ABSTRACT The objective of this study was to identify parameters, before the start of the breeding season, that affect the conception rate of precocious Nelore heifers through ultrasonographic ovarian evaluation and evaluation of weight and body condition score (BCS). A total of 407 heifers aged 404±69 days (≈14 months old), weighing 267.1±31.2 kg, and with mean BCS of 3.1±0.5, were used. Heifers were subjected to hormone treatment to induce cyclicity and, 30 days later, to a fixed-time artificial insemination (FTAI) […]

ABSTRACT Fifty-seven multiparous Awassi ewes in the breeding season were used to compare the effects of controlled internal drug release (CIDR) reuse on hormone profiles, reproductive performance, and economic production. Ewes were randomly allotted to one of three CIDR treatments: new (control), once-used, and twice-used; treatment lasted 12 days. Blood samples were collected from all groups at the time of CIDR insertion, three and six days following insertion, at withdrawal time, and at insemination. Serum estradiol (E2) and progesterone (P4) […]

The objective of this work was to evaluate the influence of low-stress handling (LSH) on reactivity score and pregnancy rate during fixed-time artificial insemination (FTAI) for extensively raised Nellore cows. Multiparous cows (n = 126) were randomly allocated into two groups: G1 (n = 66) and G2, the control group (n = 60). Group G1 was subjected to LSH, in which the animals were handled in a calm and quiet manner, without loud noises or physical aggression, using the point […]

Avaliou-se, durante um ano, o desempenho reprodutivo de 94 vacas leiteiras mestiças Bos taurus x Bos indicus submetidas a um programa de reprodução assistida. Um protocolo de inseminação artificial em tempo fixo (IATF) foi executado por meio de dispositivo intravaginal contendo progesterona e das injeções de prostaglandina F2α e de cipionato de estradiol. Por meio de ultrassonografia, entre 7 e 14 dias após as inseminações ou montas controladas, realizou-se a detecção de corpo lúteo nos ovários a fim de determinar […]