Effect of energy allowance to triplet-bearing ewes in late gestation on ewe performance, lamb viability, and growth

Peripartum energy metabolism of prolific ewes and their progeny in response to prepartum feeding and litter size

In late gestation, the increased energy demand to support the rapid fetal growth can induce an acute negative energy balance associated with a high risk of pregnancy toxemia, especially for prolific ewes (carrying two or more fetuses). The current study was conducted to evaluate the effects of dietary energy during the last 6 weeks prepartum on the energy metabolism dynamic responses and the newborn lamb metabolic profile in prolific ewes. Forty-five crossbred (Dorset × Romanov) ewes were randomly assigned to 1 of 3 dietary energy densities: ECTRL: 8.36 MJ of metabolizable energy (ME)/kg DM for weeks -6 to -3 relative to lambing, followed by 10.01 MJ ME/kg DM for weeks -2 and -1; EINCR: weekly increments from 7.99 to 12.69 MJ ME/kg DM; and EHIGH: 10.87 MJ ME/kg DM for the last 6 weeks of gestation. Dry matter intake (DMI; daily) and energy intake (MEI; daily), blood concentrations of beta-hydroxybutyrate (BHB) and glucose (every other day), as well as plasma concentrations of non-esterified fatty acids (NEFAs; weekly), BW and body condition score (BCS; twice weekly) were determined throughout the experimental period. The effect of time on DMI and MEI varied based on dietary energy densities and litter size. During the last week before lambing, DMI decreased for EHIGH and EINCR ewes, as well as for ewes carrying quadruplets. On average, during week -5 to week -2 of gestation, EHIGH promoted the highest DMI and MEI, resulting in an increase of 0.16 BCS points between the pretreatment week and week -1 prepartum. In contrast, during the same period, BCS of ECTRL and EINCR ewes decreased by 0.35 and 0.19 points, respectively, which was reflected by higher NEFA concentrations compared with EHIGH ewes. The greater litter size was also associated with decreased BCS. Compared with twin-bearing ewes, for which BCS remained stable, BCS decreased for triplet-, and even more intensively for quadruplet-bearing ewes. Consequently, plasma NEFA concentrations were higher for quadruplet-bearing ewes than for twin- and triplet-bearing ewes, especially during the last week prepartum. Blood BHB concentrations increased from 0.63 to 1.13 mM over time. Regardless of dietary treatments, in the last week prepartum, blood BHB concentrations increased for quadruplet-bearing ewes, being 2.6 and 2.2 times greater than for twin- and triplet-bearing ewes, respectively. These results suggest that dynamic responses of energy metabolism in late gestation of prolific ewes are influenced by both dietary energy level and litter size.

Improving triplet lamb survival: management practices used by commercial farmers

Introduction

Prolificacy has become an important breeding goal in sheep farming to increase farm profitability. With the adoption of improved genetics and management practices leading to increased lambing percentages, the proportion of triplet-born lambs has also increased on farms. However, mortality rates of triplet lambs are higher than for single- and twin-born lambs, and additional management inputs may be needed to support survival. The aim of this study was to identify factors that affect management practices that are considered important for triplet lamb survival by commercial farmers from the United Kingdom (UK), the Ireland (IRE), and New Zealand (NZ).

Methods

An online survey was developed and disseminated to farmers in each country, focusing on farmer demographics, flock characteristics, management practices and production outcomes. A total of 448 farmers completed the survey, from the UK (n = 168), IRE (n = 218), and NZ (n = 62).

Results

Respondents had larger flocks, higher scanning and lambing percentages than the country average for the UK and IRE. The mean percentage of triplet litters born within flocks was 9%, and lambs lost between scanning and lambing were 14% for UK, 15% for IRE, and 25% for NZ respondents (P = 0.063). Overall, 60% of all respondents reported to lamb indoors and 40% lambed outdoors, however NZ farmers almost exclusively lambed outdoors, whereas UK and IRE farmers lambed in both systems (P < 0.001). NZ farmers were more likely to rear all triplet lambs with the ewe, whereas UK and IRE farmers were more likely to remove a lamb to rear by another ewe or artificially (P < 0.001). Factors that influenced triplet lamb management practices of respondents in this study were respondent country of origin, flock size, age, and gender. In general, younger respondents (P < 0.001), and female respondents (P < 0.05), were more likely to engage in management activities that were considered to promote better triplet lamb survival, compared to older and male respondents respectively. These practices were associated with better lamb survival reported by respondents but were less likely to be carried out when flock size increased (P < 0.001).

Discussion

The results of this survey highlight future priorities or communication strategies needed to improve triplet lamb survival.

Promoting viable twin birth on single-bearing ewes in the Arabian Gulf region: reproductive, nutritional, and economic perspectives

Raising sheep and goats in the gulf region is a large entrepreneurial business. This is, of course, derived from the big demands of lamb and goat meats for citizens and expatriates. There is a major population living in the rural desert areas whose main income steps from rising local sheep and goats. Despite large number of farmers into sheep production, the country still imports from foreign countries to meet augment local demand. Thus, improving local sheep production is a means to reduce the importation of sheep from foreign land. The low twinning rates in the main two indigenous breeds (i.e., Najdi and Noemi) in the region motivated the researchers to pursue an avenue for maximizing the neonatal outcomes is a contributing factor to low level of sheep proliferation in the region. Thus, pursuing an avenue for maximizing the neonatal outcome per female is a good strategy. Application of hormonal induction protocol support reproductive efficiency by improving viable twin birth in single-bearing ewes. By applying this method, several sheep raisers could retain their business more effectively.