Reproductive traits of Angus, Criollo and reciprocal crossbred females in the temperate area of Argentina

Abstract

Reproductive performance of purebred Angus (A) and Criollo (C) cows and crossbred CA and AC cows inthe temperate area of Buenos Aires, Argentina, was assessed through the study of reproductive rates, calving date, first insemination date, number of inseminations and weight related variables. The herd was grazed on pastures all year round. Matings were by artificial insemination with visual oestrus detection, from October to December. Heifers first calving was at 3 years of age. All traits were analysed with general linear models including, as corresponded, fixed effects of dam and calf genetic groups, calving year and month, dam physiological status, calving age and first order interactions. Female genetic group adjusted means were used to estimate direct (g l ) and maternal (g M ) breed differences and heterosis (h l ) effects on reproductive traits. Weaning rate was mostly determined by oestrons detection rate. Due to the inhibitory effects of nursing on reproduction, female genetic group effects were significant for suckling cows only: mean oestrous detection rate was higher (P < 0-05) for crossbred cows (AC: 91-2 (s.e. 5-1) %; CA: 88-4 (s.e. 2-9) %) than for A (76-3 (s.e. 2-0) %) and C (49-9 (s.e. 3-3) %); direct breed effects favoured A (g lA -g' c = 26-4 (s.e. 3-7) %; P < 0-001) and h 1 was 26-7 (s.e. 3-4) % (P < 0-001). When only oestrous-detected cows were considered, direct breed effects were significant only for pregnancy rate fg' A -g' c = 8-5 (s.e. 4-4) %) whereas h 1 was significant for pregnancy (8-3 (s.e. 3-8) %), calving (9-3 (s.e. 4-1) %) and weaning (10-1 (s.e. 4-1) %) rates (P < 0-05). Criollo cows calved later than crossbred (-19 days) and A (-15 days) cows mainly due to longer post-partum anoestrous. For calving date, direct breed effects favoured A (g' A -g' c = 20-8 (s.e. 5-9) days; P <0-0-001) and h 1 was 11-4 (s.e. 2-8) days (P < 0-001). Low reproductive performance in C was not associated with live iveight at the beginning of mating. This genetic group was the latest in showing oestrous behaviour, even when not suckling. Number of inseminations was similar for the four genetic groups. These results sustain the principle of utilizing Fl Criollo-Angus cows to improve beef herd productivity, whereas they do not support the recommendation of using purebred Criollo females under this type of production system.

Evaluation of the Criollo breed Romosinuano as purebred and crossbred cows with Brahman and Angus in Florida: I. Reproduction and parturition1,2,3

“…Negative calving rate heterosis (−0.08) was detected for Nelore-Criollo crosses in Argentina (Rabasa and Holgado, 2000). The failure to detect Romosinuano-Angus calving rate heterosis in the current study differs from 0.09 reported for Angus-Criollo cows in Argentina (Corva et al, 1995) and the range of 0.02 to 0.09 for Bos taurus crosses (Spelbring et al, 1977;Peacock and Koger, 1980;Cundiff et al, 1992;Newman et al, 1993); however, Kress et al (1990) reported 0.27 for Hereford-Simmental in Montana. In the present study, Brahman-Romosinuano heterosis for calving rate appeared to be consistent with estimates a-c Within a trait (column), means that do not share a common superscript letter differ (P < 0.05).…”

“…Weaning rate heterosis was 0.13 for Guzerat-Criollo (Martínez Velásquez et al, 2006); however, it was not detected in Nellore-Criollo cows (Rabasa and Holgado, 2000). Corva et al (1995) reported a large estimate of weaning rate heterosis (0.1) for Criollo-Angus; no heterosis was detected for Romosinuano-Angus in the present study. Low estimates of heterosis for weaning rate in Bos taurus crosses were −0.03 (Gregory et al, 1978;Newman et al, 1993), but most were in the range from 0.03 to 0.07 (Cundiff et al, 1974;Peacock and Koger, 1980;Kress et al, 1992).…”

Genetic effects for reproductive performance of straightbred and crossbred Romosinuano and Angus cows in a temperate zone

“…This estimate of heterosis is at the upper range of values reported for Bos taurus cows (e.g., Cundiff et al, 1992;Newman et al, 1993) and was as high as many reported Bos indicus-British cross estimates (e.g., Cartwright et al, 1964;Prayaga, 2004). The estimate for heterosis was approximately the same as those for Argentinean CriolloAngus reproductive rates (Corva et al, 1995), although direct Criollo effects were not detected in that work.…”

“…Romosinuano cows conceived later (Po 0.02) in the breeding season than all other breed groups, which did not differ from each other (P4 0.9; Table 2). Argentinean Criollo purebreds calved 19 and 15 d later than reciprocal Angus-Criollo first cross cows and Angus cows (Corva et al, 1995); those authors attributed that to a longer post-partum anestrus period. The estimate of heterosis for day of conception (P ¼0.05) was large and favorable (Table 3), and was similar or of larger absolute size to estimates reported for what seemed to be similar traits: days from calving to first insemination or "days open" in dairy crosses (Dechow et al, 2007;Norberg et al, 2014) and birth date in Hereford-Angus crosses (Long and Gregory, 1974).…”

“…Heterosis expressed by Criollo crossbred cattle for reproduction was characterized in tropical or subtropical regions (Vergara et al, 2009;Riley et al, 2014), but has been investigated to only a limited extent in a temperate zone of the world (Corva et al, 1995), and the productivity of Criollo cattle on a harsh forage such as fescue has been characterized minimally (characteristics of milk; Burke et al, 2010). The objectives of this work were to: (1) estimate heterosis and breed direct effects for cow reproduction traits, (2) assess the effects of the type of forage grazed during the breeding season on those traits and on the estimates of heterosis and breed effects, and (3) characterize calf loss and cow removal by breed type.…”