Genetic variability of the length of postpartum anoestrus in Charolais cows and its relationship with age at puberty

Fertility records (n = 1 802) were collected from 615 Charolais primiparous and multiparous cows managed in an experimental herd over an 11-year period. The objectives of the study were to describe the genetic variability of the re-establishment of postpartum reproductive activity and the relationship with body weight (BW) and body condition score (BCS) at calving and age at puberty. The length of postpartum anoestrus was estimated based on weekly blood progesterone assays and on twice daily detection of oestrus behaviour. The first oestrus behaviour was observed 69 days (± 25 days s.d.) post-calving and the first positive progesterone measurement (≥ 1 ng mL-1) was observed at 66 days (± 22 days s.d.) for the group of easy-calving multiparous suckling cows. Estimates of heritability and repeatability were h2 = 0.12 and r = 0.38 respectively, for the interval from calving to first oestrus (ICO). Corresponding values were h2 = 0.35 and r = 0.60 for the interval from calving to the first positive progesterone test (ICP). The genetic correlation between both criteria was high (rg = 0.98). The genetic relationships between postpartum intervals and BW and BCS of the female at calving were negative: the genetic aptitude to be heavier at calving and to have high body reserves was related to shorter postpartum intervals. A favourable genetic correlation between age at puberty and postpartum intervals was found (rg between 0.45 and 0.70). The heifers which were genetically younger at puberty also had shorter postpartum intervals

Short- and mid-term effects on performance, health and qualitative behavioural assessment of Romane lambs in different milk feeding conditions

The common practice of artificially rearing lambs from prolific meat breeds of sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short- and mid-term advantages of artificially feeding fresh ewe's milk instead of commercial milk replacer on lambs' growth, health and welfare. Romane lambs were either separated from their mothers on D3 and fed with Lacaune ewes' milk (LAC, n?=?13) or milk replacer (REP, n?=?15), or they were reared by their mothers (MOT, n =?15). On D45, they were weaned, gathered in single-sex groups until the end of the study on D150. Lamb performance and biomarkers of overall health were assessed by measuring: growth, dirtiness of the perianal area, enteric pathogens in the faeces, total antioxidant status and redox status assessed by plasma reduced glutathione/oxidised glutathione ratio, and immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles were also investigated. Last, qualitative behaviour assessment (QBA) was performed as an integrated welfare criterion. Lacaune ewes' milk and REP never differed in their average daily gain but grew less than MOT lambs in the early suckling period and just after weaning. No effect was detected afterwards. On D30, LAC and REP lambs had lower total antioxidant and higher redox status than MOT lambs but did not differ among themselves. Lacaune ewes' milk and MOT had a cleaner perianal area than REP lambs on D21, while faecal pathogen infection did not vary between the treatment groups. After vaccination, LAC also had a stronger immune response on D90 compared to REP lambs. Transcriptome analysis performed on D150 showed differential gene expression, mainly in relation to inflammatory, immune and cell cycle response, between male lambs of the LAC group and those of the MOT and REP groups. Based on QBA, LAC lambs never differed from MOT lambs in their general activity and varied from REP only on D21; REP lambs were always more agitated than MOT lambs. In conclusion, artificial milk feeding impaired early growth rate, health and emotional state mainly during the milk feeding period and at weaning. Feeding artificially reared lambs with fresh ewe's milk partly mitigated some of the negative effects induced by milk replacer but without achieving the full benefit of being reared by the mother

Comportement, Adaptation, Robustesse et Approche Intégrée du Bien-être

Comportement, Adaptation, Robustesse et Approche Intégrée du Bien-être. Réunion Scientifique d'Agroscop

Continuous monitoring of cow activity to detect sub-acute rumen acidosis

Continuous monitoring of cow activity to detect sub-acute rumen acidosis. 8. European Conference on Precision Livestock Farming (ECPLF

Puberty in Charolais heifers in relation to growth rate. 2. Genetic variability

International audienc

Genetic relationship between cyclic ovarian activity in heifers and cows and beef traits in males

<p>Abstract</p> <p>Records were collected in an experimental herd over an 11-year period from purebred Charolais heifers (<it>n </it>= 351), cows (<it>n </it>= 615) and young entire bulls (<it>n </it>= 383). The objective of the study was to estimate the genetic relationship between the components of female ovarian activity (age at puberty and <it>postpartum anoestrus </it>length), their growth rate and body condition score and beef traits measured on related bulls. Two methods were used to estimate age at puberty and <it>postpartum anoestrus </it>length: the detection of oestrous behaviour and a test of cyclicity based on plasmatic progesterone assay. This study shows the existence of significant heritability estimates for the different cyclicity traits (<it>h</it>²between 0.11 and 0.38). Most of the genetic correlation coefficients between ovarian activity and growth rate of females and males are negative and favourable (<it>r</it>_gbetween -0.43 and 0.06). Cyclicity is also favourably related with body condition score in young or adult females (<it>r</it>_gbetween -0.65 and -0.22). The genetic relationship between female ovarian activity and proportion of adipose tissue in the male carcass is, however, close to zero. These results show that an antagonism between male beef traits measured in this study and female ovarian activity is unlikely to be a cause for concern in the short term.</p

Genetic relationship between cyclic ovarian activity in heifers and cows and beef traits in males

Records were collected in an experimental herd over an 11-year period from purebred Charolais heifers ($n=351$), cows ($n=615$) and young entire bulls ($n=383$). The objective of the study was to estimate the genetic relationship between the components of female ovarian activity (age at puberty and postpartum anoestrus length), their growth rate and body condition score and beef traits measured on related bulls. Two methods were used to estimate age at puberty and postpartum anoestrus length: the detection of oestrous behaviour and a test of cyclicity based on plasmatic progesterone assay. This study shows the existence of significant heritability estimates for the different cyclicity traits ($h^2$ between 0.11 and 0.38). Most of the genetic correlation coefficients between ovarian activity and growth rate of females and males are negative and favourable ($r_{\rm g}$ between $- 0.43$ and 0.06). Cyclicity is also favourably related with body condition score in young or adult females ($r_{\rm g}$ between $- 0.65$ and $- 0.22$). The genetic relationship between female ovarian activity and proportion of adipose tissue in the male carcass is, however, close to zero. These results show that an antagonism between male beef traits measured in this study and female ovarian activity is unlikely to be a cause for concern in the short term