Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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    Access to reticulated water in late-pregnancy: impacts on ewe productivity, drinking behaviour and some physiological indicators of dehydration
    (Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2025-03-02) Corner-Thomas R; Stafford K; Winchester N; Kenyon P; Sneddon N
    There has been industry debate regarding sheep access to waterways, although there is little information available on the impact of access to water on sheep productivity. It is theoretically possible for actively growing pasture to provide sufficient moisture to meet the daily water intake requirements of sheep. A study was conducted in the Manawatu region during winter across two years with single- (n = 40) and twin-bearing ewes (n = 40) in late-pregnancy. Ewes were restricted from accessing a reticulated water source (no water) or given access (water). Herbage moisture was 81.5 ± 0.7% and 84.8 ± 0.4% in 2017 and 2018, respectively. Of the 40 water treatment ewes, 45% and 55% in 2017 and 2018, respectively, were never observed to drink water. Packed cell volume and total protein concentrations remained within the normal range throughout each study. Ewe liveweight and BCS increased (P < 0.05) throughout the study period but did not differ between treatments except among single-bearing ewes in 2018. The litter weight of single- and twin-bearing ewes in the water and no water treatments did not differ (P > 0.05). These results suggest that under the conditions of the current study, ewes in late pregnancy did not require access to reticulated water.
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    Live Weight and Bone Growth from Birth to 23 Months of Age in Holstein–Friesian, Jersey and Crossbred Heifers
    (MDPI (Basel, Switzerland), 2022-06-01) Gibson MJ; Adams BR; Back PJ; Hickson RE; Dittmer KE; Rogers CW
    Selection pressure for greater milk solid production, calving ease and early puberty attainment has resulted in the alteration of the growth trajectory of New Zealand dairy heifers. Although previous data have looked at stature growth in terms of height and girth, changes in the growth trajectory as a result of seasonal growth has not been examined. In addition, the relative contributions of the appendicular skeleton and thorax in relation to height have not been considered in previous studies. Therefore, the aim of this study was to examine how the proportional contributions of stature change with increases in live weight in Holstein–Friesian, Jersey and Holstein–Friesian–Jersey crossbred heifers from birth to 23 months of age (just prior to calving). Comparisons of height, length, girth and distal and proximal forelimb length (stature) revealed that at the same live weight, measures of girth, length and height did not differ between breeds (p < 0.05). As live weight increases, the relative contribution of the distal limb to increasing height decreases, which is consistent with the cessation of physeal growth occurring earlier in the bones of the distal limb than in the proximal limb. By understanding the timing of proximal and distal growth in dairy heifers, the effect of seasonal growth on longitudinal bone growth can be identified.
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    Genetic Parameters for Maternal Performance Traits in Commercially Farmed New Zealand Beef Cattle
    (MDPI (Basel, Switzerland), 2021-08-26) Weik F; Hickson RE; Morris ST; Garrick DJ; Archer JA; Michael E D
    Maternal performance is a major driver of profitability in cow-calf beef cattle enterprises. The aim of this research was to evaluate the inheritance of maternal performance traits and examine the intercorrelation among reproduction, live weight, hip height, body condition and maternal contribution to calf weaning weight in 15-month-old heifers, 2-year-old cows and mature cows in New Zealand beef herds. Data were collected on a total of 14,241 cows and their progeny on five commercial New Zealand hill country farms. Heritabilities were low for reproductive traits in heifers and mature cows (0-0.06) but were greater in 2-year-old cows (0.12-0.21). Body condition scores were lowly (0.15-0.26) and live weights (0.42-0.48) and hip heights (0.47-0.65) highly heritable in heifers, 2-year-old cows and mature cows. Results indicate that 2-year-old cows with higher genetic potential for rebreeding ability may have greater genetic merit for live weight, hip height and body condition as heifers (rg = 0.19-0.54) but are unlikely to be larger cows at maturity (rg = -0.27--0.10). The maternal genetic effect on weaning weight had a heritability of 0.20 and was negatively genetically correlated with body condition score in lactating cows (rg = -0.55--0.40) but positively genetically correlated with rebreeding performance (rg = 0.48).
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    Productivity and Reproductive Performance of Mixed-Age Ewes across 20 Years of Selection for Ultrafine Wool in Uruguay
    (MDPI (Basel, Switzerland), 2021-08-01) Ramos Z; Blair HT; De Barbieri I; Ciappesoni G; Montossi F; Kenyon PR
    This study reports the phenotypic trends for wool, growth, and reproductive traits in mixed-age ewes after twenty years of genetic selection. Data were obtained from the Merino nucleus flock in Uruguay between 1999 and 2020. Overall, the aim of this selection flock was to reduce the fiber diameter (FD) and increase both the clean fleece weight (CFW) and live weight (LW). Data on ewe wool traits, LW, body condition score (BCS), the total number of lambs weaned (TLW), and the total LW of lambs weaned (TWW) across all lambing opportunities (1–8 mating seasons) were analyzed. Between 1292 and 2063 ewes were measured, depending on the trait considered. Ewe FD decreased by approximately 3 µm (19–16 µm), whereas greasy fleece weight (GFW) increased by 0.2 kg. This improvement in wool traits was accompanied by increases in LW at mating (3 kg), decreases in BCS at mating (approximately by 1 unit), and a small positive change in TWW across years. This study demonstrated that increasing farmer income by selecting for finer wool, heavier fleeces, and heavier animals can be obtained without compromising ewe lifetime reproduction.
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    Phenotypic Responses to Selection for Ultrafine Wool in Uruguayan Yearling Lambs
    (MDPI (Basel, Switzerland), 2021-02-22) Ramos Z; Blair HT; De Barbieri I; Ciappesoni G; Montossi F; Kenyon PR
    This study evaluated the phenotypic trends for wool and growth traits of the fine Merino genetic nucleus in Uruguay. Data were collected from one-year-old lambs over a twenty-year period (1999–2018). The overall aim of the selection flock was to reduce fiber diameter with concomitant increases in fleece and live weights. Traits analyzed included fiber diameter (FD), greasy fleece weight (GFW), coefficient of variation of FD (CVfd), staple length (SL), scoured yield (SY), live weight post-shearing (LW), eye muscle area (EMA) and fat thickness (FAT). Data from approximately 5300 one-year-old male and female lambs were analyzed. During the study period, FD decreased by approximately 3 µm, whereas GFW and LW increased by at least 0.5 and 3.0 kg, respectively. There were interactions between the sex of the individual and the year for all wool traits. Except for FAT, all other traits were affected by the dam age. This study indicates that the selection program applied in the fine Merino genetic nucleus over a twenty-year period resulted in reductions in FD and increases in GFW and LW. Therefore, the results indicate it is possible to produce ultrafine wool in semi-extensive grazing systems without compromising other economically relevant traits in one-year-old lambs.