Prepartum supplementation effects on growth and fertility in Bos indicus-cross cows

1997 ◽  
Vol 37 (2) ◽  
pp. 141 ◽  
Author(s):  
G. Fordyce ◽  
L. A. Fitzpatrick ◽  
T. J. Mullins ◽  
N. J. Cooper ◽  
D. J. Reid ◽  
...  
Keyword(s):  
Body Condition ◽  
Post Partum ◽  
Bos Indicus ◽  
Late Pregnancy ◽  
Dry Season ◽  
Pregnancy Rates ◽  
Wet Season ◽  
Calf Growth ◽  
Treatment Groups ◽  
Calving Season

Summary. Three experiments were conducted in the dry tropics of north Australia using Bos indicus-cross cows. Cows in mid–late pregnancy were either unsupplemented during the late dry season or offered ad libitum (2 kg/day) molasses with 7.4% urea (w/w) (M8U) or cottonseed meal (1 kg/day) for up to 54 days commencing 2 months before the start of the calving season. Supplementation reduced weight loss in experiments 1 and 2 (P<0.05), but had no significant effect on weight or body condition in experiment 3. Supplementation had no effect on subsequent calf growth or cow lactation yields. Following early wet season rains in experiment 1, 9 and 49% of cows were ovulating 40 and 80 days post-partum, respectively, with no effect of supplementation. In experiment 2, 10 and 100% of cows had ovulated by 60 and 200 days post-partum, respectively. At any time between 80 and 180 days post-partum, supplemented cows were more likely to be cycling (P<0.05), independent of supplementation effects on weight or body condition. The average post-partum interval to oestrus was 30 days less in cows supplemented for 42 days (P = 0.08). In experiment 3, pregnancy rates in 1/2 and 3/4 Brahmans supplemented with M8U for 54 days (MU54) or whose calves were weaned at 2–3 months of age (WEAN) were 14% higher in the latter 2 months of mating than in cows supplemented for less than 40 days. Good seasonal conditions resulted in high pregnancy rates in all mature 5/8 Brahmans; when not weaned early, their average calving to conception interval (CCI) was 54 days (s.e. = 8.5 days). Pregnancy rates of first-lactation 5/8 Brahmans (average CCI of 125 days) supplemented for 39 days or less and weaned when calves averaged 6 months of age were 14–32% lower between 2 and 9 months post-partum than in contemporaries in the MU54 or WEAN treatment groups. It was concluded that dry-season supplementation of mid- to late-pregnant Bos indicus-cross cows with an energy concentrate for 42–54 days (‘spike’ feeding) may reduce post-partum anoestrus intervals via a mechanism which is not dependent on the effects on weight or body condition.

Effects of different weaning strategies on postweaning growth rate, mortality and fertility of Bos indicus cross cattle

1990 ◽  
Vol 30 (1) ◽  
pp. 1 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
R Tyler ◽  
HP Stephenson ◽  
GWJ Mason ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bos Indicus ◽  
Dry Season ◽  
Subsequent Growth ◽  
Wet Season ◽  
Lower Growth ◽  
Treatment Groups ◽  
Pooled Data ◽  
Dry Tropics ◽  
Native Pastures

Three drafts of Brahman cross calves (phenotypically half to three-quarters Bos indicus) were either early weaned (EW) in April (mean age 5 months) or late weaned (LW) in July (mean age of 8 months). Their postweaning performance on native pastures in the dry tropics of North Queensland was monitored through to 2.5 years of age for females and 3.5 years for males. At late weaning, LW calves of both sexes were significantly (P<0.01) heavier than EW calves. Mean liveweight differences over the 3 drafts were 53.8 kg for males and 54.4 kg for females. From late weaning until final liveweight, EW animals partially compensated in growth and were on average 13.6 kg lighter at 3.5 years for males and 20.3 kg lighter at 2.5 years for females than LW animals. In draft 2, pregnancy rate at 2.5 years favoured LW heifers (P<0.05) by 38% units. Mortalities occurred only in the first dry season postweaning with 0, 5 (11.1%) and 5 (8.9%) deaths from poverty in the EW group in drafts 1 to '3 respectively but none in the LW group. Pooled data across treatment groups showed that older calves at weaning had lower growth rates during the first dry season but still had heavier final liveweights. Age at weaning did not influence subsequent growth rate in the first wet season or males in year 2 or year 3 postweaning.

20 PREGNANCY RATES IN SUCKLED BEEF COWS SYNCHRONIZED WITH PROGESTERONE INTRAVAGINAL DEVICES AND RECEIVING eCG FOURTEEN DAYS AFTER BREEDING

2010 ◽  
Vol 22 (1) ◽  
pp. 168 ◽  
Author(s):  
L. Cutaia ◽  
M. Ramos ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Body Condition ◽  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Treatment Groups ◽  
Condition Score

An experiment was designed to test the following hypotheses: (1) the administration of 400IU of eCG (Novormón, Syntex SA, Buenos Aires, Argentina) 14 days after fixed-time artificial insemination (FTAI) increases pregnancy rates in cross-breed Zebu × Bonsmara suckled cows synchronized with progesterone releasing devices (DIB 0.5, 0.5 g of progesterone, Syntex SA); and (2) pregnancy rates in cows treated with estradiol or GnRH, combined with a DIB device, are not different. Primiparous suckled cows (n = 260), between 60 and 120 days postpartum (DPP) and with a body condition score between 2.0 and 2.5 (1 to 5 scale) were used. At the beginning of the experiment (Day 0), all cows were examined by rectal palpation (only 11% had a CL), received a DIB device, and were randomly allocated to 1 of 3 treatment groups. Cows in the E2 group received 2 mg of estradiol benzoate (EB) intramuscularly (i.m.) at DIB insertion and those in the two GnRH groups received 100 μg of gonadorelin (GDR Gonasyn, Syntex SA) at the same time. On Day 7, DIB devices were removed and all cows received 500 μg of cloprostenol (Ciclase DL, Syntex SA) plus 400 IU of eCG (i.m.). Cows in the E2 group received 0.5 mg of estradiol cypionate (ECP, Cipiosyn, Syntex SA) and underwent FTAI administered by one technician, using semen from 1 of 2 bulls between 52 and 56 h later. Cows in the GnRH groups received a dose of 100 μg of gonadorelin (full GnRH group) or 50 μg of gonadorelin (1/2 GnRH group) at the time of the FTAI (52 to 56 h after DIB removal). Fourteen days after FTAI cows in the 3 groups were further subdivided (3 × 2 factorial) to receive or not 400 IU of eCG i.m. Pregnancy was determined 30 days after FTAI using real-time ultrasonography. Data were analyzed by logistic regression, taking into account the effect of the synchronization treatment, eCG or noteCG, 14 days after FTAI and sire used. No differences in pregnancy rates were found (P = 0.16) among treatment groups (E2: 39/87, 43.7%, full GnRH: 38/92, 41.3%, and 1/2 GnRH: 25/81, 30.9%). However, there was a significant (P = 0.02) effect of eCG treatment 14 days after FTAI (eCG: 60/127, 47.2% v. no eCG: 41/133, 30.8%). Furthermore, bull A (77/155, 47.1%) resulted in higher pregnancy rate (P = 0.009) than bull B (28/107, 26.2%), but there were no significant interactions between bull and synchronization treatment or eCG administration 14 days after FTAI (P > 0.1). We conclude that the application of 400 IU of eCG 14 days after FTAI increases pregnancy rates in suckled Bos taurus × Bos indicus primiparous cows with fair to poor body condition score synchronized with progesterone releasing devices. Furthermore, the use of estradiol ester or GnRH at DIB insertion and removal did not affect pregnancy rates.

39 EFFECT OF TIME OF FIXED-TIME AI ON PREGNANCY RATES IN ZEBU CROSS-BRED BEEF HEIFERS TREATED WITH PROGESTERONE RELEASING DEVICES AND ESTRADIOL CYPIONATE

2010 ◽  
Vol 22 (1) ◽  
pp. 177 ◽  
Author(s):  
M. Ramos ◽  
L. Cutaia ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Condition Score ◽  
To Receive

Two experiments were designed to evaluate the effect of the timing of fixed-time AI (FTAI) in relation to the removal of an intravaginal progesterone-releasing device (1 g of progesterone, DIB, Syntex SA, Buenos Aires, Argentina) on pregnancy rates in Bos indicus × Bos taurus cross-bred heifers. In experiment 1, 285 Bonsmara × zebu cross-bred heifers, between 18 and 24 months of age and with a body condition score (BCS) between 3.0 and 3.5 (1-5 scale) were used. On the day of initiation of treatment (Day 0), the heifers’ ovaries were palpated (92% of them had a CL) and they received a new DIB plus 2 mg of estradiol benzoate (EB; Syntex SA) and 250 μg of cloprostenol (Ciclase DL, Syntex SA). On Day 8, DIB devices were removed and all heifers received 250 μg of Ciclase plus 0.5 mg of estradiol cypionate (ECP; Cipiosyn, Syntex SA). At that time the heifers were randomly divided to receive FTAI between 48 to 49 h, 53 to 54 h, or 58 to 59 h after DIB removal. The heifers underwent FTAI with semen from 4 bulls by 2 inseminators. In experiment 2, 260 heifers from the same group as those used in experiment 1 (87% with a CL) were treated exactly as those in experiment 1, except that previously used DIB was inserted on Day 0. Pregnancy diagnosis was performed 30 days post-fixed-time AI by ultrasonography. The data were analyzed by logistic regression, taking into account the effect of time of FTAI, semen, and inseminator on pregnancy rates. In experiment 1, pregnancy rates were lower (P = 0.04) in the heifers undergoing FTAI between 48 and 49 h after DIB removal (46/95, 48.4%) than those undergoing FTAI 53 to 54 h (61/99, 61.6%) or 58 to 60 h (57/91, 62.6%) after DIB removal. However, no differences in pregnancy rates were found (P = 0.72) in experiment 2 between the 3 treatment groups, with 39/91 (42.9%) for the 48 to 49 h group, 45/89 (50.6%) for the 53 to 54 h group, and 35/89 (43.8%) for the 58 to 59 h group. There was no effect of the semen or inseminator (P > 0.2) in either experiment. We conclude that when Bos indicus × Bos taurus beef heifers are synchronized with new DIB devices and ECP, higher pregnancy rates are obtained in heifers undergoing FTAI late (between 53 to 60 h after DIB removal) than in those undergoing FTAI early (48 to 49 h after DIB removal). However, time of insemination does not apparently affect pregnancy rates when Bos indicus × Bos taurus beef heifers are synchronized with previously used DIB devices and ECP.

Creep feeding and prepartum supplementation effects on growth and fertility of Brahman-cross cattle in the dry tropics

1996 ◽  
Vol 36 (4) ◽  
pp. 389 ◽  
Author(s):  
G Fordyce ◽  
NJ Cooper ◽  
IE Kendall ◽  
BM O'Leary ◽  
Jde Faveri ◽  
...  
Keyword(s):  
Post Partum ◽  
Bos Indicus ◽  
Weather Conditions ◽  
Wet Season ◽  
Short Term ◽  
Research Committee ◽  
Creep Feeding ◽  
Dry Tropics ◽  
Creep Feed ◽  
Short Period

Post-partum anoestrus is a primary contributor to low branding rates in Bos indicus cattle herds in the dry tropics of northern Australia [Entwistle, K. W. (1983). Australian Meat Research Committee Review No. 431. To increase branding rates, it was hypothesised that creep feeding for a short period in mid-late lactation during the latter half of the growing season may trigger an earlier onset of post-partum oestrus cycling, just as short-term, high-level, prepartum supplementation can achieve. Two experiments were conducted using Fn Brahman-cross cows (1/2, 5/8 and 3/4 crosses with Beef Shorthorn) which calved from late October to late Januarv. Cows were mated from mid-late Januarv to mid-April. Calves in one treatment in both experiments had ad libitum access to creep feed (calf pellets: 16% crude protein, 10 MJ ME/kg) for 4042 days from late February to early April. In experiment 2, the effects on cow growth and fertility due to supplementation with either cottonseed meal (1.5 kg/day) or molasses with 7.4% (w/w) urea for 49 days late in the dry season before calving ('spike' feeding) were also evaluated. Control cattle were unsupplemented. Creep feed was only consumed at 0.1 and 0.4 kg/day in experiments 1 and 2, respectively. Short-term creep feeding had no consistent effects on cow liveweights, condition, or fertility, or on calf growth and temperaments under extensive grazing conditions during the tropical wet season. Spike feeding reduced weight loss by 0.2-0.4 kg/day (P<0.01). The effects on liveweights did not persist into the wet season. There were no effects on cow fertility in this year of extreme weather conditions, when 4 months of nutritional and climatic stress followed supplementation.

The influence of pre-weaning nutrition on biochemical and myofibre characteristics of bovine semitendinosus muscle

2001 ◽  
Vol 52 (9) ◽  
pp. 891 ◽  
Author(s):  
Peter G. Allingham ◽  
Gregory S. Harper ◽  
David W. Hennessy ◽  
V. Hutton Oddy
Keyword(s):  
Muscle Development ◽  
Late Pregnancy ◽  
High Energy ◽  
Eating Quality ◽  
Growth Path ◽  
Semitendinosus Muscle ◽  
Calf Growth ◽  
Treatment Groups ◽  
Sarcoplasmic Protein ◽  
Biophysical Attributes

This study investigates pre-weaning growth of cattle and its effect on biochemical and histochemical markers of muscle development and subsequent biophysical attributes of eating quality. Combinations of cow (late pregnancy to mid-lactation) and pre-weaning (varying duration of access to a high-energy ration) supplementation were used to vary calf growth to weaning in 6 treatment groups. After weaning, calves were grazed together on pasture (backgrounding) and then grown rapidly on a feedlot ration (finishing) until slaughter. Biochemical and myofibre characteristics were determined in semitendinosus muscle samples collected just prior to weaning (7 months), at the end of backgrounding (13 months), and at slaughter (17 months). The concentration of sarcoplasmic protein and the activity of lactate dehydrogenase in the muscle at weaning were associated with differences in pre-weaning growth and both variables correlated positively with liveweight at weaning. Isocitrate dehydrogenase activity varied with sex, not treatment, at weaning and at the end of backgrounding. The size of myofibres at weaning related to differences in growth path and correlated positively with liveweight. Pre-weaning growth effects on these characteristics were not evident at slaughter. Biophysical properties of the meat were not affected by earlier growth path treatment, and were not correlated with biochemical characteristics or myofibre type profile. Variation in both shear peak force and adhesion was related to sex. We conclude that the effects of divergent early life growth do not persist 10 months after weaning, at least in meat quality characteristics.

Influence of Body Condition and Restricted Suckling on Post-partum Reproductive Performance of Zebu Cows (Bos indicus) in the Humid Tropics

1996 ◽  
Vol 31 (2) ◽  
pp. 363-367 ◽  
Author(s):  
JM Bolaños ◽  
M. Forsberg ◽  
H. Kindahl ◽  
H. Rodríguez-Martínez
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Post Partum ◽  
Bos Indicus ◽  
Humid Tropics ◽  
Zebu Cows

scholarly journals 180EFFECT OF TIME OF ECG TREATMENT ON PREGNANCY RATES IN BOS INDICUS×BOS TAURUS RECIPIENTS SYNCHRONIZED WITH PROGESTERONE VAGINAL DEVICES AND TRANSFERRED WITHOUT ESTRUS DETECTION

2004 ◽  
Vol 16 (2) ◽  
pp. 212
Author(s):  
L.F. Nasser ◽  
E.L. Reis ◽  
A.M. Oliveira ◽  
G.A. Bo ◽  
P.S. Baruselli
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Bovine Embryo ◽  
Treatment Groups ◽  
Estrus Detection ◽  
Treatment Interaction

It has been shown recently that treatments with progesterone (P4)-releasing devices combined with estradiol benzoate (EB) plus P4 on Day 0, eCG and PGF on Day 5 and a second application of EB one day after device removal (Day 9) can be used successfully to transfer bovine embryos at a self-appointed time, without the necessity of estrus detection. Although the treatment solved one of the major problems in recipient management, estrus detection, it requires handling the recipients at least five times for treatments and embryo transfer. An experiment was designed to evaluate whether reducing one day of handling, by the administration of eCG and PGF at the time of removal of the P4 device (Day 8), results in comparable pregnancy rates than giving eCG on Day 5. A secondary objective was to determine the effect of injectable P4 at the time of device insertion plus EB treatment. Crossbred Bos taurus×Bos indicus beef heifers (n=301) were randomly assigned to 4 treatment groups in a 2 by 2 factorial design. All Heifers received a P4 device (DIB, Syntex, Argentina) plus 2mg EB i.m. (Syntex) at unknown stages of the estrous cycle (Day 0), with or without 50mg of P4 given i.m. at the same time. Heifers were further subdivided to receive PGF (0.150mg d-cloprostenol, Prolise, Tecnopec, Sao Paulo, Brazil) and 400IU of eCG (Novormon, Syntex) i.m. on Days 5 or 8. In all heifers, DIB devices were removed on Day 8 and 1 mg EB was administered i.m. on Day 9. Day 10 was arbitrarily considered as the day of estrus. On Day 17, heifers were bled for plasma P4 concentrations and examined by ultrasonography to determine the number of CL and their diameter. Heifers that had &gt;1 CL or a single CL with diameter ≥18mm received an in vitro-produced (IVP) embryo by nonsurgical transfer performed by the same veterinarian. Pregnancy rates were determined by ultrasonography 30 days later. The effects of Day of eCG administration (Day 5 or Day 8), P4 of treatment (E2 or E2+P4) and the day-by-P4 treatment interaction on the numbers of CL and plasma P4 were analyzed by ANOVA, and the proportion of recipients selected and pregnant were analyzed using non-parametric tests (NPAR1WAY, SAS). There was no significant effect of P4 treatment or the P4-by-day of eCG interaction in any of the parameters evaluated. However, there was a significant effect of day of eCG administration on plasma P4 concentrations (Day 5=2.4±0.3 v. Day 8=1.7±0.2; P=0.03) and the number of CL (Day 5=1.4±0.1 v. Day 8=1.1±0.0; P=0.02) on Day 17. Furthermore, the proportion of recipients pregnant/treated tended (P=0.1) to be higher in heifers in the Day 5 Group (71/151, 47.0%) than in those in the Day 8 Group (61/150, 40.7%). Although delaying the eCG and PGF administration from Day 5 to Day 8 saves one trip through the chute for treatments, it resulted in lower plasma P4 concentrations and tended to decrease pregnancy rates in bovine embryo recipients synchronized with DIB devices and EB and transferred at a fixed time. Furthermore, the administration of injectable P4 at the time of DIB insertion did not affect pregnancy rates.

Effect of reproductive status, body condition and age of Bos indicus cross cows early in a drought on survival and subsequent reproductive performance

1990 ◽  
Vol 30 (3) ◽  
pp. 315 ◽  
Author(s):  
G Fordyce ◽  
R Tyler ◽  
VJ Anderson
Keyword(s):  
Body Condition ◽  
Bos Indicus ◽  
Reproductive Status ◽  
Severe Drought ◽  
Wet Season ◽  
Drought Period ◽  
Probability Of Survival ◽  
Early Stages ◽  
Conception Rates ◽  
In Pregnancy

A herd of 802 Brahman cross cows, managed under extensive conditions (7000 ha paddock with twice-yearly handling) in a dry tropical environment, was studied during the severe drought of 1982-83. Twenty-one per cent of the cows died. Cows more advanced in pregnancy and those in poorer condition in the early stages of the drought had lower (P<0.05) survival probabilities. Cows aged over 7 years also generally had a reduced (P<0.05) probability of survival. Calf loss between confirmed pregnancy early in the drought and weaning after the following wet season was 31%. Calf loss from surviving cows was not higher than is usual in non-drought years. All deaths of lactating cows were associated with calf deaths. The practical use of these results in cost-efficient management for survival of cows in drought was then evaluated in a second study in which 293 cows were drafted into high- and low-supplement-requirement (HSR and LSR) groups in the early stages of the 1987 drought. Survival feeding in the HSR group commenced about 6 weeks earlier than would have been necessary in the LSR group. In both studies, reproductive status in the early drought period was a significant determinant of both body condition and conception rates early in the following year. Cows more advanced in pregnancy early in the drought were in poorer condition after the following wet season (P<0.05), but remained further advanced in pregnancy (P<0.05). Both body condition in the early part of the drought and age had minimal effects on performance in the following wet season, although younger cows tended to be lighter and have the lowest conception rates. Cows in better condition after the wet season had higher (P<0.05) pregnancy rates.

Effect of body condition and energy utilization on the length of post-partum anoestrus in PRID-treated and untreated post-partum Bos indicus (Zebu) cattle

1997 ◽  
Vol 65 (1) ◽  
pp. 17-24 ◽  
Author(s):  
E. Mukasa-Mugerwa ◽  
D. Anindo ◽  
A. Lahlou-Kassi ◽  
N. N. Umunna ◽  
A. Tegegne
Keyword(s):  
Body Condition ◽  
Post Partum ◽  
Average Daily Gain ◽  
Good Condition ◽  
Bos Indicus ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Ovarian Activity ◽  
Zebu Cattle ◽  
Body Reserves

AbstractForty-five Bos indicus (zebu) cows were blocked by body condition (BC) score at calving and allocated by body weight (BW) to three treatments: untreated controls (CON), and progesterone-releasing intra-vaginal device (PRID)-treated at either 45 (T45) or 60 days (T60) post partum. Cows were given food individually and blood-sampled three times a week for progesterone. Calves sucked twice a day and were weighed weekly. PRIDs resulted in only 21% of cows responding at 60 days and they did not reduce anoestrus (PPI) or calving interval (CI) (P > 0·05). Dry matter (DM) and metabolizable energy (ME) intake were 7·1 (s.e. 0·6) kg and 54·3 (s.e. 4·6) MJ/day, respectively. BC score and BW at calving, and ME intake influenced cow and calf average daily gain ranging from −580 to 625 and 331 to 868 g/day, respectively. Milk yield during the first 4 months was 507 (s.e. 97) l. Cows gained 25 kg per unit increase in condition but lost 50 kg for a unit decline. CI (mean 14·2, range 10 to 24 months) was inversely related to BC score at calving (r = −0·31) and was delayed by a long PPI (r = 0·51), ranging from 38 to 297 days. Most (95%) cows experienced one or more ‘silent ovulations’ before first oestrus, the number extending PPI length (r = 0·49, P < 0·001). Efficiency of ME utilization was higher for smaller cows of 240 (s.e. 28) kg at calving. It is concluded that: (1) PRID treatment before 60 days post partum is unlikely to reduce anoestrus in Boran zebu cattle; (2) given adequate energy intake zebu cattle in thin condition at calving initially replenish body reserves at the cost of lactation and experience more ‘silent’ ovarian activity before returning to oestrus; (3) cows in good condition at calving express maximum lactation potential, mobilizing their own body reserves to support milk production, yet resume oestrous activity earlier despite weight losses to support higher milk yields.

Influence of pasture type and supplement on fertility and liveweight of cows, and progeny growth rate in the dry tropics of northern Queensland

1983 ◽  
Vol 23 (120) ◽  
pp. 4 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
MR Clarke ◽  
ID Loxton
Keyword(s):  
Growth Rate ◽  
Reproductive Performance ◽  
Fold Increase ◽  
Dry Season ◽  
Wet Season ◽  
Calf Growth ◽  
Dry Tropics ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
One Year

The reproductive performance of cows and growth rate of their calves to weaning was examined over a four-year period (1973-1977). Cows grazed either native pasture stocked at 1cowl4 ha, or native pasture oversown with Townsville stylo (Stylosanthes humilis) and fertilized with superphosphate stocked at 1 cow/2 ha. Animals were supplemented on each pasture type with urea-molasses in the dry season, phosphorus all year round plus urea-molasses in the dry season, or were unsupplemented. Mating was for three months from mid-January. Calving began towards the end of the dry season and cows lactated through the following wet season. Cows grazing fertilized legume pasture had significantly higher conception rates and earlier calving dates in one year only. In all years, foetal and calf losses between pregnancy diagnosis and weaning were lower on native pasture than on fertilized legume pasture. Cows grazing fertilized legume pasture were generally in better body condition and heavier throughout and their calves grew faster to weaning than on native pasture. Fertilized legume pasture produced a 2.4 fold increase over that of native pasture in cow and calf liveweight per unit area (382.7 kg/ha vs 159.8 kg/ha) over the four years. Supplementation did not influence liveweight or reproductive performance of cows or calf growth rate except during the final dry season when non-supplemented cows lost significantly more weight than those supplemented with phosphorus and urea.

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