Parity Cows Research Articles

Relationship between microclimate and cow behavior and milk yield under low-temperature and high-humidity conditions

This study aimed to evaluate the relationship between temperature (T), relative humidity (RH), and temperature and humidity index (THI), milk yield (MY), rumination time (RT), and activity (AT) of dairy cows in different parities under low temperature and high humidity (LTHH). In this study, the number of samples each day was determined by all healthy cows in the barn with parity and days in milk (DIM) within 5 and 305, respectively. The box plot method was used for screening and removing outliers of dairy cow indicators after classification according to parity and DIM. To remove the effect of DIM on MY, a bivariate regression model was used to standardize the MY in milk yield index (MYI). The best bivariate regression model based on the lowest Akaike information criterion was used to analyze the relationship between behavioral parameters, MYI, and microclimate indicators for each parity. In the barn with the microclimate at a low temperature above 0°C, high RH was negatively correlated with MYI in primiparous and multiparous cows but positively correlated with AT in primiparous and multiparous cows and RT in multiparous cows (p < 0.05), so RH was a significant factor related to MYI, RT, and AT of cows. The 2-day lagged daily average T and THI were correlated with MYI in primiparous cows (p < 0.05). The inflection point value of 71.9 between AT and RH in the multiparity as the upper limit of RH was beneficial for improving comfort and MY in all parity dairy cows. Compared with MYI and RT, AT had a higher R2 with a microclimate indicator, so it could be used as a better indicator for assessing the LTHH. Comparing the R2 of multiparous cows to T (R2 = 0.0807) and THI (R2 = 0.1247), primiparous cows had higher R2 in MYI to T (R2 = 0.2833) and THI (R2 = 0.3008). Therefore, primiparous cows were more susceptible to T and THI. The inflection point values for MYI to T and THI were greater in primiparous cows than in multiparous cows, indicating that primiparous cows had a smaller tolerance range to T and THI than multiparous cows. Thus, parity should be considered when studying the relationship between MY, T, and THI under LTHH.

The effect of new and ancestral inbreeding on milk production traits in Iranian Holstein cattle.

Inbreeding depression, the reduction of fitness and performance, is due to an increase in the mating of related individuals. Based on the purge hypothesis, inbreeding and breeding over generations reduce the effect of deleterious alleles responsible for inbreeding depression. Thus, recent inbreeding is assumed to be more harmful than ancestral inbreeding. This study aimed at evaluating the effects of new and ancestral inbreeding on milk, fat and protein production in Iranian Holstein cattle. The secondary objective was to examine the changes in predicted breeding values when the inbreeding effect was included in the model's analysis. To this end, inbreeding coefficients were calculated using the pedigree of 2,394,517 Holstein cattle to achieve these goals. In addition, 419,132 records of milk, fat and protein yields of first parity cows were collected to assess inbreeding depression and breeding values. The average inbreeding coefficients were 0.83% and 1.68% for the whole population and the inbred animals, respectively. A 1% increase in classical pedigree-based inbreeding coefficient was associated with a decrease of 11.99 kg in milk, 0.39 kg in fat and 0.29 kg in protein. The effect of ancestral inbreeding was more detrimental to performance traits than the effect of new inbreeding. This result contradicted the hypothesis of purging. By including the inbreeding coefficient in the model, the rank of animals remained unchanged, but the average predicted breeding values increased. In general, inbreeding depression was observed in Iranian Holstein cows; however, no evidence of purging was observed. The average of inbreeding coefficients was not high in this population, although accounting for inbreeding coefficients in the analytical model did significantly increase the predicted breeding values. It is recommended that the analytical model incorporate the inbreeding coefficient to improve the accuracy of genetic evaluation. In future studies, inbreeding depression should be assessed using genomic data for performance and reproduction traits.

Effects of early weaning on the reproductive performance of suckled Nelore cows in the subsequent breeding season.

This study aimed to evaluate the effects of early weaning (EW) on body composition, hormone concentrations and metabolites, and reproductive performance of Nelore cows in the subsequent breeding season (BS). Suckled cows that became pregnant by timed-AI (TAI) in the 2020-BS were exposed in 2021 to early weaning at 150 d (27 primiparous [PRI] and 74 multiparous [MUL]) or conventional weaning (CW) at 240 d postpartum (30 PRI and 77 MUL). Body weight (BW) and body condition score (BCS) were determined at 2020-BS, EW, CW, prepartum, and 2021-BS. Blood samples were collected at EW, CW, prepartum (54.75 ± 0.56 d prepartum), and 2021-TAI and assayed for insulin-like growth factor-1 (IGF-I), non-esterified fatty acid (NEFA), and β-hydroxybutyrate (BHB) concentrations. In 2021-BS, cows were exposed to a P4/E2-based protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in females detected with luteolysis (D20) by Doppler ultrasound. The presence of corpus luteum (CL) on D10, estrous expression, and dominant follicle (DF) diameter, and blood perfusion (BP) on D2 and D0 were determined. Data were analyzed by ANOVA or logistic regression of SAS as a 2 × 2 factorial with main factors of parity (PRI or MUL) and weaning strategy (EW or CW). An interaction of parity and weaning strategy was not observed (P > 0.1), but the weight (kg) and BCS were greater (P < 0.05) in MUL cows at the five timepoints, and EW cows were heavier than CW at the moment of CW (541 vs. 493 kg; and 5.3 vs. 4.3), prepartum (551 vs. 506 kg; and 5.2 vs. 4.4) and 2021-BS (475 vs. 450 kg; and 4.5 vs. 3.7). Plasma urea concentration at 2021-BS was greater (P = 0.01) for PRI than for MUL. A parity-by-time interaction was observed (P ≤ 0.05) for concentrations of IGF-I, NEFA, and BHB. PRI cows had greater (P ≤ 0.05) concentrations of IGF-I at EW and greater (P ≤ 0.05) prepartum concentrations of NEFA and BHB than MUL cows. The proportion of cows with CL at D10 was not affected (P > 0.1) by weaning but was greater (P < 0.05) in MUL than in PRI cows (40.4 vs. 15.7%). The diameter of DF and proportion of BP on D0 were greater (P < 0.05) in EW cows than in CW cows. The pregnancy rate (P/AI, %) at the first TAI was greater (P < 0.05) in EW cows (60% vs. 45%), whereas no difference (P > 0.1) was observed at the second TAI. Cumulative P/AI (first and second TAIs) was greater (P < 0.05) in EW cows (81% vs. 63%). In conclusion, weaning at 150 d in Nelore cattle is a strategy to successfully recover the parous cow's body condition and to improve pregnancy success in the next BS, regardless of the cow's parity order.

Increased parity is negatively associated with survival and reproduction in different production systems.

We conducted a retrospective meta-analysis based on individual cow data to assess the associations of parity, level of production, and pasture-based or intensively fed systems with fertility. Our goal was to provide understandings of the role of parity in risks for removal and reproductive failure. Multilevel models were used to evaluate the fixed effects of parity, milk, milk solids, milk fat and protein percentage and yield, and production system [intensively fed (n = 28,675) or predominantly pasture fed (n = 4,108)] on reproductive outcomes. The outcomes were the hazard of not being bred (HNBRED), hazard of pregnancy (HPREG), pregnancy to first breeding (PREG1), and odds of becoming pregnant in a lactation (OPAL). The 32,783 cows were in 13 studies conducted in Australia (14.6% of cows), Canada (2.4% of cows), and the United States (83.0% of cows). There were 38.5% of cows in the sample in parity 1, 27.3% in parity 2, 16.7% in parity 3, 9.0% in parity 4, and 8.6% in parity ≥5. Compared with cows of parity 1, parity ≥5 cows had a greater HNBRED [hazard ratio (HR) = 2.45], lesser HPREG (HR = 0.73), and reduced OPAL (odds ratio = 0.36). However, the parity ≥5 cows had similar PREG1 to other parities except for parity 1. This suggests the possibility of a higher proportion of subfertile parity ≥5 cows than for other parities. Associations between parity and reproductive measures were influenced by the different milk production measures, indicating that milk yield and milk component percentages and yields modified the odds or hazards of successful reproduction. All milk production measures had quadratic associations with OPAL, indicating that either low or high production or concentration of solids within a cohort reduced OPAL. This reduced OPAL reflected a greater HNBRED for lower milk yield and milk protein and fat yielding cows. Both milk yield and milk protein percentage had quadratic associations with HPREG. When centered milk yield was categorized into quartiles, small differences in HPREG existed. A more marked association of milk protein percentage occurred with HPREG, with optimal HPREG at approximately 0.5% above group mean milk protein percentage. Milk fat percentage (HR = 0.901), fat yield (kg/d; HR = 0.78), protein yield (kg/d; HR = 0.71), and milk solids yield (kg/d; HR = 0.84) were all linearly associated with reduced HPREG. Difference in production systems did not have substantive effects on PREG1 but did for HNBRED, HPREG, and OPAL. Estimates of associations of parity with reproductive outcomes HNBRED, HPREG, and OPAL were influenced by milk and milk solids yield; older cows had markedly lower reproductive outcomes. Interestingly, for PREG1, there were few differences among parities and differences were less influenced by milk yield and constituent measures. The marked associations of parity with removal for all reasons, deaths and culling, and reductions in HNBRED, HPREG, and OPAL indicate a need to focus on the physiological changes with parity to produce better strategies to support optimal longevity of cows.

Associations of parity with health disorders and blood metabolite concentrations in Holstein cows in different production systems.

Data were obtained from studies in Australia, Canada, and the United States using individual cow data from 28,230 Holstein cows to evaluate associations between parity and disease. Our goal was to develop understanding of disease risks for cows of differing parity. We hypothesized that there would be increased risks of disease and changes in metabolite concentrations with increased parity. Parity ≥5 represented 2,533 cows or 9.0%, parity 4 was 9.8% (2,778), parity 3 as 19.0% (5,355), parity 2 as 28.1% (7,925), and parity 1 was 34.1% (9,639) of the sample. Of these cows, 15.5% were in Australia, 14.7% in Canada, and 69.8% in the United States. Lactational incidence (LI) risk of clinical hypocalcemia increased with parity from 0.1% for parity 1 to 13% for parity ≥5 cows. The marked increase suggests profound differences in metabolism with increased parity. The LI of clinical mastitis was 17.4%. The odds of mastitis increased with parity to 2.5 times greater in parity ≥5 than in parity 1. The LI of lameness increased with parity; specifically, the odds of lameness was 5.6 times greater for parity ≥5 than parity 1. Dystocia incidence was 8.7% and greatest for parity 1 cows. The LI of retained placenta was 7.4% and increased with parity, with the odds for parity ≥5 2.3 times greater than for parity 1. The LI of metritis was 10% and of endometritis 14%, with the greatest odds in parity 1. The LI of clinical ketosis was 3.3% with a marked increase in odds with parity. The prevalence of subclinical ketosis was 26.8% with only cows in parity 1 having lower odds than other parities. Parity ≥5 cows had greater odds (odds ratio = 1.7) of respiratory disease than parity 1 cows, which were lesser than other parities. Metabolite concentrations were evaluated in 5,154 Holstein cows in the precalving, calving, and immediate postcalving data sets. Metabolic measures near peak lactation provided 1,906 observations. Concentrations of β-hydroxybutyrate (BHB) and nonesterified fatty acids increased with parity on d 1 to 3 of lactation and at peak lactation. On d 1 to 3 after calving differences in glucose, nonesterified fatty acids, and BHB indicated a greater reliance on mobilized lipid to export energy to peripheral tissues as BHB for greater parity cows. Differences in concentrations among parity groups were marked at times, for example >0.20 mM in Ca for parity 1 and 2 to parity ≥5 and >0.33 mM for all older parities compared with parity 1 for P on the day of calving. The marked increase suggests profound differences in metabolism with increased parity are probably influenced, in part, by increased production. We found marked differences in concentrations of metabolites with parity that are consistent with reduced reproduction, health, and body condition for higher parity cows. These unfavorable differences in metabolism in Ca, P, glucose, and cholesterol concentrations for higher parity cows also complement the often-substantial differences in disease risk with parity and suggest a need to carefully consider the parity structure in study design. Managers and advisors will need to consider methods to reduce risk of health disorders tailored to cows of different ages.

Genetic analysis of production traits and body size measurements and their relationships with metabolic diseases in German Holstein cattle.

This study sheds light on the genetic complexity and interplay of production, body size, and metabolic health in dairy cattle. Phenotypes for body size-related traits from conformation classification (130,166 animals) and production (101,562 animals) of primiparous German Holstein cows were available. Additionally, 21,992, 16,641, and 7,096 animals were from herds with recordings of the metabolic diseases ketosis, displaced abomasum, and milk fever in first, second, and third lactation. Moreover, all animals were genotyped. Heritabilities of traits and genetic correlations between all traits were estimated and GWAS were performed. Heritability was between 0.240 and 0.333 for production and between 0.149 and 0.368 for body size traits. Metabolic diseases were lowly heritable, with estimates ranging from 0.011 to 0.029 in primiparous cows, from 0.008 to 0.031 in second lactation, and from 0.037 to 0.052 in third lactation. Production was found to have negative genetic correlations with body condition score (BCS; -0.279 to -0.343) and udder depth (-0.348 to -0.419). Positive correlations were observed for production and body depth (0.138-0.228), dairy character (DCH) (0.334-0.422), and stature (STAT) (0.084-0.158). In first parity cows, metabolic disease traits were unfavorably correlated with production, with genetic correlations varying from 0.111 to 0.224, implying that higher yielding cows have more metabolic problems. Genetic correlations of disease traits in second and third lactation with production in primiparous cows were low to moderate and in most cases unfavorable. While BCS was negatively correlated with metabolic diseases (-0.255 to -0.470), positive correlations were found between disease traits and DCH (0.269-0.469) as well as STAT (0.172-0.242). Thus, the results indicate that larger and sharper animals with low BCS are more susceptible to metabolic disorders. Genome-wide association studies revealed several significantly associated SNPs for production and conformation traits, confirming previous findings from literature. Moreover, for production and conformation traits, shared significant signals on Bos taurus autosome (BTA) 5 (88.36 Mb) and BTA 6 (86.40 to 87.27 Mb) were found, implying pleiotropy. Additionally, significant SNPs were observed for metabolic diseases on BTA 3, 10, 14, 17, and 26 in first lactation and on BTA 2, 6, 8, 17, and 23 in third lactation. Overall, this study provides important insights into the genetic basis and interrelations of relevant traits in today's Holstein cattle breeding programs, and findings may help to improve selection decisions.

Dynamic changes and importance of plasma concentrations of ether phospholipids, of which the majority are plasmalogens, in postpartum Holstein dairy cows.

Ethanolamine plasmalogens (EPls) and choline plasmalogens (CPls) are classes of ethanolamine ether phospholipids (ePE) and choline ether phospholipids (ePC), respectively. EPls play crucial roles in maternal and breastfed infant bodies and stimulate gonadotropin secretion by gonadotrophs. To estimate changes in and importance of plasma concentrations of EPls and CPls, utilising newly developed enzymatic fluorometric assays for ePE and ePC in postpartum Holstein cows. Plasma samples were collected from 3weeks before expected parturition until approximately 8weeks after parturition (16 primiparous and 38 multiparous cows) for analysis. Plasma concentrations of ePE and ePC, most of which are plasmalogens, declined before and increased after parturition and stabilised near the day of the first postpartum ovulation (1stOV). From weeks 2 to 3 after parturition, third-parity cows exhibited ePE concentrations that were higher than those of other parity cows. The days from parturition to 1stOV correlated with days from parturition to conception. On the day of 1stOV, milk yield correlated with plasma concentration of both ePE and ePC, while ePC concentration correlated negatively with milk fat percentage. At the early luteal phase after 1stOV, plasma ePE concentration correlated with plasma anti-Müllerian hormone concentration (r=0.39, P<0.01), and plasma ePC concentration correlated with plasma follicle-stimulating hormone concentration (r=0.43, P<0.01). The concentrations of ePE and ePC changed dramatically around parturition and 1stOV, and the concentrations correlated with important parameters for milk production and reproduction. The blood plasmalogen may play important roles in postpartum dairy cows.

Seasonality in resumption of ovarian activity and reproductive performance of postpartum Holstein cows.

It has been suggested that domestication has turned cattle from seasonal breeders to annual breeders. This study examined the seasonal differences in early postpartum ovulation and subsequent reproductive performance in 542 Holstein cows. Cows displaying corpora lutea in the ovary at 26 days postpartum were defined as early ovulators. Factors affecting the occurrence of early ovulation were analyzed, and subsequent reproductive traits were compared between cows with and without early ovulation. During the summer season, 70.6% of calving cows showed early ovulation, whereas 48.7, 39.2, and 47.2% presented this condition in autumn, winter, and spring, respectively (P < 0.01). Third parity cows showed early ovulation more often than their first parity counterparts (P < 0.05). Cows with a 2.50 to 3.00 or > 3.00 body condition score (BCS) more frequently became early ovulators than those with BCSs < 2.50 (P < 0.01). Calving year was a risk factor, and uterine abnormalities were also often risk factors for early ovulation. The survival analysis showed that seasonal differences in the occurrence of early ovulation did not completely affect the time to first service and pregnancy. Proportional hazard regression analysis revealed that calving year, parity, and early ovulation were risk factors for the time to first service and that calving year was a risk factor for the time to pregnancy. In conclusion, domesticated dairy cows maintain seasonality in postpartum ovarian activity but not in subsequent fertility.

Dry Period Length in Dairy Cattle: II. Influence on Calf Survival and Growth Performance

This study was conducted to investigate the effects of dry period length (DPL) on survival rate, gender, growth performance, mortality of Holstein calves. Data belonged to 800 Holstein cows in different parities (2nd, 3rd and ≥4th) and 800 calves delivered by these cows. DPL were classified in 5 categories (≤40, 41-50, 51-60, 61-70, ≥71 days). Calves were weighed and body dimensions (body length, wither height, hearth girth) at birth and 6th months of age. There were significant relationships between DPL and calf gender (P

Treatment protocols for claw horn lesions and their impact on lameness recovery, pain sensitivity, and lesion severity in moderately lame primiparous dairy cows.

This study aims to investigate the effects of routine treatment protocols for claw horn disruptive lesions (CHDL) on lameness recovery rates, pain sensitivity, and lesion severity in moderately lame primiparous cows. A cohort of first parity cows was recruited from a single commercial dairy herd and randomly allocated to five treatments, comprising four lame groups (LTNB, LTN, LTB, and LT) and a single group non-lame group. Eligibility criteria for the lame cows included a first lameness score (score 3/5), presence of CHDL on a single foot, good body condition score of 3.0 to 3.5, and no history of previous lameness. LTNB received a combination of therapeutic trim, administration of a non-steroidal anti-inflammatory drug (NSAID; Ketoprofen) for 3 days, and hoof block on the healthy claw. Both LTN and LTB received the same treatment as LTNB without hoof block and NSAID, respectively. LT received only a therapeutic trim, whereas non-LT (negative control) received either a therapeutic or preventive trim. Pain sensitivity was assessed using the limb withdrawal reflex while lesion severity was recorded using the International Committee Animal Records (ICAR) Atlas guide. The enrolled cows were observed at weekly intervals, and the primary outcomes were assessed 28 days after treatment. The number (%) of recovered cows was 15 of 20 (75%), 13 of 21 (61.9%), 6 of 14 (42.9%), and 6 of 15 (40%) for LTNB, LTN, LTB, and LT, respectively. LTNB had significantly higher odds of successful treatment (OR = 4.5; 95% 1.1-19.1) compared to LT. Pain sensitivity based on limb withdrawal reflex was absent in a significantly higher number of cows (15/20; 75.0%) in LTNB compared to LTB and LT. LTB had a significantly lower lesion severity score in comparison to LTN. Overall, cows with limb withdrawal at day 28 after treatment were less likely (OR = 0.06; 95% CI 0.01-0.24) to develop a non-lame score. In conclusion, the treatment with therapeutic trim, hoof block, and NSAID led to better recovery and reduced pain sensitivity in moderately lame primiparous cows with good BCS compared to those that received only therapeutic trim. Further research on the changes within the hoof capsule following various treatment protocols is needed to elucidate the clinical benefits observed in this study.

Reproductive Efficiency of Cows in Different Parity

Livestock is one of the agricultural sectors that plays an important role in providing animal products. Cows are one of the largest meat and dairy producers. The low reproductive efficiency of cattle is the biggest problem in terms of its development. Increasing reproductive efficiency through artificial insemination programs is one way to enhance livestock populations. Reproductive efficiency parameters can be measured through values of Service per Conception (S/C) and Conception Rate (CR). Service per conception and conception rate are related to cows parity. Parity is the number of calf that have been born to a cow. This study aimed to provide information on reproductive efficiency as seen from the value of S/C and CR of cows in different parieties and the factors that influence them. High rates of parity followed by high S/C score and low CR. Each animal has various values of S/C and CR. The normal range for S/C is 1.6-2.0 and 60% in CR. Several factors that affect reproductive efficiency are environment, nutrition, Body Condition Score (BCS), knowledge of farmers, inseminator skills and quality of semen used. The highest service per conception (S/C) value was at parity 5 with aged ± 7 years and the conception rate (CR) was at parity 3 aged ± 5 years.Keywords: should be written in no more than 5 (five) words or phrases.

Bacterial Etiologies of Subclinical Mastitis in Cows Jos Metropolis, Nigeria

Abstract This study was conducted to investigate the prevalence of subclinical mastitis and its contagious and environmental bacterial causes in dairy cows in Jos Metro polis of Plateau State. A total of 208 milk samples were collected aseptically from 52 lactating cows and subjected to the California Mastitis Tests (CMT). Milk samples were transferred into peptone water broth for enrichment, followed with bacteriological assays and biochemical identification of bacteria. Using R Commander version 3.6.2, data such as: breed, age, parity, lactation, and management system of cows were collected, and analysed to determine their relationship with bovine subclinical mastitis. Out of 208 quarter milk samples collected from 52 cows, 35.09 % showed subclinical mastitis. While the Cross-breed cows had 15 % subclinical mastitis recorded, the White Fulani had 78.13 %. Cows of the age 3 to 5 years had the highest prevalence of mastitis, while cows with 4 to 6 calves showed the highest prevalence in the parity category. The early lactation stage of these cows showed the highest prevalence. The environmental bacteria isolated where E. coli, K. pneumoniae, K. oxytoca, C. freundii, K. aerogenes, and Proteus sp. with E. coli having the highest frequency of 40.86 %, followed by K. Pneumoniae with 17.79 %. The contagious bacteria isolated were S. aureus, S. agalactiae, and Corynebacterium sp. with S. aureus occurring most with 69.71 %. This study concluded that the prevalence of subclinical mastitis is high in cows in the study area. It was also discovered that the breed of cow, age of cow, parity number, stage of lactation and husbandry systems have an impact on subclinical mastitis. S. aureus with the highest frequency, indicated that contagious microbes have more effect on subclinical mastitis than environmental microbes.

Fertility of dairy cows milked once daily or twice daily in New Zealand.

The objective of this study was to evaluate the reproductive performance of New Zealand dairy cows with different milking regimens. A total of 2,562 herds calving in 2017 met the criteria for inclusion in this study. The herds were classified into 5 different milking regimens: 260 herds with cows milked once daily (OAD) during the entire lactation, 1,206 herds with cows milked twice daily (TAD) during the entire lactation, 94 herds that were switched to OAD milking from TAD milking during the mating period (OAD-M), 700 herds that were switched to OAD milking from TAD milking after peak lactation (OAD-P), and 302 herds that switched to OAD milking from TAD milking at end of the lactation (OAD-E). Time from the start of mating to first service (SMFS), start of mating to conception (SMCO) and first service to conception (FSCO) were analyzed using survival analysis. Time from SMFS, SMCO and FSCO was significantly shorter in cows milked OAD compared with cows milked TAD. Also, cows milked OAD had fewer services per conception and higher mean 3-wk submission (SR21), in calf by 3 wk (PR21), in calf by 6 wk (PR42), conception to the first service (PRFS), 3-wk calving (CR21) and 6-wk calving (CR42), and lower not in calf (NIC) than herds with TAD, OAD-M, OAD-P, OAD-E milking cows. Fertility performance differed with parity; first-parity cows had lower SR21, 6-wk submission (SR42), PR21, PR42, PRFS, CR21, and CR42 values, and higher NIC values than second-parity cows. Third parity cows had the highest values for SR42, PR21, PR42, PRFS, CR21, and CR42, and lowest value for NIC compared with cows of other parities. Significant but minor interactions between milking regimen and parity existed for SMFS, SMCO, FSCO, SR21, SR42, PR21, PR42, PRFS, NIC, and CR21.

Incidence and Treatments of Bovine Mastitis and Other Diseases on 37 Dairy Farms in Wisconsin.

The aim of this research was to describe the incidence and treatments of mastitis and other common bovine diseases using one year of retrospective observational data (n = 50,329 cow-lactations) obtained from herd management software of 37 large dairy farms in Wisconsin. Incidence rate (IR) was defined as the number of first cases of each disease divided by the number of lactations per farm. Clinical mastitis (CM) remains the most diagnosed disease of dairy cows. Across all herds, the mean IR (cases per 100 cow-lactations) was 24.4 for clinical mastitis, 14.5 for foot disorders (FD), 11.2 for metritis (ME), 8.6 for ketosis (KE), 7.4 for retained fetal membranes (RFM), 4.5 for diarrhea (DI), 3.1 for displaced abomasum (DA), 2.9 for pneumonia (PN) and 1.9 for milk fever (MF). More than 30% of cows that had first cases of CM, DA, RFM, DI, and FD did not receive antibiotics. Of those treated, more than 50% of cows diagnosed with PN, ME and CM received ceftiofur as a treatment. The IR of mastitis and most other diseases was greater in older cows (parity ≥ 3) during the first 100 days of lactation and these cows were more likely to receive antibiotic treatments (as compared to younger cows diagnosed in later lactation). Cows of first and second parities in early lactation were more likely to remain in the herd after diagnosis of disease, as compared to older cows and cows in later stages of lactation. Most older cows diagnosed with CM in later lactation were culled before completion of the lactation. These results provide baseline data for disease incidence in dairy cows on modern U.S. dairy farms and reinforce the role of mastitis as an important cause of dairy cow morbidity.

79 Effects of Nutrient Restriction During Late Gestation of the First Parity on cow and Calf Performance During the Second Lactation

Abstract Fall-calving Herford-SimAngus heifers were individually fed either 100% (control; CON, n = 10) or 70% (nutrient restricted; NR, n = 12) of NASEM metabolizable energy and metabolizable protein requirements from d 160 of gestation to calving. Postpartum cows were individually fed 100% of energy and protein requirements until d 149 of lactation, then fed tall fescue hay or pasture as a single group through parity 2. Second parity cow performance and calf size were measured at birth, d 30, and d 60 post-calving. Single-quarter colostrum yield was collected pre-suckling. At d 30 and 60 of lactation, 4-hour milk yield was collected. Data were analyzed with the fixed effect of first parity nutritional plane, and calving or breeding date, calf sex, and calf sire (calf measures) were covariates. Milk yield included day and day x treatment (repeated measures). We previously reported that in parity 1, NR reduced (P ≤ 0.04) colostrum and milk yield, calf weaning weight, and dam weaning BCS. From calving to d 60 of parity 2, CON cows had greater (P ≤ 0.008) BCS and greater (P = 0.003) backfat on d 30. Additionally, CON cows had greater (P ≤ 0.002) BW compared with NR at d 30 and 60 of lactation. Calf size was not affected (P ≥ 0.17) by first parity nutritional plane except that cannon length at birth and d 60 tended (P ≤ 0.08) to be longer in CON calves. Colostrum and milk volume and weight were not affected (P ≥ 0.37) by first parity nutritional plane. Milk yield was greater (P ≤ 0.001) at d 30 than d 60. These data indicate that cow BW and energy reserves remained less in parity 2 when heifers experienced late gestational nutrient restriction, but calf size, colostrum yield, and milk yield were unaffected in the second parity.

Effect of lameness on feeding behavior of zero grazed Jersey dairy cows.

The dairy industry faces major challenges with high levels of lameness, in parallel to an increased consumer focus on animal welfare. This encourages farmers to consider more robust breeds, such as Jersey cows. As little is known about the behavior of this breed under loose housing conditions, the present study sought to describe the feeding behavior of lame and non-lame Jersey cows in different parities. Such breed-specific information of behavioral changes is needed for breed-specific herd management decisions and may contribute to identifying animals that are susceptible to developing lameness in the future, thus reducing impacts on the welfare and production of cows. Feeding data from 116 Danish Jersey cows were collected using automatic feeders, and lameness status was assessed by technicians every second week. The cows were kept in a loose housing system, with cubicles, a slatted concrete floor, and automatic milking robots. Eating time per visit and per day, the number of visits per day, and intervals between meals were analyzed using generalized linear mixed effects models. The effect of lameness was not significant for any variable. Primiparous Jersey cows had significantly longer eating times per day, shorter meal intervals, and a lower number of visits per day than older Jersey cows. Week in lactation affected the eating time per visit and per day, the number of visits, and between-meal intervals. In conclusion, we found no differences between lame and non-lame Jersey cows but between parities, which disagree with previous research on other breeds, suggesting that Jersey cows not just differ in size and looks but also in their behavioral reaction when lame. Although data from only one herd of a research center were used, this study has demonstrated the need for further research about breed-specific differences and their implications for the health and welfare of the animals.

Blood Transcriptome Analysis of Beef Cow with Different Parity Revealed Candidate Genes and Gene Networks Regulating the Postpartum Diseases.

Maternal parity is an important physiological factor influencing beef cow reproductive performance. However, there are few studies on the influence of different calving periods on early growth and postpartum diseases. Here, we conducted blood transcriptomic analysis on cows of different parities for gene discovery. We used Short Time Series Expression Miner (STEM) analysis to determine gene expression levels in cows of various parities and divided multiple parities into three main periods (nulliparous, primiparous, and multiparous) for subsequent analysis. Furthermore, the top 15,000 genes with the lowest median absolute deviation (MAD) were used to build a co-expression network using weighted correlation network analysis (WGCNA), and six independent modules were identified. Combing with Exon Wide Selection Signature (EWSS) and protein-protein interaction (PPI) analysis revealed that TPCN2, KIF22, MICAL3, RUNX2, PDE4A, TESK2, GPM6A, POLR1A, and KLHL6 involved in early growth and postpartum diseases. The GO and KEGG enrichment showed that the Parathyroid hormone synthesis, secretion, and action pathway and stem cell differentiation function-related pathways were enriched. Collectively, our study revealed candidate genes and gene networks regulating the early growth and postpartum diseases and provided new insights into the potential mechanism of reproduction advantages of different parity selection.

Pregnancy, Parturition and Resumption of Ovarian Cyclicity in Beef Cows

Communal farmers find it very difficult to control animal breeding hence fixed Time Artificial Insemination (TAI) is a promising technique. The objective of this study was to determine the effects of bull age and breed on pregnancy rate, and the post-partum interval in extensively managed communal beef cows. A total of 577 female animals with a body condition score between 2.5 and 3, from three breeds; Brahman (189), Nkone (18) and Mashona (370) were used. Fixed time artificial insemination using the ovsynch protocol was done using semen from four different bull breeds (Mashona, Tuli, Brahman and Boran) aged between 3 to 6 years. The percentage of cows identified pregnant were analysed using generalized linear mixed model PROC GLIMIXX of SAS. The effects of cow parity on PPI were evaluated using the general linear model of SAS. Conception rates were 53.2; 57.3 and 75% for Brahman, Mashona and Nguni cows respectively. Animals in their third parity had the highest conception rate. Young bulls less than 3 years of age had the least pregnancy rate while Mashona bulls had the highest pregnancy rate. There was a breed by parity interaction on PPA interval (P &lt; 0.05). It can be concluded that PGF2α and Estradiol Benzoate (EB) could be successfully used to induce and synchronize ovulation in cattle undergoing TAI, sire age significantly influenced conception rate as well as that the post-partum interval is dependent on breed and parity.

Measuring lameness prevalence: Effects of case definition and assessment frequency.

Lameness assessments are commonly conducted at a single point in time, but such assessments are subject to multiple sources of error. We conducted a longitudinal study, assessing the gait of 282 lactating dairy cows weekly during the first 12 wk of lactation, with the aim of assessing how lameness prevalence changed in relation to case definition and assessment frequency. Gait was scored using a 5-point scale where scores of 1 and 2 were considered sound, 3 was clinically lame, and 4 and 5 were severely lame. We created 5 lameness definitions using increasingly stringent thresholds based upon the number of consecutive events of locomotion score ≥3. In LAME1, a cow was considered lame when locomotion score was ≥3 at any scoring event, in LAME2, LAME3, LAME4, and LAME5, a cow was considered lame when locomotion score was 3 or higher during 2, 3, 4, and 5 consecutive scoring events, respectively. We also assessed the effect of assessment frequency on measures of prevalence and incidence using weekly assessment (ASSM1), 1 assessment every 2 wk (ASSM2), 1 assessment every 3 wk (ASSM3), and 1 assessment every 4 wk (ASSM4). Using LAME1, 69.2% of cows were considered lame at some point during the trial, with an average point prevalence of 31.8% (SD: 2.8) and average incidence rate of 10.9 cases/100 cow weeks (SD: 3.7). Lameness prevalence decreased to 28.0% when using LAME5. Survival analysis was used to assess the effects of parity, using these different case definitions. Parity is a known risk for lameness, such that case definitions and prevalence estimates should be stratified by parity to inform management decisions. Using the LAME3 criterion, primiparous cows had the highest chance of reaching 12 wk without a lameness event, and fourth and higher parities had the lowest. Weighted linear and quadratic kappa values were used to assess agreement between different assessment frequencies and lameness definitions; we found substantial to excellent agreement between ASSM1 and ASSM2 using LAME1, LAME2, and LAME3 definitions. Agreement was fair to substantial between ASSM1 and ASSM3 and low to fair between ASSM1 and ASSM4. Likewise, the agreement between LAME1 and LAME2 was fair in primiparous cows, substantial in second and third parity cows, and poor to fair in fourth and greater parity cows. We conclude that lameness prevalence estimates are dependent upon case definition and that the use of more stringent case definitions results in fewer cows classified as lame. These results suggest that routine locomotion assessments be conducted at least every 2 wk, and that cows should be defined as lame on the basis of 2 consecutive assessments.

Re-assessing the importance of linear type traits in predicting genetic merit for survival in an aging Holstein-Friesian dairy cow population.

The cumulative improvement achieved in the genetic merit for reproductive performance in dairy populations will likely improve dairy cow longevity; therefore, it is time to reassess whether linear type traits are still suitable predictors of survival in an aging dairy cow population. The objective of the present study was therefore to estimate the genetic correlations between linear type traits and survival from one parity to the next and, in doing so, evaluate if those genetic correlations change with advancing parity. After edits, 152,894 lactation survival records (first to ninth parity) were available from 52,447 Holstein-Friesian cows, along with linear type trait records from 52,121 Holstein-Friesian cows. A series of bivariate random regression models were used to estimate the genetic covariances between survival in different parities and each linear type trait. Heritability estimates for survival per parity ranged from 0.02 (SE = 0.004; first parity) to 0.05 (SE = 0.01; ninth parity). Pairwise genetic correlations between survival among different parities varied from 0.42 (first and ninth parity) to 1.00 (eighth to ninth parity), with the strength of these genetic correlations being inversely related to the interval between the compared parities. The genetic correlations between survival and the individual linear type traits varied across parities for 9 of the 20 linear type traits examined, but the correlations with only 3 of these linear type traits strengthened as the cows aged; these 3 traits were rear udder height, teat length, and udder depth. Given that linear type traits are frequently scored in first parity and are genetically correlated with survival in older parities, they may be suitable early predictors of survival, especially for later parity cows. Additionally, the direction of the genetic correlations between survival and rear udder height, teat length, and udder depth did not change between parities; hence, selection for survival in older parities using these linear type traits should not hinder genetic improvement for survival in younger parities.