Reproduction in Domestic Animals

208 PS Brar and AS NandaZebu breed; country of observationsPostpartumanoestrousperiod (days)Services perconception ICI (days) ReferenceTable 1. Postpartum fertility traitsin some breeds of zebu cows inAsiaPunganur; India 152 ± 14 1.57 ± 0.1 473 ± 18 Bramhaiah et al. (2003)Ongole; India 113 ± 2 1.53 ± 0.1 407 ± 2 Baburao and Rao (1999)Sahiwal; India 292 ± 15 – 582 ± 15 Katiyar et al. (1993)Non-descript indigenous; Indonesia 151 ± 56 3.0 – Tjiptosumirat et al. (2007)Non-descript indigenous; Malaysia 114 ± 63 2.8 – Nordin et al. (2007)Non-descript indigenous; Myammar 125 ± 32 1.6 – Win et al. (2007)Table 2. Characteristics of follicular waves in Rathi cowsParameterFollicular wavesWave onset (days) 2.10 ± 0.4 10.55 ± 0.6Wave duration (days) 13.35 ± 1.7 10.45 ± 1.0Max. diameter (mm) of dominant follicle 11.75 ± 1.6 14.65 ± 1.2Day of max. diameter (days) 5.00 ± 0.6 17.5 ± 0.5Growth rate (mm ⁄ day) 1.81 ± 0.3 1.16 ± 0.2Growth period (days) 3.10 ± 0.5 8.90 ± 0.8Onset of atresia (days) 10.50 ± 1.1 –Length of atresia (days) 6.50 ± 0.8 –Atresia rate (mm ⁄ day) 0.55 ± 0.2 –Largest subordinate follicle diameter (mm) 7.42 ± 0.6 7.60 ± 0.9with ACTH, indicating that adrenal glands can be anextra ovarian source of progesterone (Bolanos et al.1997).The overall average oestradiol concentrations on days–1, 0, 5, 10, 14, 18 and 22 of oestrus in Rathi cows were29.36 ± 6.90, 37.25 ± 8.00, 18.24 ± 1.58,24.77 ± 4.22, 21.76 ± 5.50, 22.35 ± 3.81 and34.97 ± 7.74 pM, respectively (Purohit et al. 2000).These values are much lower than in western breeds,especially during oestrus (Dobson 1978). This may bethe cause for a very high incidence of silent oestrus inRathi cows under Indian conditions.Postpartum ReproductionAsian zebu cattle have high incidence of postpartumanoestrus (48.7%, Abeygunawardena and Dematawewa2004) leading to very long ‘open days’ (113–291 days;Table 1). Anoestrous zebu crosses continued to havebasal concentrations of FSH (0.75 ± 0.10 nM) andoestradiol-17 b (6.31 ± 0.62 pM; Mondhe et al. 1989)for very long-period postpartum and exhibited the firstprogesterone rise above 2.0 nM by 66.1 ± 6.8 dayspostpartum (Lyimo et al. 2004). In approximately 45%of zebu crosses, the first postpartum oestrous cycles wereof short duration (3.18 nM, which indicated ovulation followed by activeluteal functions, were noticed as early as 25 dayspostpartum in Ongole cattle and the first standingoestrus was observed between 40 and 45 dayspostpartum (Venkantanaidu et al. 2007). This suggeststhat under favourable conditions, the Asian zebu cattlehave the potential of breeding as early in postpartumperiod as their western counterparts. This has furtherbeen vindicated by the performance of zebu cattle rearedunder relatively better environmental and nutritionalconditions in North and South Americas (Chenoweth1994; Bo et al. 2003).Crossbreeding zebu with exotic dairy breedssubstantially improved their milk production but hadvariable effects on reproduction. While Akhtar et al.(2007) reported elongation of ICI in crosses of pure cowswith Pakistani indigenous breeds, others claimedsignificant improvement in their various reproductiontraits, at least in F1 generation. The F2 generation with>75% exotic blood, however, started having multipletype of reproductive problems. The average ICIincreased from 437 ± 28.9 days in F1 generation to451 ± 34.3 days in F2 onwards with >80% HFinheritance (Singh 2005). The gross uterine involutionin zebu cows was completed by approximately 30 days ofcalving but was delayed to 35.14 ± 1.21 days in cowswith >75% exotic blood (Deshmukh and Kaikini 1990).Endocrine Interventions to Hasten Onset ofPostpartum Ovarian ActivityAssessment of circulatory progesterone profiles has beensuccessfully used for early diagnosis of pregnancy incertain South Asian zebu cattle (Boettcher 2007). Thiswould allow early interventions in non-pregnant cows tohave overall beneficiary effects on cattle production.Progesterone radioimmunoassay (RIA) was 100accurate in diagnosing non-pregnancy and 84–90%pregnancy on 20–24 days after artificial insemination(AI) in Bangladesh, Malaysia, Indonesia and Myanmarzebu cattle (Nordin et al. 2007; Shamsuddin et al. 2007;Tjiptosumirat et al. 2007).Certain hormonal interventions that have commonlybeen used to improve reproductive efficiency in Bostaurus have also been investigated in certain Bos indicusbreeds. Exogenous administration of GnRH,progestogens and ⁄ or PGF 2µ hastened the onset ofovarian activity and induced ovulation in postpartumanoestrous zebu cows. Single injection of 250 lg GnRH(ReceptalÒ, Intervet, Holland) induced ovulation inAsian zebu cows having good body condition score(BCS) and well-grown follicles on the ovariesÓ 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag