Weaning rate, birth weight, and weaning weight of Jawarandu and Boer crossbreed goat from naturally serviced and artificially inseminated does

Two types of mating had been practiced in the crossbreed of Jawarandu does and Boer buck that produced Boerja goat, the natural service and artificial insemination. This study aimed to compare the weaning rate, birth weight, and weaning weight of offspring from both mating methods and analyze the different birth and weaning weights on different sex and birth type. A total of 271 kids were born from naturally serviced (NS) and artificially inseminated (AI) does (221 and 50, respectively). All kids were managed in the same condition. The number of kid died pre-weaning, birth weight, and weaning weight were recorded and analyzed. The result showed that the weaning rate of AI kids was significantly higher than NS kids. The birth and weaning weights of kids from both groups were not significantly different. Male and single kids had heavier birth and weaning weights than female and twin kids. Overall, the survival rate of AI kids until weaning is better than NS kids. The birth and weaning weight in NS and AI are not different but male and single kids are heavier than female and twin kids in both groups.

PSVIII-16 Effect of estrous synchronization with natural service or fixed-timed artificial insemination with conventional or gender-skewed semen in beef females

Reproductive efficiency is critical for profitability, and age at weaning critically impacts weaning weight. The objective was to evaluate estrous synchronization and/or AI with conventional (CON) or gender-skewed (SEXED) semen on calving distribution. Beef females (n=1,620) were either 1) synchronized (7-CIDR:Syn) or not synchronized (Nonsyn) and mated to bulls, 2) synchronized (7-d CIDR) and mated to bulls (SynNS) or artificially inseminated (SynAI), or 3) synchronized (7-d CO-Synch plus CIDR) and AIed with CON or SEXED semen. Calving distribution and gender were determined at birth and were analyzed using the GLIMMIX procedure in SAS. Synchronization resulted in more calves born from d1 to 14 (P < 0.01; 62% vs 47%) of the calving season. There was no differences (P = 0.31) between Syn and Nonsyn in the percent of calves born after d21, but between d22 and 42, more (P = 0.04) calves were born in the Nonsyn group. A greater proportion (P < 0.02; 46% vs 38%) of calves were born in SynNS between d1 and 14 compared to SynAI. There was no difference between treatments (P > 0.12) from d1 to 42, but more calves were born for SynAI after d43. With SEXED semen, there were no differences (P > 0.14) between CON and SEXED for the proportion of calves born from d1 to 14 or d1 to 21; however, more of the desired gender were born in the SEXED group during d1 to 14 of the calving season (P < 0.01; 84% vs 68%). More total calves were born from d22 to 42 in the SEXED group compared to the CON group (P < 0.05; 49% vs 33%). In summary, synchronization increased the proportion of females that calved early in the calving season, and SEXED semen increased the proportion of the desired gender born early in the calving season.

88 Impacts of Body Condition Score at Initiation of the Breeding Season on Reproductive Performance and Overall Productivity of Bos Taurus and B. Indicus Beef Cows

Responses of Bos taurus (BT) and B. indicus (BI) beef cows were compared according to their body condition score (BCS) at initiation of breeding season. Cows were assigned to an estrus synchronization + AI protocol and classified as BCS < 5.0 (LBCS, BT, n = 158; BI, n = 248) or BCS ≥ 5.0 (HBCS; BT, n = 173; BI, n = 122). Pregnancy status was verified via transrectal ultrasonography at 30 and 40 d after AI for BI and BT cows, respectively. All BT cows were exposed to natural service for 50 d (beginning 18 d after AI), and all non-pregnant BI cows were immediately exposed to natural service for 60 d. Pregnancy rates to AI did not differ (P ≥ 0.16) between HBCS or LBCS cows (60.9 vs. 53.5% for BT; 37.0 vs. 31.4% for BI; respectively). Pregnancy rates to natural service were greater (P = 0.03) in HBCS BT cows compared with LBCS (82.7 vs. 67.9%; respectively) but did not differ in BI cows (78.9 vs. 71.5%; respectively). Calving rate was greater (P < 0.03) in HBCS cows, which also calved earlier (P < 0.01) compared with LBCS (93.7 vs. 85.1% in BT, 83.6 vs. 73.3% in BI; respectively). HBCS Cows weaned more (P ≤ 0.05) calves compared with LBCS, which were older (P ≤ 0.04) (215 vs. 211 d in BT, 219 vs. 209 d in BI; respectively) and heavier (P ≤ 0.09) at weaning (258 vs. 252 kg in BT, 213 vs. 203 d in BI; respectively). Lastly, kg of calf weaned/cow was greater (P ≤ 0.03) in HBCS cows compared with LBCS (221 vs. 200 d in BT, 159 vs. 129 d in BI; respectively). Therefore, HBCS cows had greater reproductive efficiency and overall productivity, and this was observed in both BT and BI.

PSXIII-23 Influence of reproductive technologies on post weaning calf performance and carcass characteristics

The experiment objective was to evaluate the impact of assisted reproductive technologies on post weaning calf performance. Calves born following various reproductive treatments (synchronized natural service and synchronized AI) in 10 herds over 2 years were fed to reach a target backfat (BF) of 1.27 cm, sent to harvest, and carcass data collected. Calves were classified into calving groups as natural service born early (NS-Early, n = 189), natural service born late (NS-Late, n = 203), or AI sired born early (AI-Early, n = 116). Data were analyzed using the MIXED procedure in SAS with calving group, year and calf gender in the model. Weaning weights were similar between AI-Early and NS-Early; however, earlier born calves (AI-Early and NS-Early) were heavier (P < 0.0001) than NS-Late. AI-Early calves had heavier finished bodyweight (622.2 kg: P = 0.0024) compared to NS-Early (601.4 kg) and heavier HCW compared to both NS-Early and NS-Late (P < 0.01). NS-Early calves reached 1.27 cm BF in fewer days than AI-Early (261 d and 275 d, respectively; P < 0.01) with NS-late requiring the most days on feed to reach the same endpoint (296 d, P < 0.01). No differences in Quality Grade, Yield Grade, REA, marbling, or BF were detected between AI-Early, NS-Early, and NS-Late, or between early- and late-born calves (P > 0.38). Late-born calves required 29 more days on feed (P < 0.001) to reach 1.27 cm BF resulting in greater final bodyweight compared to early-born calves (625.5 kg and 612.8 kg, respectively; P = 0.04); however, hot carcass weights were similar between early- and late-born calves. Reproductive technologies that increase the number of calves born early in the calving season increased weaning weight and post weaning growth performance, but compared to high quality natural service sires, AI did not improve carcass characteristics.

Major management factors associated with reproductive performance and disorders in cows at Rajshahi region of Bangladesh

Background: The present study was conducted with the objective of assessing major factors that affect the reproductive performance and disorders of dairy cows in Rajshahi region. Methods: A cross-sectional study was conducted during the period from January 2014 to June 2015. Data on herd size, feed quality, breeding, grazing, management system, reproductive disorders, age at puberty, age at firs calving, post-partum heat period, service per conception, days open and calving interval of 500 cows were collected from farm owners by administering a questionnaire. We recorded the important diseases contacting farmers by mobile phone and visiting the farms. The effect of farm size, rearing system, feed quality and preventive measure on reproductive performance were evaluated by analysis of variance and Duncan multiple range test. Unpaired T-test was used to compare the reproductive performance according to breeding. Chi-square test was used to compare between two categories of a dichotomous outcome.. Results: The age at puberty, age at first calving, post-partum heat period, service per conception, days open and calving interval were 26.42±0.22 m, 35.48±0.22 m, 121.85±3.48 days, 1.93±0.04, 136.80±3.57 days and 401.04±3.94 days, respectively. Farm size had significant effect (P<0.05) on all reproductive traits (RT) except on service per conception and days open. The best reproductive performance (RP) was found in small size farm, good quality of feed, AI breeding method and preventive measure by veterinarian. Among the disorders, anoestrus, abortion, repeat breeding, retained placenta were most prevalent followed by dystocia, mastitis, vaginal prolapse, pyometra, metritis, uterine prolapse, milk fever, and still birth. The highest prevalence of reproductive disorders (RD) was found in intensive rearing system (39.8%). The prevalence of all RDs was higher in artificially inseminated cows (59.6%) than those bred by natural service (19.0%). Conclusion: The study revealed a lower RP of dairy cows and higher prevalence of RDs. The better reproductive performance was recorded in small than large and medium farms. Good quality of feed should be offered to dairy cow for better reproductive performance. Artificial insemination should also be preferred than natural service for better reproductive performance. Measures to control reproductive diseases should be undertaken in large herds and intensive housing system.

A retrospective analysis of bull:cow ratio effects on pregnancy rates of beef cows previously enrolled in fixed-time artificial insemination protocols

This retrospective study aimed to determine if the number of cows exposed per bull affects pregnancy rates of cows returning to estrus after fixed-time artificial insemination (FTAI). Data were compiled over the course of 13 breeding seasons (6 fall and 7 spring seasons) between 2010 and 2017 from the Virginia Department of Corrections herd. Available records contained data from 17 farms and 324 groups of cows (average 47 cows/group). Multiparous cows and heifers (average age per group: 5.11 ± 0.14 years; n = 14,868) were exposed to FTAI. After FTAI, animals were placed on pasture with bulls diagnosed as fertile by a breeding soundness exam for natural service of cows who did not become pregnant to FTAI (n = 7,248; average 22 cows/group). Animals were classified as pregnant to FTAI, to natural service on first return to estrus, or to natural service on second or subsequent estrus determined by fetal aging at pregnancy diagnosis. The bull:cow ratio for the total number of cows exposed ranged from 1:9 to 1:73 with an average of 1:31. The bull:cow ratio considering only open cows exposed after FTAI ranged from 1:2 to 1:44 with an average of 1:14. There was significant negative, small correlation between the bull:cow ratio for total number of cows exposed and return to estrus pregnancy rate in fall breeding seasons (P = 0.01, r 2 = 0.04) but not in spring (P = 0.90). There was a significant negative, small correlation between bull:cow ratio of open cows exposed and pregnancy rates to first return to estrus in fall herds with a single sire (P &lt; 0.001, r 2 = 0.11). There was no correlation in fall herds using multiple sires or spring herds (P ≥ 0.12). Bull:cow ratio accounted for only 1 – 11% of variation in the pregnancy rates, thus we conclude that a decreased bull:cow ratio (up to 1:73) did not affect natural service return to estrus pregnancy rate. Cattlemen may consider a reduced number of bulls needed for natural service breeding after FTAI, which can decrease bull related costs and increase the economic feasibility of adopting FTAI protocols.

Comparison of reproductive performance of AI- and natural service-sired beef females under commercial management

The objective of this study was to assess differences in reproductive performance of natural service and artificial insemination (AI) sired beef females based on pregnancy outcomes, age at first calving, and calving interval. Data were sourced from 8,938 cows sired by AI bulls and 3,320 cows sired by natural service bulls between 2010 and 2017. All cows were in a commercial Angus herd with 17 management units located throughout Virginia and represented spring and fall calving seasons. All calves were born to dams managed with estrus synchronization. Pregnancy was analyzed with generalized linear mixed models and other reproductive measures with linear mixed models in R. Six models were evaluated with the dependent variables of pregnancy status at the first diagnosis, pregnancy status at the second diagnosis, pregnancy type (AI or natural service) at the first diagnosis, pregnancy type at the second diagnosis, calving interval, and age at first calving. Independent variables differed by model but included sire type of the female (AI or natural service), pre-breeding measures of age, weight, and body condition score, postpartum interval, sex of the calf nursing the cow, and management group. No differences were observed between AI- and natural service-sired females based on pregnancy status at first and second pregnancy diagnosis (P &gt; 0.05). Sire type was only found to be significant for age at first calving (P &lt; 0.05) with AI-sired females being 26.6 ± 1.6 days older at their first calving, which was expected because AI-sired females were born early in the calving season making them older at breeding. Surprisingly, age and body condition score were not significant predictors of pregnancy (P &gt; 0.05). Body weight at breeding was not significant for pregnancy (P &gt; 0.05) but was significant for age at first calving (P &lt; 0.05). These data suggested that lighter heifers calved earlier which contradicts our original hypothesis. Overall, commercial Angus females sired by AI or natural service bulls had similar reproductive performance. Factors that were commonly associated with reproductive success were not significant in this commercial Angus herd managed with estrus synchronization. Given the size of these data, the importance of body condition, age, and weight should be reassessed in modern genetics and management practices.

Study on Dairy Cattle, Breeding Management Practices in Milkshed and Non-milkshed Areas of Bikaner District (Rajasthan)

Background: This investigation provides the data of breeding management practices followed by the livestock owners of milkshed and non-milkshed areas and analyze the effect of operation flood program in milkshed area of Bikaner district of Rajasthan in respect to dairy cattle breeding management practices.Methods: In order to achieve the objectives of this study a field survey was conducted. The information required to complete the study were collected from milkshed and non-milkshed villages of Bikaner district. The data was collected by using the pretested interview schedule by visit to their farm to take visual observations and actual measurements of the various desired aspects. The collected data was tabulated and subjected to various statistical methods to draw meaningful inferences. Result: Impact of operation flood programme could most appreciably be seen on the improvement of breeds and breeding methods. Significantly (P less than 0.01) higher percentage of Rathi and crossbreds (41.89% and 13.14%) were found in milkshed area with the low incidence of natural service in comparison to non-milkshed area having low percentage of pure and crossbred cattle with high incidence of natural service. A significantly higher percentage (54.11%) of dairy cattle owners in milkshed area get their cattle inseminated/crossed after 7-12 hours of detection of heat, whereas in non-milkshed area only 32.22% get their cattle inseminated/crossed after 7-12 hours of heat detection. The operation flood program had statistically significant (P less than 0.05) effect on milkshed area with respect to genetic improvement of their stock.

Case Study: On-farm Demonstration for the Impact of Applied Reproductive Technologies

Demonstrating the implementation of, and results from, applied management technologies on privately held farms is an essential method for Extension educators. A commercial cow/calf herd, for which the management was being transitioned to a younger family member, was used for this multi-year demonstration. Beginning summer 2019, the cow herd was inventoried and evaluated, and a plan was put in place to improve profitability through enhanced reproductive management. Initial evaluation showed an overall pregnancy rate of 75.6% with a 153 d calving season for cows and breeding age heifers (n = 209). Non-pregnant and un-sound cattle were sold (n = 56). The average initial BCS was a 4.5 (1 to 9 scale). Estrus synchronization for natural service was utilized in the first breeding season (Fall 2019) to condense the subsequent calving season. Melengestrol acetate (MGA) was fed at a rate of 0.5 mg/head/d for 7 d and bulls introduced on he last day MGA was fed. Also in year 1, timed artificial Insemination was used to breed purchased (n = 37) and home raised (n = 18) replacement heifers. A group of pregnant cows ranging in age from 5 to 8 years (n = 47) were also purchased in year 1. Ultrasonography was used to detect pregnancy and estimate calving date on 30 d post AI, and 30 d post bull removal. Year 2 pregnancy rate was 93% for heifers and 88% for cows with a 131 d estimated calving interval for all cows and heifers (n = 255), with 94% expected to calve in the first 90 days. In summary, while it is difficult to eliminate year-over-year variables, a combination of culling strategy and estrus synchronization for both natural service and AI resulted in an increased proportion of cows and heifers calving earlier in the calving season, which is expected to improve marketing potential and profitability of the resulting calf crop. Condensing the calving interval provides opportunity to introduce additional reproductive management practices. Results from this demonstration will be incorporated into Extension educational curricula.