ± SE) before weaning. After weaning till calving, CInt_1 calves tended to have greater plasma NEFA concentration than CInt_3-calves. During the first 100 DIM, a longer CInt of the dams resulted in lower plasma IGF_1 (CInt_2), lower milk lactose (CInt_3), and lower fat- and protein-corrected milk (FPCM; CInt_2) in offspring, compared with shorter CInt of the dams (CInt_1). Collectively, a longer CInt in dams did not affect birth weight of their calves or BW during the weaning or rearing phase. From birth till weaning, a longer CInt in dams resulted in less anti-KLH IgG and lower plasma NEFA concentration in plasma of the calves. During the first lactation of their offspring, a longer CInt in dams can result in a lower plasma IGF_1 and FPCM during the first 100 DIM, although effects were not present in all CInt categories.

Test accuracy of metabolic indicators in predicting decreased fertility in dairy cows

Ovarian superstimulation-ovum pick-up (OPU) technology facilitates the rapid propagation of animals with excellent genetic potential, substantially shortening the interval between generations. Research regarding OPU implementation during the voluntary waiting period (VWP), a phase with potential for maximizing genetic gains in high-yield herds, is limited. We aimed to optimize the dosage and frequency of follicle-stimulating hormone (FSH) injections in postpartum cows to develop an ovarian superstimulation protocol during the VWP for OPU-IVF and assess its effect on milk production and reproductive performance. Cows with more than three parities and within the top 10% of 305-day milk yield were selected as OPU donors. Donor cows were eligible for ovarian superstimulation starting at 40 days in milk (DIM) if they had completed uterine involution and showed no signs of intrauterine infection. Two superstimulation protocols were compared: three injections of 167 IU FSH (FSH-3 group) and five injections of 100 IU FSH (FSH-5 group). Donor cows underwent OPU between DIM 40 and 75, followed by a 10 to 15-d waiting period before artificial insemination (AI). A total of 95 cows (113 OPU sessions) were assigned to the FSH-5 group and 116 cows (135 OPU sessions) to the FSH-3 group. Milk yield data during this period and subsequent reproduction records of these donor cows were compared with those of nondonor cows. The results showed that the FSH-3 group achieved better results, including more 2 to 6-mm follicles and 6 to 10-mm follicles, a greater total follicle count, and greater recovery of cumulus-oocyte complexes (P < 0.05). Additionally, the FSH-3 group produced more greater-grade oocytes, resulting in better production of blastocysts (P < 0.05). Although the application of superstimulation-OPU to donor cows during the VWP delayed the DIM of the first AI (P < 0.05), it significantly increased the pregnancy rate (P < 0.05) and did not affect the subsequent reproductive performance of the parity. Milk yield temporarily declined on the day of OPU, but it gradually recovered. In summary, the FSH-3 protocol generated an average of more than four embryos per cow during the VWP without compromising reproductive performance, including service and pregnancy rates. These results suggest that the FSH-3 protocol is an effective strategy for obtaining embryos from high-yield cows during the VWP, enhancing genetic gain and accelerating breeding programs with minimal effect on future fertility.

Effect of a targeted reproductive management program based on automated detection of estrus during the voluntary waiting period on reproductive performance of lactating dairy cows

This study was conducted to determine the prevalence of Listeria spp . in milk and feces of dairy cows as well as stool of pregnant women in Sharkia and Dakahlia Governorates, Egypt. Three hundred and fifty samples including; normal raw milk (n=200), mastitis milk (n=50), feces of dairy cattle (n=50) and stool of pregnant women (n=50) were randomly collected. Listeria spp. were isolated on Oxford agar and then subjected to biochemical and molecular identification. The overall isolation rate of Listeria spp. was 16%. The prevalence rates of Listeria monocytogenes were 8%, 4%, 2% and 4% in feces of dairy cows, normal milk, mastitis milk and stool of pregnant women, respectively. The prevalence of L. ivanovii and L. welshimeri in milk of dairy cows were 6% and 4%, respectively. L. monocytogenes isolates were molecularly confirmed to the species level by amplification of 16S rRNA gene. The distribution of internalin A (inlA) and internalin B (inlB) was determined in 15 identified L. monocytogenes isolates. The overall prevalence of inlA gene and inlB gene in L. monocytogenes isolates from different sources were 80% and 40%, respectively. Two L. monocytogenes isolates from normal raw milk and feces of dairy cows didn’t harbor both inlA and inlB genes. Listeria spp. isolated from normal milk, feces, mastitis milk and stool of pregnant women, potentially can cause human illness and abortion in pregnant women. Internalin (A&B) genes are considered the best indicator for virulence determination of L. monocytogenes isolated from different sources.

The primary objective of this randomized controlled experiment was to evaluate the insemination dynamic and reproductive performance of cows managed with a targeted reproductive management (TRM) program designed to prioritize artificial insemination (AI) at detected estrus (AIE) and optimize timing of AI by grouping cows based on detection of estrus during the voluntary waiting period (VWP). Our secondary objective was to evaluate reproductive outcomes for cows with or without estrus during the VWP. Lactating Holstein cows fitted with an ear-attached sensor for detection of estrus were randomly assigned to a TRM treatment that prioritized AIE based on detection of estrus during the VWP (TP-AIE; n = 488), a non-TRM treatment that prioritized AIE (P-AIE; n = 489), or an all timed AI (TAI) treatment with extended VWP (ALL-TAI; n = 491). In TP-AIE, cows with or without automated estrus alerts (AEA) recorded during the VWP received AIE if detected in estrus for at least 31 ± 3 or 17 ± 3 d after a 49 d VWP, respectively. Cows not AIE with or without AEA during the VWP received TAI after Ovsynch with progesterone supplementation and 2 PGF2α treatments (P4-Ov) at 90 ± 3 or 74 ± 3 d in milk (DIM), respectively. In P-AIE, cows received AIE if detected in estrus for 24 ± 3 d after a 49 d VWP, and if not AIE received TAI at 83 ± 3 DIM after P4-Ov. In ALL-TAI, cows received TAI at 83 ± 3 DIM after a Double-Ovsynch protocol. Data were analyzed by logistic and Cox's proportional hazard regression. The proportion of cows AIE did not differ for TP-AIE (71.0%) and P-AIE (74.6%). Overall P/AI at 39 d after first service was greater for the ALL-TAI (47.6%) than for the P-AIE (40.2%) and TP-AIE (39.5%) treatments. The hazard of pregnancy up to 150 DIM was greater for cows in TP-AIE (hazard ratio = 1.2; 95% confidence interval: 1.1-1.4) and P-AIE (hazard ratio = 1.2; 95% confidence interval: 1.1-1.4) than for cows in the ALL-TAI treatment which resulted in median time to pregnancy of 89, 89, and 107 d. Conversely, the proportion of cows pregnant at 150 DIM did not differ (ALL-TAI 78.5%, P-AIE 76.3%, TP-AIE 76.0%). Except for a few outcomes for which no difference was observed, cows detected in estrus during the VWP had better performance than cows not detected in estrus. Cows with AEA during the VWP were more likely to receive AIE, had greater P/AI, and greater pregnancy rate up to 150 DIM regardless of first service management. We conclude that a TRM program designed to prioritize AIE by grouping cows based on detection of estrus during the VWP was an effective strategy to submit cows for first service resulting in similar or improved performance than a non-TRM program that prioritized AIE or an all-TAI program with extended VWP. Also, AEA recorded during the VWP might be used as a strategy for identifying subgroups of cows with different reproductive performance.

Metabolic status of dairy cows influences reproductive tract and fertility in postpartum period. A study with 89 estrus dairy cows was performed to study the relationships among the concentration of metabolic hormones and ultrasound traits of genital system in heat dairy cows. Cows in estrus were examined with transrectal ultrasonography and palpation, and their blood samples were collected nearly to the time of insemination. Ultrasonography images of the uterine horns, ovarian follicles, and corpus luteum were recorded and interpreted. The concentration of insulin-like growth factor-1 (IGF-1), non-esterified fatty acids (NEFA), and β-hydroxyl butyric acid (BHBA) was determined in the serum samples of estrus cows. This study indicated that the correlation between ultrasound traits of uterus and metabolite hormones was not significant at the clean test in estrus dairy cows. Moreover, there was no relationship between serum level of IGF-1, NEFA, and BHBA with either dominant follicle diameter or existence of corpus luteum (CL). Significant association between ultrasound properties of the uterus and ovaries and metabolic hormone (IGF-1, NEFA, and BHBA) concentrations did not reveal in estrus dairy cows at day 28 ± 3 postpartum.

Hepatic mRNA expression of acid labile subunit and deiodinase 1 differs between cows selected for high versus low concentrations of insulin-like growth factor 1 in late pregnancy

Periparturient Changes in Secretion and Mammary Uptake of Insulin and in Concentrations of Insulin and Insulin-Like Growth Factors in Milk of Dairy Cows