Browsing by Author "Hickson RE"

Now showing 1 - 19 of 19
  • Thumbnail Image
    Item
    Carcass characteristics and meat quality of Hereford sired steers born to beef-cross-dairy and Angus breeding cows.
    (2016-11) Coleman LW; Hickson RE; Schreurs NM; Martin NP; Kenyon PR; Lopez-Villalobos N; Morris ST
    Steers from Angus, Angus×Holstein Friesian, Angus×Holstein Friesian-Jersey and Angus×Jersey cows and a Hereford sire were measured for their carcass and meat quality characteristics. Steers from the Angus×Holstein Friesian cows had a greater final body weight and carcass weight (P<0.05). Steers from Angus×Jersey cows had the lowest carcass weight and dressing-out percentage (P<0.05). There was a greater fat depth over the rump at 12 and 18months of age for the steers from Angus cows (P<0.05) but, not at 24months of age. The steers had similar meat quality characteristics across the breed groups. Steers from Angus×Holstein Friesian and Angus×Jersey cows had a higher ratio of n6 to n3 fatty acids. Using beef-cross-dairy cows to produce steers for meat production does not impact on meat quality. Using Jersey in the breed cross reduced the carcass tissues in the live weight and the potential meat yield.
  • Thumbnail Image
    Item
    Days to calving and intercalving interval in beef and dairy-beef crossbred cows
    Morris ST; Hickson RE; Martin NP; Kenyon PR
    One important attribute of a beef-breeding cow is the ability to wean a calf every year. Furthermore, an earlierborn calf is likely to be heavier at weaning and its dam has more opportunity to conceive again during the following breeding season. In a spring-calving system under the seasonal pastoral-grazing system in New Zealand, a 365- day intercalving interval is desirable. A normal gestation length is 280 days leaving 85 days for a cow to resume oestrous cycles and conceive again to maintain the 365- day calving interval. Literature estimates of the interval between calving and the first oestrous cycle post-calving are 53-82 days for mixed-aged beef-breeding cows and 81-95 days for first-lactation beef-breeding cows (Hickson et al. 2012; Knight & Nicoll 1978; Morris et al. 1978; Smeaton et al. 1986), indicating that a 365-day calving interval is difficult to maintain. An alternative reproductive performance measure to intercalving interval, and favoured in naturally mated beefcow herds, is days to calving, that is defined as the number of days from the start of joining to the day of calving. Days to calving has become the standard fertility trait for genetic evaluation (Meyer et al. 1990; 1991; Johnston & Bunter 1996). A study was conducted to investigate the effects of breed group, year of calving and conception cycle on intercalving intervals and days to calving in straight-bred Angus and Angus-cross-Friesian, Angus-cross-Jersey and Angus-cross-Kiwicross cows from first mating as heifers through to their sixth calving.
  • Thumbnail Image
    Item
    Does ewe nutrition during pregnancy affect the neonatal behaviour of twin-born lambs?
    (2016) Gronqvist GV; Hickson RE; Corner-Thomas RA; Kenyon PR; Stafford KJ; Morris ST
    In this experiment the effects of feeding treatments from mid pregnancy until lambing on the behaviour of twin-bearing ewes and their lambs were investigated. Fifty seven four-year-old Romney ewes were offered a medium (1164 ± 31.6 and 819 ± 16.0 kg DM/ ha pre- and post-grazing pasture mass, respectively) or ad libitum (2181 ± 47.6 and 1431 ± 24.6 kg DM/ha pre- and post-grazing pasture mass, respectively) feeding treatment from day 76 of pregnancy until after lambing. At ear-tagging the time taken for the lambs to stand, make contact with, suck from and follow their dam was recorded. A maternal behaviour score based on the distance the ewe moved away from her lambs during tagging was also recorded. Survival analysis showed that lambs born to ewes offered the medium feeding treatment from mid pregnancy until lambing were quicker to stand, suck and follow compared with lambs born to ewes offered the ad libitum feeding treatment (P<0.05). It is unclear whether these behaviours indicate that lambs born to ewes in the medium treatment were more vigorous or that they had unmet needs that prompted the apparent increase in vigour. Ewe feeding treatments did not affect the maternal behaviour of the ewes.
  • Thumbnail Image
    Item
    Effect of Breeding Heavier Romney Ewe Lambs at Seven Months of Age on Lamb Production and Efficiency over Their First Three Breeding Seasons
    (MDPI (Basel, Switzerland), 2021-12-07) Haslin E; Corner-Thomas RA; Kenyon PR; Pettigrew EJ; Hickson RE; Morris ST; Blair HT
    This experiment examined the effect of breeding heavier ewe lambs on lamb production and their efficiency over their first three breeding seasons. Two groups of ewe lambs were bred at seven months of age at an average pre-breeding live weight of either 47.9 ± 0.36 kg (heavy; n = 135) or 44.9 ± 0.49 kg (control; n = 135). Ewe live weight, number of lambs born and weaned, and lamb live weight were recorded until 39 months of age, and efficiency was calculated for each ewe. Although the number and lamb weaning weight did not differ between treatments over three years, when data were pooled, heavier ewe lambs at breeding weaned a greater number of lambs over the three-year period. The total lamb weaning weight over the three-year period increased by 2% for each additional kilogram at ewe lamb breeding. Breeding heavier ewe lambs had no effect on efficiency. These results suggest that although breeding heavier ewe lambs had a positive effect on lamb production over the three-year period, it had no effect on efficiency. Before final recommendations can be made, lifetime performance and longevity to five years of age of heavier ewe lambs at breeding are required.
  • Thumbnail Image
    Item
    Effects of yard weaning and human contact compared to paddock weaning on the liveweight gain and stress reactivity of beef cattle
    (Taylor and Francis Group, 2023-09-03) Cranston LM; Ramsay BA; Schoorl J-AAJ; Stayton KM; Greaves A; Shanks RD; van Kampen CJ; Cockrem JF; Beausoleil NJ; Morris ST; Sneddon NW; Hickson RE
    In New Zealand beef herds, calves undergo ‘paddock weaning’ by separating calves and cows into different paddocks. Anecdotal evidence indicates ‘yard weaning’ whereby calves are yarded and receive regular human contact during weaning may improve long-term stress reactivity and growth rates. Calves were allocated to one of three treatments for seven days post-separation from dams: paddock weaned with minimal human interaction (PN), paddock weaned with daily human interaction (PV), yard weaned with daily human interaction (YV). Calf liveweight, behavioural and physiological measures of stress reactivity and faecal corticosterone concentration were measured. Until day seven, YV calves lost less liveweight than PV or PN calves (0.5 kg vs. 3.5 and 4.8 kg P < 0.05). On day seven, PN calves had a 23% greater heart rate compared to YV calves and a greater faecal corticosterone concentration than PV and YV calves (in cohort 2 only) (P < 0.05). This indicates, regular non-aversive human contact during weaning may reduce stress associated with the weaning process itself and reduced stress reactivity to subsequent handling and restraint. However, this effect was transient with no consistent longer-term benefits over traditional paddock weaning, in terms of growth or stress reactivity to human handling.
  • Thumbnail Image
    Item
    Estimation of genetic parameters and individual and maternal breed, heterosis, and recombination loss effects for production and fertility traits of spring-calved cows milked once daily or twice daily in New Zealand
    (Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association, 2023-01) Jayawardana JMDR; Lopez-Villalobos N; Hickson RE; McNaughton LR
    The objectives of this study were to estimate genetic parameters and individual and maternal breed, heterosis, and recombination loss effects for milk production and fertility traits of Holstein Friesian (F), Jersey (J), and crossbred Holstein Friesian and Jersey (F × J) cows milked once daily (OAD) or twice daily (TAD) in New Zealand. Data on 278,776 lactations from 30,217 OAD and 170,680 TAD milking cows across 644 spring-calving herds were available. Genetic parameters and individual and maternal breed, heterosis, and recombination loss estimates were obtained from univariate animal models. Heritability and repeatability estimates for milk production, milk composition, and fertility traits were consistent across the milking frequencies. Heritability estimates for yields of milk, fat, protein, and lactose varied between 0.21 and 0.29 in OAD and TAD. Heritability estimates for fertility traits ranged from 0.01 to 0.08 in both populations, and estimates were slightly greater in TAD than OAD milking cows. In both milking populations, individual breed effects for yields were in favor of F cows; however, maternal breed effects for yields were in favor of J dams. Jersey cows were more fertile than the F cows in both milking populations, but maternal breed effects for fertility traits were in favor of F dams. Individual heterosis effects were favorable for all traits and were consistent across milking regimens. Crossbred F × J cows had significantly shorter intervals from start of mating to first service and from start of mating to conception, and a higher proportion of 3-wk submission, 3-wk in calf, and 3-wk calving relative to the average of purebred F and J cows. Recombination loss effects were not always unfavorable for production and fertility traits, but most estimates were small with larger standard errors. Favorable maternal heterosis effects were associated with production traits in both milking systems, but maternal heterosis effects were less likely to influence reproductive performance.
  • Thumbnail Image
    Item
    Fertility of dairy cows milked once daily or twice daily in New Zealand.
    (Elsevier, 2022-11) Jayawardana JMDR; Lopez-Villalobos N; McNaughton LR; Hickson RE
    The objective of this study was to evaluate the reproductive performance of New Zealand dairy cows with different milking regimens. A total of 2,562 herds calving in 2017 met the criteria for inclusion in this study. The herds were classified into 5 different milking regimens: 260 herds with cows milked once daily (OAD) during the entire lactation, 1,206 herds with cows milked twice daily (TAD) during the entire lactation, 94 herds that were switched to OAD milking from TAD milking during the mating period (OAD-M), 700 herds that were switched to OAD milking from TAD milking after peak lactation (OAD-P), and 302 herds that switched to OAD milking from TAD milking at end of the lactation (OAD-E). Time from the start of mating to first service (SMFS), start of mating to conception (SMCO) and first service to conception (FSCO) were analyzed using survival analysis. Time from SMFS, SMCO and FSCO was significantly shorter in cows milked OAD compared with cows milked TAD. Also, cows milked OAD had fewer services per conception and higher mean 3-wk submission (SR21), in calf by 3 wk (PR21), in calf by 6 wk (PR42), conception to the first service (PRFS), 3-wk calving (CR21) and 6-wk calving (CR42), and lower not in calf (NIC) than herds with TAD, OAD-M, OAD-P, OAD-E milking cows. Fertility performance differed with parity; first-parity cows had lower SR21, 6-wk submission (SR42), PR21, PR42, PRFS, CR21, and CR42 values, and higher NIC values than second-parity cows. Third parity cows had the highest values for SR42, PR21, PR42, PRFS, CR21, and CR42, and lowest value for NIC compared with cows of other parities. Significant but minor interactions between milking regimen and parity existed for SMFS, SMCO, FSCO, SR21, SR42, PR21, PR42, PRFS, NIC, and CR21.
  • Thumbnail Image
    Item
    Genetic Parameters for Growth, Ultrasound and Carcass Traits in New Zealand Beef Cattle and Their Correlations with Maternal Performance
    (MDPI, (Basel, Switzerland), 2021-12-23) Weik F; Hickson RE; Morris ST; Garrick DJ; Archer JA
    Research has shown that enhancing finishing performance in beef cows is feasible; however, any adverse impact of selection strategies for finishing performance on the performance of the maternal herd should be taken into account. The aim of this research was to examine the inheritance of growth, ultrasound and carcass traits in finishing beef cattle and to evaluate their correlations with maternal performance traits. Data were collected from a nationwide progeny test on commercial New Zealand hill country farms comprising a total of 4473 beef cows and their progeny. Most finishing traits were moderately to highly heritable (0.28-0.58) with the exception of meat or fat colour and ossification (0.00-0.12). Ultrasound scan traits had high genetic correlations with corresponding traits measured at slaughter (rg = 0.53-0.95) and may be used as a selection tool for improved genetic merit of the beef carcass. Fat content determined via ultrasound scanning in the live animal or at slaughter in finishing cattle is positively genetically correlated with rebreeding performance (rg = 0.22-0.39) in female herd replacements and negatively correlated with mature cow live weight (rg = -0.40 to -0.19). Low-magnitude associations were observed between the genetic merit for carcass fat traits with body condition in mature cows.
  • Thumbnail Image
    Item
    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).
  • Thumbnail Image
    Item
    Genome-Wide Association Studies of Live Weight at First Breeding at Eight Months of Age and Pregnancy Status of Ewe Lambs
    (MDPI (Basel, Switzerland), 2023-03-27) Haslin E; Pettigrew EJ; Hickson RE; Kenyon PR; Gedye KR; Lopez-Villalobos N; Jayawardana JMDR; Morris ST; Blair HT; Ahmad SM
    This study estimated genetic parameters and identified candidate genes associated with live weight, and the occurrence of pregnancy in 1327 Romney ewe lambs using genome-wide association studies. Phenotypic traits considered were the occurrence of pregnancy in ewe lambs and live weight at eight months of age. Genetic parameters were estimated, and genomic variation was assessed using 13,500 single-nucleotide polymorphic markers (SNPs). Ewe lamb live weight had medium genomic heritability and was positively genetically correlated with occurrence of pregnancy. This suggests that selection for heavier ewe lambs is possible and would likely improve the occurrence of pregnancy in ewe lambs. No SNPs were associated with the occurrence of pregnancy; however, three candidate genes were associated with ewe lamb live weight. Tenascin C (TNC), TNF superfamily member 8 (TNFSF8) and Collagen type XXVIII alpha 1 chain (COL28A1) are involved in extracellular matrix organization and regulation of cell fate in the immune system. TNC may be involved in ewe lamb growth, and therefore, could be of interest for selection of ewe lamb replacements. The association between ewe lamb live weight and TNFSF8 and COL28A1 is unclear. Further research is needed using a larger population to determine whether the genes identified can be used for genomic selection of replacement ewe lambs.
  • Thumbnail Image
    Item
    Genomic Regions Associated with Milk Composition and Fertility Traits in Spring-Calved Dairy Cows in New Zealand
    (MDPI (Basel, Switzerland), 2023-04-01) Jayawardana JMDR; Lopez-Villalobos N; McNaughton LR; Hickson RE; Ayaz A; Ullah F; Saqib S
    The objective of this study was to identify genomic regions and genes that are associated with the milk composition and fertility traits of spring-calved dairy cows in New Zealand. Phenotypic data from the 2014-2015 and 2021-2022 calving seasons in two Massey University dairy herds were used. We identified 73 SNPs that were significantly associated with 58 potential candidate genes for milk composition and fertility traits. Four SNPs on chromosome 14 were highly significant for both fat and protein percentages, and the associated genes were DGAT1, SLC52A2, CPSF1, and MROH1. For fertility traits, significant associations were detected for intervals from the start of mating to first service, the start of mating to conception, first service to conception, calving to first service, and 6-wk submission, 6-wk in-calf, conception to first service in the first 3 weeks of the breeding season, and not in calf and 6-wk calving rates. Gene Ontology revealed 10 candidate genes (KCNH5, HS6ST3, GLS, ENSBTAG00000051479, STAT1, STAT4, GPD2, SH3PXD2A, EVA1C, and ARMH3) that were significantly associated with fertility traits. The biological functions of these genes are related to reducing the metabolic stress of cows and increasing insulin secretion during the mating period, early embryonic development, foetal growth, and maternal lipid metabolism during the pregnancy period.
  • Thumbnail Image
    Item
    Growth and Carcass Characteristics of Beef-Cross-Dairy-Breed Heifers and Steers Born to Different Dam Breeds.
    (MDPI (Basel, Switzerland), 2022-03-29) Williamson HR; Schreurs NM; Morris ST; Hickson RE; Ebrahimie E
    Approximately two thirds of the annual beef kill in New Zealand originates from the dairy industry. The recent increase in Jersey genetics in the dairy herd will inevitably result in an increase in Jersey genetics entering the beef herd from retention of dairy-origin calves for finishing. Limited literature is available on the effect of dam breed on the performance of beef-cross-dairy-breed progeny. The aim of this study was to investigate the effect of dam breed from dams with varying proportions of Friesian and Jersey genetics on growth traits and carcass characteristics of their 24-month-old beef-cross-dairy-breed heifer and steer progeny. Liveweights of 142 heifers and 203 steers from Friesian (F), Friesian-cross (FX), Friesian-Jersey (FJ) and Jersey-cross (JX) dams were recorded at birth, weaning, as yearlings and at slaughter. Carcass characteristics were also recorded. At each point measured, liveweight was greatest for calves born to F dams. Calves born to F dams took 93 days to reach a weaning weight of 100 kg, whereas those from FX, FJ and JX dams took 99, 101 and 102 days, respectively. Carcass weight was greatest for progeny of F dams (286 kg, compared with 279, 275 and 276 for progeny of FX, FJ and JX dams, respectively). The progeny of JX dams had yellower fat than all other dam breed groups and a greater incidence of excessively yellow fat (fat score ≥ 5).
  • Thumbnail Image
    Item
    Growth, carcass and meat quality characteristics of Charolais-sired steers and heifers born to Angus-cross-dairy and Angus breeding cows
    (Elsevier Ltd, 2023-07) Coleman LW; Schreurs NM; Kenyon PR; Morris ST; Hickson RE
    Charolais-sired heifers and steers from Angus, Angus × Holstein-Friesian, Angus × Holstein-Friesian-Jersey and Angus × Jersey cows were measured for growth, carcass, and meat quality characteristics. Despite differences in weaning weight and growth rate, the progeny of different breed-crosses did not differ in final live weight or carcass weight (P > 0.05). Carcass and meat quality characteristics did not differ among breed-crosses (P > 0.05), except for fat that was more yellow in progeny from Angus and Angus-cross-Jersey dams. Steers were slaughtered older and had heavier carcasses with greater fat depth and intramuscular fat than heifers. Meat quality differed between the sex classes, with steers having greater pH and shear force, redder meat, and yellower fat than heifers. Angus-cross-dairy cows when crossed with a beef breed sire such as the Charolais will provide progeny for meat production which are competitive to beef breeds for beef finishing and meat production and therefore, a useful mechanism to utilize surplus animals from the dairy industry.
  • Thumbnail Image
    Item
    Growth, milk production, reproductive performance, and stayability of dairy heifers born from 2-year-old or mixed-age dams
    (Elsevier Inc and Fass Inc on behalf of the American Dairy Science Association, 2021-11) Handcock RC; Lopez-Villalobos N; Back PJ; Hickson RE; McNaughton LR
    Keeping replacement heifers that were the progeny of primiparous cows mated by artificial insemination enhances rates of genetic gain. Previous research has shown that heifers that were the progeny of primiparous cows were lighter at birth and grew at a slower rate to first calving compared with heifers born to multiparous dams. Furthermore, heifers that were heavier before first calving produced more milk than did lighter heifers. This study aimed to determine whether there were body weight, milk production, or reproductive disadvantages for heifers born from primiparous compared with multiparous dams. Data comprised body weight records from 189,936 New Zealand dairy heifers. Dams were allocated to 4 groups according to their age: 2 yr old (n = 13,717), 3 yr old (n = 39,258), 4 to 8 yr old (n = 120,859), and 9 yr or older (n = 16,102). Heifers that were the progeny of 2-year-old dams were lighter from 3 to 21 mo of age than heifers that were the progeny of 3-yr-old and 4- to 8-yr-old dams. The progeny of 2- and 3-yr-old dams produced similar milk solids yields (± standard error of the mean) during their first lactation (304.9 ± 1.6 and 304.1 ± 1.5 kg, respectively), but more than that of 4- to 8-yr-old dams (302.4 ± 1.5). Furthermore, the progeny of 2-yr-old dams had similar stayabilities to first, second, and third calving to that of the progeny of 4- to 8-yr-old and ≥9-yr-old dams. Reproductive performance, as measured by calving and recalving rates was similar in first-calving heifers of all age-of-dam classes. Additionally, second and third calving rates were similar for the progeny of 2- and 3-yr-old dams. Interestingly, the progeny of dams ≥9 yr old had the lowest milk solids production in first (297.8 ± 1.6 kg), second (341.6 ± 1.8 kg), and third lactations (393.2 ± 2.4 kg). Based on the results of this study, keeping replacements from dams aged 9 yr and over could not be recommended. Furthermore, heifers born to 2-yr-old dams were lighter but produced more milk than heifers from older dams, in addition to having superior genetic merit.
  • Thumbnail Image
    Item
    Intake of milk and pasture and growth rate of calves reared by cows with high or low potential for milk production
    (CSIRO Publishing, 29/11/2016) Roca Fraga FJ; Lopez-Villalobos N; Martin NP; Kenyon PR; Morris ST; Hickson RE
    Milk production of cows influences calf weaning weight, which is the major driver for economic return in a cow–calf operation. The growth trajectory of 64 steer calves resulting from a terminal cross between Angus or Simmental bulls with Angus, Angus cross Holstein Friesian, Angus cross Jersey and Angus cross KiwiCross cows was examined during the pre-weaning period from birth (D0) to weaning (D148) and during the post-weaning period until a year of age (D365). Random regression models were used to model milk intake and liveweight of calves throughout lactation. These models were a good fit to the data (r2 = 0.77 for milk intake and r2 = 0.99 for liveweight). Total energy intake from milk was greater (P < 0.05) for the Angus cross Holstein Friesian-, Angus cross Jersey- and Angus cross KiwiCross-reared steers than for those reared by Angus dams. Additional milk intake increased liveweight of steers from D90 to D365, but the magnitude of the effect decreased as the calves aged. Simmental-sired steers had a greater liveweight response to additional milk intake than Angus-sired steers at D120 and D148, probably reflecting greater growth potential from out-crossed calves.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Measures of Bone Morphology in the Medial and Lateral Condyles of the Metacarpus in Beef Cross Dairy Cattle at 8–12 and 24 Months of Age
    (MDPI (Basel, Switzerland), 2022-09-01) Gibson MJ; Hickson RE; Dittmer KE; Back PJ; Rogers CW
    Bone morphology in the mid-diaphysis of the metacarpus in cattle and the effect of puberty and age has been well described. However, there is limited information on how age and not attaining puberty affects bone morphology in the epiphysis of the metacarpus. The metacarpus is comprised of the third and fourth metacarpal bones fused together to create a medial and lateral epiphysis. When a cow is in stance phase there is greater pressure on the medial claw; however, the effect of this difference in loading on bone has not been described. Therefore, the aim of this experiment was to describe bone morphology in the medial and lateral epiphysis of the metacarpus at the age of puberty in steers. The metacarpus was collected from beef cross dairy steers at approximately one and two years of age. The distal epiphysis of the metacarpus was scanned using peripheral quantitative computed tomography (pQCT). Measures were corrected for body weight and demonstrated a lack of bone growth cessation at one year of age. The lack of difference in bone morphology in the medial and lateral condyles of the distal metacarpus reflects the even loading distribution observed in the forelimb of cattle.
  • Thumbnail Image
    Item
    The effect of nutrition and body condition of triplet-bearing ewes during late pregnancy on the behaviour of ewes and lambs
    (Asian-Australasian Journal of Animal Sciences, 2018-12) Gronqvist GV; Corner-Thomas RA; Kenyon PR; Stafford KJ; Morris ST; Hickson RE
    OBJECTIVE: Triplet-born lambs are less likely to survive to weaning than twin-born or single-born lambs. Appropriate ewe-lamb bonding behaviours and lamb vigour behaviours are necessary for survival of lambs. The aim of this experiment was to determine whether maternal nutrition during late pregnancy influenced behaviour of the ewe and her lambs soon after birth, and to determine whether mid-pregnancy body condition score (BCS) influenced any behavioural response. METHODS: The experiments included ewes that were in BCS 2.0, 2.5, or 3.0 in mid-pregnancy and were fed either ad libitum or to pregnancy-maintenance requirements in late-pregnancy (day 115 until 136 in experiment one, and day 128 until 141 in experiment two). The time taken for lambs to stand, contact dam, suck from dam and follow dam was recorded three to 18 h after birth. The number of high- and low-pitched bleats emitted by the ewe and lambs was recorded, along with maternal behaviour score (MBS) of the ewe. Lambs in experiment two underwent a maternal-recognition test at 12 or 24 h. RESULTS: There were significant effects of feeding treatment on bleating behaviour of ewes and lambs, but these were inconsistent among BCS groups and between experiments. Lamb vigour behaviours were not affected by feeding treatment. In experiment one, there was no effect of feeding treatment or BCS on MBS, but in experiment two, ewes in BCS3 in mid-pregnancy had greater MBS than ewes in BCS2 in mid-pregnancy (MBS 3.1/5 vs MBS 2.1/5; p<0.05). CONCLUSION: Given there were no repeatable effects on behaviour of ewes and lambs, ad libitum feeding rather than feeding for pregnancy-maintenance requirements cannot be used to improve behaviours soon after birth of triplet-bearing ewes in BCS 2-3 and their lambs in extensive pastoral conditions.
  • Thumbnail Image
    Item
    The influence of age and breed of cow on colostrum indicators of suckled beef calves
    (2016) Hickson RE; Back PJ; Martin NP; Kenyon PR; Morris ST
    Rearing a calf to weaning is a key measure of performance in a beef breeding cow herd. Adequate intake of colostral antibodies by the calf in the first few hours of life is important for passive transfer of immunity, and so is beneficial for calf survival. This experiment aimed to examine the role of udder conformation, maternal age and breed-cross on the colostral status of suckled calves. Udder conformation of Angus, Angus-cross-Friesian, Angus-cross-Jersey and Angus-cross-Kiwicross cows was scored according to Animal Evaluation Limited and BreedPlan standards, and colostral status of calves was determined based on gamma glutamyltransferase activity, immunoglobulin G and total protein concentrations at 24-48 hours of age. Udder conformation was similar (P>0.05) among breed-crosses except Angus cows had looser front udder attachment, lower rear udder attachment and less desirable udders overall than Angus-cross-dairy cows (P<0.05). Most udder conformation scores did not affect colostral status of calves. The exception was teat placement score, for which more outward-pointing teats were associated with improved colostrum status of calves (P<0.05). Survival to weaning was greater for calves with adequate compared with inadequate colostral status (P<0.001).