Daily activity measures and milk yield immediately before and after a fertile estrus and during the period of expected return to estrus after insemination in dairy cows.

The objective of this study was to characterize changes in milk yield and other physical measures during a 7-d periestrual period encompassing estrus (d 0) and during a 16-d period of expected return to estrus beginning at d 17 after artificial insemination (AI) until pregnancy status was determined on d 32. Lactating dairy cows milked thrice daily were fitted with CowManager SensOor ear tags (Agis) capable of assessing real-time eating, rumination, resting, high activity (estrus), ear-surface temperature, and heat alerts. Data were uploaded to the cloud, downloaded daily into Excel (Microsoft Corp.) spreadsheets, averaged to produce daily means for each activity, and analyzed as repeated measures relative to estrus or to d 17 after AI. Daily milk was unchanged during the periestrual period but was greater in nonpregnant cows that failed to return to estrus (NP-NR) during d 21 through 26 compared with NP cows that returned to estrus (NP-R) and pregnant (PREG) cows during that same period. Daily ear-surface temperature was greater during d 1 to 3 compared with d 0 and averaged 0.6 to 1.7°C greater from d 17 through 32 in NP-NR cows compared with NP-R and PREG cows. Daily rumination and resting times reached nadirs on d 0, with decreases occurring 48 h before estrus. Both rumination and resting times increased by 25 or 81% on the day after estrus, respectively. Rumination and resting times were less in NP-R cows during d 22 through 26 compared with NP-NR and PREG cows. In contrast, daily eating time was greatest on the day of estrus compared with 3 d before and after estrus. The NP-R cows spent more time eating during d 17 through 32 compared with NP-NR and PREG cows. High activity increased by 97% during 48 h before estrus, peaked at estrus, and decreased to a constant level during d 1 through 3. The NP-R cows had greater high activity on d 22 through 26 compared with NP-NR and PREG cows. We conclude that resting and rumination activity decreased to daily nadirs, whereas eating and high activity peaked on the day of estrus. Fertile estrus was associated with 12% greater high activity, 11% less resting time, and 6% less rumination time. In addition, cows that returned to estrus after AI had greater daily eating and high activity times and less rumination and resting time during the period of expected return to estrus after AI compared with pregnant cows and cows failing to return to estrus.

Transition dairy cow health is associated with first postpartum ovulation risk, metabolic status, milk production, rumination, and physical activity.

Our objective was to determine the association of health status during the first 60 d in milk (DIM) and first postpartum ovulation risk, physical activities recorded by an activity monitor, and metabolic and milk measures in Holstein cows. Late-gestation heifers and close-up dry cows in 1 herd fitted with CowManager SensOors (Agis, Harmelen, the Netherlands) were enrolled in the study 3 wk before expected parturition to assess ear skin temperature and daily rumination, eating, inactivity, and activity times. Blood samples were collected at calving (d 0), and on d 3, 7, and 14 to assess concentrations of free fatty acids, ß-hydroxybutyrate (BHB), calcium, glucose, and haptoglobin. In addition, weekly measures were conducted for body condition, body weight, and progesterone through 63 ± 3 DIM when ovulation was synchronized (GnRH-1 - 7 d - PGF2α - 24 h - PGF2α - 32 h - GnRH-2 - 16 h - artificial insemination). Disease diagnosed in 68 of 160 cows (42.5%) was distributed equally between primiparous (48.5%) and multiparous (51.5%) cows. Cows were classified as diseased when any case of metritis, digestive disorders, ketosis, hypocalcemia, calving problems, mastitis, or lameness occurred during the first 60 DIM. Odds of early ovulation by median postpartum d 33 was 1.92 times greater in healthy than diseased cows. Incidence of individual diseases included metritis (18.8%), digestive disorders (17.5%), ketosis (BHB >10 mg/dL; 11.9%), hypocalcemia (Ca <2.2 mmol/L; 10.6%), calving problems (6.3%), mastitis (3.1%), and lameness (3.1%). Odds of early ovulation were 2.48, 2.65, and 5.72 times greater in healthy cows compared with cows diagnosed with metritis, digestive disorders, or ketosis, respectively. Diseased compared with healthy cows had greater concentrations of free fatty acids, BHB, haptoglobin, greater rectal temperature, and lesser concentration of serum calcium on d 0, 3, 7, and 14 than healthy cows. Plasma glucose was not affected by health status, but was lesser in concentration on d 3, 7, and 14 compared with day of calving. Weekly (calving through 9 wk) body condition scores tended to be and weekly body weights were greater in healthy compared with diseased cows. Activity measures differed by health status during prepartum (d -14 through -1) and postpartum (d 0 through 20) periods except for eating time. Healthy cows spent less time being inactive during both periods compared with diseased cows and had greater postpartum rumination times than diseased cows. Mean daily milk yield during the first 14 wk in milk was greater in healthy than diseased cows by 2.1 ± 0.8 kg. We conclude that disease negatively affects early postpartum ovulation risk and is associated with measurable changes in periparturient physical activity and postpartum metabolic profiles.

Impact of reproductive technologies on dairy food production in the dairy industry.

Reproductive technologies drive the efficiency of managing dairy cows because the lactation cycle of the dairy cow depends on regular calving to renew lactation yields. Achieving timely pregnancies to allow calving every 12-14 months, therefore, is critical in modern dairy production. To meet the demands to produce sufficient milk for fluid and dairy products, various technologies are applied to enhance efficiencies on the dairy farm. Artificial insemination (AI), embryo transfer, ultrasonographic and chemical detection of pregnancy, various monitors that detect or predict estrus, and handheld communication and testing devices allow managers to retrieve information to make cow-side decisions about health and reproductive status. Genomic testing of young potential sires or young heifers is now possible and can provide information about their genetic merit years before any progeny tests can be completed. In many countries, the challenge faced by dairy producers is their ability to afford these technologies in the face of rising feed and labor costs and volatile milk prices received at the farm gate. Government policies often place obstacles, trade barriers, and unfunded mandates that preclude operations from making a modest profit. Unlike nearly all other manufacturing industries, agriculture producers have little control over the price received for their products. Therefore, dairy production is vulnerable to many uncontrolled factors including climate, government policy, economic conditions, and skilled labor shortages. It is clear that the impact of emerging and current reproductive technologies is critical to the management of dairy cattle to produce sufficient milk to meet consumer demands for quality fluid and dairy products.

Pregnancy risk in beef and dairy cows after supplementing semen with transforming growth factor beta-1 at the time of artificial insemination.

Our objective was to determine if the addition of a concentrated human recombinant transforming growth factor beta-1 (TGF) to bovine semen at the time of AI would result in increased risk of pregnancy in beef and dairy cows. Suckled beef cows (n = 1,132) in 11 herds across 2 states and lactating dairy cows (n = 2,208) in one organic-certified herd were enrolled. Beef cows received fixed-time AI (FTAI) following a 7 d CO-Synch + controlled internal drug release estrous synchronization protocol. Dairy cows were inseminated following observation of natural estrus expression. Cows received either no treatment as a control (CON) or 10 ng of TGF in 10 µL added through the cut-end of a thawed straw of semen immediately prior to AI. At the time of FTAI of beef cows, the mean ±â€…SD age was 5.0 ±â€…2.4 yr, BCS was 5.3 ±â€…0.7, and days postpartum was 78.2 ±â€…15.5 d. The overall pregnancy risk (PR) in beef cows was 55.2% to AI and 90.5% season-long. PR in beef cows was not affected (P = 0.27) by the addition of TGF (53.1% vs. 58.1%). Furthermore, there was no difference (P = 0.88) for season-long PR in beef cows that received TGF (91.2% vs. 91.5%). At the time of insemination of dairy cows, the mean ±â€…SD lactation was 3.0 ±â€…1.3 lactations, BCS was 2.9 ±â€…0.3, days in milk was 115.6 ±â€…56.6 d, and cows had received 2.4 ±â€…1.5 inseminations/cow. The overall pregnancy risk to AI in dairy cows was 23.1%. PR to AI for dairy cows was not affected (P = 0.32) by addition of TGF (22.0% vs. 23.8%). In conclusion, PR to AI was not affected by addition of TGF to thawed semen immediately prior to AI in beef or dairy cows.

Seminal plasma is the fluid portion of the ejaculate that is routinely removed or significantly diluted when preparing semen for artificial insemination. Seminal plasma has been shown to elicit changes to the tissues of the uterus at the time of insemination that improves pregnancy outcomes in rodents and swine. Here, we supplemented the molecule of seminal plasma, transforming growth factor beta-1, to semen at the time of artificial insemination in an attempt to improve pregnancy rates in beef and dairy cattle. In total, 3,340 cows were inseminated; half received no treatment, and the other half received a supplementation of transforming growth factor beta-1. We found that supplementing transforming growth factor beta-1 did not improve the pregnancy rate in beef or dairy cattle. We conclude that the pregnancy rate was not affected by the supplementation of transforming growth factor beta-1 to semen at the time of insemination. Future studies should consider the effects of transforming growth factor beta-1 on other pregnancy outcomes, such as calving rate, birth weight, and postnatal growth.

Changes in body condition score from calving to first insemination and milk yield, pregnancy per AI, and pregnancy loss in lactating dairy cows: A meta-analysis.

We determined the association of body condition score (BCS) at calving, at first postpartum artificial insemination (AI), and change in BCS between calving and first AI on pregnancy per AI (P/AI) at 30-45 d, pregnancy loss to 60-85 d, and milk yield in lactating dairy cows. Outcome data were included from 15 studies and 47 herd-year combinations. Additional variables included season of AI, herd, days in milk at first AI, parity, and of mean daily milk yield within 2 wk of first AI. The BCS scale employed was a standard 1-5 scale (1 = severe under conditioning or emaciated and 5 = severe over conditioning) with 0.25 cut points. Presynchronization treatments that included PGF2α and GnRH increased (P < 0.05) the proportion of cows with luteal function before AI compared with PGF2α alone. Compared with no presynchronization treatment those that included PGF2α or PGF2α and GnRH increased (P < 0.05) first P/AI. Cows having BCS ≥2.75 at AI had greater (P < 0.01) first P/AI than cows with BCS <2.75. As BCS at first AI increased, P/AI increased in a linear (P = 0.04) fashion and was greater in cows expressing estrus when BCS at AI was <2.50. Presynchronization had no association with P/AI for cows with BCS at calving <3.00 compared with those with BCS ≥3.00. In contrast, multiparous cows tended (P = 0.06) to have greater P/AI when they calved with BCS ≥3.00 compared with <3.00. Increasing BCS at AI was associated with decreased (P = 0.01) pregnancy loss. Pregnancy per AI did not differ among cows according to the magnitude of prebreeding BCS loss, but more multiparous cows losing more than 0.5 units of BCS tended to have greater pregnancy losses in second-parity cows (P = 0.09) and in cows of third or greater (P < 0.001) parity. Daily milk yields at first AI differed among parities as expected, but a parity by BCS at calving interaction was detected (P = 0.008). Daily milk yield at first AI decreased (P < 0.001) linearly as BCS at AI increased, with an exacerbated greater negative effect during summer. More prebreeding loss in BCS was associated with more (P < 0.05) milk yield in first- and second-parity cows. We concluded that greater BCS at first AI was associated with improved P/AI, but magnitude of prebreeding BCS loss was not associated with P/AI. In contrast, more pregnancy loss was associated with more prebreeding BCS loss in multiparous cows. Cow having lesser BCS at AI and greater prebreeding loss in BCS produced more milk than their herd mates of greater BCS and lesser prebreeding loss in BCS, respectively.

Direct contact may affect the efficacy of stallion exposure in hastening the onset of cyclicity in anestrous mares.

Introducing males to seasonally anestrous females has been shown to increase LH concentrations and hasten the first ovulation in ewes and goat does. Investigation of this sociosexual phenomenon in mares has not been well studied. The objective of this study was to determine if direct or indirect exposure of anestrous mares to a stallion would result in a similar increase in LH and hasten the first ovulation. In late February, mares were stratified by parity and age and assigned randomly to three treatments (n = 7/treatment): (1) DXP (direct exposure; mares housed adjacent to stallion and allowed direct contact for 2 h for 3 d/wk by placing the stallion into a cage in the center of a tease pen); (2) IXP (indirect exposure; mares housed in an adjacent pen to the stallion but not allowed direct contact); and (3) CON (control; mares housed away from stallion and not allowed direct or indirect exposure). During the first, third, and fifth treatment days, blood was collected hourly for 8 h beginning just before treatment initiation for measurement of LH and prolactin (PRL) concentrations. Hormone concentrations were analyzed as repeated measures and time from the first day of treatment to ovulation was analyzed using one-way ANOVA. Interval from treatment initiation to first ovulation did not differ (P > 0.05) among treatments: 36.3 ± 6.7, 42.8 ± 4.2, and 48.3 ± 4.2 d for DXP, IXP, and CON, respectively. When comparing the mares based on social status within treatment and level of direct interaction with the stallion, socially dominant DXP mares ovulated sooner (P < 0.05) than socially subordinate DXP mares (23.8 ± 3.2 and 53.0 ± 6.8 d, respectively). Although LH concentrations did not differ (P > 0.05) among treatments, a significant (P < 0.05) day effect was detected with concentrations being greater on the fifth treatment day compared with the first and third days. Concentrations of PRL were greater (P < 0.05) in IXP compared with DXP and CON, regardless of treatment day. Regardless of treatment, PRL concentrations were greater (P < 0.05) on the third treatment day, compared with the first and fifth days. We conclude that exposure of anestrous mares to a stallion, whether direct or indirect, to anestrous mares failed to elicit the same effects that have been observed in short-day breeders. The effect of stallion exposure on the onset of cyclicity in anestrous mares may be dependent on the duration of direct contact.

Evaluation of seasonal patterns and herd-level traits associated with insemination risk in large dairy herds in Kansas.

Adequate identification of estrus is crucial to achieve satisfactory reproductive performance in dairy farms. Even though several studies evaluated expression and identification of estrus at the cow level, limited data exist regarding estrus identification parameters at the herd level. The objectives of this study were to use data from large dairy farms located in Kansas to describe temporal patterns of insemination risk (IR), and to investigate associations between IR and various herd-level factors. Nine herds that housed lactating cows in dry-lots or free-stalls were used in the study. Data from 2012 to 2017 were extracted and categorized in 21-day intervals in a total of 85 cycles, which were classified by season of the year. Mean (SD) IR was 67.6% (4.0) and increased 0.067% (0.009) for each 21-day cycle during the period evaluated. Annual, semi-annual, and trimestral IR peaks were detected using autoregressive integrated moving average analysis. Most of these variations, however, were considered minimal and likely not of economic concern for commercial herds. Insemination risk was greatest during autumn, but did not differ among winter, spring, and summer. Insemination risk was not associated with herd milk yield per season, incidence risk of mastitis during first 21 days in milk, proportion of primiparous cows in the milking herd, or voluntary waiting period of multiparous cows. Herds that housed lactating dairy cows in dry-lots had IR 2.4 percentage points greater than free-stall herds. In addition, mortality during the first 60 days in milk, and category of voluntary waiting period for primiparous cows were associated with IR. In conclusion, seasonal variability in IR was minimal, with increased values observed during the autumn. Insemination risk was greater for dry-lot than free-stall herds. In addition, reduced mortality of lactating cows by 60 days in milk and longer voluntary waiting period for primiparous cows seem to favor greater IR.

Synchronization and Artificial Insemination Strategies in Dairy Herds.

Timed artificial insemination (AI) programs are commonly used in the dairy industry for lactating cows, but less so in replacement heifers. Excellent programs using combinations of prostaglandin F2α and gonadotropin-releasing hormone in protocols relying on timed AI without detection of estrus or in protocols that combine timed AI with inseminations performed after detected estrus are able to achieve acceptable pregnancy percentages. In herds with excellent estrus detection, timed AI programs serve as a failsafe system to address cows or heifers not yet inseminated after a defined period of estrus detection.

Conception rates of dairy cows following early not-pregnant diagnosis by ultrasonography and subsequent treatments with shortened Ovsynch protocol.

Our objective was to determine the feasibility of prompt reinsemination of dairy cows when diagnosed not pregnant 27-29 days after first-service timed AI (TAI). We assumed that a first-wave dominant follicle was present at that time that would ovulate in response to GnRH once precocious luteal regression was induced after administration of PGF(2alpha). Cows that had not been detected in estrus and reinseminated by Days 27-29 after a first-service TAI were diagnosed not pregnant by ultrasonography. Nonpregnant cows from three herds were assigned randomly to receive either no further treatment until reinsemination (controls; n=189); 25mg i.m. of PGF(2alpha) and then reinsemination according to detected estrus (81 of 108) or at 72-80h after PGF(2alpha) treatment (PGF) in the absence of estrus (27 of 108); or 25mg i.m. of PGF(2alpha) followed by 100 microg i.m. of GnRH 48h later (PGF+GnRH) and then reinsemination after detection of estrus (9 of 160) or at 16-20h after GnRH (151 of 160). Blood samples were collected at the time of the not-pregnant diagnosis and again 48h later. Concentrations of progesterone before treatment with PGF(2alpha) were elevated (<1ng/ml) in 61% of the cows when PGF(2alpha) was administered and 81% of the cows given PGF(2alpha) had low (<1ng/ml) concentrations of progesterone 48h after PGF(2alpha). Treated cows were re-inseminated earlier (P<0.01; 31+/-1days) after first-service TAI than controls (55+/-1days). Conception rates after treatment were not different among treatments: PGF (22%), PGF+GnRH (23%), and control (23%). Average intervals from calving to conception were 22-23 days less (P<0.001) in treated cows than in controls. We concluded that treating nonpregnant cows with PGF(2alpha) on Days 27-29 after insemination produced acceptable conception rates when inseminations were made after detected estrus or when TAI was used after GnRH treatment. Further, both treatments reduced days between first-service TAI and second inseminations, and days from calving to conception.

Associations of adiponectin and fertility estimates in Holstein bulls.

Adiponectin is a pleiotropic regulator of numerous biological functions, including gonadal steroidogenesis and might play a role in sperm structures and functions. The objectives were to: (1) determine associations among serum concentrations of adiponectin, testosterone, and prolactin, and the sperm DNA fragmentation index; (2) associate sperm adiponectin mRNA abundance with estimates of fertility (sire conception rate); and (3) determine sperm protein expression of adiponectin and its receptor in pre- and postcapacitated sperm from Holstein bulls. In experiment 1, biweekly serum concentrations of adiponectin, prolactin, and testosterone were greater (P < 0.05) for high fertility bulls compared with average and low fertility bulls. Furthermore, sperm DNA fragmentation index was greater (P < 0.05) for low fertility compared with both average and high fertility bulls. In experiment 2, samples of sperm from a single collection from commercial Holstein bulls (N = 34) were used to evaluate relative sperm mRNA expression of adiponectin and its receptors, AdipoR1 and AdipoR2, and protein levels of adiponectin and its receptors, AdipoR1 and AdipoR2, in pre- and postcapacitation sperm. The mRNA abundance of adiponectin and its receptors, AdipoR1 and AdipoR2, were greater for high fertility bulls (>2 to ≤4 sire conception rate) compared with average (≥2 to ≤2) and low (>-2 to ≤-4) fertility bulls. Based on the sperm capacitation assay, average fertility bulls had a greater percentage of acrosome-reacted sperm at 5 hours than high and low fertility bulls, whereas high fertility bulls had a greater percentage of acrosome-reacted sperm than low fertility bulls. After capacitation, levels of adiponectin protein were lower in average fertility bulls, AdipoR1 was lower in all fertility groups, and AdipoR2 was lower in average and high fertility bulls. In conclusion, adiponectin and its receptors had vital roles in sperm structural and functional traits and consequently they were associated with fertility. In addition to its role in steroidogenesis and sperm capacitation, adiponectin might be involved in sperm-egg fusion and fertilization.