The objectives of this study were to compare oestrous synchronization expression and conception rate following timed artificial insemination (TAI) with frozen–thawed X‐sexed or unsexed semen in dairy and beef cows. For this study, 227 cows (dairy, n = 130 and beef, n = 97) were assigned to a 9‐day Ovsynch + controlled intravaginal drug release (CIDR) protocol. All cows were TAI using X‐sexed or unsexed semen from 8 sires. Each semen type was obtained from 4 sires [2 dairy (Holstein Friesian) and 2 beef (Angus)]. Pregnancy detection was performed on Days 35, 65 and 95 following TAI by transrectal ultrasonography and hand palpation. The proportion of oestrus expression was higher in dairy (85.3%) cows compared with beef (65.0%) cows (p < .05). Overall, dairy (X‐sexed, 61.9% and unsexed, 62.0%) cows had greater conception rates on Day 35 compared to beef (X‐sexed, 56.0% and unsexed, 52.2%) cows (p < .05). Concurrently, on Day 95, overall conception rates in dairy (X‐sexed, 41.4% and unsexed, 48.5%) cows were greater than beef (X‐sexed, 38.0% and unsexed, 37.0%) cows (p < .05). Pregnancy/embryo losses between Days 35 and 65 in dairy (X‐sexed, 33.3% and unsexed, 18.2%) cows and beef (X‐sexed, 28.6% and unsexed, 29.2%) cows were recorded (p < .05). Dairy (X‐sexed, 7.7% and unsexed, 8.3%) cows had higher incidence of pregnancy losses between Days 66 and 95 when compared to beef (X‐sexed, 5.0% and unsexed, 0.0%) cows (p < .05). Oestrous expression and conception rates in dairy and beef cows were satisfactory. Advanced reproductive biotechnologies can successfully utilize gender‐ablated semen in organized emerging cattle farming systems.

The present study aimed to evaluate an oestrous synchronization protocol and oestrus response before AI in cows from an organised communal production system. A total of 74 cows Bos indicus (Brahman) and Bos taurus/indicus hybrid (Nguni) type from different communal farmers were screened based on: age (3 to 8 years), body condition score of ≥3 (1–5 scale), not pregnant (excluding heifers), 90 days postpartum, number of parities, good mothering ability, and negative for contagious abortion. Selected cows were subjected to a 9-day OvSynch+CIDR protocol. In brief, the protocol included the insertion of controlled intravaginal drug release (CIDR®, Pfizer Laboratories) devices in the reproductive tract (vagina) containing 1.9g of progesterone in each cow on Day 0 with first oestradiol benzoate (Oestradiol benzoate®, VTech) 2-mL intramuscular (IM) injection. Pregnant mare serum gonadotrophin (PMSG; Chronogest®, Intervet International B.V.) 2.5-mL (IM) injection on Day 5. Removal of CIDR and (IM) injection of prostaglandin F2α (PGF2α; Estrumate®, Intervet South Africa (Pty.) Ltd.) 2mL on Day 8. Following CIDR removal, a heat mount detector (Kamar®) was applied on the individual cow’s tail head for oestrus observation (signs of heat) with second oestradiol benzoate 1-mL (IM) injection on Day 9. AI was performed 36h following withdrawal of the CIDR. Frozen/thawed semen from Bonsmara bulls (n=2) of known and proven fertility was used for AI. The GameteTek Cryo-Mobile laboratory was used during thawing of semen straws. and sperm motility and morphological traits were immediately evaluated by computer-assisted sperm analysis (Sperm Class Analyzer®) before each individual cow was inseminated. Pregnancy diagnosis was performed 90 days after timed AI by ultrasound and transrectal palpation. Data were analysed using the logistic regression procedure of SAS (SAS Institute Inc.), with synchronisation response and conception being treated as binary response variables. All cows were synchronized successfully and an oestrus response rate of 100% was recorded. Pregnancy rates were similar (37.8% vs. 38.9%) for both Bos indicus and Bos taurus/indicus hybrid cattle. Bulls total sperm motility of ≥75% were recorded, following thawing of semen straws. Thus, there was no effect of bull on pregnancy. In conclusion, acceptable oestrus synchronization response was achieved in this communal setup. Superior genetic materials can be successfully introduced through assisted reproductive technologies in organised communal production systems.

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