Percentage Of Cows Research Articles

Comparison of diagnostic methods for uterine health in dairy cattle on different days postpartum

BackgroundUterine health status is a key factor for dairy management.MethodsThe uteri of 28 Holstein cows were assessed weekly by three different methods: ultrasonography (UT), Metricheck device (MT) and cytobrush (CYT),...

Intrafollicular lipopolysaccharide injection delays ovulation in cows

The aim of this study was to evaluate effects of intra-follicular (i.f.) treatment with lipopolysaccharide (LPS) on follicular and luteal development in cows. There were 18 non-lactating cows assigned to two groups to address this aim: control group (n = 9), which received an i.f. injection of saline; and LPS group (n = 9), which received an i.f. injection of 1 μg of LPS per mL of follicular fluid. Cows were treated with an intravaginal P4 releasing device (IVD) and estradiol benzoate on D0. On D4 and D5 cows were treated with cloprostenol sodium and on D7 the IVD was removed. At 12 h after IVD removal, cows were administered the i.f. injection of LPS or saline. After administration of these treatments, follicular development was evaluated every 12 h until ovulation. The LPS treatment increased blood flow in pre-ovulatory follicles (P = 0.05). Follicle growth was reduced by LPS injection (P < 0.02) resulting a longer period to the time of ovulation for cows in the LPS than control group (P = 0.03). The percentage of cows having ovulations was less for the LPS than control group (P = 0.03). The diameter of the CL, CL blood flow and P4 concentrations 5 and 12 days after ovulation did not differ between groups (P> 0.05). In conclusion, intra-follicular treatment with LPS resulted in a decreased rate of follicle growth, delayed timing of ovulations and a lesser number of cows having ovulations.

IMPACT OF INTRAVAGINAL PROBIOTICS INOCULATION ON REPRODUCTIVE PERFORMANCE OF HOLSTEIN DAIRY CATTLE DURING TRANSITION PERIOD

In this study we tested the hypothesis that intravaginal infusions of lactic acid bacteria (LAB) around calving would improve uterine involution and reproductive performance of dairy cows. The probiotic culture used in this study was a mixture of 2 LAB strains isolated previously from the vaginal tract of healthy pregnant heifers. Forty pregnant 2nd lactation dairy cows 2 wk before the expected day of calving were assigned to one of 2 groups, first group was the control group (C) receiving 1 mL of media only, and the 2nd group was the treated group (T) receiving 1 mL of media enriched with probiotic bacteria at 1010 to 1012 cfu / treatment. Intravaginal infusions were performed once during wk −2, −1, +1, +2, +3, and +4 relative to parturition with probiotic bacteria. All cows were observed for reproductive performance and reproductive diseases until next conception using ultrasonography. The incidence of uterine infections in the multiparous cows were measured. Days open, conception rate at 1st, 2nd and 3rd insemination and repeat breeders (%) were calculated. Incidence of purulent and foul-smelling discharges on +1, +2, +3 and +4 wk relative to parturition and numbers of cows in the clean-up program were measured, cervix diameters (C.D) and uterine horn diameters (U.H.D) were measured at days (22-29) and days (38-45) postpartum. Ovarian structures and endometritis were determined. Results revealed that uterine and cervical involution of postpartum dairy cows were earlier in cows treated with LAB. Cows showed purulent and fowl smelling discharges are fewer in number in treated group than control, also data showed that percentage of cows in the cleanup program was higher in the control group (40%) than in the treated group (20%). The averaged insemination number per conception was lesser in the treated group (2.55) than control (4). The conception rate at 1st insemination and 3rd insemination was higher in the treated group (35%, 20%) than in control one (25%, 10%), and the %of repeated breeder cows was lower in the treated group (30%) than control (40%), finally days open in the treated group (116.4) was much lower than in the control (154.72). Therefore it can be conclude that, intravaginal treatment of transition dairy cows with a mixture of lactic acid bacteria (LAB) could improve uterine involution, lower the incidence rates of uterine infections, and improve the reproductive performance.

Assessment of Variability in Yearlong Relative Loose Mineral Intake and Range Cow Productivity in North American Northern Great Plains

Background: Appraisal of the effectiveness of supplementary mineral nutrition in grazing range cattle to promote growth and reproduction is lacking due to an inability of methods to measure cause and effect relationships, record variability of grazed diet mineral concentrations, evaluation of cattle presence at mineral feeder, measurement of shifting requirements due to changes in physiological stage and a lack of accurate mineral supplement intake quantification. Methods and findings: This study evaluated cattle presence at mineral feeder, relative mineral intake and its association with calf Body Weight (BW) at birth and weaning, cow BW change and calving interval (d). Cross-bred cows grazed native range with access to mineral feeders containing 34% salt, 57% macro/microminerals, 9% distillers’ grains and 1% titanium (Ti) as titanium dioxide for sixteen months from August 2010 to November 2011. Motion activated cameras were used to record ear tags of 106 cross-bred cows as their heads approached the open range mineral tub. Mineral feeder tubs were placed near water sources to promote contact of cattle with mineral supply. Rectal fecal samples were collected at 1 or 2-months interval and were analyzed for Ti content. Filtered samples were transferred to 15 ml falcon tubes for Ti analysis using inductively-coupled plasma mass spectrometry analytical technique (USFS Bozeman Fish Technology Center, Bozeman, Montana, USA). It was assumed that fecal Ti was positively related to mineral consumption. Cows were assigned to one of four fecal Ti concentration clusters based on their mean Ti concentration: (1) low (3 to 5 ppm, n=23), (2) mid-low (5 to 6 ppm, n=36), (3) mid-high (6 to 7 ppm, n=26) and (4) high (7 to 11 ppm, n=21). Data were analyzed using Proc Mixed SAS (SAS Inst., Inc., Cary, NC) and a model including Ti cluster and cow age (2 to 11 years) as a covariate. The percent of cows at mineral tub each day differed (p<0.01) by season. In late growing season (July-October), 48 ± 3.9% of herd visited the tub daily compared to 31 ± 3.4% in fall and winter dormancy (November-March) and 27 ± 4.1% during spring growth (April-June). Average consumption based on amount of mineral fed was greatest (p<0.01) during forage dormancy and spring growth (53 ± 3.8 g hd-1 d-1) and lowest during late growing season (38 ± 3.5 g hd-1 d-1). Regardless of fecal Ti concentration, all groups had similar 2011 calf BW at birth (p<0.22) and weaning (p=0.89), cow BW change (2010-2011) p=0.71 and 2010 to 2011 and 2011 to 2012 calving interval (p=0.85). In addition, mean fecal Ti in 18 non-pregnant and 88 pregnant cows were 6.22 ppm and 5.95 ppm (p=0.68), indicating no differences in mineral consumption between non-pregnant and pregnant cows. Conclusion: During the late growing season, cow activity at a mineral tub was highest but mineral disappearance from the tub was the lowest. Range in mean fecal Ti of individual cows represented a 3-fold divergence in Ti dilution indicating a magnitude difference in mineral consumption. If mineral consumption was a primary production limitation in the year of this study, then differences would be expected for the production traits evaluated influenced by predicted mineral intake.

ЗАБОЛЕВАНИЯ МОЛОЧНОЙ ЖЕЛЕЗЫ И ПОЛОВЫХ ОРГАНОВ КОРОВ В ПОСЛЕРОДОВЫЙ ПЕРИОД

Mastitis-endometritis syndrome at the beginning of lactation in cows is one of the most economically significant diseases of dairy cattle, since the measures of treatment and prevention are financially costly and, very importantly, difficult to recover. In this regard, further study of the relationship of these diseases in the postpartum period is of great practical importance. In the course of work, the percentage of cows with placenta retention, endometritis and mastitis, separately, as well as jointly occurring in the postpartum period (the first month after calving) was determined. It was found that of 590 calving cows and heifers in the first month after calving revealed 322 or 54.5% of animals with postpartum pathology, including endometritis, detention of the afterbirth and mastitis. Among postpartum diseases of cows in the surveyed economy dominated by endometritis (43.2% of the number of calving cows) with various forms of inflammation of the endometrium. Detention of placenta and mastitis amounted to 20.0% and 17.8% of the number of calving animals or 2.2 and 2.4 times less compared to endometritis. The analysis of the results found that the number of postpartum diseases averaged 0.8 per calving cow or 1.5 per sick cow (P>0.999). A direct average relationship between the diseases of cows in the postpartum period of endometritis and mastitis was established, with a correlation coefficient (r) of 0.48; a direct strong relationship between endometritis and placenta retention was 0.83 at P>0.999.

Second prostaglandin F2α treatment during Ovsynch protocol does not improve fertility outcomes in dairy cows.

The objective of this study was to evaluate the effect of a second prostaglandin F2α (PGF2α) treatment during Ovsynch on luteal regression and fertility in dairy cows, compared with standard Ovsynch. The study was conducted on 111 Holstein Friesian multiparous cows on commercial dairy farm. The cows in the experimental group (n=48) received two treatments of PGF2α 24 hours apart during Ovsynch. The cows in the control group (n=63) were synchronized with standard Ovsynch. To assess the progesterone (P4) concentration blood samples were collected at the day of PGF2α treatment and at the 2nd GnRH treatment. Pregnancy was evaluated by ultrasound examination 37-40 days after timed artificial insemination (TAI) by ultrasound. Cows diagnosed pregnant were re-examined between days 70-80 after TAI. The percentage of cows with complete corpus luteum (CL) regression (P4⟨0.5 ng/ml at the time of the 2nd GnRH treatment) was 89.6 % after two PGF2α treatments and 88.9 % after one PGF2α treatment. There were no statistically significant differences (p>0.05) in the pregnancies per artificial insemination (P/AI) between the experimental and control group (P/AI). However, the pregnancy loss rate was lower in cows receiving two PGF2α treatments than in the control animals (0.0 % vs. 6.4 %; p⟨0.05). In conclusion, the second PGF2α treatment during Ovsynch protocol had no significant effect on CL regression and P/AI in dairy cows. The pregnancy losses until days 75-80 after TAI were significantly lower after two PGF2α treatments than after one PGF2α treatment.

The combination of β-carotene and vitamins improve the pregnancy rate at first fixed-time artificial insemination in grazing beef cows

The aim of this experiment was to evaluate the effects of feeding the combination of β-carotene and vitamins (ADE and biotin) on reproductive performance of grazing beef cows. A total of 430 suckled multiparous Nellore cows (Bos indicus, initial body weigh = 417 ± 58 kg) were used in a randomized block design. At the beginning of the trial (30 days before fixed-time artificial insemination - FTAI) animals were assigned according to calving date, body condition score (BCS) and blocked according to blood β-carotene concentration. Treatments were: Control (mineral supplement: no β-carotene and vitamins) and Treated (combination of 500 mg β-carotene, 70,000 IU Vit. A, 10,000 IU Vit. D3, 500 mg Vit. E and 10 mg biotin/cow/day into the mineral supplement). Animals were synchronized using estradiol/progesterone (E2/P4) based protocol. Pregnancy rate was evaluated 30 days after FTAI and 30 days after the end of breeding season. No difference in the cyclicity rate [presence of corpus luteum (CL); P = 0.31] before FTAI synchronization protocol on day 11 was observed. The percentage of cows in estrus between P4 device removal and FTAI did not differ between groups at first (P = 0.39) and second FTAI (P = 0.18). The combination of β-carotene and vitamins into the mineral supplement increased the pregnancy rate at first FTAI: Control: 57.6% (125/217) vs. Treated: 66.7% (142/213; P = 0.04) but not at second FTAI: Control: 55.4% (51/92) vs. Treated: 50.7% (36/71; P = 0.52) and to the natural mating: Control: 46.3% (19/41) vs. Treated: 31.4% (11/35; P = 0.07) or at the end of breeding season Control: 89.9% (195/217) vs. Treated: 88.7% (189/213; P = 0.77). In the non-pregnant cows, the occurrence of CL did not differ between groups at first (P = 0.93) and second (P = 0.89) pregnancy diagnostics. Treated cows had greater embryo thoracic width at second pregnancy diagnostic compared to Control cows (P = 0.003). Positive correlations were observed between the pregnancy rate at first FTAI (day 30) and BCS at day 11 (P = 0.05), largest follicle at day 2 (P = 0.01), and blood β-carotene concentration on day -11 (P = 0.06) of FTAI protocol. Including the combination of β-carotene, vitamins ADE and biotin into mineral supplement for grazing beef cows increases the conception rate at first FTAI and can be a tool to optimize the reproductive performance.

Assessment of acoustic pulse therapy (APT), a non-antibiotic treatment for dairy cows with clinical and subclinical mastitis.

Clinical and subclinical mastitis affects 30% of cows and is regarded as the most significant economic burden on the dairy farm reducing milk yield and quality and increasing culling rate. A proprietary Acoustic Pulse Therapy (APT) device was developed specifically for treating dairy cows. The APT device was designed to produce deep penetrating acoustic pulses that are distributed over a large treated area at a therapeutic level. This paper presents findings from a clinical assessment of this technology for the treatment of dairy cows with subclinical and clinical mastitis. In subclinical mastitis, a group of 116 cows from 3 herds were identified with subclinical intramammary infection and enrolled in the study; 78 cows were assigned to the treatment group and 38 cows to the control group. Significant differences (P<0.001) were found where 70.5% of the cows in the treatment group returned to normal milk production, compared with only 18.4% of the control group. Daily milk yields of the treated cows increased significantly (P<0.05) and the percentage of cows with log somatic cell count under 5.6 cells/mL was significantly higher (P<0.001). Milk of the infected quarters appeared normal with lactose greater than 4.8%, but this difference was not significant. Of the treated cows with identified bacteria, 52.6% of the quarters were cured, while in the control group only 25.0% (P<0.001). Specifically, all cows identified with Escherichia coli in the treatment group were cured, with 66.6% cured with no intervention in the control. Spontaneous cure of glands infected with coagulase negative staphylococci (CNS) and Streptococci was low while treatment successfully increased the cure of CNS from 13.3% to 53.8% and that of Streptococci from 18.2% to 36.4%. Of the 4 cows identified with Staphylococcus aureus, 3 were cured. The clinical mastitis study group included 29 infected cows that were submitted either to a gold standard antibiotic treatment subgroup of 16 cows (n = 16) or to an APT treatment subgroup of 13 cows (n = 13). A cure of 18.7% was shown for the antibiotic treatment, of which logSCC returned to <5.6 cell/mL and 56.2% were culled. A cure of 76.9% was shown for the APT treatment with only one cow culled (7.7%).

Eficiencia reproductiva de Ovsynch + CIDR en vacas Holstein bajo un esquema de inseminación artificial a tiempo fijo en el norte de México

Se evaluó el uso de Ovsynch más dispositivo intravaginal de liberación controlada de progesterona (CIDR) en vacas altas productoras. El estudio se llevó en la Comarca Lagunera (25° 44´ N, 103° 10´ O a 1,111 msnm) durante diciembre y enero. Las vacas (n=100) se pre-sincronizaron con dos inyecciones de PGF2α a los 35 y 47 días posparto y asignadas a dos tratamientos (n= 50): 1) El grupo OV recibió el protocolo Ovsynch: 100 μg de GnRH (i.m.; día 1), 25 mg de PGF2α (i.m.; día 7) y 100 μg GnRH (i.m.; día 9); 2) El grupo (OV+C) recibió el protocolo Ovsynch más un CIDR (1.38 g), retirado siete días después. Todas las vacas se expusieron a un protocolo de inseminación artificial a tiempo fijo (IATF; 16 a 20 h posteriores a la última inyección). Se registró tanto el porcentaje de preñez, el número de vacas repitiendo celo considerando dos periodos (≤24 y ≥25 días post-inseminación), así como los días de retorno al celo. Mientras que no existió diferencia entre grupos para tasa de preñez (OV= 28 %, OV+C= 32 %; P&gt;0.05), el porcentaje de vacas que manifestaron celo después de la IATF difirió (P&lt;0.05) entre tratamientos durante los dos periodos estudiados, 28 vs 62 % ≤24 días; 69 vs 35 % ≥25 días; OV y OV+C, respectivamente. El promedio de días en que repitieron celo fue menor (P&lt;0.05) en el OV+C (25 ± 1.6 vs 30 ± 1.3). El tratamiento Ovsynch+CIDR no mejoró la tasa de preñez; sin embargo, redujo la latencia en el retorno al celo, destacando como una alternativa para disminuir los días a la siguiente IA, y potencialmente para mejorar la eficiencia reproductiva y el retorno económico del hato lechero.

Spatial Distribution of Preantral Follicles in the Equine Ovary

The aim of this study was to evaluate effects of intra-follicular (i.f.) treatment with lipopolysaccharide (LPS) on follicular and luteal development in cows. There were 18 non-lactating cows assigned to two groups to address this aim: control group (n = 9), which received an i.f. injection of saline; and LPS group (n = 9), which received an i.f. injection of 1 μg of LPS per mL of follicular fluid. Cows were treated with an intravaginal P4 releasing device (IVD) and estradiol benzoate on D0. On D4 and D5 cows were treated with cloprostenol sodium and on D7 the IVD was removed. At 12 h after IVD removal, cows were administered the i.f. injection of LPS or saline. After administration of these treatments, follicular development was evaluated every 12 h until ovulation. The LPS treatment increased blood flow in pre-ovulatory follicles (P = 0.05). Follicle growth was reduced by LPS injection (P < 0.02) resulting a longer period to the time of ovulation for cows in the LPS than control group (P = 0.03). The percentage of cows having ovulations was less for the LPS than control group (P = 0.03). The diameter of the CL, CL blood flow and P4 concentrations 5 and 12 days after ovulation did not differ between groups (P> 0.05). In conclusion, intra-follicular treatment with LPS resulted in a decreased rate of follicle growth, delayed timing of ovulations and a lesser number of cows having ovulations.

An investigation on the possibility of using eCG for presynchronization prior to ovsynch in dairy cow

Background: Presynchronization could enhance fertility in timed breeding programs. The best presynchronization method has to justify biological requirements and to provide practical and economic advantages. OBJECTIVES: Present study investigated the effectiveness of presynchronization with equine chorionic gonadotropin (eCG) before ovsynch (eCG-ovsynch) compared to conventional presynch-ovsynch program (2PG-ovsynch) in lactating cows. METHODS: Healthy lactating cyclic Holstein cows (n=110) without any particular pre, peri and post parturient problems were selected for this study. The first insemination following timed breeding program was conducted at 57 days after calving. Ovsynch (timed breeding program) consisted of two GnRH analogue injections, at 7 days before and 56 hours after PG, followed by insemination, 16 hours after the second GnRH. Cows in 2PG-Ovsynch group (n=55) received two PGs, 14 days apart, followed by ovsynch program 12 days later. Cows in eCG-Ovsynch group (n=55) received eCG (500 IU, IM), 84 hours before ovsynch program. Pregnancy was confirmed 40 d after insemination by rectal palpation. Progesterone concentrations were evaluated at presynchronization, at the first GnRH and at PG of ovsynch program. RESULTS: The respective first service conception rates, days open and service per conception were similar between 2PG-ovsynch (45.45%; 94.0±6.30 days; 1.95) and eCG-ovsynch (40%; 90.1±4.58 days; 1.81) groups (p>0.05). The percentage of cows with high progesterone concentrations increased significantly from the first GnRH (38.2%) until PG (85.4%) in eCG-ovsynch group (p<0.05). The percentage of cows with high progesterone concentrations at the time of PG injection of ovsynch program was greater in eCG-ovsynch (85.4%) compared to 2PG-ovsynch (69%). CONCLUSIONS: Administration of eCG (500 IU), 84 hours prior to ovsynch could optimize timed breeding program biologically, practically and economically in lactating dairy cows.

Relationship between herd size and measures of animal welfare on dairy cattle farms with freestall housing in Germany

The objective of this study was to examine the association of herd size with animal welfare in dairy cattle herds. Therefore, 80 conventional dairy cattle farms were classified by the number of cows into 4 herd size classes, C1 (<100 cows), C2 (100-299 cows), C3 (300-499 cows), and C4 (≥500 cows), and assessed using multiple animal-based measures of the Welfare Quality Assessment protocol for dairy cattle. Data were recorded from April 2014 to September 2016 by an experienced single assessor in northern Germany. Each farm was visited 2 times at an interval of 6 mo (summer period and winter period) to avoid seasonal effects on the outcome. The average herd size was 383 ± 356 Holstein-Friesian cows (range 45 to 1,629). Only farms with freestall (cubicle) housing and a maximum of 6 h access to pasture per day were included in the study. Data were statistically analyzed using a generalized linear mixed model. None of the farms reached the highest overall rating of "excellent." The majority of the farms were classified as "enhanced" (30%) or "acceptable" (66%), and at 6 assessments the farms were rated as "not classified" (4%). Regarding single indicators, mean trough length per cow, percentage of cows with nasal discharge, and vulvar discharge increased with increasing herd size, whereas it was vice versa for displacements of cows. Percentage of lean cows, percentage of dirty lower legs, and duration of the process of lying down showed a curvilinear relationship with the number of cows per farm. Herd size was not associated with any other measures of the Welfare Quality protocol. In conclusion, herd size effects were small, and consequently herd size cannot be considered as a feasible indicator of the on-farm animal welfare level. Housing conditions and management practices seem to have a greater effect on animal welfare than the number of dairy cows per farm.

Vitamin A concentrations in dairy cows of Thessaloniki 's county

Avitaminosis A is stilla serius metabolic problem for cattle in Greece. The purpose of this research work was to investigate the blood vitamin A concentrations in dairy cows of Thessaloniki 's area. The research was conducted in 51 dairy cow farms; whole blood samples from 10 female adult animals per farm, as well as samples from the feedstuffs in use, were collected. Of the total 510 examined cows, 38% showed lower than normal vitamin A concentration in blood plasma (&lt;0,20 μ^ηιΐ), 15% marginal (0,20-0,24 μg/ml) and 47% normal concentration values (&gt;0,25 μg/ml). It should be noted that, of the total 510 examined cows only 7% showed extremely deficient concentration of vitamin A in blood plasma (&lt;0,05 μg/ml). The determination of total carotene concentration in feedstuffs from those farms, indicated that only the corn ensilage and the fresh grass contained the appropriate amount of carotene. The above results, in correlation with corresponding results from previous researches, indicate that there is a decrease in the percentage of cows with subnormal vitamin A concentration. This may be attributed to more frequent use of corn silage, and more systematic addition of vitamin A in concentrate feeds. This research provides evidence that some dairy cow genotypes, with high milk yields, may balance their needs only by vitamin A supplementation, it means that maybe the ration carotenes alone are no sufficient vitamin A source for these cows. Furthermore, the results of this research suggest that the absence of a regulator mechanism for the carotene concentration in the cattle blood plasma may be possible.

Use of prostaglandin F2α as ovulatory stimulus for synchronizing dairy cattle

The aim of this study was to evaluate if prostaglandin F2α (PGF) can be used to induce ovulation in a GnRH-progesterone based protocol. In Experiment 1 crossbred dairy cows (n=32) were synchronized with a progesterone-GnRH based protocol for seven days, where the luteolytic dose of 150μg PGF was given 24h prior progesterone device removal (CIDR). On Day 8 cows were separated into two groups to receive: 1) 2mL of Saline (Control Group, n=15) or 2) 150μg of PGF (PGF Group, n=17). Ovulation rate was higher in the PGF than Control group (100% vs 53.3%, P=0.001, Odds ratio=30.88). The percentage of cows that ovulated synchronously tended to be higher in the PGF than Control group (P=0.1, Odds ratio=9.6). Experiment 2 was performed in a cross-over (3×3) design. Crossbred dairy cows (n=25) received a CIDR for seven days and GnRH on Day 0. Seven days later 150μg of PGF was given and the progesterone device was removed, and 24h later cows were distributed into three groups to receive: 1) 2mL of Saline (Control Group, n=25), 2) 150μg of PGF (PGF Group, n=25) or 3) 1mg of ECP (ECP Group, n=23). Diameter of ovulatory follicle was larger in the PGF and Control than ECP Group (P=0.002, Effect size>4.0). Synchronized ovulation rate (between 72 and 96h after CIDR removal) tended to be higher in PGF group in Control group (P=0.1, Odds ratio=0.35). Results suggest that PGF is equally efficient to ECP to induce synchronized ovulation in dairy cows subjected to progesterone-GnRH based protocols.

Effect of dose and timing of prostaglandin F2α treatments during a Resynch protocol on luteal regression and fertility to timed artificial insemination in lactating Holstein cows

Our objective was to evaluate the effect of a second PGF2α treatment (25 mg of dinoprost) or a double dose of PGF2α (50 mg of dinoprost) during a Resynch protocol on luteal regression and pregnancies per artificial insemination (P/AI) in lactating dairy cows. Lactating Holstein cows (n = 1,100) were randomly assigned at a nonpregnancy diagnosis to receive (1) Ovsynch (control: 100 µg of GnRH; 7 d, 25 mg of PGF2α; 56 h, 100 µg of GnRH), (2) Ovsynch with a second PGF2α treatment (GPPG: 100 µg of GnRH; 7 d, 25 mg of PGF2α; 24 h, 25 mg of PGF2α; 32 h, 100 µg of GnRH), or (3) Ovsynch with a double dose of PGF2α (GDDP: 100 µg of GnRH; 7 d, 50 mg of PGF2α; 56 h, 100 µg of GnRH). All cows received timed artificial insemination (TAI) approximately 16 h after the second GnRH treatment (G2). Pregnancy diagnosis was performed by transrectal palpation 39 ± 3 d after TAI, and pregnancy status was reconfirmed 66 d after TAI. Blood samples collected from a subset of cows in each treatment at the first PGF2α treatment (n = 394) and at G2 (n = 367) were assayed for progesterone (P4). Data were analyzed by logistic regression using the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC). At 39 d after TAI, GPPG cows tended to have more P/AI than control cows [35% (137/387) vs. 31% (107/349)], whereas P/AI for GDDP cows [32% (118/364)] did not differ from that for control cows. Pregnancy loss from 38 to 66 d did not differ among treatments and was 8% (30/362). The percentage of cows with complete luteal regression (P4 <0.4 ng/mL at G2) tended to differ among treatments and was greater for GPPG cows than for GDDP and control cows (94% vs. 88% vs. 88%, respectively). Overall, cows with P4 <1 ng/mL at the first PGF2α treatment had fewer P/AI than cows with P4 ≥1 ng/mL (27% vs. 38%), whereas cows with P4 ≥0.4 ng/mL at G2 had fewer P/AI than cows with P4 <0.4 ng/mL (15% vs. 38%). We conclude that adding a second PGF2α treatment 24 h after the first within a Resynch protocol tended to increase the proportion of cows undergoing complete luteal regression and P/AI, whereas treatment with a double dose of PGF2α at a single time did not.

Subacute ruminal acidosis affects fermentation and endotoxin concentration in the rumen and relative expression of the CD14/TLR4/MD2 genes involved in lipopolysaccharide systemic immune response in dairy cows

The first objective of this study was to investigate the effects of subacute ruminal acidosis (SARA) on fermentation, ruminal free lipopolysaccharides (LPS), and expression of the cluster of differentiation 14 (CD14), toll-like receptor 4 (TLR4), and myeloid differentiation protein 2 (MD2) complex in white blood cells involved in the systemic immune response in dairy cows. The second objective was a study of whether increased expression of the LPS receptor complex led to increases in the concentrations of plasma high-density lipoprotein (HDL) and serum Ca. Three hundred five dairy cows located in 13 Polish high-yielding dairy commercial farms were selected according to their days in milk (40-150 d; average = 75), 305-d milk yield (10,070-12,041 kg; average = 10,940), and number of lactations (primiparous, n = 139 and multiparous, n = 166). Next, the herds were segregated into 3 groups based on the percentages of cows with an assigned value of ruminal fluid pH: SARA-positive, SARA-risk, and SARA-negative herds. Moreover, 305 selected dairy cows were divided according to the classification based on ruminal fluid pH into 3 groups as healthy (pH >5.81), risk (pH 5.8-5.6) and acidotic cows (pH <5.6). Rumen fluid samples were collected via rumenocentesis. In the AC group, we recorded higher concentrations of ruminal free LPS [4.57 Log10 endotoxin units (EU)/mL; 42,206 EU/mL] compared with the healthy group (4.48 Log10 EU/mL; 34,179 EU/mL). Similarly, the concentration of ruminal free LPS was higher in SARA-positive herds (4.60 Log10 EU/mL; 43,000 EU/mL) compared with SARA-negative herds (4.47 Log10 EU/mL; 32,225 EU/mL). The relative mRNA abundance of genes associated with the function of LPS receptors, such as CD14, TLR4, and MD2, in white blood cells differed between all experimental groups on both cow and herd levels. In the acidotic group, we recorded higher concentrations of HDL (78.16 vs. 68.32 mg/dL) and serum amyloid A (10.80 vs. 9.16 µg/mL) and lower concentrations of Ca (8.26 vs. 10.16 mg/dL) and haptoglobin (470.19 vs. 516.85 ng/mL) compared with the healthy group. Similar results were obtained in the SARA herd status analysis, but the concentration of lipopolysaccharide-binding protein differed statistically. Moreover, the pH of ruminal fluid was negatively correlated with relative mRNA abundance of genes such as CD14, TLR4, MD2, and concentrations of serum HDL and serum amyloid A, although positively correlated with serum Ca. The results indicated that decreases in ruminal fluid pH increased the release of free LPS into the rumen and stimulated the expression of the LPS receptor complex and immune response. Moreover, an increase in the expression of the LPS receptor led to higher concentrations of plasma HDL and lower serum Ca, which may be a protective mechanism against endotoxemia. However, the biological significance of these results needs to be investigated further in larger field trials.

Relationship between pH of ruminal fluid during subacute ruminal acidosis and physiological response of the Polish Holstein-Friesian dairy cows.

The aim of the study was to investigate the effect of ruminal fluid pH depression on biochemical indices of blood, urine, feces, and milk, and to determine which of them may be helpful as a marker for the diagnosis of subacute ruminal acidosis (SARA). Ruminal fluid samples were obtained by rumenocentesis from 305 cows representing 13 commercial dairy herds. The herds were selected based on percentages of cows with an assigned value of ruminal fluid pH segregated into three groups as: SARA-positive herd, if at least 25% of the ruminal fluid samples indicated a pH < 5.6; SARA-risk herd, if less than 25% of ruminal fluid samples indicated a pH < 5.6, but at least 33% showed a pH ≤ 5.8; and SARA-negative herd, if less than 25% of the ruminal fluid samples indicated a pH < 5.6, but less than 33% exhibited a pH = 5.8. Moreover, the dairy cows were divided according to the ruminal fluid pH into three groups as follows: healthy cows (HC, pH>5.80, n = 196), risk cows (RC, pH 5.8 - 5.6, n = 51), and acidotic cows (AC, pH < 5.6, n = 58). Almost 19% (58/305) of the cows were classified as acidotic (pH < 5.6) and 46.2% of the herds as SARA-positive. In the AC group, higher concentrations of insulin-like growth factor-I (IGF-I), non-esterified fatty acids (NEFA), rectal temperature and lower blood pH, compared with those of the HC group, were recorded. Moreover, in the SARA-positive herds, higher concentrations of IGF-I and the lowest blood pH, compared with SARA-negative herds, were observed. The lowering of ruminal fluid pH increased the blood IGF-I and NEFA concentrations and the rectal temperature and decreased the blood pH. These measures are indicators of the physiological changes that occur as part of the pathogenesis of the condition and may be helpful for the diagnosis of the SARA syndrome when serial measurements are conducted.

Comparison of 2 protocols to increase circulating progesterone concentration before timed artificial insemination in lactating dairy cows with or without elevated body temperature

Two treatments designed to increase circulating progesterone concentration (P4) during preovulatory follicle development were compared. One treatment used 2 intravaginal P4 implants (controlled internal drug-releasing inserts; CIDR) and the other used a GnRH treatment at beginning of the protocol. Lactating Holstein cows that had been diagnosed as nonpregnant were randomly assigned to receive timed artificial insemination (TAI) following 1 of 2 treatments (n = 1,638 breedings): (1) GnRH: CIDR+ 2 mg of estradiol (E2) benzoate + 100 µg of GnRH on d -11, PGF2α on d -4, CIDR withdrawal + 1.0 mg of E2-cypionate + PGF2α) on d -2, and TAI on d 0; or (2) 2CIDR: 2 CIDR + 2 mg of E2-benzoate on d -11, 1 CIDR withdrawn + PGF2α on d -4, second CIDR withdrawn + 1.0 mg of E2-cypionate + PGF2α on d -2, and TAI on d 0. Milk yield was measured daily between d 0 and d 7. Rectal temperature was measured using a digital thermometer at d 0 and 7, and elevated body temperature was defined as an average rectal temperature ≥39.1°C. Pregnancy diagnoses were performed on d 32 and 60 after TAI. We detected no effect of treatments on pregnancy per AI or pregnancy loss regardless of elevated body temperature, body condition score, parity, milk yield, or presence or absence of a corpus luteum (CL) on d -11 or d -4. Pregnancy per AI at 60 d was reduced [elevated body temperature = 22.8% (162/709), no elevated body temperature 34.1% (279/817)] and pregnancy loss tended to increase [elevated body temperature = 20.2% (41/203), no elevated body temperature 14.4% (47/326)] in cows with elevated body temperature. Various physiological measurements associated with greater fertility were also reduced in cows with elevated body temperature, such as percentage of cows with a CL at PGF2α (decreased 7.9%), ovulatory follicle diameter (decreased 0.51 mm), expression of estrus (decreased 5.1%), and ovulation near TAI (decreased 2.8%) compared with cows without elevated body temperature. A greater proportion of cows (30.2%) had a CL at PGF2α in the GnRH treatment [74.1% (570/763)] than in the 2CIDR treatment [56.9% (434/763)]; however, circulating P4 concentration was greater at the time of PGF2α treatment (d -4) for cows 2CIDR (4.26 ± 0.13 ng/mL) than in cows in GnRH (3.99 ± 0.14 ng/mL). Thus, these 2 protocols yield similar fertility results that might be due to somewhat different physiological alterations. Treatment with GnRH increased the proportion of cows with a CL at PGF2α; however, the 2CIDR protocol increased circulating P4 under all circumstances.

Re-direction of maternal behaviour in dairy cows

In the milk producing industry, most aspects of maternal behaviour are discouraged, but milk production is actively maintained in the absence of the calf. The process of milk let down, is mediated, at least partly, by oxytocin, which has been shown to play a central role in facilitating maternal bonding (i.e. attachment). Here we show that cows express an elevated need for tactile stimulation, as shown by high utilization of automated brushes, in the first weeks following parturition. To this aim, we followed the use of automated brushes by 136 cows across 305days from the time of calf separation. On the day that followed parturition, 90% of cows used the brush, for an average duration of 357.6±456.7s/d. In the following weeks, the average daily duration of brush usage declined to an average of 108.4±142.9s/d for the rest of the lactation period (i.e. 305days), with the percent of cows using the brush decreasing to an average of 81±39%. Increased usage of the brush was also documented in the hour following each milking session (on average, 12% of the cows used the brush for 6.2s/h), compared to the hour that preceded milking (on average, 8% of the cows used the brush for 4.7s/h). The position of the brush (i.e. when installed next to the feeding bunk or on the opposite side of the cowshed), did not affect usage patterns, suggesting that 1. the increased use of the brushes during this time period cannot be simply explained by the higher need for energy during the first weeks following calving and the incidental use of brush located next to the feed bunk and 2. that the motivation of cows to use the brush following parturition, when expected to be in a negative energy balance, exceeds the energetic cost involved in utilizing distant brushes. The fact that brush usage (in both near and distant brushes) was found to be at its peak following parturition, and decrease rather than increase in the weeks following parturition, when energy resources are slowly recovering, further supports our hypothesis. Our results suggest that cows may re-direct their need to engage in contact with their calf (i.e. a process aimed to facilitate maternal bonding) towards an object.

Cure rate of postpartum endometritis after different treatments in high produce dairy cows

The main objective of this study was to compare the common treatment methods of clinical endometritis (CE) including injection of PGF2a and intrauterine infusion of cephapirin benzathine (CB) with intrauterine infusion of 50% dextrose solution (DEX) and intrauterine infusion of liquid paraffin (LP) in dairy cows. To this end, 188 lactating Holstein cows with clinical signs of endometritis were randomly assigned into five treatment groups and cytological smear was prepared. In group 1 (n = 37), cows were treated with intrauterine infusion of CB. In the second group (n = 53), the treatment protocol included intramuscular injection of 500-mg cloprostenol sodium in cows with corpus luteum (CL) in their ovaries. In group 3 (n = 43), cows were treated with intrauterine infusion of DEX solution. In group 4 (n = 35), cows were treated with intrauterine infusion of LP solution and 20 untreated cows were assigned into a control group (group 5). Clinical treatment rates were 62.2, 66, 60.5, 54.3, and 50% in CB, PG, DEX, LP, and control groups, respectively (P ≥ 0.05). In the cytological assessment, there was no significant difference in reduction in the neutrophil’s number in the second examination after treatment (P ≥ 0.05). Percentage of cows with clean vaginal discharge in the second examination is higher in cows with CL than cows without CL in all five groups, but this difference was not significant (P ≥ 0.05). According to the result of this study, future large studies are required for assessment of DEX and LP as alternative therapies for the treatment of CE instead of antibiotics.